commit 1aa6e8d6e9f5af25c24a2484d774f9a879aa873a
author Ronald Cron <ronald.cron@arm.com> Thu Feb 23 09:46:54 2023 +0100
committer Ronald Cron <ronald.cron@arm.com> Thu Feb 23 09:48:50 2023 +0100
tree 438cba68e47d80e5a6a302a5ad26434af24cd992
parent d89360b87bb5bcf09a21c74a799056c49260b260

Restore same PSK length enforcement

Restore same PSK length enforcement in
conf_psk and set_hs_psk, whether the
negotiated protocol is TLS 1.2 or TLS 1.3.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>

include/mbedtls/mbedtls_config.h

diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 9ae51c9..4c676c5 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -3761,7 +3761,7 @@
  */
 //#define MBEDTLS_SSL_DTLS_MAX_BUFFERING             32768
 
-//#define MBEDTLS_PSK_MAX_LEN               32 /**< Max size of TLS pre-shared keys, in bytes (default 256 bits) */
+//#define MBEDTLS_PSK_MAX_LEN               32 /**< Max size of TLS pre-shared keys, in bytes (default 256 or 384 bits) */
 //#define MBEDTLS_SSL_COOKIE_TIMEOUT        60 /**< Default expiration delay of DTLS cookies, in seconds if HAVE_TIME, or in number of cookies issued */
 
 /**

include/mbedtls/ssl.h

diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 4b954bb..0df142d 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -599,8 +599,22 @@
  * Size defines
  */
 #if !defined(MBEDTLS_PSK_MAX_LEN)
-#define MBEDTLS_PSK_MAX_LEN            32 /* 256 bits */
+/*
+ * If the library supports TLS 1.3 tickets and the cipher suite
+ * TLS1-3-AES-256-GCM-SHA384, set the PSK maximum length to 48 instead of 32.
+ * That way, the TLS 1.3 client and server are able to resume sessions where
+ * the cipher suite was TLS1-3-AES-256-GCM-SHA384 (pre-shared keys are 48
+ * bytes long is that case).
+ */
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && \
+    defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+    defined(MBEDTLS_AES_C) && defined(MBEDTLS_GCM_C) && \
+    defined(MBEDTLS_HAS_ALG_SHA_384_VIA_MD_OR_PSA_BASED_ON_USE_PSA)
+#define MBEDTLS_PSK_MAX_LEN 48 /* 384 bits */
+#else
+#define MBEDTLS_PSK_MAX_LEN 32 /* 256 bits */
 #endif
+#endif /* !MBEDTLS_PSK_MAX_LEN */
 
 /* Dummy type used only for its size */
 union mbedtls_ssl_premaster_secret {

library/ssl_tls.c

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 4312f15..86f5c0b 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2145,12 +2145,9 @@
         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
     }
 
-#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
-    if (ssl->tls_version == MBEDTLS_SSL_VERSION_TLS1_2 &&
-        psk_len > MBEDTLS_PSK_MAX_LEN) {
+    if (psk_len > MBEDTLS_PSK_MAX_LEN) {
         return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
     }
-#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
 
     ssl_remove_psk(ssl);
 

tests/ssl-opt.sh

diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index b1ee654..6794068 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -13239,7 +13239,7 @@
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED
 run_test    "TLS 1.3: NewSessionTicket: Basic check, G->m" \
             "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=4" \
-            "$G_NEXT_CLI localhost -d 4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3 -V -r" \
+            "$G_NEXT_CLI localhost -d 4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:-AES-256-GCM -V -r" \
             0 \
             -c "Connecting again- trying to resume previous session" \
             -c "NEW SESSION TICKET (4) was received" \