random: improve variable naming, clear extract buffer
- split the SHA variables apart into hash and workspace
- rename data to extract
- wipe extract and workspace after hashing
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/random.c b/drivers/char/random.c
index a2329a1..d125a4b 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -765,9 +765,9 @@
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 @@
*/
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 @@
* 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,