Added support for TLS_FALLBACK_SCSV.

[BearSSL] / tools / client.c

diff --git a/tools/client.c b/tools/client.c
index 90ba7e5..2c2985f 100644 (file)
--- a/tools/client.c
+++ b/tools/client.c
@@ -149,6 +149,8 @@ usage_client(void)
 "   -hf names       add support for some hash functions (comma-separated)\n");
        fprintf(stderr,
 "   -minhello len   set minimum ClientHello length (in bytes)\n");
+       fprintf(stderr,
+"   -fallback       send the TLS_FALLBACK_SCSV (i.e. claim a downgrade)\n");
 }
 
 /* see brssl.h */
@@ -177,6 +179,7 @@ do_client(int argc, char *argv[])
        unsigned char *iobuf;
        size_t iobuf_len;
        size_t minhello_len;
+       int fallback;
        int fd;
 
        retcode = 0;
@@ -196,6 +199,7 @@ do_client(int argc, char *argv[])
        iobuf = NULL;
        iobuf_len = 0;
        minhello_len = (size_t)-1;
+       fallback = 0;
        fd = -1;
        for (i = 0; i < argc; i ++) {
                const char *arg;
@@ -376,6 +380,8 @@ do_client(int argc, char *argv[])
                                usage_client();
                                goto client_exit_error;
                        }
+               } else if (eqstr(arg, "-fallback")) {
+                       fallback = 1;
                } else {
                        fprintf(stderr, "ERROR: unknown option: '%s'\n", arg);
                        usage_client();
@@ -457,7 +463,7 @@ do_client(int argc, char *argv[])
        /*
         * Compute implementation requirements and inject implementations.
         */
-       suite_ids = xmalloc(num_suites * sizeof *suite_ids);
+       suite_ids = xmalloc((num_suites + 1) * sizeof *suite_ids);
        br_ssl_client_zero(&cc);
        br_ssl_engine_set_versions(&cc.eng, vmin, vmax);
        dnhash = NULL;
@@ -557,6 +563,9 @@ do_client(int argc, char *argv[])
                        br_ssl_engine_set_ec(&cc.eng, &br_ec_prime_i31);
                }
        }
+       if (fallback) {
+               suite_ids[num_suites ++] = 0x5600;
+       }
        br_ssl_engine_set_suites(&cc.eng, suite_ids, num_suites);
 
        for (u = 0; hash_functions[u].name; u ++) {