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eternalwrt-mt798x/package/libs/mbedtls/patches/002-ssl-narrow-TLS-1.2-RSA-PSS-handling-and-add-interop-.patch
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Magnus KrokenandHauke Mehrtens e65001e3e7 mbedtls: backport upstream patches to fix TLS 1.2 client issues 
Fix a TLS 1.2 regression that caused clients to reject valid
ServerKeyExchange signatures using RSA-PSS signature algorithms.

The TLS 1.2 regression resulted in errors like:
$ curl https://api.domeneshop.no/v0/
curl: (35) ssl_handshake returned: (-0x6600) SSL - A field in a message was incorrect or inconsistent with other fields

Fixes: https://github.com/openwrt/openwrt/issues/22874
Fixes: https://github.com/openwrt/openwrt/issues/23116
Fixes: f48ef0040b ("mbedtls: update to 3.6.6")
Signed-off-by: Magnus Kroken <mkroken@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/23066
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
2026-05-05 00:27:58 +02:00

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From 3833db7c7cb167e8eda2ec5e07da70cd834e88d4 Mon Sep 17 00:00:00 2001
From: Viktor Sokolovskiy <maokaman@gmail.com>
Date: Fri, 17 Apr 2026 18:52:34 +0300
Subject: [PATCH] ssl: narrow TLS 1.2 RSA-PSS handling and add interop coverage
Narrow TLS 1.2 RSA-PSS handling to the client ServerKeyExchange parse path and add OpenSSL and GnuTLS interoperability tests.
Signed-off-by: Viktor Sokolovskiy <maokaman@gmail.com>
---
ChangeLog.d/fix-tls12-rsa-pss-sigalgs.txt | 3 +-
library/ssl_misc.h | 19 -------
library/ssl_tls12_client.c | 63 +++++++++++++++++++----
tests/ssl-opt.sh | 38 +++++++++++++-
tests/suites/test_suite_ssl.data | 12 -----
tests/suites/test_suite_ssl.function | 8 ---
6 files changed, 91 insertions(+), 52 deletions(-)
--- a/ChangeLog.d/fix-tls12-rsa-pss-sigalgs.txt
+++ b/ChangeLog.d/fix-tls12-rsa-pss-sigalgs.txt
@@ -1,3 +1,4 @@
Bugfix
* Fix a TLS 1.2 regression that caused clients to reject valid
- ServerKeyExchange signatures using RSA-PSS signature scheme values.
+ ServerKeyExchange signatures using RSA-PSS signature algorithms.
+ Fixes #10668.
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -2591,25 +2591,6 @@ static inline int mbedtls_ssl_get_pk_typ
static inline int mbedtls_ssl_tls12_sig_alg_is_supported(
const uint16_t sig_alg)
{
-#if defined(PSA_WANT_ALG_RSA_PSS)
- switch (sig_alg) {
-#if defined(PSA_WANT_ALG_SHA_256)
- case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256:
- return 1;
-#endif
-#if defined(PSA_WANT_ALG_SHA_384)
- case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384:
- return 1;
-#endif
-#if defined(PSA_WANT_ALG_SHA_512)
- case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512:
- return 1;
-#endif
- default:
- break;
- }
-#endif /* PSA_WANT_ALG_RSA_PSS */
-
/* High byte is hash */
unsigned char hash = MBEDTLS_BYTE_1(sig_alg);
unsigned char sig = MBEDTLS_BYTE_0(sig_alg);
--- a/library/ssl_tls12_client.c
+++ b/library/ssl_tls12_client.c
@@ -13,6 +13,7 @@
#include "mbedtls/ssl.h"
#include "ssl_client.h"
+#include "ssl_debug_helpers.h"
#include "ssl_misc.h"
#include "debug_internal.h"
#include "mbedtls/error.h"
@@ -2087,32 +2088,72 @@ static int ssl_parse_signature_algorithm
{
if (mbedtls_ssl_get_pk_type_and_md_alg_from_sig_alg(sig_alg, pk_alg, md_alg) != 0) {
MBEDTLS_SSL_DEBUG_MSG(1,
- ("Server used unsupported value in SigAlg extension 0x%04x",
- sig_alg));
+ ("Server used unsupported %s signature algorithm",
+ mbedtls_ssl_sig_alg_to_str(sig_alg)));
return MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER;
}
/*
- * mbedtls_ssl_get_pk_sigalg_and_md_alg_from_sig_alg() understands sig_alg code points across
- * TLS versions. Make sure that the received sig_alg extension is valid in TLS 1.2.
+ * mbedtls_ssl_get_pk_type_and_md_alg_from_sig_alg() understands
+ * signature algorithm code points from both TLS 1.2 and TLS 1.3. Make sure
+ * that the selected signature algorithm is acceptable when TLS 1.2 is
+ * negotiated.
+ *
+ * In TLS 1.2, RSA-PSS signature algorithms (rsa_pss_rsae_*) are not
+ * defined by RFC 5246. However, RFC 8446 Section 4.2.3 requires that
+ * implementations which advertise support for RSASSA-PSS must be
+ * prepared to accept such signatures even when TLS 1.2 is negotiated,
+ * provided they were offered in the signature_algorithms extension.
+ *
+ * Therefore, we allow rsa_pss_rsae_* here if:
+ * - the implementation supports them, and
+ * - they were offered in the signature_algorithms extension (checked by
+ * `mbedtls_ssl_sig_alg_is_offered()` below).
+ *
+ * If we were to add full support for rsa_pss_rsae_* signature algorithms
+ * in TLS 1.2, we should then integrate RSA-PSS into the TLS 1.2 signature
+ * algorithm support logic (`mbedtls_ssl_tls12_sig_alg_is_supported()`)
+ * instead of handling it as a special case here.
*/
if (!mbedtls_ssl_sig_alg_is_supported(ssl, sig_alg)) {
- MBEDTLS_SSL_DEBUG_MSG(1,
- ("Server used unsupported value in SigAlg extension 0x%04x",
- sig_alg));
- return MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER;
+ switch (sig_alg) {
+#if defined(PSA_WANT_ALG_RSA_PSS)
+#if defined(PSA_WANT_ALG_SHA_256)
+ case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256:
+#endif
+#if defined(PSA_WANT_ALG_SHA_384)
+ case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384:
+#endif
+#if defined(PSA_WANT_ALG_SHA_512)
+ case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512:
+#endif
+#if defined(PSA_WANT_ALG_SHA_256) || defined(PSA_WANT_ALG_SHA_384) || defined(PSA_WANT_ALG_SHA_512)
+ MBEDTLS_SSL_DEBUG_MSG(3,
+ ("Accepting TLS 1.2 RSA-PSS signature algorithm %s via compatibility exception",
+ mbedtls_ssl_sig_alg_to_str(sig_alg)));
+ break;
+#endif
+#endif /* PSA_WANT_ALG_RSA_PSS */
+ default:
+ MBEDTLS_SSL_DEBUG_MSG(1,
+ ("Server used unsupported %s signature algorithm",
+ mbedtls_ssl_sig_alg_to_str(sig_alg)));
+ return MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER;
+ }
}
/*
* Check if the signature algorithm is acceptable
*/
if (!mbedtls_ssl_sig_alg_is_offered(ssl, sig_alg)) {
- MBEDTLS_SSL_DEBUG_MSG(1, ("Server used SigAlg value 0x%04x that was not offered", sig_alg));
+ MBEDTLS_SSL_DEBUG_MSG(1,
+ ("Server used the signature algorithm %s that was not offered",
+ mbedtls_ssl_sig_alg_to_str(sig_alg)));
return MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER;
}
- MBEDTLS_SSL_DEBUG_MSG(2, ("Server used SignatureAlgorithm %d", sig_alg & 0x00FF));
- MBEDTLS_SSL_DEBUG_MSG(2, ("Server used HashAlgorithm %d", sig_alg >> 8));
+ MBEDTLS_SSL_DEBUG_MSG(2, ("Server used the signature algorithm %s",
+ mbedtls_ssl_sig_alg_to_str(sig_alg)));
return 0;
}
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -14948,7 +14948,6 @@ run_test "TLS 1.2: Check rsa_pss_rsae
-c "Protocol is TLSv1.2" \
-c "HTTP/1.0 200 [Oo][Kk]"
-
requires_gnutls_tls1_3
requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
requires_config_enabled MBEDTLS_DEBUG_C
@@ -14964,6 +14963,43 @@ run_test "TLS 1.2: Check rsa_pss_rsae
-c "Protocol is TLSv1.2" \
-c "HTTP/1.0 200 [Oo][Kk]"
+requires_openssl_tls1_3_with_compatible_ephemeral
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled PSA_WANT_ALG_RSA_PSS
+requires_config_enabled PSA_WANT_ALG_SHA_256
+run_test "TLS 1.2: Server forces TLS 1.2 and rsa_pss_rsae_sha256, m->O" \
+ "$O_NEXT_SRV_NO_CERT -cert $DATA_FILES_PATH/server2-sha256.crt -key $DATA_FILES_PATH/server2.key
+ -tls1_2 -sigalgs rsa_pss_rsae_sha256 " \
+ "$P_CLI debug_level=3" \
+ 0 \
+ -c "sent signature scheme \\[804\\] rsa_pss_rsae_sha256" \
+ -c "Perform .* computation of digest of ServerKeyExchange" \
+ -c "Server used the signature algorithm rsa_pss_rsae_sha256" \
+ -c "Protocol is TLSv1.2" \
+ -c "HTTP/1.0 200 [Oo][Kk]"
+
+requires_gnutls_tls1_3
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled PSA_WANT_ALG_RSA_PSS
+requires_config_enabled PSA_WANT_ALG_SHA_256
+run_test "TLS 1.2: Server forces TLS 1.2 and rsa_pss_rsae_sha256, m->G" \
+ "$G_NEXT_SRV_NO_CERT --x509certfile $DATA_FILES_PATH/server2-sha256.crt --x509keyfile $DATA_FILES_PATH/server2.key
+ --disable-client-cert
+ --priority=NORMAL:-VERS-ALL:+VERS-TLS1.2:-SIGN-ALL:+SIGN-RSA-PSS-RSAE-SHA256" \
+ "$P_CLI debug_level=3" \
+ 0 \
+ -c "sent signature scheme \\[804\\] rsa_pss_rsae_sha256" \
+ -c "Perform .* computation of digest of ServerKeyExchange" \
+ -c "Server used the signature algorithm rsa_pss_rsae_sha256" \
+ -c "Protocol is TLSv1.2" \
+ -c "HTTP/1.0 200 [Oo][Kk]"
+
requires_config_enabled MBEDTLS_SSL_SRV_C
requires_config_enabled MBEDTLS_DEBUG_C
requires_config_enabled MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
--- a/tests/suites/test_suite_ssl.data
+++ b/tests/suites/test_suite_ssl.data
@@ -3546,15 +3546,3 @@ send_invalid_sig_alg:MBEDTLS_SSL_SIG_ECD
Default verify_result before doing a handshake
verify_result_without_handshake
-
-TLS 1.2 accepts rsa_pss_rsae_sha256 in signature_algorithm
-depends_on:PSA_WANT_ALG_RSA_PSS:PSA_WANT_ALG_SHA_256
-ssl_tls12_sig_alg_supported:MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256:1
-
-TLS 1.2 accepts rsa_pss_rsae_sha384 in signature_algorithm
-depends_on:PSA_WANT_ALG_RSA_PSS:PSA_WANT_ALG_SHA_384
-ssl_tls12_sig_alg_supported:MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384:1
-
-TLS 1.2 accepts rsa_pss_rsae_sha512 in signature_algorithm
-depends_on:PSA_WANT_ALG_RSA_PSS:PSA_WANT_ALG_SHA_512
-ssl_tls12_sig_alg_supported:MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512:1
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -5861,14 +5861,6 @@ exit:
}
/* END_CASE */
-/* BEGIN_CASE depends_on:MBEDTLS_SSL_PROTO_TLS1_2:MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
-void ssl_tls12_sig_alg_supported(int sig_alg, int expected)
-{
- TEST_EQUAL(mbedtls_ssl_tls12_sig_alg_is_supported((uint16_t) sig_alg),
- expected);
-}
-/* END_CASE */
-
/* BEGIN_CASE depends_on:MBEDTLS_SSL_KEYING_MATERIAL_EXPORT:MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED:PSA_WANT_ECC_SECP_R1_384:PSA_WANT_ALG_SHA_256 */
void ssl_tls_exporter_consistent_result(int proto, int exported_key_length, int use_context)
{
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