diff options
Diffstat (limited to 'kernel/cfi.c')
| -rw-r--r-- | kernel/cfi.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/kernel/cfi.c b/kernel/cfi.c index 08caad776717..4dad04ead06c 100644 --- a/kernel/cfi.c +++ b/kernel/cfi.c @@ -5,8 +5,12 @@ * Copyright (C) 2022 Google LLC */ +#include <linux/bpf.h> +#include <linux/cfi_types.h> #include <linux/cfi.h> +bool cfi_warn __ro_after_init = IS_ENABLED(CONFIG_CFI_PERMISSIVE); + enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr, unsigned long *target, u32 type) { @@ -17,7 +21,7 @@ enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr, pr_err("CFI failure at %pS (no target information)\n", (void *)addr); - if (IS_ENABLED(CONFIG_CFI_PERMISSIVE)) { + if (cfi_warn) { __warn(NULL, 0, (void *)addr, 0, regs, NULL); return BUG_TRAP_TYPE_WARN; } @@ -25,6 +29,19 @@ enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr, return BUG_TRAP_TYPE_BUG; } +/* + * Declare two non-existent functions with types that match bpf_func_t and + * bpf_callback_t pointers, and use DEFINE_CFI_TYPE to define type hash + * variables for each function type. The cfi_bpf_* variables are used by + * arch-specific BPF JIT implementations to ensure indirectly callable JIT + * code has matching CFI type hashes. + */ +extern typeof(*(bpf_func_t)0) __bpf_prog_runX; +DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX); + +extern typeof(*(bpf_callback_t)0) __bpf_callback_fn; +DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn); + #ifdef CONFIG_ARCH_USES_CFI_TRAPS static inline unsigned long trap_address(s32 *p) { @@ -71,14 +88,11 @@ static bool is_module_cfi_trap(unsigned long addr) struct module *mod; bool found = false; - rcu_read_lock_sched_notrace(); - + guard(rcu)(); mod = __module_address(addr); if (mod) found = is_trap(addr, mod->kcfi_traps, mod->kcfi_traps_end); - rcu_read_unlock_sched_notrace(); - return found; } #else /* CONFIG_MODULES */ |