[openssl-commits] [openssl] OpenSSL_1_0_2-stable update

[Matt Caswell]

The branch OpenSSL_1_0_2-stable has been updated
       via  68f11e82d9c19e104f34bd5186decc98566738ca (commit)
      from  15d81749322c3498027105f8ee44e8c25479d475 (commit)


- Log -----------------------------------------------------------------
commit 68f11e82d9c19e104f34bd5186decc98566738ca
Author: Matt Caswell <matt at openssl.org>
Date:   Thu Sep 8 14:32:27 2016 +0100

    Add some sanity checks around usage of t_fromb64()
    
    The internal SRP function t_fromb64() converts from base64 to binary. It
    does not validate that the size of the destination is sufficiently large -
    that is up to the callers. In some places there was such a check, but not
    in others.
    
    Add an argument to t_fromb64() to provide the size of the destination
    buffer and validate that we don't write too much data. Also add some sanity
    checks to the callers where appropriate.
    
    With thanks to Shi Lei for reporting this issue.
    
    Reviewed-by: Richard Levitte <levitte at openssl.org>
    (cherry picked from commit 73f0df8331910d6726d45ecaab12bd93cc48b4e2)

-----------------------------------------------------------------------

Summary of changes:
 crypto/srp/srp_vfy.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/crypto/srp/srp_vfy.c b/crypto/srp/srp_vfy.c
index af557a1..a8ec52a 100644
--- a/crypto/srp/srp_vfy.c
+++ b/crypto/srp/srp_vfy.c
@@ -80,7 +80,7 @@ static char b64table[] =
 /*
  * Convert a base64 string into raw byte array representation.
  */
-static int t_fromb64(unsigned char *a, const char *src)
+static int t_fromb64(unsigned char *a, size_t alen, const char *src)
 {
     char *loc;
     int i, j;
@@ -89,6 +89,9 @@ static int t_fromb64(unsigned char *a, const char *src)
     while (*src && (*src == ' ' || *src == '\t' || *src == '\n'))
         ++src;
     size = strlen(src);
+    if (alen > INT_MAX || size > (int)alen)
+        return -1;
+
     i = 0;
     while (i < size) {
         loc = strchr(b64table, src[i]);
@@ -231,13 +234,25 @@ static int SRP_user_pwd_set_sv(SRP_user_pwd *vinfo, const char *s,
     unsigned char tmp[MAX_LEN];
     int len;
 
-    if (strlen(s) > MAX_LEN || strlen(v) > MAX_LEN)
+    vinfo->v = NULL;
+    vinfo->s = NULL;
+
+    len = t_fromb64(tmp, sizeof(tmp), v);
+    if (len < 0)
         return 0;
-    len = t_fromb64(tmp, v);
     if (NULL == (vinfo->v = BN_bin2bn(tmp, len, NULL)))
         return 0;
-    len = t_fromb64(tmp, s);
-    return ((vinfo->s = BN_bin2bn(tmp, len, NULL)) != NULL);
+    len = t_fromb64(tmp, sizeof(tmp), s);
+    if (len < 0)
+        goto err;
+    vinfo->s = BN_bin2bn(tmp, len, NULL);
+    if (vinfo->s == NULL)
+        goto err;
+    return 1;
+ err:
+    BN_free(vinfo->v);
+    vinfo->v = NULL;
+    return 0;
 }
 
 static int SRP_user_pwd_set_sv_BN(SRP_user_pwd *vinfo, BIGNUM *s, BIGNUM *v)
@@ -307,10 +322,13 @@ static SRP_gN_cache *SRP_gN_new_init(const char *ch)
     if (newgN == NULL)
         return NULL;
 
+    len = t_fromb64(tmp, sizeof(tmp), ch);
+    if (len < 0)
+        goto err;
+
     if ((newgN->b64_bn = BUF_strdup(ch)) == NULL)
         goto err;
 
-    len = t_fromb64(tmp, ch);
     if ((newgN->bn = BN_bin2bn(tmp, len, NULL)))
         return newgN;
 
@@ -580,10 +598,10 @@ char *SRP_create_verifier(const char *user, const char *pass, char **salt,
         goto err;
 
     if (N) {
-        if (!(len = t_fromb64(tmp, N)))
+        if (!(len = t_fromb64(tmp, sizeof(tmp), N)))
             goto err;
         N_bn = BN_bin2bn(tmp, len, NULL);
-        if (!(len = t_fromb64(tmp, g)))
+        if (!(len = t_fromb64(tmp, sizeof(tmp), g)))
             goto err;
         g_bn = BN_bin2bn(tmp, len, NULL);
         defgNid = "*";
@@ -602,7 +620,7 @@ char *SRP_create_verifier(const char *user, const char *pass, char **salt,
 
         s = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
     } else {
-        if (!(len = t_fromb64(tmp2, *salt)))
+        if (!(len = t_fromb64(tmp2, sizeof(tmp2), *salt)))
             goto err;
         s = BN_bin2bn(tmp2, len, NULL);
     }