diff options
Diffstat (limited to 'lib/vsprintf.c')
| -rw-r--r-- | lib/vsprintf.c | 119 |
1 files changed, 54 insertions, 65 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 3b8129dd374c..3c1853a9d1c0 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -49,10 +49,15 @@ #include <asm/page.h> /* for PAGE_SIZE */ #include <asm/byteorder.h> /* cpu_to_le16 */ +#include <asm/unaligned.h> #include <linux/string_helpers.h> #include "kstrtox.h" +/* Disable pointer hashing if requested */ +bool no_hash_pointers __ro_after_init; +EXPORT_SYMBOL_GPL(no_hash_pointers); + static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base) { const char *cp; @@ -745,59 +750,37 @@ static int __init debug_boot_weak_hash_enable(char *str) } early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable); -static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key); -static siphash_key_t ptr_key __read_mostly; +static DEFINE_STATIC_KEY_FALSE(filled_random_ptr_key); static void enable_ptr_key_workfn(struct work_struct *work) { - get_random_bytes(&ptr_key, sizeof(ptr_key)); - /* Needs to run from preemptible context */ - static_branch_disable(¬_filled_random_ptr_key); + static_branch_enable(&filled_random_ptr_key); } -static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn); - -static void fill_random_ptr_key(struct random_ready_callback *unused) +/* Maps a pointer to a 32 bit unique identifier. */ +static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out) { - /* This may be in an interrupt handler. */ - queue_work(system_unbound_wq, &enable_ptr_key_work); -} + static siphash_key_t ptr_key __read_mostly; + unsigned long hashval; -static struct random_ready_callback random_ready = { - .func = fill_random_ptr_key -}; + if (!static_branch_likely(&filled_random_ptr_key)) { + static bool filled = false; + static DEFINE_SPINLOCK(filling); + static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn); + unsigned long flags; -static int __init initialize_ptr_random(void) -{ - int key_size = sizeof(ptr_key); - int ret; - - /* Use hw RNG if available. */ - if (get_random_bytes_arch(&ptr_key, key_size) == key_size) { - static_branch_disable(¬_filled_random_ptr_key); - return 0; - } + if (!system_unbound_wq || !rng_is_initialized() || + !spin_trylock_irqsave(&filling, flags)) + return -EAGAIN; - ret = add_random_ready_callback(&random_ready); - if (!ret) { - return 0; - } else if (ret == -EALREADY) { - /* This is in preemptible context */ - enable_ptr_key_workfn(&enable_ptr_key_work); - return 0; + if (!filled) { + get_random_bytes(&ptr_key, sizeof(ptr_key)); + queue_work(system_unbound_wq, &enable_ptr_key_work); + filled = true; + } + spin_unlock_irqrestore(&filling, flags); } - return ret; -} -early_initcall(initialize_ptr_random); - -/* Maps a pointer to a 32 bit unique identifier. */ -static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out) -{ - unsigned long hashval; - - if (static_branch_unlikely(¬_filled_random_ptr_key)) - return -EAGAIN; #ifdef CONFIG_64BIT hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key); @@ -848,6 +831,19 @@ static char *ptr_to_id(char *buf, char *end, const void *ptr, return pointer_string(buf, end, (const void *)hashval, spec); } +static char *default_pointer(char *buf, char *end, const void *ptr, + struct printf_spec spec) +{ + /* + * default is to _not_ leak addresses, so hash before printing, + * unless no_hash_pointers is specified on the command line. + */ + if (unlikely(no_hash_pointers)) + return pointer_string(buf, end, ptr, spec); + + return ptr_to_id(buf, end, ptr, spec); +} + int kptr_restrict __read_mostly; static noinline_for_stack @@ -857,7 +853,7 @@ char *restricted_pointer(char *buf, char *end, const void *ptr, switch (kptr_restrict) { case 0: /* Handle as %p, hash and do _not_ leak addresses. */ - return ptr_to_id(buf, end, ptr, spec); + return default_pointer(buf, end, ptr, spec); case 1: { const struct cred *cred; @@ -1761,7 +1757,7 @@ char *fourcc_string(char *buf, char *end, const u32 *fourcc, char output[sizeof("0123 little-endian (0x01234567)")]; char *p = output; unsigned int i; - u32 val; + u32 orig, val; if (fmt[1] != 'c' || fmt[2] != 'c') return error_string(buf, end, "(%p4?)", spec); @@ -1769,21 +1765,23 @@ char *fourcc_string(char *buf, char *end, const u32 *fourcc, if (check_pointer(&buf, end, fourcc, spec)) return buf; - val = *fourcc & ~BIT(31); + orig = get_unaligned(fourcc); + val = orig & ~BIT(31); - for (i = 0; i < sizeof(*fourcc); i++) { + for (i = 0; i < sizeof(u32); i++) { unsigned char c = val >> (i * 8); /* Print non-control ASCII characters as-is, dot otherwise */ *p++ = isascii(c) && isprint(c) ? c : '.'; } - strcpy(p, *fourcc & BIT(31) ? " big-endian" : " little-endian"); + *p++ = ' '; + strcpy(p, orig & BIT(31) ? "big-endian" : "little-endian"); p += strlen(p); *p++ = ' '; *p++ = '('; - p = special_hex_number(p, output + sizeof(output) - 2, *fourcc, sizeof(u32)); + p = special_hex_number(p, output + sizeof(output) - 2, orig, sizeof(u32)); *p++ = ')'; *p = '\0'; @@ -2223,10 +2221,6 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, return widen_string(buf, buf - buf_start, end, spec); } -/* Disable pointer hashing if requested */ -bool no_hash_pointers __ro_after_init; -EXPORT_SYMBOL_GPL(no_hash_pointers); - int __init no_hash_pointers_enable(char *str) { if (no_hash_pointers) @@ -2455,7 +2449,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'e': /* %pe with a non-ERR_PTR gets treated as plain %p */ if (!IS_ERR(ptr)) - break; + return default_pointer(buf, end, ptr, spec); return err_ptr(buf, end, ptr, spec); case 'u': case 'k': @@ -2465,16 +2459,9 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, default: return error_string(buf, end, "(einval)", spec); } + default: + return default_pointer(buf, end, ptr, spec); } - - /* - * default is to _not_ leak addresses, so hash before printing, - * unless no_hash_pointers is specified on the command line. - */ - if (unlikely(no_hash_pointers)) - return pointer_string(buf, end, ptr, spec); - else - return ptr_to_id(buf, end, ptr, spec); } /* @@ -2895,13 +2882,15 @@ int vscnprintf(char *buf, size_t size, const char *fmt, va_list args) { int i; + if (unlikely(!size)) + return 0; + i = vsnprintf(buf, size, fmt, args); if (likely(i < size)) return i; - if (size != 0) - return size - 1; - return 0; + + return size - 1; } EXPORT_SYMBOL(vscnprintf); |