Properly check EVP_VerifyFinal() and similar return values

(CVE-2008-5077).
Submitted by: Ben Laurie, Bodo Moeller, Google Security Team

CHANGES

@@ -4,6 +4,10 @@
 
  Changes between 0.9.8i and 0.9.8j  [xx XXX xxxx]
 
+  *) Properly check EVP_VerifyFinal() and similar return values
+     (CVE-2008-5077).
+     [Ben Laurie, Bodo Moeller, Google Security Team]
+
   *) Enable TLS extensions by default.
      [Ben Laurie]
 

apps/speed.c

@@ -2132,7 +2132,7 @@ int MAIN(int argc, char **argv)
 				{
 				ret=RSA_verify(NID_md5_sha1, buf,36, buf2,
 					rsa_num, rsa_key[j]);
-				if (ret == 0)
+				if (ret <= 0)
 					{
 					BIO_printf(bio_err,
 						"RSA verify failure\n");

apps/spkac.c

@@ -285,7 +285,7 @@ bad:
 	pkey = NETSCAPE_SPKI_get_pubkey(spki);
 	if(verify) {
 		i = NETSCAPE_SPKI_verify(spki, pkey);
-		if(i) BIO_printf(bio_err, "Signature OK\n");
+		if (i > 0) BIO_printf(bio_err, "Signature OK\n");
 		else {
 			BIO_printf(bio_err, "Signature Failure\n");
 			ERR_print_errors(bio_err);

apps/verify.c

@@ -266,7 +266,7 @@ static int check(X509_STORE *ctx, char *file, STACK_OF(X509) *uchain, STACK_OF(X
 
 	ret=0;
 end:
-	if (i)
+	if (i > 0)
 		{
 		fprintf(stdout,"OK\n");
 		ret=1;
@@ -367,4 +367,3 @@ static int MS_CALLBACK cb(int ok, X509_STORE_CTX *ctx)
 		ERR_clear_error();
 	return(ok);
 	}
-

apps/x509.c

@@ -1151,7 +1151,7 @@ static int x509_certify(X509_STORE *ctx, char *CAfile, const EVP_MD *digest,
 	/* NOTE: this certificate can/should be self signed, unless it was
 	 * a certificate request in which case it is not. */
 	X509_STORE_CTX_set_cert(&xsc,x);
-	if (!reqfile && !X509_verify_cert(&xsc))
+	if (!reqfile && X509_verify_cert(&xsc) <= 0)
 		goto end;
 
 	if (!X509_check_private_key(xca,pkey))

crypto/cms/cms_sd.c

@@ -830,7 +830,7 @@ int CMS_SignerInfo_verify(CMS_SignerInfo *si)
 	cms_fixup_mctx(&mctx, si->pkey);
 	r = EVP_VerifyFinal(&mctx,
 			si->signature->data, si->signature->length, si->pkey);
-	if (!r)
+	if (r <= 0)
 		CMSerr(CMS_F_CMS_SIGNERINFO_VERIFY, CMS_R_VERIFICATION_FAILURE);
 	err:
 	EVP_MD_CTX_cleanup(&mctx);

ssl/s2_clnt.c

@@ -1044,7 +1044,7 @@ int ssl2_set_certificate(SSL *s, int type, int len, const unsigned char *data)
 
 	i=ssl_verify_cert_chain(s,sk);
 		
-	if ((s->verify_mode != SSL_VERIFY_NONE) && (!i))
+	if ((s->verify_mode != SSL_VERIFY_NONE) && (i <= 0))
 		{
 		SSLerr(SSL_F_SSL2_SET_CERTIFICATE,SSL_R_CERTIFICATE_VERIFY_FAILED);
 		goto err;

ssl/s2_srvr.c

@@ -1054,7 +1054,7 @@ static int request_certificate(SSL *s)
 
 	i=ssl_verify_cert_chain(s,sk);
 
-	if (i)	/* we like the packet, now check the chksum */
+	if (i > 0)	/* we like the packet, now check the chksum */
 		{
 		EVP_MD_CTX ctx;
 		EVP_PKEY *pkey=NULL;
@@ -1083,7 +1083,7 @@ static int request_certificate(SSL *s)
 		EVP_PKEY_free(pkey);
 		EVP_MD_CTX_cleanup(&ctx);
 
-		if (i) 
+		if (i > 0)
 			{
 			if (s->session->peer != NULL)
 				X509_free(s->session->peer);

ssl/s3_clnt.c

@@ -972,7 +972,7 @@ int ssl3_get_server_certificate(SSL *s)
 		}
 
 	i=ssl_verify_cert_chain(s,sk);
-	if ((s->verify_mode != SSL_VERIFY_NONE) && (!i)
+	if ((s->verify_mode != SSL_VERIFY_NONE) && (i <= 0)
 #ifndef OPENSSL_NO_KRB5
 	        && (s->s3->tmp.new_cipher->algorithms & (SSL_MKEY_MASK|SSL_AUTH_MASK))
 	        != (SSL_aKRB5|SSL_kKRB5)
@@ -1459,7 +1459,7 @@ int ssl3_get_key_exchange(SSL *s)
 			EVP_VerifyUpdate(&md_ctx,&(s->s3->client_random[0]),SSL3_RANDOM_SIZE);
 			EVP_VerifyUpdate(&md_ctx,&(s->s3->server_random[0]),SSL3_RANDOM_SIZE);
 			EVP_VerifyUpdate(&md_ctx,param,param_len);
-			if (!EVP_VerifyFinal(&md_ctx,p,(int)n,pkey))
+			if (EVP_VerifyFinal(&md_ctx,p,(int)n,pkey) <= 0)
 				{
 				/* bad signature */
 				al=SSL_AD_DECRYPT_ERROR;
@@ -1477,7 +1477,7 @@ int ssl3_get_key_exchange(SSL *s)
 			EVP_VerifyUpdate(&md_ctx,&(s->s3->client_random[0]),SSL3_RANDOM_SIZE);
 			EVP_VerifyUpdate(&md_ctx,&(s->s3->server_random[0]),SSL3_RANDOM_SIZE);
 			EVP_VerifyUpdate(&md_ctx,param,param_len);
-			if (!EVP_VerifyFinal(&md_ctx,p,(int)n,pkey))
+			if (EVP_VerifyFinal(&md_ctx,p,(int)n,pkey) <= 0)
 				{
 				/* bad signature */
 				al=SSL_AD_DECRYPT_ERROR;

ssl/s3_srvr.c

@@ -2566,7 +2566,7 @@ int ssl3_get_client_certificate(SSL *s)
 	else
 		{
 		i=ssl_verify_cert_chain(s,sk);
-		if (!i)
+		if (i <= 0)
 			{
 			al=ssl_verify_alarm_type(s->verify_result);
 			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_NO_CERTIFICATE_RETURNED);

ssl/ssltest.c

@@ -2093,7 +2093,7 @@ static int MS_CALLBACK app_verify_callback(X509_STORE_CTX *ctx, void *arg)
 
 	if (cb_arg->proxy_auth)
 		{
-		if (ok)
+		if (ok > 0)
 			{
 			const char *cond_end = NULL;