[Pkg-telepathy-commits] [libnice] 111/265: stun: Use SHA1 iteration functions directly in HMAC calculation

[Simon McVittie]

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smcv pushed a commit to branch debian
in repository libnice.

commit 10cfd76d5b7e3e58e36542b64663a98789f5eb3f
Author: Philip Withnall <philip.withnall at collabora.co.uk>
Date:   Wed Jan 8 08:26:41 2014 +0000

    stun: Use SHA1 iteration functions directly in HMAC calculation
    
    Rather than using an intermediate method which takes a vector of
    buffers, just use the SHA1 iteration functions directly in the HMAC
    calculations. This eliminates several cases where the vector of buffers
    was of fixed length, and it was actually taking more code to set up and
    pass the vector than it would have to call the iteration functions
    directly.
---
 stun/sha1.c | 79 ++++++++++++++++++++-----------------------------------------
 1 file changed, 26 insertions(+), 53 deletions(-)

diff --git a/stun/sha1.c b/stun/sha1.c
index 2bedfca..6c95d27 100644
--- a/stun/sha1.c
+++ b/stun/sha1.c
@@ -270,7 +270,12 @@ void HMACInit(HMAC_CTX* context, const uint8_t *key, size_t key_len)
 
   /* if key is longer than 64 bytes reset it to key = SHA1(key) */
   if (key_len > 64) {
-    sha1_vector(1, &key, &key_len, tk);
+    SHA1_CTX sha1_ctx;
+
+    SHA1Init(&sha1_ctx);
+    SHA1Update(&sha1_ctx, key, key_len);
+    SHA1Final(tk, &sha1_ctx);
+
     key = tk;
     key_len = 20;
   }
@@ -301,9 +306,8 @@ void HMACFinal(unsigned char digest[20], HMAC_CTX *context)
 
   unsigned char opad[64]; /* padding - key XORd with opad */
   unsigned char sha1_digest[SHA1_MAC_LEN];
-  const uint8_t *_addr[2];
-  size_t _len[2];
   size_t i;
+  SHA1_CTX outer_sha1_ctx;
 
   SHA1Final (sha1_digest, &context->context);
 
@@ -315,11 +319,10 @@ void HMACFinal(unsigned char digest[20], HMAC_CTX *context)
     opad[i] ^= 0x5c;
 
   /* perform outer SHA1 */
-  _addr[0] = opad;
-  _len[0] = 64;
-  _addr[1] = sha1_digest;
-  _len[1] = SHA1_MAC_LEN;
-  sha1_vector(2, _addr, _len, digest);
+  SHA1Init(&outer_sha1_ctx);
+  SHA1Update(&outer_sha1_ctx, opad, 64);
+  SHA1Update(&outer_sha1_ctx, sha1_digest, SHA1_MAC_LEN);
+  SHA1Final(digest, &outer_sha1_ctx);
 }
 
 
@@ -339,20 +342,15 @@ void hmac_sha1_vector(const uint8_t *key, size_t key_len, size_t num_elem,
 {
   unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
   unsigned char tk[20];
-  const uint8_t *_addr[6];
-  size_t _len[6], i;
-
-  if (num_elem > 5) {
-    /*
-     * Fixed limit on the number of fragments to avoid having to
-     * allocate memory (which could fail).
-     */
-    return;
-  }
+  size_t i;
+  SHA1_CTX sha1_ctx;
 
   /* if key is longer than 64 bytes reset it to key = SHA1(key) */
   if (key_len > 64) {
-    sha1_vector(1, &key, &key_len, tk);
+    SHA1Init(&sha1_ctx);
+    SHA1Update(&sha1_ctx, key, key_len);
+    SHA1Final(tk, &sha1_ctx);
+
     key = tk;
     key_len = 20;
   }
@@ -374,13 +372,11 @@ void hmac_sha1_vector(const uint8_t *key, size_t key_len, size_t num_elem,
     k_pad[i] ^= 0x36;
 
   /* perform inner SHA1 */
-  _addr[0] = k_pad;
-  _len[0] = 64;
-  for (i = 0; i < num_elem; i++) {
-    _addr[i + 1] = addr[i];
-    _len[i + 1] = len[i];
-  }
-  sha1_vector(1 + num_elem, _addr, _len, mac);
+  SHA1Init(&sha1_ctx);
+  SHA1Update(&sha1_ctx, k_pad, 64);
+  for (i = 0; i < num_elem; i++)
+    SHA1Update(&sha1_ctx, addr[i], len[i]);
+  SHA1Final(mac, &sha1_ctx);
 
   memset(k_pad, 0, sizeof(k_pad));
   memcpy(k_pad, key, key_len);
@@ -389,11 +385,10 @@ void hmac_sha1_vector(const uint8_t *key, size_t key_len, size_t num_elem,
     k_pad[i] ^= 0x5c;
 
   /* perform outer SHA1 */
-  _addr[0] = k_pad;
-  _len[0] = 64;
-  _addr[1] = mac;
-  _len[1] = SHA1_MAC_LEN;
-  sha1_vector(2, _addr, _len, mac);
+  SHA1Init(&sha1_ctx);
+  SHA1Update(&sha1_ctx, k_pad, 64);
+  SHA1Update(&sha1_ctx, mac, SHA1_MAC_LEN);
+  SHA1Final(mac, &sha1_ctx);
 }
 
 
@@ -460,25 +455,3 @@ void sha1_prf(const uint8_t *key, size_t key_len, const char *label,
     counter++;
   }
 }
-
-/**
- * sha1_vector:
- * @num_elem: Number of elements in the data vector
- * @addr: Pointers to the data areas
- * @len: Lengths of the data blocks
- * @mac: Buffer for the hash
- *
- * SHA-1 hash for data vector
- */
-void sha1_vector(size_t num_elem, const uint8_t *addr[], const size_t *len,
-    uint8_t *mac)
-{
-  SHA1_CTX ctx;
-  size_t i;
-
-  SHA1Init(&ctx);
-  for (i = 0; i < num_elem; i++)
-    SHA1Update(&ctx, addr[i], len[i]);
-  SHA1Final(mac, &ctx);
-}
-

-- 
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