Check SRP parameters early.
[openssl.git] / ssl / tls_srp.c
index c363fc3..1aa90c5 100644 (file)
@@ -410,16 +410,45 @@ err:
        return ret;
        }
 
-int SRP_Calc_A_param(SSL *s)
+int srp_verify_server_param(SSL *s, int *al)
        {
-       unsigned char rnd[SSL_MAX_MASTER_KEY_LENGTH];
+       SRP_CTX *srp = &s->srp_ctx;
+       /* Sanity check parameters: we can quickly check B % N == 0
+        * by checking B != 0 since B < N
+        */
+       if (BN_ucmp(srp->g, srp->N) >=0 || BN_ucmp(srp->B, srp->N) >= 0
+               || BN_is_zero(srp->B))
+               {
+               *al = SSL3_AD_ILLEGAL_PARAMETER;
+               return 0;
+               }
 
-       if (BN_num_bits(s->srp_ctx.N) < s->srp_ctx.strength)
+       if (BN_num_bits(srp->N) < srp->strength)
+               {
+               *al = TLS1_AD_INSUFFICIENT_SECURITY;
                return 0;
+               }
 
-       if (s->srp_ctx.SRP_verify_param_callback ==NULL && 
-               !SRP_check_known_gN_param(s->srp_ctx.g,s->srp_ctx.N))
+       if (srp->SRP_verify_param_callback)
+               {
+               if (srp->SRP_verify_param_callback(s, srp->SRP_cb_arg) <= 0)
+                       {
+                       *al = TLS1_AD_INSUFFICIENT_SECURITY;
+                       return 0;
+                       }
+               }
+       else if(!SRP_check_known_gN_param(srp->g, srp->N))
+               {
+               *al = TLS1_AD_INSUFFICIENT_SECURITY;
                return 0;
+               }
+
+       return 1;
+       }
+
+int SRP_Calc_A_param(SSL *s)
+       {
+       unsigned char rnd[SSL_MAX_MASTER_KEY_LENGTH];
 
        if (RAND_bytes(rnd, sizeof(rnd)) <= 0)
                return 0;
@@ -429,10 +458,6 @@ int SRP_Calc_A_param(SSL *s)
        if (!(s->srp_ctx.A = SRP_Calc_A(s->srp_ctx.a,s->srp_ctx.N,s->srp_ctx.g)))
                return 0;
 
-       /* We can have a callback to verify SRP param!! */
-       if (s->srp_ctx.SRP_verify_param_callback !=NULL) 
-               return s->srp_ctx.SRP_verify_param_callback(s,s->srp_ctx.SRP_cb_arg);
-
        return 1;
        }