Make truncated hmac a runtime option server-side
Reading the documentation of ssl_set_truncated_hmac() may give the impression
I changed the default for clients but I didn't, the old documentation was
wrong.
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 08f2ff8..d962d5b 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -109,6 +109,7 @@
#define DFL_MAX_VERSION -1
#define DFL_AUTH_MODE SSL_VERIFY_OPTIONAL
#define DFL_MFL_CODE SSL_MAX_FRAG_LEN_NONE
+#define DFL_TRUNC_HMAC -1
#define DFL_TICKETS SSL_SESSION_TICKETS_ENABLED
#define DFL_TICKET_TIMEOUT -1
#define DFL_CACHE_MAX -1
@@ -171,6 +172,7 @@
int max_version; /* maximum protocol version accepted */
int auth_mode; /* verify mode for connection */
unsigned char mfl_code; /* code for maximum fragment length */
+ int trunc_hmac; /* accept truncated hmac? */
int tickets; /* enable / disable session tickets */
int ticket_timeout; /* session ticket lifetime */
int cache_max; /* max number of session cache entries */
@@ -295,6 +297,13 @@
#define USAGE_MAX_FRAG_LEN ""
#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
+#define USAGE_TRUNC_HMAC \
+ " trunc_hmac=%%d default: library default\n"
+#else
+#define USAGE_TRUNC_HMAC ""
+#endif
+
#if defined(POLARSSL_SSL_ALPN)
#define USAGE_ALPN \
" alpn=%%s default: \"\" (disabled)\n" \
@@ -341,6 +350,7 @@
USAGE_TICKETS \
USAGE_CACHE \
USAGE_MAX_FRAG_LEN \
+ USAGE_TRUNC_HMAC \
USAGE_ALPN \
USAGE_EMS \
USAGE_ETM \
@@ -726,6 +736,7 @@
opt.max_version = DFL_MAX_VERSION;
opt.auth_mode = DFL_AUTH_MODE;
opt.mfl_code = DFL_MFL_CODE;
+ opt.trunc_hmac = DFL_TRUNC_HMAC;
opt.tickets = DFL_TICKETS;
opt.ticket_timeout = DFL_TICKET_TIMEOUT;
opt.cache_max = DFL_CACHE_MAX;
@@ -902,6 +913,15 @@
{
opt.alpn_string = q;
}
+ else if( strcmp( p, "trunc_hmac" ) == 0 )
+ {
+ switch( atoi( q ) )
+ {
+ case 0: opt.trunc_hmac = SSL_TRUNC_HMAC_DISABLED; break;
+ case 1: opt.trunc_hmac = SSL_TRUNC_HMAC_ENABLED; break;
+ default: goto usage;
+ }
+ }
else if( strcmp( p, "extended_ms" ) == 0 )
{
switch( atoi( q ) )
@@ -1297,6 +1317,11 @@
};
#endif
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
+ if( opt.trunc_hmac != DFL_TRUNC_HMAC )
+ ssl_set_truncated_hmac( &ssl, opt.trunc_hmac );
+#endif
+
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
if( opt.extended_ms != DFL_EXTENDED_MS )
ssl_set_extended_master_secret( &ssl, opt.extended_ms );