diff options
Diffstat (limited to 'kernel/trace/bpf_trace.c')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 2876 |
1 files changed, 2566 insertions, 310 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 8b068adb9da1..d57727abaade 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -6,17 +6,43 @@ #include <linux/types.h> #include <linux/slab.h> #include <linux/bpf.h> +#include <linux/bpf_verifier.h> #include <linux/bpf_perf_event.h> +#include <linux/btf.h> #include <linux/filter.h> #include <linux/uaccess.h> #include <linux/ctype.h> #include <linux/kprobes.h> +#include <linux/spinlock.h> #include <linux/syscalls.h> #include <linux/error-injection.h> +#include <linux/btf_ids.h> +#include <linux/bpf_lsm.h> +#include <linux/fprobe.h> +#include <linux/bsearch.h> +#include <linux/sort.h> +#include <linux/key.h> +#include <linux/namei.h> + +#include <net/bpf_sk_storage.h> + +#include <uapi/linux/bpf.h> +#include <uapi/linux/btf.h> + +#include <asm/tlb.h> #include "trace_probe.h" #include "trace.h" +#define CREATE_TRACE_POINTS +#include "bpf_trace.h" + +#define bpf_event_rcu_dereference(p) \ + rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) + +#define MAX_UPROBE_MULTI_CNT (1U << 20) +#define MAX_KPROBE_MULTI_CNT (1U << 20) + #ifdef CONFIG_MODULES struct bpf_trace_module { struct module *module; @@ -57,6 +83,15 @@ static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); +static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size, + u64 flags, const struct btf **btf, + s32 *btf_id); +static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx); +static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx); + +static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx); +static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx); + /** * trace_call_bpf - invoke BPF program * @call: tracepoint event @@ -75,10 +110,7 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) { unsigned int ret; - if (in_nmi()) /* not supported yet */ - return 1; - - preempt_disable(); + cant_sleep(); if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { /* @@ -87,6 +119,9 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) * and don't send kprobe event into ring-buffer, * so return zero here */ + rcu_read_lock(); + bpf_prog_inc_misses_counters(rcu_dereference(call->prog_array)); + rcu_read_unlock(); ret = 0; goto out; } @@ -95,7 +130,7 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock * to all call sites, we did a bpf_prog_array_valid() there to check * whether call->prog_array is empty or not, which is - * a heurisitc to speed up execution. + * a heuristic to speed up execution. * * If bpf_prog_array_valid() fetched prog_array was * non-NULL, we go into trace_call_bpf() and do the actual @@ -106,15 +141,16 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) * out of events when it was updated in between this and the * rcu_dereference() which is accepted risk. */ - ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN); + rcu_read_lock(); + ret = bpf_prog_run_array(rcu_dereference(call->prog_array), + ctx, bpf_prog_run); + rcu_read_unlock(); out: __this_cpu_dec(bpf_prog_active); - preempt_enable(); return ret; } -EXPORT_SYMBOL_GPL(trace_call_bpf); #ifdef CONFIG_BPF_KPROBE_OVERRIDE BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) @@ -133,19 +169,132 @@ static const struct bpf_func_proto bpf_override_return_proto = { }; #endif -BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) +static __always_inline int +bpf_probe_read_user_common(void *dst, u32 size, const void __user *unsafe_ptr) +{ + int ret; + + ret = copy_from_user_nofault(dst, unsafe_ptr, size); + if (unlikely(ret < 0)) + memset(dst, 0, size); + return ret; +} + +BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size, + const void __user *, unsafe_ptr) +{ + return bpf_probe_read_user_common(dst, size, unsafe_ptr); +} + +const struct bpf_func_proto bpf_probe_read_user_proto = { + .func = bpf_probe_read_user, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_UNINIT_MEM, + .arg2_type = ARG_CONST_SIZE_OR_ZERO, + .arg3_type = ARG_ANYTHING, +}; + +static __always_inline int +bpf_probe_read_user_str_common(void *dst, u32 size, + const void __user *unsafe_ptr) { int ret; - ret = probe_kernel_read(dst, unsafe_ptr, size); + /* + * NB: We rely on strncpy_from_user() not copying junk past the NUL + * terminator into `dst`. + * + * strncpy_from_user() does long-sized strides in the fast path. If the + * strncpy does not mask out the bytes after the NUL in `unsafe_ptr`, + * then there could be junk after the NUL in `dst`. If user takes `dst` + * and keys a hash map with it, then semantically identical strings can + * occupy multiple entries in the map. + */ + ret = strncpy_from_user_nofault(dst, unsafe_ptr, size); if (unlikely(ret < 0)) memset(dst, 0, size); + return ret; +} + +BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size, + const void __user *, unsafe_ptr) +{ + return bpf_probe_read_user_str_common(dst, size, unsafe_ptr); +} + +const struct bpf_func_proto bpf_probe_read_user_str_proto = { + .func = bpf_probe_read_user_str, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_UNINIT_MEM, + .arg2_type = ARG_CONST_SIZE_OR_ZERO, + .arg3_type = ARG_ANYTHING, +}; + +BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size, + const void *, unsafe_ptr) +{ + return bpf_probe_read_kernel_common(dst, size, unsafe_ptr); +} +const struct bpf_func_proto bpf_probe_read_kernel_proto = { + .func = bpf_probe_read_kernel, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_UNINIT_MEM, + .arg2_type = ARG_CONST_SIZE_OR_ZERO, + .arg3_type = ARG_ANYTHING, +}; + +static __always_inline int +bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr) +{ + int ret; + + /* + * The strncpy_from_kernel_nofault() call will likely not fill the + * entire buffer, but that's okay in this circumstance as we're probing + * arbitrary memory anyway similar to bpf_probe_read_*() and might + * as well probe the stack. Thus, memory is explicitly cleared + * only in error case, so that improper users ignoring return + * code altogether don't copy garbage; otherwise length of string + * is returned that can be used for bpf_perf_event_output() et al. + */ + ret = strncpy_from_kernel_nofault(dst, unsafe_ptr, size); + if (unlikely(ret < 0)) + memset(dst, 0, size); return ret; } -static const struct bpf_func_proto bpf_probe_read_proto = { - .func = bpf_probe_read, +BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size, + const void *, unsafe_ptr) +{ + return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr); +} + +const struct bpf_func_proto bpf_probe_read_kernel_str_proto = { + .func = bpf_probe_read_kernel_str, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_UNINIT_MEM, + .arg2_type = ARG_CONST_SIZE_OR_ZERO, + .arg3_type = ARG_ANYTHING, +}; + +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE +BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size, + const void *, unsafe_ptr) +{ + if ((unsigned long)unsafe_ptr < TASK_SIZE) { + return bpf_probe_read_user_common(dst, size, + (__force void __user *)unsafe_ptr); + } + return bpf_probe_read_kernel_common(dst, size, unsafe_ptr); +} + +static const struct bpf_func_proto bpf_probe_read_compat_proto = { + .func = bpf_probe_read_compat, .gpl_only = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_UNINIT_MEM, @@ -153,7 +302,27 @@ static const struct bpf_func_proto bpf_probe_read_proto = { .arg3_type = ARG_ANYTHING, }; -BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, +BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size, + const void *, unsafe_ptr) +{ + if ((unsigned long)unsafe_ptr < TASK_SIZE) { + return bpf_probe_read_user_str_common(dst, size, + (__force void __user *)unsafe_ptr); + } + return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr); +} + +static const struct bpf_func_proto bpf_probe_read_compat_str_proto = { + .func = bpf_probe_read_compat_str, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_UNINIT_MEM, + .arg2_type = ARG_CONST_SIZE_OR_ZERO, + .arg3_type = ARG_ANYTHING, +}; +#endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */ + +BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src, u32, size) { /* @@ -163,17 +332,19 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, * access_ok() should prevent writing to non-user memory, but in * some situations (nommu, temporary switch, etc) access_ok() does * not provide enough validation, hence the check on KERNEL_DS. + * + * nmi_uaccess_okay() ensures the probe is not run in an interim + * state, when the task or mm are switched. This is specifically + * required to prevent the use of temporary mm. */ if (unlikely(in_interrupt() || current->flags & (PF_KTHREAD | PF_EXITING))) return -EPERM; - if (unlikely(uaccess_kernel())) - return -EPERM; - if (!access_ok(unsafe_ptr, size)) + if (unlikely(!nmi_uaccess_okay())) return -EPERM; - return probe_kernel_write(unsafe_ptr, src, size); + return copy_to_user_nofault(unsafe_ptr, src, size); } static const struct bpf_func_proto bpf_probe_write_user_proto = { @@ -181,154 +352,187 @@ static const struct bpf_func_proto bpf_probe_write_user_proto = { .gpl_only = true, .ret_type = RET_INTEGER, .arg1_type = ARG_ANYTHING, - .arg2_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg3_type = ARG_CONST_SIZE, }; -static const struct bpf_func_proto *bpf_get_probe_write_proto(void) -{ - pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", - current->comm, task_pid_nr(current)); - - return &bpf_probe_write_user_proto; -} +#define MAX_TRACE_PRINTK_VARARGS 3 +#define BPF_TRACE_PRINTK_SIZE 1024 -/* - * Only limited trace_printk() conversion specifiers allowed: - * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s - */ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, u64, arg2, u64, arg3) { - bool str_seen = false; - int mod[3] = {}; - int fmt_cnt = 0; - u64 unsafe_addr; - char buf[64]; - int i; - - /* - * bpf_check()->check_func_arg()->check_stack_boundary() - * guarantees that fmt points to bpf program stack, - * fmt_size bytes of it were initialized and fmt_size > 0 - */ - if (fmt[--fmt_size] != 0) - return -EINVAL; - - /* check format string for allowed specifiers */ - for (i = 0; i < fmt_size; i++) { - if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) - return -EINVAL; - - if (fmt[i] != '%') - continue; + u64 args[MAX_TRACE_PRINTK_VARARGS] = { arg1, arg2, arg3 }; + struct bpf_bprintf_data data = { + .get_bin_args = true, + .get_buf = true, + }; + int ret; - if (fmt_cnt >= 3) - return -EINVAL; + ret = bpf_bprintf_prepare(fmt, fmt_size, args, + MAX_TRACE_PRINTK_VARARGS, &data); + if (ret < 0) + return ret; - /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ - i++; - if (fmt[i] == 'l') { - mod[fmt_cnt]++; - i++; - } else if (fmt[i] == 'p' || fmt[i] == 's') { - mod[fmt_cnt]++; - /* disallow any further format extensions */ - if (fmt[i + 1] != 0 && - !isspace(fmt[i + 1]) && - !ispunct(fmt[i + 1])) - return -EINVAL; - fmt_cnt++; - if (fmt[i] == 's') { - if (str_seen) - /* allow only one '%s' per fmt string */ - return -EINVAL; - str_seen = true; - - switch (fmt_cnt) { - case 1: - unsafe_addr = arg1; - arg1 = (long) buf; - break; - case 2: - unsafe_addr = arg2; - arg2 = (long) buf; - break; - case 3: - unsafe_addr = arg3; - arg3 = (long) buf; - break; - } - buf[0] = 0; - strncpy_from_unsafe(buf, - (void *) (long) unsafe_addr, - sizeof(buf)); - } - continue; - } + ret = bstr_printf(data.buf, MAX_BPRINTF_BUF, fmt, data.bin_args); - if (fmt[i] == 'l') { - mod[fmt_cnt]++; - i++; - } + trace_bpf_trace_printk(data.buf); - if (fmt[i] != 'i' && fmt[i] != 'd' && - fmt[i] != 'u' && fmt[i] != 'x') - return -EINVAL; - fmt_cnt++; - } + bpf_bprintf_cleanup(&data); -/* Horrid workaround for getting va_list handling working with different - * argument type combinations generically for 32 and 64 bit archs. - */ -#define __BPF_TP_EMIT() __BPF_ARG3_TP() -#define __BPF_TP(...) \ - __trace_printk(0 /* Fake ip */, \ - fmt, ##__VA_ARGS__) - -#define __BPF_ARG1_TP(...) \ - ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ - ? __BPF_TP(arg1, ##__VA_ARGS__) \ - : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ - ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ - : __BPF_TP((u32)arg1, ##__VA_ARGS__))) - -#define __BPF_ARG2_TP(...) \ - ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ - ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ - : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ - ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ - : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) - -#define __BPF_ARG3_TP(...) \ - ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ - ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ - : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ - ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ - : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) - - return __BPF_TP_EMIT(); + return ret; } static const struct bpf_func_proto bpf_trace_printk_proto = { .func = bpf_trace_printk, .gpl_only = true, .ret_type = RET_INTEGER, - .arg1_type = ARG_PTR_TO_MEM, + .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg2_type = ARG_CONST_SIZE, }; -const struct bpf_func_proto *bpf_get_trace_printk_proto(void) +static void __set_printk_clr_event(struct work_struct *work) { /* - * this program might be calling bpf_trace_printk, - * so allocate per-cpu printk buffers + * This program might be calling bpf_trace_printk, + * so enable the associated bpf_trace/bpf_trace_printk event. + * Repeat this each time as it is possible a user has + * disabled bpf_trace_printk events. By loading a program + * calling bpf_trace_printk() however the user has expressed + * the intent to see such events. */ - trace_printk_init_buffers(); + if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1)) + pr_warn_ratelimited("could not enable bpf_trace_printk events"); +} +static DECLARE_WORK(set_printk_work, __set_printk_clr_event); +const struct bpf_func_proto *bpf_get_trace_printk_proto(void) +{ + schedule_work(&set_printk_work); return &bpf_trace_printk_proto; } +BPF_CALL_4(bpf_trace_vprintk, char *, fmt, u32, fmt_size, const void *, args, + u32, data_len) +{ + struct bpf_bprintf_data data = { + .get_bin_args = true, + .get_buf = true, + }; + int ret, num_args; + + if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 || + (data_len && !args)) + return -EINVAL; + num_args = data_len / 8; + + ret = bpf_bprintf_prepare(fmt, fmt_size, args, num_args, &data); + if (ret < 0) + return ret; + + ret = bstr_printf(data.buf, MAX_BPRINTF_BUF, fmt, data.bin_args); + + trace_bpf_trace_printk(data.buf); + + bpf_bprintf_cleanup(&data); + + return ret; +} + +static const struct bpf_func_proto bpf_trace_vprintk_proto = { + .func = bpf_trace_vprintk, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY, + .arg2_type = ARG_CONST_SIZE, + .arg3_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY, + .arg4_type = ARG_CONST_SIZE_OR_ZERO, +}; + +const struct bpf_func_proto *bpf_get_trace_vprintk_proto(void) +{ + schedule_work(&set_printk_work); + return &bpf_trace_vprintk_proto; +} + +BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, + const void *, args, u32, data_len) +{ + struct bpf_bprintf_data data = { + .get_bin_args = true, + }; + int err, num_args; + + if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 || + (data_len && !args)) + return -EINVAL; + num_args = data_len / 8; + + err = bpf_bprintf_prepare(fmt, fmt_size, args, num_args, &data); + if (err < 0) + return err; + + seq_bprintf(m, fmt, data.bin_args); + + bpf_bprintf_cleanup(&data); + + return seq_has_overflowed(m) ? -EOVERFLOW : 0; +} + +BTF_ID_LIST_SINGLE(btf_seq_file_ids, struct, seq_file) + +static const struct bpf_func_proto bpf_seq_printf_proto = { + .func = bpf_seq_printf, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &btf_seq_file_ids[0], + .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, + .arg3_type = ARG_CONST_SIZE, + .arg4_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + +BPF_CALL_3(bpf_seq_write, struct seq_file *, m, const void *, data, u32, len) +{ + return seq_write(m, data, len) ? -EOVERFLOW : 0; +} + +static const struct bpf_func_proto bpf_seq_write_proto = { + .func = bpf_seq_write, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &btf_seq_file_ids[0], + .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, + .arg3_type = ARG_CONST_SIZE_OR_ZERO, +}; + +BPF_CALL_4(bpf_seq_printf_btf, struct seq_file *, m, struct btf_ptr *, ptr, + u32, btf_ptr_size, u64, flags) +{ + const struct btf *btf; + s32 btf_id; + int ret; + + ret = bpf_btf_printf_prepare(ptr, btf_ptr_size, flags, &btf, &btf_id); + if (ret) + return ret; + + return btf_type_seq_show_flags(btf, btf_id, ptr->ptr, m, flags); +} + +static const struct bpf_func_proto bpf_seq_printf_btf_proto = { + .func = bpf_seq_printf_btf, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &btf_seq_file_ids[0], + .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, + .arg3_type = ARG_CONST_SIZE_OR_ZERO, + .arg4_type = ARG_ANYTHING, +}; + static __always_inline int get_map_perf_counter(struct bpf_map *map, u64 flags, u64 *value, u64 *enabled, u64 *running) @@ -367,7 +571,7 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) return value; } -static const struct bpf_func_proto bpf_perf_event_read_proto = { +const struct bpf_func_proto bpf_perf_event_read_proto = { .func = bpf_perf_event_read, .gpl_only = true, .ret_type = RET_INTEGER, @@ -402,11 +606,15 @@ static const struct bpf_func_proto bpf_perf_event_read_value_proto = { .arg4_type = ARG_CONST_SIZE, }; -static DEFINE_PER_CPU(struct perf_sample_data, bpf_trace_sd); +const struct bpf_func_proto *bpf_get_perf_event_read_value_proto(void) +{ + return &bpf_perf_event_read_value_proto; +} static __always_inline u64 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, - u64 flags, struct perf_sample_data *sd) + u64 flags, struct perf_raw_record *raw, + struct perf_sample_data *sd) { struct bpf_array *array = container_of(map, struct bpf_array, map); unsigned int cpu = smp_processor_id(); @@ -431,28 +639,57 @@ __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, if (unlikely(event->oncpu != cpu)) return -EOPNOTSUPP; - perf_event_output(event, sd, regs); - return 0; + perf_sample_save_raw_data(sd, event, raw); + + return perf_event_output(event, sd, regs); } +/* + * Support executing tracepoints in normal, irq, and nmi context that each call + * bpf_perf_event_output + */ +struct bpf_trace_sample_data { + struct perf_sample_data sds[3]; +}; + +static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); +static DEFINE_PER_CPU(int, bpf_trace_nest_level); BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, u64, flags, void *, data, u64, size) { - struct perf_sample_data *sd = this_cpu_ptr(&bpf_trace_sd); + struct bpf_trace_sample_data *sds; struct perf_raw_record raw = { .frag = { .size = size, .data = data, }, }; + struct perf_sample_data *sd; + int nest_level, err; - if (unlikely(flags & ~(BPF_F_INDEX_MASK))) - return -EINVAL; + preempt_disable(); + sds = this_cpu_ptr(&bpf_trace_sds); + nest_level = this_cpu_inc_return(bpf_trace_nest_level); + + if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { + err = -EBUSY; + goto out; + } + + sd = &sds->sds[nest_level - 1]; + + if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { + err = -EINVAL; + goto out; + } perf_sample_data_init(sd, 0, 0); - sd->raw = &raw; - return __bpf_perf_event_output(regs, map, flags, sd); + err = __bpf_perf_event_output(regs, map, flags, &raw, sd); +out: + this_cpu_dec(bpf_trace_nest_level); + preempt_enable(); + return err; } static const struct bpf_func_proto bpf_perf_event_output_proto = { @@ -462,18 +699,20 @@ static const struct bpf_func_proto bpf_perf_event_output_proto = { .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_ANYTHING, - .arg4_type = ARG_PTR_TO_MEM, + .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg5_type = ARG_CONST_SIZE_OR_ZERO, }; -static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs); -static DEFINE_PER_CPU(struct perf_sample_data, bpf_misc_sd); +static DEFINE_PER_CPU(int, bpf_event_output_nest_level); +struct bpf_nested_pt_regs { + struct pt_regs regs[3]; +}; +static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs); +static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds); u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) { - struct perf_sample_data *sd = this_cpu_ptr(&bpf_misc_sd); - struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs); struct perf_raw_frag frag = { .copy = ctx_copy, .size = ctx_size, @@ -488,12 +727,29 @@ u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, .data = meta, }, }; + struct perf_sample_data *sd; + struct pt_regs *regs; + int nest_level; + u64 ret; + + preempt_disable(); + nest_level = this_cpu_inc_return(bpf_event_output_nest_level); + + if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) { + ret = -EBUSY; + goto out; + } + sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]); + regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]); perf_fetch_caller_regs(regs); perf_sample_data_init(sd, 0, 0); - sd->raw = &raw; - return __bpf_perf_event_output(regs, map, flags, sd); + ret = __bpf_perf_event_output(regs, map, flags, &raw, sd); +out: + this_cpu_dec(bpf_event_output_nest_level); + preempt_enable(); + return ret; } BPF_CALL_0(bpf_get_current_task) @@ -501,114 +757,549 @@ BPF_CALL_0(bpf_get_current_task) return (long) current; } -static const struct bpf_func_proto bpf_get_current_task_proto = { +const struct bpf_func_proto bpf_get_current_task_proto = { .func = bpf_get_current_task, .gpl_only = true, .ret_type = RET_INTEGER, }; -BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) +BPF_CALL_0(bpf_get_current_task_btf) { - struct bpf_array *array = container_of(map, struct bpf_array, map); - struct cgroup *cgrp; + return (unsigned long) current; +} - if (unlikely(idx >= array->map.max_entries)) - return -E2BIG; +const struct bpf_func_proto bpf_get_current_task_btf_proto = { + .func = bpf_get_current_task_btf, + .gpl_only = true, + .ret_type = RET_PTR_TO_BTF_ID_TRUSTED, + .ret_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], +}; + +BPF_CALL_1(bpf_task_pt_regs, struct task_struct *, task) +{ + return (unsigned long) task_pt_regs(task); +} + +BTF_ID_LIST_SINGLE(bpf_task_pt_regs_ids, struct, pt_regs) + +const struct bpf_func_proto bpf_task_pt_regs_proto = { + .func = bpf_task_pt_regs, + .gpl_only = true, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], + .ret_type = RET_PTR_TO_BTF_ID, + .ret_btf_id = &bpf_task_pt_regs_ids[0], +}; + +struct send_signal_irq_work { + struct irq_work irq_work; + struct task_struct *task; + u32 sig; + enum pid_type type; + bool has_siginfo; + struct kernel_siginfo info; +}; + +static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); + +static void do_bpf_send_signal(struct irq_work *entry) +{ + struct send_signal_irq_work *work; + struct kernel_siginfo *siginfo; - cgrp = READ_ONCE(array->ptrs[idx]); - if (unlikely(!cgrp)) - return -EAGAIN; + work = container_of(entry, struct send_signal_irq_work, irq_work); + siginfo = work->has_siginfo ? &work->info : SEND_SIG_PRIV; - return task_under_cgroup_hierarchy(current, cgrp); + group_send_sig_info(work->sig, siginfo, work->task, work->type); + put_task_struct(work->task); } -static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { - .func = bpf_current_task_under_cgroup, - .gpl_only = false, - .ret_type = RET_INTEGER, - .arg1_type = ARG_CONST_MAP_PTR, - .arg2_type = ARG_ANYTHING, +static int bpf_send_signal_common(u32 sig, enum pid_type type, struct task_struct *task, u64 value) +{ + struct send_signal_irq_work *work = NULL; + struct kernel_siginfo info; + struct kernel_siginfo *siginfo; + + if (!task) { + task = current; + siginfo = SEND_SIG_PRIV; + } else { + clear_siginfo(&info); + info.si_signo = sig; + info.si_errno = 0; + info.si_code = SI_KERNEL; + info.si_pid = 0; + info.si_uid = 0; + info.si_value.sival_ptr = (void *)(unsigned long)value; + siginfo = &info; + } + + /* Similar to bpf_probe_write_user, task needs to be + * in a sound condition and kernel memory access be + * permitted in order to send signal to the current + * task. + */ + if (unlikely(task->flags & (PF_KTHREAD | PF_EXITING))) + return -EPERM; + if (unlikely(!nmi_uaccess_okay())) + return -EPERM; + /* Task should not be pid=1 to avoid kernel panic. */ + if (unlikely(is_global_init(task))) + return -EPERM; + + if (preempt_count() != 0 || irqs_disabled()) { + /* Do an early check on signal validity. Otherwise, + * the error is lost in deferred irq_work. + */ + if (unlikely(!valid_signal(sig))) + return -EINVAL; + + work = this_cpu_ptr(&send_signal_work); + if (irq_work_is_busy(&work->irq_work)) + return -EBUSY; + + /* Add the current task, which is the target of sending signal, + * to the irq_work. The current task may change when queued + * irq works get executed. + */ + work->task = get_task_struct(task); + work->has_siginfo = siginfo == &info; + if (work->has_siginfo) + copy_siginfo(&work->info, &info); + work->sig = sig; + work->type = type; + irq_work_queue(&work->irq_work); + return 0; + } + + return group_send_sig_info(sig, siginfo, task, type); +} + +BPF_CALL_1(bpf_send_signal, u32, sig) +{ + return bpf_send_signal_common(sig, PIDTYPE_TGID, NULL, 0); +} + +const struct bpf_func_proto bpf_send_signal_proto = { + .func = bpf_send_signal, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, }; -BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size, - const void *, unsafe_ptr) +BPF_CALL_1(bpf_send_signal_thread, u32, sig) { - int ret; + return bpf_send_signal_common(sig, PIDTYPE_PID, NULL, 0); +} + +const struct bpf_func_proto bpf_send_signal_thread_proto = { + .func = bpf_send_signal_thread, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, +}; + +BPF_CALL_3(bpf_d_path, const struct path *, path, char *, buf, u32, sz) +{ + struct path copy; + long len; + char *p; + + if (!sz) + return 0; /* - * The strncpy_from_unsafe() call will likely not fill the entire - * buffer, but that's okay in this circumstance as we're probing - * arbitrary memory anyway similar to bpf_probe_read() and might - * as well probe the stack. Thus, memory is explicitly cleared - * only in error case, so that improper users ignoring return - * code altogether don't copy garbage; otherwise length of string - * is returned that can be used for bpf_perf_event_output() et al. + * The path pointer is verified as trusted and safe to use, + * but let's double check it's valid anyway to workaround + * potentially broken verifier. */ - ret = strncpy_from_unsafe(dst, unsafe_ptr, size); - if (unlikely(ret < 0)) - memset(dst, 0, size); + len = copy_from_kernel_nofault(©, path, sizeof(*path)); + if (len < 0) + return len; - return ret; + p = d_path(©, buf, sz); + if (IS_ERR(p)) { + len = PTR_ERR(p); + } else { + len = buf + sz - p; + memmove(buf, p, len); + } + + return len; +} + +BTF_SET_START(btf_allowlist_d_path) +#ifdef CONFIG_SECURITY +BTF_ID(func, security_file_permission) +BTF_ID(func, security_inode_getattr) +BTF_ID(func, security_file_open) +#endif +#ifdef CONFIG_SECURITY_PATH +BTF_ID(func, security_path_truncate) +#endif +BTF_ID(func, vfs_truncate) +BTF_ID(func, vfs_fallocate) +BTF_ID(func, dentry_open) +BTF_ID(func, vfs_getattr) +BTF_ID(func, filp_close) +BTF_SET_END(btf_allowlist_d_path) + +static bool bpf_d_path_allowed(const struct bpf_prog *prog) +{ + if (prog->type == BPF_PROG_TYPE_TRACING && + prog->expected_attach_type == BPF_TRACE_ITER) + return true; + + if (prog->type == BPF_PROG_TYPE_LSM) + return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id); + + return btf_id_set_contains(&btf_allowlist_d_path, + prog->aux->attach_btf_id); +} + +BTF_ID_LIST_SINGLE(bpf_d_path_btf_ids, struct, path) + +static const struct bpf_func_proto bpf_d_path_proto = { + .func = bpf_d_path, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_d_path_btf_ids[0], + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE_OR_ZERO, + .allowed = bpf_d_path_allowed, +}; + +#define BTF_F_ALL (BTF_F_COMPACT | BTF_F_NONAME | \ + BTF_F_PTR_RAW | BTF_F_ZERO) + +static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size, + u64 flags, const struct btf **btf, + s32 *btf_id) +{ + const struct btf_type *t; + + if (unlikely(flags & ~(BTF_F_ALL))) + return -EINVAL; + + if (btf_ptr_size != sizeof(struct btf_ptr)) + return -EINVAL; + + *btf = bpf_get_btf_vmlinux(); + + if (IS_ERR_OR_NULL(*btf)) + return IS_ERR(*btf) ? PTR_ERR(*btf) : -EINVAL; + + if (ptr->type_id > 0) + *btf_id = ptr->type_id; + else + return -EINVAL; + + if (*btf_id > 0) + t = btf_type_by_id(*btf, *btf_id); + if (*btf_id <= 0 || !t) + return -ENOENT; + + return 0; +} + +BPF_CALL_5(bpf_snprintf_btf, char *, str, u32, str_size, struct btf_ptr *, ptr, + u32, btf_ptr_size, u64, flags) +{ + const struct btf *btf; + s32 btf_id; + int ret; + + ret = bpf_btf_printf_prepare(ptr, btf_ptr_size, flags, &btf, &btf_id); + if (ret) + return ret; + + return btf_type_snprintf_show(btf, btf_id, ptr->ptr, str, str_size, + flags); +} + +const struct bpf_func_proto bpf_snprintf_btf_proto = { + .func = bpf_snprintf_btf, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_CONST_SIZE, + .arg3_type = ARG_PTR_TO_MEM | MEM_RDONLY, + .arg4_type = ARG_CONST_SIZE, + .arg5_type = ARG_ANYTHING, +}; + +BPF_CALL_1(bpf_get_func_ip_tracing, void *, ctx) +{ + /* This helper call is inlined by verifier. */ + return ((u64 *)ctx)[-2]; +} + +static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = { + .func = bpf_get_func_ip_tracing, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +static inline unsigned long get_entry_ip(unsigned long fentry_ip) +{ +#ifdef CONFIG_X86_KERNEL_IBT + if (is_endbr((void *)(fentry_ip - ENDBR_INSN_SIZE))) + fentry_ip -= ENDBR_INSN_SIZE; +#endif + return fentry_ip; +} + +BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs) +{ + struct bpf_trace_run_ctx *run_ctx __maybe_unused; + struct kprobe *kp; + +#ifdef CONFIG_UPROBES + run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); + if (run_ctx->is_uprobe) + return ((struct uprobe_dispatch_data *)current->utask->vaddr)->bp_addr; +#endif + + kp = kprobe_running(); + + if (!kp || !(kp->flags & KPROBE_FLAG_ON_FUNC_ENTRY)) + return 0; + + return get_entry_ip((uintptr_t)kp->addr); } -static const struct bpf_func_proto bpf_probe_read_str_proto = { - .func = bpf_probe_read_str, +static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = { + .func = bpf_get_func_ip_kprobe, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_func_ip_kprobe_multi, struct pt_regs *, regs) +{ + return bpf_kprobe_multi_entry_ip(current->bpf_ctx); +} + +static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe_multi = { + .func = bpf_get_func_ip_kprobe_multi, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_attach_cookie_kprobe_multi, struct pt_regs *, regs) +{ + return bpf_kprobe_multi_cookie(current->bpf_ctx); +} + +static const struct bpf_func_proto bpf_get_attach_cookie_proto_kmulti = { + .func = bpf_get_attach_cookie_kprobe_multi, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_func_ip_uprobe_multi, struct pt_regs *, regs) +{ + return bpf_uprobe_multi_entry_ip(current->bpf_ctx); +} + +static const struct bpf_func_proto bpf_get_func_ip_proto_uprobe_multi = { + .func = bpf_get_func_ip_uprobe_multi, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_attach_cookie_uprobe_multi, struct pt_regs *, regs) +{ + return bpf_uprobe_multi_cookie(current->bpf_ctx); +} + +static const struct bpf_func_proto bpf_get_attach_cookie_proto_umulti = { + .func = bpf_get_attach_cookie_uprobe_multi, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_attach_cookie_trace, void *, ctx) +{ + struct bpf_trace_run_ctx *run_ctx; + + run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); + return run_ctx->bpf_cookie; +} + +static const struct bpf_func_proto bpf_get_attach_cookie_proto_trace = { + .func = bpf_get_attach_cookie_trace, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_attach_cookie_pe, struct bpf_perf_event_data_kern *, ctx) +{ + return ctx->event->bpf_cookie; +} + +static const struct bpf_func_proto bpf_get_attach_cookie_proto_pe = { + .func = bpf_get_attach_cookie_pe, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_1(bpf_get_attach_cookie_tracing, void *, ctx) +{ + struct bpf_trace_run_ctx *run_ctx; + + run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx); + return run_ctx->bpf_cookie; +} + +static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = { + .func = bpf_get_attach_cookie_tracing, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + +BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags) +{ + static const u32 br_entry_size = sizeof(struct perf_branch_entry); + u32 entry_cnt = size / br_entry_size; + + entry_cnt = static_call(perf_snapshot_branch_stack)(buf, entry_cnt); + + if (unlikely(flags)) + return -EINVAL; + + if (!entry_cnt) + return -ENOENT; + + return entry_cnt * br_entry_size; +} + +const struct bpf_func_proto bpf_get_branch_snapshot_proto = { + .func = bpf_get_branch_snapshot, .gpl_only = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_UNINIT_MEM, .arg2_type = ARG_CONST_SIZE_OR_ZERO, - .arg3_type = ARG_ANYTHING, +}; + +BPF_CALL_3(get_func_arg, void *, ctx, u32, n, u64 *, value) +{ + /* This helper call is inlined by verifier. */ + u64 nr_args = ((u64 *)ctx)[-1]; + + if ((u64) n >= nr_args) + return -EINVAL; + *value = ((u64 *)ctx)[n]; + return 0; +} + +static const struct bpf_func_proto bpf_get_func_arg_proto = { + .func = get_func_arg, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED, + .arg3_size = sizeof(u64), +}; + +BPF_CALL_2(get_func_ret, void *, ctx, u64 *, value) +{ + /* This helper call is inlined by verifier. */ + u64 nr_args = ((u64 *)ctx)[-1]; + + *value = ((u64 *)ctx)[nr_args]; + return 0; +} + +static const struct bpf_func_proto bpf_get_func_ret_proto = { + .func = get_func_ret, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED, + .arg2_size = sizeof(u64), +}; + +BPF_CALL_1(get_func_arg_cnt, void *, ctx) +{ + /* This helper call is inlined by verifier. */ + return ((u64 *)ctx)[-1]; +} + +static const struct bpf_func_proto bpf_get_func_arg_cnt_proto = { + .func = get_func_arg_cnt, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, }; static const struct bpf_func_proto * -tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { + const struct bpf_func_proto *func_proto; + switch (func_id) { - case BPF_FUNC_map_lookup_elem: - return &bpf_map_lookup_elem_proto; - case BPF_FUNC_map_update_elem: - return &bpf_map_update_elem_proto; - case BPF_FUNC_map_delete_elem: - return &bpf_map_delete_elem_proto; - case BPF_FUNC_probe_read: - return &bpf_probe_read_proto; - case BPF_FUNC_ktime_get_ns: - return &bpf_ktime_get_ns_proto; - case BPF_FUNC_tail_call: - return &bpf_tail_call_proto; - case BPF_FUNC_get_current_pid_tgid: - return &bpf_get_current_pid_tgid_proto; - case BPF_FUNC_get_current_task: - return &bpf_get_current_task_proto; - case BPF_FUNC_get_current_uid_gid: - return &bpf_get_current_uid_gid_proto; - case BPF_FUNC_get_current_comm: - return &bpf_get_current_comm_proto; - case BPF_FUNC_trace_printk: - return bpf_get_trace_printk_proto(); case BPF_FUNC_get_smp_processor_id: return &bpf_get_smp_processor_id_proto; - case BPF_FUNC_get_numa_node_id: - return &bpf_get_numa_node_id_proto; - case BPF_FUNC_perf_event_read: - return &bpf_perf_event_read_proto; - case BPF_FUNC_probe_write_user: - return bpf_get_probe_write_proto(); - case BPF_FUNC_current_task_under_cgroup: - return &bpf_current_task_under_cgroup_proto; - case BPF_FUNC_get_prandom_u32: - return &bpf_get_prandom_u32_proto; +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE + case BPF_FUNC_probe_read: + return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ? + NULL : &bpf_probe_read_compat_proto; case BPF_FUNC_probe_read_str: - return &bpf_probe_read_str_proto; -#ifdef CONFIG_CGROUPS - case BPF_FUNC_get_current_cgroup_id: - return &bpf_get_current_cgroup_id_proto; + return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ? + NULL : &bpf_probe_read_compat_str_proto; #endif + case BPF_FUNC_get_func_ip: + return &bpf_get_func_ip_proto_tracing; + default: + break; + } + + func_proto = bpf_base_func_proto(func_id, prog); + if (func_proto) + return func_proto; + + if (!bpf_token_capable(prog->aux->token, CAP_SYS_ADMIN)) + return NULL; + + switch (func_id) { + case BPF_FUNC_probe_write_user: + return security_locked_down(LOCKDOWN_BPF_WRITE_USER) < 0 ? + NULL : &bpf_probe_write_user_proto; default: return NULL; } } +static bool is_kprobe_multi(const struct bpf_prog *prog) +{ + return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI || + prog->expected_attach_type == BPF_TRACE_KPROBE_SESSION; +} + +static inline bool is_kprobe_session(const struct bpf_prog *prog) +{ + return prog->expected_attach_type == BPF_TRACE_KPROBE_SESSION; +} + +static inline bool is_uprobe_multi(const struct bpf_prog *prog) +{ + return prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI || + prog->expected_attach_type == BPF_TRACE_UPROBE_SESSION; +} + +static inline bool is_uprobe_session(const struct bpf_prog *prog) +{ + return prog->expected_attach_type == BPF_TRACE_UPROBE_SESSION; +} + static const struct bpf_func_proto * kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -618,15 +1309,25 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_get_stackid: return &bpf_get_stackid_proto; case BPF_FUNC_get_stack: - return &bpf_get_stack_proto; - case BPF_FUNC_perf_event_read_value: - return &bpf_perf_event_read_value_proto; + return prog->sleepable ? &bpf_get_stack_sleepable_proto : &bpf_get_stack_proto; #ifdef CONFIG_BPF_KPROBE_OVERRIDE case BPF_FUNC_override_return: return &bpf_override_return_proto; #endif + case BPF_FUNC_get_func_ip: + if (is_kprobe_multi(prog)) + return &bpf_get_func_ip_proto_kprobe_multi; + if (is_uprobe_multi(prog)) + return &bpf_get_func_ip_proto_uprobe_multi; + return &bpf_get_func_ip_proto_kprobe; + case BPF_FUNC_get_attach_cookie: + if (is_kprobe_multi(prog)) + return &bpf_get_attach_cookie_proto_kmulti; + if (is_uprobe_multi(prog)) + return &bpf_get_attach_cookie_proto_umulti; + return &bpf_get_attach_cookie_proto_trace; default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); } } @@ -637,8 +1338,6 @@ static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type { if (off < 0 || off >= sizeof(struct pt_regs)) return false; - if (type != BPF_READ) - return false; if (off % size != 0) return false; /* @@ -648,6 +1347,9 @@ static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type if (off + size > sizeof(struct pt_regs)) return false; + if (type == BPF_WRITE) + prog->aux->kprobe_write_ctx = true; + return true; } @@ -679,7 +1381,7 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_ANYTHING, - .arg4_type = ARG_PTR_TO_MEM, + .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg5_type = ARG_CONST_SIZE_OR_ZERO, }; @@ -735,8 +1437,10 @@ tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_stackid_proto_tp; case BPF_FUNC_get_stack: return &bpf_get_stack_proto_tp; + case BPF_FUNC_get_attach_cookie: + return &bpf_get_attach_cookie_proto_trace; default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); } } @@ -789,6 +1493,44 @@ static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { .arg3_type = ARG_CONST_SIZE, }; +BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx, + void *, buf, u32, size, u64, flags) +{ + static const u32 br_entry_size = sizeof(struct perf_branch_entry); + struct perf_branch_stack *br_stack = ctx->data->br_stack; + u32 to_copy; + + if (unlikely(flags & ~BPF_F_GET_BRANCH_RECORDS_SIZE)) + return -EINVAL; + + if (unlikely(!(ctx->data->sample_flags & PERF_SAMPLE_BRANCH_STACK))) + return -ENOENT; + + if (unlikely(!br_stack)) + return -ENOENT; + + if (flags & BPF_F_GET_BRANCH_RECORDS_SIZE) + return br_stack->nr * br_entry_size; + + if (!buf || (size % br_entry_size != 0)) + return -EINVAL; + + to_copy = min_t(u32, br_stack->nr * br_entry_size, size); + memcpy(buf, br_stack->entries, to_copy); + + return to_copy; +} + +static const struct bpf_func_proto bpf_read_branch_records_proto = { + .func = bpf_read_branch_records, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_MEM_OR_NULL, + .arg3_type = ARG_CONST_SIZE_OR_ZERO, + .arg4_type = ARG_ANYTHING, +}; + static const struct bpf_func_proto * pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -796,29 +1538,65 @@ pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_perf_event_output: return &bpf_perf_event_output_proto_tp; case BPF_FUNC_get_stackid: - return &bpf_get_stackid_proto_tp; + return &bpf_get_stackid_proto_pe; case BPF_FUNC_get_stack: - return &bpf_get_stack_proto_tp; + return &bpf_get_stack_proto_pe; case BPF_FUNC_perf_prog_read_value: return &bpf_perf_prog_read_value_proto; + case BPF_FUNC_read_branch_records: + return &bpf_read_branch_records_proto; + case BPF_FUNC_get_attach_cookie: + return &bpf_get_attach_cookie_proto_pe; default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); } } /* * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp * to avoid potential recursive reuse issue when/if tracepoints are added - * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack + * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. + * + * Since raw tracepoints run despite bpf_prog_active, support concurrent usage + * in normal, irq, and nmi context. */ -static DEFINE_PER_CPU(struct pt_regs, bpf_raw_tp_regs); +struct bpf_raw_tp_regs { + struct pt_regs regs[3]; +}; +static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); +static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); +static struct pt_regs *get_bpf_raw_tp_regs(void) +{ + struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); + int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); + + if (nest_level > ARRAY_SIZE(tp_regs->regs)) { + this_cpu_dec(bpf_raw_tp_nest_level); + return ERR_PTR(-EBUSY); + } + + return &tp_regs->regs[nest_level - 1]; +} + +static void put_bpf_raw_tp_regs(void) +{ + this_cpu_dec(bpf_raw_tp_nest_level); +} + BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, struct bpf_map *, map, u64, flags, void *, data, u64, size) { - struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + struct pt_regs *regs = get_bpf_raw_tp_regs(); + int ret; + + if (IS_ERR(regs)) + return PTR_ERR(regs); perf_fetch_caller_regs(regs); - return ____bpf_perf_event_output(regs, map, flags, data, size); + ret = ____bpf_perf_event_output(regs, map, flags, data, size); + + put_bpf_raw_tp_regs(); + return ret; } static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { @@ -828,19 +1606,29 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { .arg1_type = ARG_PTR_TO_CTX, .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_ANYTHING, - .arg4_type = ARG_PTR_TO_MEM, + .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg5_type = ARG_CONST_SIZE_OR_ZERO, }; +extern const struct bpf_func_proto bpf_skb_output_proto; +extern const struct bpf_func_proto bpf_xdp_output_proto; +extern const struct bpf_func_proto bpf_xdp_get_buff_len_trace_proto; + BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, struct bpf_map *, map, u64, flags) { - struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + struct pt_regs *regs = get_bpf_raw_tp_regs(); + int ret; + + if (IS_ERR(regs)) + return PTR_ERR(regs); perf_fetch_caller_regs(regs); /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ - return bpf_get_stackid((unsigned long) regs, (unsigned long) map, - flags, 0, 0); + ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, + flags, 0, 0); + put_bpf_raw_tp_regs(); + return ret; } static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { @@ -855,11 +1643,17 @@ static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, void *, buf, u32, size, u64, flags) { - struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + struct pt_regs *regs = get_bpf_raw_tp_regs(); + int ret; + + if (IS_ERR(regs)) + return PTR_ERR(regs); perf_fetch_caller_regs(regs); - return bpf_get_stack((unsigned long) regs, (unsigned long) buf, - (unsigned long) size, flags, 0); + ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, + (unsigned long) size, flags, 0); + put_bpf_raw_tp_regs(); + return ret; } static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { @@ -867,7 +1661,7 @@ static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { .gpl_only = true, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg3_type = ARG_CONST_SIZE_OR_ZERO, .arg4_type = ARG_ANYTHING, }; @@ -882,8 +1676,79 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_stackid_proto_raw_tp; case BPF_FUNC_get_stack: return &bpf_get_stack_proto_raw_tp; + case BPF_FUNC_get_attach_cookie: + return &bpf_get_attach_cookie_proto_tracing; default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); + } +} + +const struct bpf_func_proto * +tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + const struct bpf_func_proto *fn; + + switch (func_id) { +#ifdef CONFIG_NET + case BPF_FUNC_skb_output: + return &bpf_skb_output_proto; + case BPF_FUNC_xdp_output: + return &bpf_xdp_output_proto; + case BPF_FUNC_skc_to_tcp6_sock: + return &bpf_skc_to_tcp6_sock_proto; + case BPF_FUNC_skc_to_tcp_sock: + return &bpf_skc_to_tcp_sock_proto; + case BPF_FUNC_skc_to_tcp_timewait_sock: + return &bpf_skc_to_tcp_timewait_sock_proto; + case BPF_FUNC_skc_to_tcp_request_sock: + return &bpf_skc_to_tcp_request_sock_proto; + case BPF_FUNC_skc_to_udp6_sock: + return &bpf_skc_to_udp6_sock_proto; + case BPF_FUNC_skc_to_unix_sock: + return &bpf_skc_to_unix_sock_proto; + case BPF_FUNC_skc_to_mptcp_sock: + return &bpf_skc_to_mptcp_sock_proto; + case BPF_FUNC_sk_storage_get: + return &bpf_sk_storage_get_tracing_proto; + case BPF_FUNC_sk_storage_delete: + return &bpf_sk_storage_delete_tracing_proto; + case BPF_FUNC_sock_from_file: + return &bpf_sock_from_file_proto; + case BPF_FUNC_get_socket_cookie: + return &bpf_get_socket_ptr_cookie_proto; + case BPF_FUNC_xdp_get_buff_len: + return &bpf_xdp_get_buff_len_trace_proto; +#endif + case BPF_FUNC_seq_printf: + return prog->expected_attach_type == BPF_TRACE_ITER ? + &bpf_seq_printf_proto : + NULL; + case BPF_FUNC_seq_write: + return prog->expected_attach_type == BPF_TRACE_ITER ? + &bpf_seq_write_proto : + NULL; + case BPF_FUNC_seq_printf_btf: + return prog->expected_attach_type == BPF_TRACE_ITER ? + &bpf_seq_printf_btf_proto : + NULL; + case BPF_FUNC_d_path: + return &bpf_d_path_proto; + case BPF_FUNC_get_func_arg: + return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_proto : NULL; + case BPF_FUNC_get_func_ret: + return bpf_prog_has_trampoline(prog) ? &bpf_get_func_ret_proto : NULL; + case BPF_FUNC_get_func_arg_cnt: + return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_cnt_proto : NULL; + case BPF_FUNC_get_attach_cookie: + if (prog->type == BPF_PROG_TYPE_TRACING && + prog->expected_attach_type == BPF_TRACE_RAW_TP) + return &bpf_get_attach_cookie_proto_tracing; + return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto_tracing : NULL; + default: + fn = raw_tp_prog_func_proto(func_id, prog); + if (!fn && prog->expected_attach_type == BPF_TRACE_ITER) + fn = bpf_iter_get_func_proto(func_id, prog); + return fn; } } @@ -892,14 +1757,22 @@ static bool raw_tp_prog_is_valid_access(int off, int size, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { - /* largest tracepoint in the kernel has 12 args */ - if (off < 0 || off >= sizeof(__u64) * 12) - return false; - if (type != BPF_READ) - return false; - if (off % size != 0) - return false; - return true; + return bpf_tracing_ctx_access(off, size, type); +} + +static bool tracing_prog_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + return bpf_tracing_btf_ctx_access(off, size, type, prog, info); +} + +int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog, + const union bpf_attr *kattr, + union bpf_attr __user *uattr) +{ + return -ENOTSUPP; } const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { @@ -908,6 +1781,39 @@ const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { }; const struct bpf_prog_ops raw_tracepoint_prog_ops = { +#ifdef CONFIG_NET + .test_run = bpf_prog_test_run_raw_tp, +#endif +}; + +const struct bpf_verifier_ops tracing_verifier_ops = { + .get_func_proto = tracing_prog_func_proto, + .is_valid_access = tracing_prog_is_valid_access, +}; + +const struct bpf_prog_ops tracing_prog_ops = { + .test_run = bpf_prog_test_run_tracing, +}; + +static bool raw_tp_writable_prog_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + if (off == 0) { + if (size != sizeof(u64) || type != BPF_READ) + return false; + info->reg_type = PTR_TO_TP_BUFFER; + } + return raw_tp_prog_is_valid_access(off, size, type, prog, info); +} + +const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { + .get_func_proto = raw_tp_prog_func_proto, + .is_valid_access = raw_tp_writable_prog_is_valid_access, +}; + +const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { }; static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, @@ -998,9 +1904,10 @@ static DEFINE_MUTEX(bpf_event_mutex); #define BPF_TRACE_MAX_PROGS 64 int perf_event_attach_bpf_prog(struct perf_event *event, - struct bpf_prog *prog) + struct bpf_prog *prog, + u64 bpf_cookie) { - struct bpf_prog_array __rcu *old_array; + struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; int ret = -EEXIST; @@ -1018,21 +1925,22 @@ int perf_event_attach_bpf_prog(struct perf_event *event, if (event->prog) goto unlock; - old_array = event->tp_event->prog_array; + old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); if (old_array && bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { ret = -E2BIG; goto unlock; } - ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); + ret = bpf_prog_array_copy(old_array, NULL, prog, bpf_cookie, &new_array); if (ret < 0) goto unlock; /* set the new array to event->tp_event and set event->prog */ event->prog = prog; + event->bpf_cookie = bpf_cookie; rcu_assign_pointer(event->tp_event->prog_array, new_array); - bpf_prog_array_free(old_array); + bpf_prog_array_free_sleepable(old_array); unlock: mutex_unlock(&bpf_event_mutex); @@ -1041,8 +1949,9 @@ unlock: void perf_event_detach_bpf_prog(struct perf_event *event) { - struct bpf_prog_array __rcu *old_array; + struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; + struct bpf_prog *prog = NULL; int ret; mutex_lock(&bpf_event_mutex); @@ -1050,32 +1959,46 @@ void perf_event_detach_bpf_prog(struct perf_event *event) if (!event->prog) goto unlock; - old_array = event->tp_event->prog_array; - ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); - if (ret == -ENOENT) - goto unlock; + old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); + if (!old_array) + goto put; + + ret = bpf_prog_array_copy(old_array, event->prog, NULL, 0, &new_array); if (ret < 0) { bpf_prog_array_delete_safe(old_array, event->prog); } else { rcu_assign_pointer(event->tp_event->prog_array, new_array); - bpf_prog_array_free(old_array); + bpf_prog_array_free_sleepable(old_array); } - bpf_prog_put(event->prog); +put: + prog = event->prog; event->prog = NULL; unlock: mutex_unlock(&bpf_event_mutex); + + if (prog) { + /* + * It could be that the bpf_prog is not sleepable (and will be freed + * via normal RCU), but is called from a point that supports sleepable + * programs and uses tasks-trace-RCU. + */ + synchronize_rcu_tasks_trace(); + + bpf_prog_put(prog); + } } int perf_event_query_prog_array(struct perf_event *event, void __user *info) { struct perf_event_query_bpf __user *uquery = info; struct perf_event_query_bpf query = {}; + struct bpf_prog_array *progs; u32 *ids, prog_cnt, ids_len; int ret; - if (!capable(CAP_SYS_ADMIN)) + if (!perfmon_capable()) return -EPERM; if (event->attr.type != PERF_TYPE_TRACEPOINT) return -EINVAL; @@ -1096,10 +2019,8 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) */ mutex_lock(&bpf_event_mutex); - ret = bpf_prog_array_copy_info(event->tp_event->prog_array, - ids, - ids_len, - &prog_cnt); + progs = bpf_event_rcu_dereference(event->tp_event->prog_array); + ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt); mutex_unlock(&bpf_event_mutex); if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || @@ -1127,20 +2048,36 @@ struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) { - struct module *mod = __module_address((unsigned long)btp); + struct module *mod; - if (mod) - module_put(mod); + guard(rcu)(); + mod = __module_address((unsigned long)btp); + module_put(mod); } static __always_inline -void __bpf_trace_run(struct bpf_prog *prog, u64 *args) +void __bpf_trace_run(struct bpf_raw_tp_link *link, u64 *args) { + struct bpf_prog *prog = link->link.prog; + struct bpf_run_ctx *old_run_ctx; + struct bpf_trace_run_ctx run_ctx; + + cant_sleep(); + if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) { + bpf_prog_inc_misses_counter(prog); + goto out; + } + + run_ctx.bpf_cookie = link->cookie; + old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); + rcu_read_lock(); - preempt_disable(); - (void) BPF_PROG_RUN(prog, args); - preempt_enable(); + (void) bpf_prog_run(prog, args); rcu_read_unlock(); + + bpf_reset_run_ctx(old_run_ctx); +out: + this_cpu_dec(*(prog->active)); } #define UNPACK(...) __VA_ARGS__ @@ -1167,12 +2104,12 @@ void __bpf_trace_run(struct bpf_prog *prog, u64 *args) #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 #define BPF_TRACE_DEFN_x(x) \ - void bpf_trace_run##x(struct bpf_prog *prog, \ + void bpf_trace_run##x(struct bpf_raw_tp_link *link, \ REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ { \ u64 args[x]; \ REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ - __bpf_trace_run(prog, args); \ + __bpf_trace_run(link, args); \ } \ EXPORT_SYMBOL_GPL(bpf_trace_run##x) BPF_TRACE_DEFN_x(1); @@ -1188,9 +2125,10 @@ BPF_TRACE_DEFN_x(10); BPF_TRACE_DEFN_x(11); BPF_TRACE_DEFN_x(12); -static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_raw_tp_link *link) { struct tracepoint *tp = btp->tp; + struct bpf_prog *prog = link->link.prog; /* * check that program doesn't access arguments beyond what's @@ -1199,32 +2137,21 @@ static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog * if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) return -EINVAL; - return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); -} - -int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) -{ - int err; + if (prog->aux->max_tp_access > btp->writable_size) + return -EINVAL; - mutex_lock(&bpf_event_mutex); - err = __bpf_probe_register(btp, prog); - mutex_unlock(&bpf_event_mutex); - return err; + return tracepoint_probe_register_may_exist(tp, (void *)btp->bpf_func, link); } -int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_raw_tp_link *link) { - int err; - - mutex_lock(&bpf_event_mutex); - err = tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); - mutex_unlock(&bpf_event_mutex); - return err; + return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, link); } int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, u32 *fd_type, const char **buf, - u64 *probe_offset, u64 *probe_addr) + u64 *probe_offset, u64 *probe_addr, + unsigned long *missed) { bool is_tracepoint, is_syscall_tp; struct bpf_prog *prog; @@ -1246,22 +2173,26 @@ int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, if (is_tracepoint || is_syscall_tp) { *buf = is_tracepoint ? event->tp_event->tp->name : event->tp_event->name; - *fd_type = BPF_FD_TYPE_TRACEPOINT; - *probe_offset = 0x0; - *probe_addr = 0x0; + /* We allow NULL pointer for tracepoint */ + if (fd_type) + *fd_type = BPF_FD_TYPE_TRACEPOINT; + if (probe_offset) + *probe_offset = 0x0; + if (probe_addr) + *probe_addr = 0x0; } else { /* kprobe/uprobe */ err = -EOPNOTSUPP; #ifdef CONFIG_KPROBE_EVENTS if (flags & TRACE_EVENT_FL_KPROBE) err = bpf_get_kprobe_info(event, fd_type, buf, - probe_offset, probe_addr, + probe_offset, probe_addr, missed, event->attr.type == PERF_TYPE_TRACEPOINT); #endif #ifdef CONFIG_UPROBE_EVENTS if (flags & TRACE_EVENT_FL_UPROBE) err = bpf_get_uprobe_info(event, fd_type, buf, - probe_offset, + probe_offset, probe_addr, event->attr.type == PERF_TYPE_TRACEPOINT); #endif } @@ -1269,15 +2200,31 @@ int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, return err; } +static int __init send_signal_irq_work_init(void) +{ + int cpu; + struct send_signal_irq_work *work; + + for_each_possible_cpu(cpu) { + work = per_cpu_ptr(&send_signal_work, cpu); + init_irq_work(&work->irq_work, do_bpf_send_signal); + } + return 0; +} + +subsys_initcall(send_signal_irq_work_init); + #ifdef CONFIG_MODULES -int bpf_event_notify(struct notifier_block *nb, unsigned long op, void *module) +static int bpf_event_notify(struct notifier_block *nb, unsigned long op, + void *module) { struct bpf_trace_module *btm, *tmp; struct module *mod = module; + int ret = 0; if (mod->num_bpf_raw_events == 0 || (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) - return 0; + goto out; mutex_lock(&bpf_module_mutex); @@ -1287,6 +2234,8 @@ int bpf_event_notify(struct notifier_block *nb, unsigned long op, void *module) if (btm) { btm->module = module; list_add(&btm->list, &bpf_trace_modules); + } else { + ret = -ENOMEM; } break; case MODULE_STATE_GOING: @@ -1302,14 +2251,15 @@ int bpf_event_notify(struct notifier_block *nb, unsigned long op, void *module) mutex_unlock(&bpf_module_mutex); - return 0; +out: + return notifier_from_errno(ret); } static struct notifier_block bpf_module_nb = { .notifier_call = bpf_event_notify, }; -int __init bpf_event_init(void) +static int __init bpf_event_init(void) { register_module_notifier(&bpf_module_nb); return 0; @@ -1317,3 +2267,1309 @@ int __init bpf_event_init(void) fs_initcall(bpf_event_init); #endif /* CONFIG_MODULES */ + +struct bpf_session_run_ctx { + struct bpf_run_ctx run_ctx; + bool is_return; + void *data; +}; + +#ifdef CONFIG_FPROBE +struct bpf_kprobe_multi_link { + struct bpf_link link; + struct fprobe fp; + unsigned long *addrs; + u64 *cookies; + u32 cnt; + u32 mods_cnt; + struct module **mods; +}; + +struct bpf_kprobe_multi_run_ctx { + struct bpf_session_run_ctx session_ctx; + struct bpf_kprobe_multi_link *link; + unsigned long entry_ip; +}; + +struct user_syms { + const char **syms; + char *buf; +}; + +#ifndef CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs); +#define bpf_kprobe_multi_pt_regs_ptr() this_cpu_ptr(&bpf_kprobe_multi_pt_regs) +#else +#define bpf_kprobe_multi_pt_regs_ptr() (NULL) +#endif + +static unsigned long ftrace_get_entry_ip(unsigned long fentry_ip) +{ + unsigned long ip = ftrace_get_symaddr(fentry_ip); + + return ip ? : fentry_ip; +} + +static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt) +{ + unsigned long __user usymbol; + const char **syms = NULL; + char *buf = NULL, *p; + int err = -ENOMEM; + unsigned int i; + + syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL); + if (!syms) + goto error; + + buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL); + if (!buf) + goto error; + + for (p = buf, i = 0; i < cnt; i++) { + if (__get_user(usymbol, usyms + i)) { + err = -EFAULT; + goto error; + } + err = strncpy_from_user(p, (const char __user *) usymbol, KSYM_NAME_LEN); + if (err == KSYM_NAME_LEN) + err = -E2BIG; + if (err < 0) + goto error; + syms[i] = p; + p += err + 1; + } + + us->syms = syms; + us->buf = buf; + return 0; + +error: + if (err) { + kvfree(syms); + kvfree(buf); + } + return err; +} + +static void kprobe_multi_put_modules(struct module **mods, u32 cnt) +{ + u32 i; + + for (i = 0; i < cnt; i++) + module_put(mods[i]); +} + +static void free_user_syms(struct user_syms *us) +{ + kvfree(us->syms); + kvfree(us->buf); +} + +static void bpf_kprobe_multi_link_release(struct bpf_link *link) +{ + struct bpf_kprobe_multi_link *kmulti_link; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + unregister_fprobe(&kmulti_link->fp); + kprobe_multi_put_modules(kmulti_link->mods, kmulti_link->mods_cnt); +} + +static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link) +{ + struct bpf_kprobe_multi_link *kmulti_link; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + kvfree(kmulti_link->addrs); + kvfree(kmulti_link->cookies); + kfree(kmulti_link->mods); + kfree(kmulti_link); +} + +static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + u64 __user *ucookies = u64_to_user_ptr(info->kprobe_multi.cookies); + u64 __user *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs); + struct bpf_kprobe_multi_link *kmulti_link; + u32 ucount = info->kprobe_multi.count; + int err = 0, i; + + if (!uaddrs ^ !ucount) + return -EINVAL; + if (ucookies && !ucount) + return -EINVAL; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + info->kprobe_multi.count = kmulti_link->cnt; + info->kprobe_multi.flags = kmulti_link->link.flags; + info->kprobe_multi.missed = kmulti_link->fp.nmissed; + + if (!uaddrs) + return 0; + if (ucount < kmulti_link->cnt) + err = -ENOSPC; + else + ucount = kmulti_link->cnt; + + if (ucookies) { + if (kmulti_link->cookies) { + if (copy_to_user(ucookies, kmulti_link->cookies, ucount * sizeof(u64))) + return -EFAULT; + } else { + for (i = 0; i < ucount; i++) { + if (put_user(0, ucookies + i)) + return -EFAULT; + } + } + } + + if (kallsyms_show_value(current_cred())) { + if (copy_to_user(uaddrs, kmulti_link->addrs, ucount * sizeof(u64))) + return -EFAULT; + } else { + for (i = 0; i < ucount; i++) { + if (put_user(0, uaddrs + i)) + return -EFAULT; + } + } + return err; +} + +#ifdef CONFIG_PROC_FS +static void bpf_kprobe_multi_show_fdinfo(const struct bpf_link *link, + struct seq_file *seq) +{ + struct bpf_kprobe_multi_link *kmulti_link; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + + seq_printf(seq, + "kprobe_cnt:\t%u\n" + "missed:\t%lu\n", + kmulti_link->cnt, + kmulti_link->fp.nmissed); + + seq_printf(seq, "%s\t %s\n", "cookie", "func"); + for (int i = 0; i < kmulti_link->cnt; i++) { + seq_printf(seq, + "%llu\t %pS\n", + kmulti_link->cookies[i], + (void *)kmulti_link->addrs[i]); + } +} +#endif + +static const struct bpf_link_ops bpf_kprobe_multi_link_lops = { + .release = bpf_kprobe_multi_link_release, + .dealloc_deferred = bpf_kprobe_multi_link_dealloc, + .fill_link_info = bpf_kprobe_multi_link_fill_link_info, +#ifdef CONFIG_PROC_FS + .show_fdinfo = bpf_kprobe_multi_show_fdinfo, +#endif +}; + +static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv) +{ + const struct bpf_kprobe_multi_link *link = priv; + unsigned long *addr_a = a, *addr_b = b; + u64 *cookie_a, *cookie_b; + + cookie_a = link->cookies + (addr_a - link->addrs); + cookie_b = link->cookies + (addr_b - link->addrs); + + /* swap addr_a/addr_b and cookie_a/cookie_b values */ + swap(*addr_a, *addr_b); + swap(*cookie_a, *cookie_b); +} + +static int bpf_kprobe_multi_addrs_cmp(const void *a, const void *b) +{ + const unsigned long *addr_a = a, *addr_b = b; + + if (*addr_a == *addr_b) + return 0; + return *addr_a < *addr_b ? -1 : 1; +} + +static int bpf_kprobe_multi_cookie_cmp(const void *a, const void *b, const void *priv) +{ + return bpf_kprobe_multi_addrs_cmp(a, b); +} + +static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx) +{ + struct bpf_kprobe_multi_run_ctx *run_ctx; + struct bpf_kprobe_multi_link *link; + u64 *cookie, entry_ip; + unsigned long *addr; + + if (WARN_ON_ONCE(!ctx)) + return 0; + run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, + session_ctx.run_ctx); + link = run_ctx->link; + if (!link->cookies) + return 0; + entry_ip = run_ctx->entry_ip; + addr = bsearch(&entry_ip, link->addrs, link->cnt, sizeof(entry_ip), + bpf_kprobe_multi_addrs_cmp); + if (!addr) + return 0; + cookie = link->cookies + (addr - link->addrs); + return *cookie; +} + +static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) +{ + struct bpf_kprobe_multi_run_ctx *run_ctx; + + run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, + session_ctx.run_ctx); + return run_ctx->entry_ip; +} + +static __always_inline int +kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, + unsigned long entry_ip, struct ftrace_regs *fregs, + bool is_return, void *data) +{ + struct bpf_kprobe_multi_run_ctx run_ctx = { + .session_ctx = { + .is_return = is_return, + .data = data, + }, + .link = link, + .entry_ip = entry_ip, + }; + struct bpf_run_ctx *old_run_ctx; + struct pt_regs *regs; + int err; + + /* + * graph tracer framework ensures we won't migrate, so there is no need + * to use migrate_disable for bpf_prog_run again. The check here just for + * __this_cpu_inc_return. + */ + cant_sleep(); + + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { + bpf_prog_inc_misses_counter(link->link.prog); + err = 1; + goto out; + } + + rcu_read_lock(); + regs = ftrace_partial_regs(fregs, bpf_kprobe_multi_pt_regs_ptr()); + old_run_ctx = bpf_set_run_ctx(&run_ctx.session_ctx.run_ctx); + err = bpf_prog_run(link->link.prog, regs); + bpf_reset_run_ctx(old_run_ctx); + rcu_read_unlock(); + + out: + __this_cpu_dec(bpf_prog_active); + return err; +} + +static int +kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, + unsigned long ret_ip, struct ftrace_regs *fregs, + void *data) +{ + struct bpf_kprobe_multi_link *link; + int err; + + link = container_of(fp, struct bpf_kprobe_multi_link, fp); + err = kprobe_multi_link_prog_run(link, ftrace_get_entry_ip(fentry_ip), + fregs, false, data); + return is_kprobe_session(link->link.prog) ? err : 0; +} + +static void +kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, + unsigned long ret_ip, struct ftrace_regs *fregs, + void *data) +{ + struct bpf_kprobe_multi_link *link; + + link = container_of(fp, struct bpf_kprobe_multi_link, fp); + kprobe_multi_link_prog_run(link, ftrace_get_entry_ip(fentry_ip), + fregs, true, data); +} + +static int symbols_cmp_r(const void *a, const void *b, const void *priv) +{ + const char **str_a = (const char **) a; + const char **str_b = (const char **) b; + + return strcmp(*str_a, *str_b); +} + +struct multi_symbols_sort { + const char **funcs; + u64 *cookies; +}; + +static void symbols_swap_r(void *a, void *b, int size, const void *priv) +{ + const struct multi_symbols_sort *data = priv; + const char **name_a = a, **name_b = b; + + swap(*name_a, *name_b); + + /* If defined, swap also related cookies. */ + if (data->cookies) { + u64 *cookie_a, *cookie_b; + + cookie_a = data->cookies + (name_a - data->funcs); + cookie_b = data->cookies + (name_b - data->funcs); + swap(*cookie_a, *cookie_b); + } +} + +struct modules_array { + struct module **mods; + int mods_cnt; + int mods_cap; +}; + +static int add_module(struct modules_array *arr, struct module *mod) +{ + struct module **mods; + + if (arr->mods_cnt == arr->mods_cap) { + arr->mods_cap = max(16, arr->mods_cap * 3 / 2); + mods = krealloc_array(arr->mods, arr->mods_cap, sizeof(*mods), GFP_KERNEL); + if (!mods) + return -ENOMEM; + arr->mods = mods; + } + + arr->mods[arr->mods_cnt] = mod; + arr->mods_cnt++; + return 0; +} + +static bool has_module(struct modules_array *arr, struct module *mod) +{ + int i; + + for (i = arr->mods_cnt - 1; i >= 0; i--) { + if (arr->mods[i] == mod) + return true; + } + return false; +} + +static int get_modules_for_addrs(struct module ***mods, unsigned long *addrs, u32 addrs_cnt) +{ + struct modules_array arr = {}; + u32 i, err = 0; + + for (i = 0; i < addrs_cnt; i++) { + bool skip_add = false; + struct module *mod; + + scoped_guard(rcu) { + mod = __module_address(addrs[i]); + /* Either no module or it's already stored */ + if (!mod || has_module(&arr, mod)) { + skip_add = true; + break; /* scoped_guard */ + } + if (!try_module_get(mod)) + err = -EINVAL; + } + if (skip_add) + continue; + if (err) + break; + err = add_module(&arr, mod); + if (err) { + module_put(mod); + break; + } + } + + /* We return either err < 0 in case of error, ... */ + if (err) { + kprobe_multi_put_modules(arr.mods, arr.mods_cnt); + kfree(arr.mods); + return err; + } + + /* or number of modules found if everything is ok. */ + *mods = arr.mods; + return arr.mods_cnt; +} + +static int addrs_check_error_injection_list(unsigned long *addrs, u32 cnt) +{ + u32 i; + + for (i = 0; i < cnt; i++) { + if (!within_error_injection_list(addrs[i])) + return -EINVAL; + } + return 0; +} + +int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + struct bpf_kprobe_multi_link *link = NULL; + struct bpf_link_primer link_primer; + void __user *ucookies; + unsigned long *addrs; + u32 flags, cnt, size; + void __user *uaddrs; + u64 *cookies = NULL; + void __user *usyms; + int err; + + /* no support for 32bit archs yet */ + if (sizeof(u64) != sizeof(void *)) + return -EOPNOTSUPP; + + if (attr->link_create.flags) + return -EINVAL; + + if (!is_kprobe_multi(prog)) + return -EINVAL; + + /* Writing to context is not allowed for kprobes. */ + if (prog->aux->kprobe_write_ctx) + return -EINVAL; + + flags = attr->link_create.kprobe_multi.flags; + if (flags & ~BPF_F_KPROBE_MULTI_RETURN) + return -EINVAL; + + uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs); + usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms); + if (!!uaddrs == !!usyms) + return -EINVAL; + + cnt = attr->link_create.kprobe_multi.cnt; + if (!cnt) + return -EINVAL; + if (cnt > MAX_KPROBE_MULTI_CNT) + return -E2BIG; + + size = cnt * sizeof(*addrs); + addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL); + if (!addrs) + return -ENOMEM; + + ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); + if (ucookies) { + cookies = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL); + if (!cookies) { + err = -ENOMEM; + goto error; + } + if (copy_from_user(cookies, ucookies, size)) { + err = -EFAULT; + goto error; + } + } + + if (uaddrs) { + if (copy_from_user(addrs, uaddrs, size)) { + err = -EFAULT; + goto error; + } + } else { + struct multi_symbols_sort data = { + .cookies = cookies, + }; + struct user_syms us; + + err = copy_user_syms(&us, usyms, cnt); + if (err) + goto error; + + if (cookies) + data.funcs = us.syms; + + sort_r(us.syms, cnt, sizeof(*us.syms), symbols_cmp_r, + symbols_swap_r, &data); + + err = ftrace_lookup_symbols(us.syms, cnt, addrs); + free_user_syms(&us); + if (err) + goto error; + } + + if (prog->kprobe_override && addrs_check_error_injection_list(addrs, cnt)) { + err = -EINVAL; + goto error; + } + + link = kzalloc(sizeof(*link), GFP_KERNEL); + if (!link) { + err = -ENOMEM; + goto error; + } + + bpf_link_init(&link->link, BPF_LINK_TYPE_KPROBE_MULTI, + &bpf_kprobe_multi_link_lops, prog, attr->link_create.attach_type); + + err = bpf_link_prime(&link->link, &link_primer); + if (err) + goto error; + + if (!(flags & BPF_F_KPROBE_MULTI_RETURN)) + link->fp.entry_handler = kprobe_multi_link_handler; + if ((flags & BPF_F_KPROBE_MULTI_RETURN) || is_kprobe_session(prog)) + link->fp.exit_handler = kprobe_multi_link_exit_handler; + if (is_kprobe_session(prog)) + link->fp.entry_data_size = sizeof(u64); + + link->addrs = addrs; + link->cookies = cookies; + link->cnt = cnt; + link->link.flags = flags; + + if (cookies) { + /* + * Sorting addresses will trigger sorting cookies as well + * (check bpf_kprobe_multi_cookie_swap). This way we can + * find cookie based on the address in bpf_get_attach_cookie + * helper. + */ + sort_r(addrs, cnt, sizeof(*addrs), + bpf_kprobe_multi_cookie_cmp, + bpf_kprobe_multi_cookie_swap, + link); + } + + err = get_modules_for_addrs(&link->mods, addrs, cnt); + if (err < 0) { + bpf_link_cleanup(&link_primer); + return err; + } + link->mods_cnt = err; + + err = register_fprobe_ips(&link->fp, addrs, cnt); + if (err) { + kprobe_multi_put_modules(link->mods, link->mods_cnt); + bpf_link_cleanup(&link_primer); + return err; + } + + return bpf_link_settle(&link_primer); + +error: + kfree(link); + kvfree(addrs); + kvfree(cookies); + return err; +} +#else /* !CONFIG_FPROBE */ +int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + return -EOPNOTSUPP; +} +static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx) +{ + return 0; +} +static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) +{ + return 0; +} +#endif + +#ifdef CONFIG_UPROBES +struct bpf_uprobe_multi_link; + +struct bpf_uprobe { + struct bpf_uprobe_multi_link *link; + loff_t offset; + unsigned long ref_ctr_offset; + u64 cookie; + struct uprobe *uprobe; + struct uprobe_consumer consumer; + bool session; +}; + +struct bpf_uprobe_multi_link { + struct path path; + struct bpf_link link; + u32 cnt; + struct bpf_uprobe *uprobes; + struct task_struct *task; +}; + +struct bpf_uprobe_multi_run_ctx { + struct bpf_session_run_ctx session_ctx; + unsigned long entry_ip; + struct bpf_uprobe *uprobe; +}; + +static void bpf_uprobe_unregister(struct bpf_uprobe *uprobes, u32 cnt) +{ + u32 i; + + for (i = 0; i < cnt; i++) + uprobe_unregister_nosync(uprobes[i].uprobe, &uprobes[i].consumer); + + if (cnt) + uprobe_unregister_sync(); +} + +static void bpf_uprobe_multi_link_release(struct bpf_link *link) +{ + struct bpf_uprobe_multi_link *umulti_link; + + umulti_link = container_of(link, struct bpf_uprobe_multi_link, link); + bpf_uprobe_unregister(umulti_link->uprobes, umulti_link->cnt); + if (umulti_link->task) + put_task_struct(umulti_link->task); + path_put(&umulti_link->path); +} + +static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link) +{ + struct bpf_uprobe_multi_link *umulti_link; + + umulti_link = container_of(link, struct bpf_uprobe_multi_link, link); + kvfree(umulti_link->uprobes); + kfree(umulti_link); +} + +static int bpf_uprobe_multi_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + u64 __user *uref_ctr_offsets = u64_to_user_ptr(info->uprobe_multi.ref_ctr_offsets); + u64 __user *ucookies = u64_to_user_ptr(info->uprobe_multi.cookies); + u64 __user *uoffsets = u64_to_user_ptr(info->uprobe_multi.offsets); + u64 __user *upath = u64_to_user_ptr(info->uprobe_multi.path); + u32 upath_size = info->uprobe_multi.path_size; + struct bpf_uprobe_multi_link *umulti_link; + u32 ucount = info->uprobe_multi.count; + int err = 0, i; + char *p, *buf; + long left = 0; + + if (!upath ^ !upath_size) + return -EINVAL; + + if ((uoffsets || uref_ctr_offsets || ucookies) && !ucount) + return -EINVAL; + + umulti_link = container_of(link, struct bpf_uprobe_multi_link, link); + info->uprobe_multi.count = umulti_link->cnt; + info->uprobe_multi.flags = umulti_link->link.flags; + info->uprobe_multi.pid = umulti_link->task ? + task_pid_nr_ns(umulti_link->task, task_active_pid_ns(current)) : 0; + + upath_size = upath_size ? min_t(u32, upath_size, PATH_MAX) : PATH_MAX; + buf = kmalloc(upath_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + p = d_path(&umulti_link->path, buf, upath_size); + if (IS_ERR(p)) { + kfree(buf); + return PTR_ERR(p); + } + upath_size = buf + upath_size - p; + + if (upath) + left = copy_to_user(upath, p, upath_size); + kfree(buf); + if (left) + return -EFAULT; + info->uprobe_multi.path_size = upath_size; + + if (!uoffsets && !ucookies && !uref_ctr_offsets) + return 0; + + if (ucount < umulti_link->cnt) + err = -ENOSPC; + else + ucount = umulti_link->cnt; + + for (i = 0; i < ucount; i++) { + if (uoffsets && + put_user(umulti_link->uprobes[i].offset, uoffsets + i)) + return -EFAULT; + if (uref_ctr_offsets && + put_user(umulti_link->uprobes[i].ref_ctr_offset, uref_ctr_offsets + i)) + return -EFAULT; + if (ucookies && + put_user(umulti_link->uprobes[i].cookie, ucookies + i)) + return -EFAULT; + } + + return err; +} + +#ifdef CONFIG_PROC_FS +static void bpf_uprobe_multi_show_fdinfo(const struct bpf_link *link, + struct seq_file *seq) +{ + struct bpf_uprobe_multi_link *umulti_link; + char *p, *buf; + pid_t pid; + + umulti_link = container_of(link, struct bpf_uprobe_multi_link, link); + + buf = kmalloc(PATH_MAX, GFP_KERNEL); + if (!buf) + return; + + p = d_path(&umulti_link->path, buf, PATH_MAX); + if (IS_ERR(p)) { + kfree(buf); + return; + } + + pid = umulti_link->task ? + task_pid_nr_ns(umulti_link->task, task_active_pid_ns(current)) : 0; + seq_printf(seq, + "uprobe_cnt:\t%u\n" + "pid:\t%u\n" + "path:\t%s\n", + umulti_link->cnt, pid, p); + + seq_printf(seq, "%s\t %s\t %s\n", "cookie", "offset", "ref_ctr_offset"); + for (int i = 0; i < umulti_link->cnt; i++) { + seq_printf(seq, + "%llu\t %#llx\t %#lx\n", + umulti_link->uprobes[i].cookie, + umulti_link->uprobes[i].offset, + umulti_link->uprobes[i].ref_ctr_offset); + } + + kfree(buf); +} +#endif + +static const struct bpf_link_ops bpf_uprobe_multi_link_lops = { + .release = bpf_uprobe_multi_link_release, + .dealloc_deferred = bpf_uprobe_multi_link_dealloc, + .fill_link_info = bpf_uprobe_multi_link_fill_link_info, +#ifdef CONFIG_PROC_FS + .show_fdinfo = bpf_uprobe_multi_show_fdinfo, +#endif +}; + +static int uprobe_prog_run(struct bpf_uprobe *uprobe, + unsigned long entry_ip, + struct pt_regs *regs, + bool is_return, void *data) +{ + struct bpf_uprobe_multi_link *link = uprobe->link; + struct bpf_uprobe_multi_run_ctx run_ctx = { + .session_ctx = { + .is_return = is_return, + .data = data, + }, + .entry_ip = entry_ip, + .uprobe = uprobe, + }; + struct bpf_prog *prog = link->link.prog; + bool sleepable = prog->sleepable; + struct bpf_run_ctx *old_run_ctx; + int err; + + if (link->task && !same_thread_group(current, link->task)) + return 0; + + if (sleepable) + rcu_read_lock_trace(); + else + rcu_read_lock(); + + migrate_disable(); + + old_run_ctx = bpf_set_run_ctx(&run_ctx.session_ctx.run_ctx); + err = bpf_prog_run(link->link.prog, regs); + bpf_reset_run_ctx(old_run_ctx); + + migrate_enable(); + + if (sleepable) + rcu_read_unlock_trace(); + else + rcu_read_unlock(); + return err; +} + +static bool +uprobe_multi_link_filter(struct uprobe_consumer *con, struct mm_struct *mm) +{ + struct bpf_uprobe *uprobe; + + uprobe = container_of(con, struct bpf_uprobe, consumer); + return uprobe->link->task->mm == mm; +} + +static int +uprobe_multi_link_handler(struct uprobe_consumer *con, struct pt_regs *regs, + __u64 *data) +{ + struct bpf_uprobe *uprobe; + int ret; + + uprobe = container_of(con, struct bpf_uprobe, consumer); + ret = uprobe_prog_run(uprobe, instruction_pointer(regs), regs, false, data); + if (uprobe->session) + return ret ? UPROBE_HANDLER_IGNORE : 0; + return 0; +} + +static int +uprobe_multi_link_ret_handler(struct uprobe_consumer *con, unsigned long func, struct pt_regs *regs, + __u64 *data) +{ + struct bpf_uprobe *uprobe; + + uprobe = container_of(con, struct bpf_uprobe, consumer); + uprobe_prog_run(uprobe, func, regs, true, data); + return 0; +} + +static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx) +{ + struct bpf_uprobe_multi_run_ctx *run_ctx; + + run_ctx = container_of(current->bpf_ctx, struct bpf_uprobe_multi_run_ctx, + session_ctx.run_ctx); + return run_ctx->entry_ip; +} + +static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx) +{ + struct bpf_uprobe_multi_run_ctx *run_ctx; + + run_ctx = container_of(current->bpf_ctx, struct bpf_uprobe_multi_run_ctx, + session_ctx.run_ctx); + return run_ctx->uprobe->cookie; +} + +int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + struct bpf_uprobe_multi_link *link = NULL; + unsigned long __user *uref_ctr_offsets; + struct bpf_link_primer link_primer; + struct bpf_uprobe *uprobes = NULL; + struct task_struct *task = NULL; + unsigned long __user *uoffsets; + u64 __user *ucookies; + void __user *upath; + u32 flags, cnt, i; + struct path path; + char *name; + pid_t pid; + int err; + + /* no support for 32bit archs yet */ + if (sizeof(u64) != sizeof(void *)) + return -EOPNOTSUPP; + + if (attr->link_create.flags) + return -EINVAL; + + if (!is_uprobe_multi(prog)) + return -EINVAL; + + flags = attr->link_create.uprobe_multi.flags; + if (flags & ~BPF_F_UPROBE_MULTI_RETURN) + return -EINVAL; + + /* + * path, offsets and cnt are mandatory, + * ref_ctr_offsets and cookies are optional + */ + upath = u64_to_user_ptr(attr->link_create.uprobe_multi.path); + uoffsets = u64_to_user_ptr(attr->link_create.uprobe_multi.offsets); + cnt = attr->link_create.uprobe_multi.cnt; + pid = attr->link_create.uprobe_multi.pid; + + if (!upath || !uoffsets || !cnt || pid < 0) + return -EINVAL; + if (cnt > MAX_UPROBE_MULTI_CNT) + return -E2BIG; + + uref_ctr_offsets = u64_to_user_ptr(attr->link_create.uprobe_multi.ref_ctr_offsets); + ucookies = u64_to_user_ptr(attr->link_create.uprobe_multi.cookies); + + name = strndup_user(upath, PATH_MAX); + if (IS_ERR(name)) { + err = PTR_ERR(name); + return err; + } + + err = kern_path(name, LOOKUP_FOLLOW, &path); + kfree(name); + if (err) + return err; + + if (!d_is_reg(path.dentry)) { + err = -EBADF; + goto error_path_put; + } + + if (pid) { + rcu_read_lock(); + task = get_pid_task(find_vpid(pid), PIDTYPE_TGID); + rcu_read_unlock(); + if (!task) { + err = -ESRCH; + goto error_path_put; + } + } + + err = -ENOMEM; + + link = kzalloc(sizeof(*link), GFP_KERNEL); + uprobes = kvcalloc(cnt, sizeof(*uprobes), GFP_KERNEL); + + if (!uprobes || !link) + goto error_free; + + for (i = 0; i < cnt; i++) { + if (__get_user(uprobes[i].offset, uoffsets + i)) { + err = -EFAULT; + goto error_free; + } + if (uprobes[i].offset < 0) { + err = -EINVAL; + goto error_free; + } + if (uref_ctr_offsets && __get_user(uprobes[i].ref_ctr_offset, uref_ctr_offsets + i)) { + err = -EFAULT; + goto error_free; + } + if (ucookies && __get_user(uprobes[i].cookie, ucookies + i)) { + err = -EFAULT; + goto error_free; + } + + uprobes[i].link = link; + + if (!(flags & BPF_F_UPROBE_MULTI_RETURN)) + uprobes[i].consumer.handler = uprobe_multi_link_handler; + if (flags & BPF_F_UPROBE_MULTI_RETURN || is_uprobe_session(prog)) + uprobes[i].consumer.ret_handler = uprobe_multi_link_ret_handler; + if (is_uprobe_session(prog)) + uprobes[i].session = true; + if (pid) + uprobes[i].consumer.filter = uprobe_multi_link_filter; + } + + link->cnt = cnt; + link->uprobes = uprobes; + link->path = path; + link->task = task; + link->link.flags = flags; + + bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI, + &bpf_uprobe_multi_link_lops, prog, attr->link_create.attach_type); + + for (i = 0; i < cnt; i++) { + uprobes[i].uprobe = uprobe_register(d_real_inode(link->path.dentry), + uprobes[i].offset, + uprobes[i].ref_ctr_offset, + &uprobes[i].consumer); + if (IS_ERR(uprobes[i].uprobe)) { + err = PTR_ERR(uprobes[i].uprobe); + link->cnt = i; + goto error_unregister; + } + } + + err = bpf_link_prime(&link->link, &link_primer); + if (err) + goto error_unregister; + + return bpf_link_settle(&link_primer); + +error_unregister: + bpf_uprobe_unregister(uprobes, link->cnt); + +error_free: + kvfree(uprobes); + kfree(link); + if (task) + put_task_struct(task); +error_path_put: + path_put(&path); + return err; +} +#else /* !CONFIG_UPROBES */ +int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + return -EOPNOTSUPP; +} +static u64 bpf_uprobe_multi_cookie(struct bpf_run_ctx *ctx) +{ + return 0; +} +static u64 bpf_uprobe_multi_entry_ip(struct bpf_run_ctx *ctx) +{ + return 0; +} +#endif /* CONFIG_UPROBES */ + +__bpf_kfunc_start_defs(); + +__bpf_kfunc bool bpf_session_is_return(void) +{ + struct bpf_session_run_ctx *session_ctx; + + session_ctx = container_of(current->bpf_ctx, struct bpf_session_run_ctx, run_ctx); + return session_ctx->is_return; +} + +__bpf_kfunc __u64 *bpf_session_cookie(void) +{ + struct bpf_session_run_ctx *session_ctx; + + session_ctx = container_of(current->bpf_ctx, struct bpf_session_run_ctx, run_ctx); + return session_ctx->data; +} + +__bpf_kfunc_end_defs(); + +BTF_KFUNCS_START(kprobe_multi_kfunc_set_ids) +BTF_ID_FLAGS(func, bpf_session_is_return) +BTF_ID_FLAGS(func, bpf_session_cookie) +BTF_KFUNCS_END(kprobe_multi_kfunc_set_ids) + +static int bpf_kprobe_multi_filter(const struct bpf_prog *prog, u32 kfunc_id) +{ + if (!btf_id_set8_contains(&kprobe_multi_kfunc_set_ids, kfunc_id)) + return 0; + + if (!is_kprobe_session(prog) && !is_uprobe_session(prog)) + return -EACCES; + + return 0; +} + +static const struct btf_kfunc_id_set bpf_kprobe_multi_kfunc_set = { + .owner = THIS_MODULE, + .set = &kprobe_multi_kfunc_set_ids, + .filter = bpf_kprobe_multi_filter, +}; + +static int __init bpf_kprobe_multi_kfuncs_init(void) +{ + return register_btf_kfunc_id_set(BPF_PROG_TYPE_KPROBE, &bpf_kprobe_multi_kfunc_set); +} + +late_initcall(bpf_kprobe_multi_kfuncs_init); + +typedef int (*copy_fn_t)(void *dst, const void *src, u32 size, struct task_struct *tsk); + +/* + * The __always_inline is to make sure the compiler doesn't + * generate indirect calls into callbacks, which is expensive, + * on some kernel configurations. This allows compiler to put + * direct calls into all the specific callback implementations + * (copy_user_data_sleepable, copy_user_data_nofault, and so on) + */ +static __always_inline int __bpf_dynptr_copy_str(struct bpf_dynptr *dptr, u64 doff, u64 size, + const void *unsafe_src, + copy_fn_t str_copy_fn, + struct task_struct *tsk) +{ + struct bpf_dynptr_kern *dst; + u64 chunk_sz, off; + void *dst_slice; + int cnt, err; + char buf[256]; + + dst_slice = bpf_dynptr_slice_rdwr(dptr, doff, NULL, size); + if (likely(dst_slice)) + return str_copy_fn(dst_slice, unsafe_src, size, tsk); + + dst = (struct bpf_dynptr_kern *)dptr; + if (bpf_dynptr_check_off_len(dst, doff, size)) + return -E2BIG; + + for (off = 0; off < size; off += chunk_sz - 1) { + chunk_sz = min_t(u64, sizeof(buf), size - off); + /* Expect str_copy_fn to return count of copied bytes, including + * zero terminator. Next iteration increment off by chunk_sz - 1 to + * overwrite NUL. + */ + cnt = str_copy_fn(buf, unsafe_src + off, chunk_sz, tsk); + if (cnt < 0) + return cnt; + err = __bpf_dynptr_write(dst, doff + off, buf, cnt, 0); + if (err) + return err; + if (cnt < chunk_sz || chunk_sz == 1) /* we are done */ + return off + cnt; + } + return off; +} + +static __always_inline int __bpf_dynptr_copy(const struct bpf_dynptr *dptr, u64 doff, + u64 size, const void *unsafe_src, + copy_fn_t copy_fn, struct task_struct *tsk) +{ + struct bpf_dynptr_kern *dst; + void *dst_slice; + char buf[256]; + u64 off, chunk_sz; + int err; + + dst_slice = bpf_dynptr_slice_rdwr(dptr, doff, NULL, size); + if (likely(dst_slice)) + return copy_fn(dst_slice, unsafe_src, size, tsk); + + dst = (struct bpf_dynptr_kern *)dptr; + if (bpf_dynptr_check_off_len(dst, doff, size)) + return -E2BIG; + + for (off = 0; off < size; off += chunk_sz) { + chunk_sz = min_t(u64, sizeof(buf), size - off); + err = copy_fn(buf, unsafe_src + off, chunk_sz, tsk); + if (err) + return err; + err = __bpf_dynptr_write(dst, doff + off, buf, chunk_sz, 0); + if (err) + return err; + } + return 0; +} + +static __always_inline int copy_user_data_nofault(void *dst, const void *unsafe_src, + u32 size, struct task_struct *tsk) +{ + return copy_from_user_nofault(dst, (const void __user *)unsafe_src, size); +} + +static __always_inline int copy_user_data_sleepable(void *dst, const void *unsafe_src, + u32 size, struct task_struct *tsk) +{ + int ret; + + if (!tsk) { /* Read from the current task */ + ret = copy_from_user(dst, (const void __user *)unsafe_src, size); + if (ret) + return -EFAULT; + return 0; + } + + ret = access_process_vm(tsk, (unsigned long)unsafe_src, dst, size, 0); + if (ret != size) + return -EFAULT; + return 0; +} + +static __always_inline int copy_kernel_data_nofault(void *dst, const void *unsafe_src, + u32 size, struct task_struct *tsk) +{ + return copy_from_kernel_nofault(dst, unsafe_src, size); +} + +static __always_inline int copy_user_str_nofault(void *dst, const void *unsafe_src, + u32 size, struct task_struct *tsk) +{ + return strncpy_from_user_nofault(dst, (const void __user *)unsafe_src, size); +} + +static __always_inline int copy_user_str_sleepable(void *dst, const void *unsafe_src, + u32 size, struct task_struct *tsk) +{ + int ret; + + if (unlikely(size == 0)) + return 0; + + if (tsk) { + ret = copy_remote_vm_str(tsk, (unsigned long)unsafe_src, dst, size, 0); + } else { + ret = strncpy_from_user(dst, (const void __user *)unsafe_src, size - 1); + /* strncpy_from_user does not guarantee NUL termination */ + if (ret >= 0) + ((char *)dst)[ret] = '\0'; + } + + if (ret < 0) + return ret; + return ret + 1; +} + +static __always_inline int copy_kernel_str_nofault(void *dst, const void *unsafe_src, + u32 size, struct task_struct *tsk) +{ + return strncpy_from_kernel_nofault(dst, unsafe_src, size); +} + +__bpf_kfunc_start_defs(); + +__bpf_kfunc int bpf_send_signal_task(struct task_struct *task, int sig, enum pid_type type, + u64 value) +{ + if (type != PIDTYPE_PID && type != PIDTYPE_TGID) + return -EINVAL; + + return bpf_send_signal_common(sig, type, task, value); +} + +__bpf_kfunc int bpf_probe_read_user_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void __user *unsafe_ptr__ign) +{ + return __bpf_dynptr_copy(dptr, off, size, (const void *)unsafe_ptr__ign, + copy_user_data_nofault, NULL); +} + +__bpf_kfunc int bpf_probe_read_kernel_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void *unsafe_ptr__ign) +{ + return __bpf_dynptr_copy(dptr, off, size, unsafe_ptr__ign, + copy_kernel_data_nofault, NULL); +} + +__bpf_kfunc int bpf_probe_read_user_str_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void __user *unsafe_ptr__ign) +{ + return __bpf_dynptr_copy_str(dptr, off, size, (const void *)unsafe_ptr__ign, + copy_user_str_nofault, NULL); +} + +__bpf_kfunc int bpf_probe_read_kernel_str_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void *unsafe_ptr__ign) +{ + return __bpf_dynptr_copy_str(dptr, off, size, unsafe_ptr__ign, + copy_kernel_str_nofault, NULL); +} + +__bpf_kfunc int bpf_copy_from_user_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void __user *unsafe_ptr__ign) +{ + return __bpf_dynptr_copy(dptr, off, size, (const void *)unsafe_ptr__ign, + copy_user_data_sleepable, NULL); +} + +__bpf_kfunc int bpf_copy_from_user_str_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void __user *unsafe_ptr__ign) +{ + return __bpf_dynptr_copy_str(dptr, off, size, (const void *)unsafe_ptr__ign, + copy_user_str_sleepable, NULL); +} + +__bpf_kfunc int bpf_copy_from_user_task_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void __user *unsafe_ptr__ign, + struct task_struct *tsk) +{ + return __bpf_dynptr_copy(dptr, off, size, (const void *)unsafe_ptr__ign, + copy_user_data_sleepable, tsk); +} + +__bpf_kfunc int bpf_copy_from_user_task_str_dynptr(struct bpf_dynptr *dptr, u64 off, + u64 size, const void __user *unsafe_ptr__ign, + struct task_struct *tsk) +{ + return __bpf_dynptr_copy_str(dptr, off, size, (const void *)unsafe_ptr__ign, + copy_user_str_sleepable, tsk); +} + +__bpf_kfunc_end_defs(); |