diff options
| -rw-r--r-- | drivers/char/random.c | 10 | ||||
| -rw-r--r-- | include/linux/string.h | 2 | ||||
| -rw-r--r-- | lib/string.c | 16 |
3 files changed, 23 insertions, 5 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index c244f0ed61d6..edf45ae694a1 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -954,8 +954,8 @@ static void extract_buf(struct entropy_store *r, __u8 *out) * pool while mixing, and hash one final time. */ sha_transform(hash.w, extract, workspace); - memset(extract, 0, sizeof(extract)); - memset(workspace, 0, sizeof(workspace)); + memzero_explicit(extract, sizeof(extract)); + memzero_explicit(workspace, sizeof(workspace)); /* * In case the hash function has some recognizable output @@ -978,7 +978,7 @@ static void extract_buf(struct entropy_store *r, __u8 *out) } memcpy(out, &hash, EXTRACT_SIZE); - memset(&hash, 0, sizeof(hash)); + memzero_explicit(&hash, sizeof(hash)); } static ssize_t extract_entropy(struct entropy_store *r, void *buf, @@ -1010,7 +1010,7 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf, } /* Wipe data just returned from memory */ - memset(tmp, 0, sizeof(tmp)); + memzero_explicit(tmp, sizeof(tmp)); return ret; } @@ -1047,7 +1047,7 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf, } /* Wipe data just returned from memory */ - memset(tmp, 0, sizeof(tmp)); + memzero_explicit(tmp, sizeof(tmp)); return ret; } diff --git a/include/linux/string.h b/include/linux/string.h index e033564f10ba..8515a4dbc1c9 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -144,5 +144,7 @@ static inline bool strstarts(const char *str, const char *prefix) { return strncmp(str, prefix, strlen(prefix)) == 0; } + +void memzero_explicit(void *s, size_t count); #endif #endif /* _LINUX_STRING_H_ */ diff --git a/lib/string.c b/lib/string.c index dc4a86341f91..40136f6f8ea3 100644 --- a/lib/string.c +++ b/lib/string.c @@ -583,6 +583,22 @@ void *memset(void *s, int c, size_t count) EXPORT_SYMBOL(memset); #endif +/** + * memzero_explicit - Fill a region of memory (e.g. sensitive + * keying data) with 0s. + * @s: Pointer to the start of the area. + * @count: The size of the area. + * + * memzero_explicit() doesn't need an arch-specific version as + * it just invokes the one of memset() implicitly. + */ +void memzero_explicit(void *s, size_t count) +{ + memset(s, 0, count); + OPTIMIZER_HIDE_VAR(s); +} +EXPORT_SYMBOL(memzero_explicit); + #ifndef __HAVE_ARCH_MEMCPY /** * memcpy - Copy one area of memory to another |