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Commit 602b6aee authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds
Browse files

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: default avatarMatt Mackall <mpm@selenic.com>
Acked-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f717221b

drivers/char/random.c

+7 −5
Original line number Original line Diff line number Diff line
@@ -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)

static void extract_buf(struct entropy_store *r, __u8 *out)

{

{

	int i, x;

	int i;

	__u32 data[16], buf[5 + SHA_WORKSPACE_WORDS];

	__u32 data[16], buf[5 + SHA_WORKSPACE_WORDS];





	sha_init(buf);

	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

	 * attempts to find previous ouputs), unless the hash

	 * function can be inverted.

	 * function can be inverted.

	 */

	 */

	for (i = 0, x = 0; i < r->poolinfo->poolwords; i += 16, x+=2) {

	for (i = 0; i < r->poolinfo->poolwords; i += 16) {

		sha_transform(buf, (__u8 *)r->pool+i, buf + 5);

		/* hash blocks of 16 words = 512 bits */

		add_entropy_words(r, &buf[x % 5], 1);

		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

	 * portion of the pool while mixing, and hash one

	 * final time.

	 * 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);

	sha_transform(buf, (__u8 *)data, buf + 5);





	/*

	/*