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| author | Matt Mackall <mpm@selenic.com> | 2007-05-30 04:54:27 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-30 05:09:34 +0200 |
| commit | 602b6aeefe8932dd8bb15014e8fe6bb25d736361 (patch) | |
| tree | 7f6eb6fe0a492b91679785705389b043b7406986 /drivers/char/random.c | |
| parent | Merge branch 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/rolan... (diff) | |
| download | linux-602b6aeefe8932dd8bb15014e8fe6bb25d736361.tar.xz linux-602b6aeefe8932dd8bb15014e8fe6bb25d736361.zip | |
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>
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 46c1b97748b6..9705b439448a 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -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); /* |