Modifies P_hash() to hash the seed and label separately

Thereby not restricting the implementation of prf to MAX_SEED_SIZE
MAX_SEED_SIZE is not used anymore

Signed-off-by: Sahana Prasad <sahana@redhat.com>

diff --git a/lib/nettle/int/tls1-prf.c b/lib/nettle/int/tls1-prf.c
index 6763d76cc96aae92e67e27feaa8953d33117926a..19ca5d34dc8cbc59cd3326ec5d753bdb763b0633 100644 (file)
--- a/lib/nettle/int/tls1-prf.c
+++ b/lib/nettle/int/tls1-prf.c
@@ -48,6 +48,7 @@ P_hash( void *mac_ctx,
        nettle_hash_digest_func *digest,
        size_t digest_size,
        size_t seed_size, const uint8_t *seed,
+       size_t label_size, const char *label,
        size_t dst_length,
        uint8_t *dst)
 {
@@ -60,6 +61,7 @@ P_hash( void *mac_ctx,
 
        while(left > 0) {
                if (started == 0) { /* A(0) */
+                       update(mac_ctx, label_size, (const uint8_t *)label); /* hash label */
                        update(mac_ctx, seed_size, seed);
                        started = 1;
                } else {
@@ -68,6 +70,7 @@ P_hash( void *mac_ctx,
                digest(mac_ctx, digest_size, Atmp); /* store A(i) */
 
                update(mac_ctx, digest_size, Atmp); /* hash A(i) */
+               update(mac_ctx, label_size, (const uint8_t *)label); /* hash label */
                update(mac_ctx, seed_size, seed); /* hash seed */
 
                if (left < (ssize_t)digest_size)
@@ -88,19 +91,15 @@ tls10_prf(size_t secret_size, const uint8_t *secret,
          size_t seed_size, const uint8_t *seed,
          size_t length, uint8_t *dst)
 {
-       int l_s, cseed_size = seed_size + label_size;
+       int l_s;
        const uint8_t *s1, *s2;
        struct hmac_md5_ctx md5_ctx;
        struct hmac_sha1_ctx sha1_ctx;
        uint8_t o1[MAX_PRF_BYTES];
-       uint8_t cseed[MAX_SEED_SIZE];
 
-       if (cseed_size > MAX_SEED_SIZE || length > MAX_PRF_BYTES)
+       if (length > MAX_PRF_BYTES)
                return 0;
 
-       memcpy(cseed, label, label_size);
-       memcpy(&cseed[label_size], seed, seed_size);
-
        l_s = secret_size / 2;
        s1 = &secret[0];
        s2 = &secret[l_s];
@@ -113,14 +112,14 @@ tls10_prf(size_t secret_size, const uint8_t *secret,
        P_hash(&md5_ctx, (nettle_hash_update_func*)hmac_md5_update,
                (nettle_hash_digest_func*)hmac_md5_digest,
                MD5_DIGEST_SIZE,
-               cseed_size, cseed, length, o1);
+               seed_size, seed, label_size, label, length, o1);
 
        hmac_sha1_set_key(&sha1_ctx, l_s, s2);
 
        P_hash(&sha1_ctx, (nettle_hash_update_func*)hmac_sha1_update,
                (nettle_hash_digest_func*)hmac_sha1_digest,
                SHA1_DIGEST_SIZE,
-               cseed_size, cseed, length, dst);
+               seed_size, seed, label_size, label, length, dst);
 
        memxor(dst, o1, length);
 
@@ -153,17 +152,8 @@ tls12_prf(void *mac_ctx,
          size_t seed_size, const uint8_t *seed,
          size_t length, uint8_t *dst)
 {
-       size_t cseed_size = seed_size + label_size;
-       uint8_t cseed[MAX_SEED_SIZE];
-
-       if (cseed_size > MAX_SEED_SIZE)
-               return 0;
-
-       memcpy(cseed, label, label_size);
-       memcpy(&cseed[label_size], seed, seed_size);
-
        P_hash(mac_ctx, update, digest, digest_size,
-               cseed_size, cseed, length, dst);
+               seed_size, seed, label_size, label, length, dst);
 
        return 1;
 }

diff --git a/lib/nettle/int/tls1-prf.h b/lib/nettle/int/tls1-prf.h
index f5d9c827020cf061464d3a820c56d97e774d0634..e79d1c8639898d2fec1166159f55147ed8e6e543 100644 (file)
--- a/lib/nettle/int/tls1-prf.h
+++ b/lib/nettle/int/tls1-prf.h
@@ -25,7 +25,6 @@
 
 #include <nettle/nettle-meta.h>
 
-#define MAX_SEED_SIZE 200
 #define MAX_PRF_BYTES 200
 
 /* Namespace mangling */