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random: fix error in entropy extraction 

Fix cast error in entropy extraction.
Add comments explaining the magic 16.
Remove extra confusing loop variable.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matt Mackall 2007-05-29 21:54:27 -05:00 committed by Linus Torvalds
parent f717221b4e
commit 602b6aeefe
1 changed files with 7 additions and 5 deletions
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12
drivers/char/random.c
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@ -760,7 +760,7 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
static void extract_buf(struct entropy_store *r, __u8 *out)
{
int i, x;
int i;
__u32 data[16], buf[5 + SHA_WORKSPACE_WORDS];
sha_init(buf);
@ -772,9 +772,11 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
* attempts to find previous ouputs), unless the hash
* function can be inverted.
*/
for (i = 0, x = 0; i < r->poolinfo->poolwords; i += 16, x+=2) {
sha_transform(buf, (__u8 *)r->pool+i, buf + 5);
add_entropy_words(r, &buf[x % 5], 1);
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);
/* feed back portion of the resulting hash */
add_entropy_words(r, &buf[i % 5], 1);
}
/*
@ -782,7 +784,7 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
* portion of the pool while mixing, and hash one
* final time.
*/
__add_entropy_words(r, &buf[x % 5], 1, data);
__add_entropy_words(r, &buf[i % 5], 1, data);
sha_transform(buf, (__u8 *)data, buf + 5);
/*