From: Matt Mackall <mpm@selenic.com>
Clean up SHA hash function for moving to lib/
Do proper endian conversion
Provide sha_init function
Add kerneldoc
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/char/random.c | 76 +++++++++++++++++++-----------------------
1 files changed, 36 insertions(+), 40 deletions(-)
diff -puN drivers/char/random.c~random-pt4-cleanup-sha-interface drivers/char/random.c
--- 25/drivers/char/random.c~random-pt4-cleanup-sha-interface 2005-02-22 18:17:07.000000000 -0800
+++ 25-akpm/drivers/char/random.c 2005-02-22 18:17:07.000000000 -0800
@@ -671,29 +671,6 @@ void add_disk_randomness(struct gendisk
EXPORT_SYMBOL(add_disk_randomness);
-/******************************************************************
- *
- * Hash function definition
- *
- *******************************************************************/
-
-/*
- * This chunk of code defines a function
- * void sha_transform(__u32 digest[HASH_BUFFER_SIZE + HASH_EXTRA_SIZE],
- * __u32 const data[16])
- *
- * The function hashes the input data to produce a digest in the first
- * HASH_BUFFER_SIZE words of the digest[] array, and uses HASH_EXTRA_SIZE
- * more words for internal purposes. (This buffer is exported so the
- * caller can wipe it once rather than this code doing it each call,
- * and tacking it onto the end of the digest[] array is the quick and
- * dirty way of doing it.)
- *
- * For /dev/random purposes, the length of the data being hashed is
- * fixed in length, so appending a bit count in the usual way is not
- * cryptographically necessary.
- */
-
#define HASH_BUFFER_SIZE 5
#define EXTRACT_SIZE 10
#define HASH_EXTRA_SIZE 80
@@ -717,20 +694,32 @@ EXPORT_SYMBOL(add_disk_randomness);
#define K3 0x8F1BBCDCL /* Rounds 40-59: sqrt(5) * 2^30 */
#define K4 0xCA62C1D6L /* Rounds 60-79: sqrt(10) * 2^30 */
-static void sha_transform(__u32 digest[85], __u32 const data[16])
+/*
+ * sha_transform: single block SHA1 transform
+ *
+ * @digest: 160 bit digest to update
+ * @data: 512 bytes of data to hash
+ * @W: 80 words of workspace
+ *
+ * This function generates a SHA1 digest for a single. Be warned, it
+ * does not handle padding and message digest, do not confuse it with
+ * the full FIPS 180-1 digest algorithm for variable length messages.
+ */
+static void sha_transform(__u32 digest[5], const char *data, __u32 W[80])
{
- __u32 A, B, C, D, E; /* Local vars */
+ __u32 A, B, C, D, E;
__u32 TEMP;
int i;
-#define W (digest + HASH_BUFFER_SIZE) /* Expanded data array */
+ memset(W, 0, sizeof(W));
+ for (i = 0; i < 16; i++)
+ W[i] = be32_to_cpu(((const __u32 *)data)[i]);
/*
* Do the preliminary expansion of 16 to 80 words. Doing it
* out-of-line line this is faster than doing it in-line on
* register-starved machines like the x86, and not really any
* slower on real processors.
*/
- memcpy(W, data, 16*sizeof(__u32));
for (i = 0; i < 64; i++) {
TEMP = W[i] ^ W[i+2] ^ W[i+8] ^ W[i+13];
W[i+16] = rol32(TEMP, 1);
@@ -768,7 +757,6 @@ static void sha_transform(__u32 digest[8
digest[4] += E;
/* W is wiped by the caller */
-#undef W
}
#undef f1
@@ -780,6 +768,20 @@ static void sha_transform(__u32 digest[8
#undef K3
#undef K4
+/*
+ * sha_init: initialize the vectors for a SHA1 digest
+ *
+ * @buf: vector to initialize
+ */
+static void sha_init(__u32 *buf)
+{
+ buf[0] = 0x67452301;
+ buf[1] = 0xefcdab89;
+ buf[2] = 0x98badcfe;
+ buf[3] = 0x10325476;
+ buf[4] = 0xc3d2e1f0;
+}
+
/*********************************************************************
*
* Entropy extraction routines
@@ -870,13 +872,7 @@ static void extract_buf(struct entropy_s
int i, x;
__u32 data[16], buf[85];
- /* Hash the pool to get the output */
- buf[0] = 0x67452301;
- buf[1] = 0xefcdab89;
- buf[2] = 0x98badcfe;
- buf[3] = 0x10325476;
- buf[4] = 0xc3d2e1f0;
-
+ sha_init(buf);
/*
* As we hash the pool, we mix intermediate values of
* the hash back into the pool. This eliminates
@@ -886,7 +882,7 @@ static void extract_buf(struct entropy_s
* function can be inverted.
*/
for (i = 0, x = 0; i < r->poolinfo->poolwords; i += 16, x+=2) {
- sha_transform(buf, r->pool+i);
+ sha_transform(buf, (__u8 *)r->pool+i, buf + 5);
add_entropy_words(r, &buf[x % 5], 1);
}
@@ -896,7 +892,7 @@ static void extract_buf(struct entropy_s
* final time.
*/
__add_entropy_words(r, &buf[x % 5], 1, data);
- sha_transform(buf, data);
+ sha_transform(buf, (__u8 *)data, buf + 5);
/*
* In case the hash function has some recognizable
@@ -1774,7 +1770,7 @@ __u32 secure_tcp_syn_cookie(__u32 saddr,
tmp[0]=saddr;
tmp[1]=daddr;
tmp[2]=(sport << 16) + dport;
- sha_transform(tmp+16, tmp);
+ sha_transform(tmp+16, (__u8 *)tmp, tmp + 16 + 5);
seq = tmp[17] + sseq + (count << COOKIEBITS);
memcpy(tmp + 3, syncookie_secret[1], sizeof(syncookie_secret[1]));
@@ -1782,7 +1778,7 @@ __u32 secure_tcp_syn_cookie(__u32 saddr,
tmp[1]=daddr;
tmp[2]=(sport << 16) + dport;
tmp[3] = count; /* minute counter */
- sha_transform(tmp + 16, tmp);
+ sha_transform(tmp + 16, (__u8 *)tmp, tmp + 16 + 5);
/* Add in the second hash and the data */
return seq + ((tmp[17] + data) & COOKIEMASK);
@@ -1811,7 +1807,7 @@ __u32 check_tcp_syn_cookie(__u32 cookie,
tmp[0]=saddr;
tmp[1]=daddr;
tmp[2]=(sport << 16) + dport;
- sha_transform(tmp + 16, tmp);
+ sha_transform(tmp + 16, (__u8 *)tmp, tmp + 16 + 5);
cookie -= tmp[17] + sseq;
/* Cookie is now reduced to (count * 2^24) ^ (hash % 2^24) */
_