Commit c458a331 authored by Bodo Möller's avatar Bodo Möller
Browse files

DSA verification should insist that r and s are in the allowed range.

parent 7953b8ff

CHANGES

+4 −0
Original line number Diff line number Diff line
@@ -11,6 +11,10 @@ 
         *) applies to 0.9.6a (/0.9.6b) and 0.9.7

         +) applies to 0.9.7 only



  *) In dsa_do_verify (crypto/dsa/dsa_ossl.c), verify that r and s are

     positive and less than q.

     [Bodo Moeller]



  +) Enhance the general user interface with mechanisms for inner control

     and with pssibilities to have yes/no kind of prompts.

     [Richard Levitte]

crypto/dsa/dsa_ossl.c

+11 −0
Original line number Diff line number Diff line
@@ -246,6 +246,17 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, 
	BN_init(&u2);

	BN_init(&t1);



	if (BN_is_zero(sig->r) || sig->r->neg || BN_ucmp(sig->r, dsa->q) >= 0)

		{

		ret = 0;

		goto err;

		}

	if (BN_is_zero(sig->s) || sig->s->neg || BN_ucmp(sig->s, dsa->q) >= 0)

		{

		ret = 0;

		goto err;

		}



	/* Calculate W = inv(S) mod Q

	 * save W in u2 */

	if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err;