From: Matt Mackall - split the SHA variables apart into hash and workspace - rename data to extract - wipe extract and workspace after hashing Signed-off-by: Matt Mackall Cc: Theodore Ts'o Signed-off-by: Andrew Morton --- drivers/char/random.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff -puN drivers/char/random.c~random-improve-variable-naming-clear-extract-buffer drivers/char/random.c --- a/drivers/char/random.c~random-improve-variable-naming-clear-extract-buffer +++ a/drivers/char/random.c @@ -765,9 +765,9 @@ static size_t account(struct entropy_sto static void extract_buf(struct entropy_store *r, __u8 *out) { int i; - __u32 data[16], buf[5 + SHA_WORKSPACE_WORDS]; + __u32 extract[16], hash[5], workspace[SHA_WORKSPACE_WORDS]; - sha_init(buf); + sha_init(hash); /* * As we hash the pool, we mix intermediate values of * the hash back into the pool. This eliminates @@ -778,9 +778,9 @@ static void extract_buf(struct entropy_s */ for (i = 0; i < r->poolinfo->poolwords; i += 16) { /* hash blocks of 16 words = 512 bits */ - sha_transform(buf, (__u8 *)(r->pool + i), buf + 5); + sha_transform(hash, (__u8 *)(r->pool + i), workspace); /* feed back portion of the resulting hash */ - add_entropy_words(r, &buf[i % 5], 1); + add_entropy_words(r, &hash[i % 5], 1); } /* @@ -788,19 +788,21 @@ static void extract_buf(struct entropy_s * portion of the pool while mixing, and hash one * final time. */ - __add_entropy_words(r, &buf[i % 5], 1, data); - sha_transform(buf, (__u8 *)data, buf + 5); + __add_entropy_words(r, &hash[i % 5], 1, extract); + sha_transform(hash, (__u8 *)extract, workspace); + memset(extract, 0, sizeof(extract)); + memset(workspace, 0, sizeof(workspace)); /* * In case the hash function has some recognizable * output pattern, we fold it in half. */ - buf[0] ^= buf[3]; - buf[1] ^= buf[4]; - buf[2] ^= rol32(buf[2], 16); - memcpy(out, buf, EXTRACT_SIZE); - memset(buf, 0, sizeof(buf)); + hash[0] ^= hash[3]; + hash[1] ^= hash[4]; + hash[2] ^= rol32(hash[2], 16); + memcpy(out, hash, EXTRACT_SIZE); + memset(hash, 0, sizeof(hash)); } static ssize_t extract_entropy(struct entropy_store *r, void *buf, _