Merge branch 'research/Test-on-Android-5-#6543' into develop

1 files changed, 68 insertions, 55 deletions

diff --git a/app/openssl/ssl/s3_srvr.c b/app/openssl/ssl/s3_srvr.c
index f83c9366..a42fc9e3 100644
--- a/app/openssl/ssl/s3_srvr.c
+++ b/app/openssl/ssl/s3_srvr.c
@@ -154,6 +154,7 @@
 #include <stdio.h>
 #include "ssl_locl.h"
 #include "kssl_lcl.h"
+#include "../crypto/constant_time_locl.h"
 #include <openssl/buffer.h>
 #include <openssl/rand.h>
 #include <openssl/objects.h>
@@ -414,11 +415,10 @@ int ssl3_accept(SSL *s)
 		case SSL3_ST_SW_CERT_B:
 			/* Check if it is anon DH or anon ECDH, */
 			/* non-RSA PSK or KRB5 or SRP */
-			if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
+			if (!(s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL|SSL_aKRB5|SSL_aSRP))
 				/* Among PSK ciphersuites only RSA_PSK uses server certificate */
 				&& !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aPSK &&
-					 !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kRSA))
-				&& !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5))
+					 !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kRSA)))
 				{
 				ret=ssl3_send_server_certificate(s);
 				if (ret <= 0) goto end;
@@ -524,7 +524,9 @@ int ssl3_accept(SSL *s)
 				  * (against the specs, but s3_clnt.c accepts this for SSL 3) */
 				 !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) ||
 				 /* never request cert in Kerberos ciphersuites */
-				(s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5)
+				(s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5) ||
+				/* don't request certificate for SRP auth */
+				(s->s3->tmp.new_cipher->algorithm_auth & SSL_aSRP)
 				/* With normal PSK Certificates and
 				 * Certificate Requests are omitted */
 				|| (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK))
@@ -1905,7 +1907,7 @@ int ssl3_send_server_key_exchange(SSL *s)
 			n+=2+nr[i];
 			}
 
-		if (!(alg_a & SSL_aNULL)
+		if (!(alg_a & (SSL_aNULL|SSL_aSRP))
 			/* Among PSK ciphersuites only RSA uses a certificate */
 			&& !((alg_a & SSL_aPSK) && !(alg_k & SSL_kRSA)))
 			{
@@ -2325,6 +2327,10 @@ int ssl3_get_client_key_exchange(SSL *s)
 #ifndef OPENSSL_NO_RSA
 	if (alg_k & SSL_kRSA)
 		{
+		unsigned char rand_premaster_secret[SSL_MAX_MASTER_KEY_LENGTH];
+		int decrypt_len;
+		unsigned char decrypt_good, version_good;
+
 		/* FIX THIS UP EAY EAY EAY EAY */
 		if (s->s3->tmp.use_rsa_tmp)
 			{
@@ -2372,54 +2378,61 @@ int ssl3_get_client_key_exchange(SSL *s)
 				n=i;
 			}
 
-		i=RSA_private_decrypt((int)n,p,p,rsa,RSA_PKCS1_PADDING);
-
-		al = -1;
-		
-		if (i != SSL_MAX_MASTER_KEY_LENGTH)
-			{
-			al=SSL_AD_DECODE_ERROR;
-			/* SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_BAD_RSA_DECRYPT); */
-			}
+		/* We must not leak whether a decryption failure occurs because
+		 * of Bleichenbacher's attack on PKCS #1 v1.5 RSA padding (see
+		 * RFC 2246, section 7.4.7.1). The code follows that advice of
+		 * the TLS RFC and generates a random premaster secret for the
+		 * case that the decrypt fails. See
+		 * https://tools.ietf.org/html/rfc5246#section-7.4.7.1 */
 
-		if ((al == -1) && !((p[0] == (s->client_version>>8)) && (p[1] == (s->client_version & 0xff))))
-			{
-			/* The premaster secret must contain the same version number as the
-			 * ClientHello to detect version rollback attacks (strangely, the
-			 * protocol does not offer such protection for DH ciphersuites).
-			 * However, buggy clients exist that send the negotiated protocol
-			 * version instead if the server does not support the requested
-			 * protocol version.
-			 * If SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such clients. */
-			if (!((s->options & SSL_OP_TLS_ROLLBACK_BUG) &&
-				(p[0] == (s->version>>8)) && (p[1] == (s->version & 0xff))))
-				{
-				al=SSL_AD_DECODE_ERROR;
-				/* SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_BAD_PROTOCOL_VERSION_NUMBER); */
-
-				/* The Klima-Pokorny-Rosa extension of Bleichenbacher's attack
-				 * (http://eprint.iacr.org/2003/052/) exploits the version
-				 * number check as a "bad version oracle" -- an alert would
-				 * reveal that the plaintext corresponding to some ciphertext
-				 * made up by the adversary is properly formatted except
-				 * that the version number is wrong.  To avoid such attacks,
-				 * we should treat this just like any other decryption error. */
-				}
+		/* should be RAND_bytes, but we cannot work around a failure. */
+		if (RAND_pseudo_bytes(rand_premaster_secret,
+				      sizeof(rand_premaster_secret)) <= 0)
+			goto err;
+		decrypt_len = RSA_private_decrypt((int)n,p,p,rsa,RSA_PKCS1_PADDING);
+		ERR_clear_error();
+
+		/* decrypt_len should be SSL_MAX_MASTER_KEY_LENGTH.
+		 * decrypt_good will be 0xff if so and zero otherwise. */
+		decrypt_good = constant_time_eq_int_8(decrypt_len, SSL_MAX_MASTER_KEY_LENGTH);
+
+		/* If the version in the decrypted pre-master secret is correct
+		 * then version_good will be 0xff, otherwise it'll be zero.
+		 * The Klima-Pokorny-Rosa extension of Bleichenbacher's attack
+		 * (http://eprint.iacr.org/2003/052/) exploits the version
+		 * number check as a "bad version oracle". Thus version checks
+		 * are done in constant time and are treated like any other
+		 * decryption error. */
+		version_good = constant_time_eq_8(p[0], (unsigned)(s->client_version>>8));
+		version_good &= constant_time_eq_8(p[1], (unsigned)(s->client_version&0xff));
+
+		/* The premaster secret must contain the same version number as
+		 * the ClientHello to detect version rollback attacks
+		 * (strangely, the protocol does not offer such protection for
+		 * DH ciphersuites). However, buggy clients exist that send the
+		 * negotiated protocol version instead if the server does not
+		 * support the requested protocol version. If
+		 * SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such clients. */
+		if (s->options & SSL_OP_TLS_ROLLBACK_BUG)
+			{
+			unsigned char workaround_good;
+			workaround_good = constant_time_eq_8(p[0], (unsigned)(s->version>>8));
+			workaround_good &= constant_time_eq_8(p[1], (unsigned)(s->version&0xff));
+			version_good |= workaround_good;
+			}
+
+		/* Both decryption and version must be good for decrypt_good
+		 * to remain non-zero (0xff). */
+		decrypt_good &= version_good;
+
+		/* Now copy rand_premaster_secret over p using
+		 * decrypt_good_mask. */
+		for (i = 0; i < (int) sizeof(rand_premaster_secret); i++)
+			{
+			p[i] = constant_time_select_8(decrypt_good, p[i],
+						      rand_premaster_secret[i]);
 			}
 
-		if (al != -1)
-			{
-			/* Some decryption failure -- use random value instead as countermeasure
-			 * against Bleichenbacher's attack on PKCS #1 v1.5 RSA padding
-			 * (see RFC 2246, section 7.4.7.1). */
-			ERR_clear_error();
-			i = SSL_MAX_MASTER_KEY_LENGTH;
-			p[0] = s->client_version >> 8;
-			p[1] = s->client_version & 0xff;
-			if (RAND_pseudo_bytes(p+2, i-2) <= 0) /* should be RAND_bytes, but we cannot work around a failure */
-				goto err;
-			}
-	
 		s->session->master_key_length=
 			s->method->ssl3_enc->generate_master_secret(s,
 				s->session->master_key,
@@ -2837,7 +2850,7 @@ int ssl3_get_client_key_exchange(SSL *s)
 		/* ECDHE PSK ciphersuites from RFC 5489 */
 	    if ((alg_a & SSL_aPSK) && psk_len != 0)
 			{
-			pre_ms_len = 2+psk_len+2+i;
+			pre_ms_len = 2+i+2+psk_len;
 			pre_ms = OPENSSL_malloc(pre_ms_len);
 			if (pre_ms == NULL)
 				{
@@ -2847,11 +2860,11 @@ int ssl3_get_client_key_exchange(SSL *s)
 				}
 			memset(pre_ms, 0, pre_ms_len);
 			t = pre_ms;
-			s2n(psk_len, t);
-			memcpy(t, psk, psk_len);
-			t += psk_len;
 			s2n(i, t);
 			memcpy(t, p, i);
+			t += i;
+			s2n(psk_len, t);
+			memcpy(t, psk, psk_len);
 			s->session->master_key_length = s->method->ssl3_enc \
 				-> generate_master_secret(s,
 					s->session->master_key, pre_ms, pre_ms_len);
@@ -3009,7 +3022,7 @@ int ssl3_get_cert_verify(SSL *s)
 		SSL3_ST_SR_CERT_VRFY_A,
 		SSL3_ST_SR_CERT_VRFY_B,
 		-1,
-		516, /* Enough for 4096 bit RSA key with TLS v1.2 */
+		SSL3_RT_MAX_PLAIN_LENGTH,
 		&ok);
 
 	if (!ok) return((int)n);