And client fuzzer

Reviewed-by: Rich Salz <rsalz@openssl.org>
GH: #2041

2 files changed, 99 insertions, 2 deletions

diff --git a/fuzz/build.info b/fuzz/build.info
index eade218937..a5cc6f44b9 100644
--- a/fuzz/build.info
+++ b/fuzz/build.info
@@ -9,7 +9,7 @@
 -}
 
 IF[{- !$disabled{"fuzz-afl"} || !$disabled{"fuzz-libfuzzer"} -}]
-  PROGRAMS_NO_INST=asn1 asn1parse bignum bndiv conf crl server x509
+  PROGRAMS_NO_INST=asn1 asn1parse bignum bndiv client conf crl server x509
 
   IF[{- !$disabled{"cms"} -}]
     PROGRAMS_NO_INST=cms
@@ -35,6 +35,10 @@ IF[{- !$disabled{"fuzz-afl"} || !$disabled{"fuzz-libfuzzer"} -}]
   INCLUDE[bndiv]=../include {- $ex_inc -}
   DEPEND[bndiv]=../libcrypto {- $ex_lib -}
 
+  SOURCE[client]=client.c driver.c
+  INCLUDE[client]=../include {- $ex_inc -}
+  DEPEND[client]=../libcrypto ../libssl {- $ex_lib -}
+
   SOURCE[cms]=cms.c driver.c
   INCLUDE[cms]=../include {- $ex_inc -}
   DEPEND[cms]=../libcrypto {- $ex_lib -}
@@ -61,7 +65,7 @@ IF[{- !$disabled{"fuzz-afl"} || !$disabled{"fuzz-libfuzzer"} -}]
 ENDIF
 
 IF[{- !$disabled{tests} -}]
-  PROGRAMS_NO_INST=asn1-test asn1parse-test bignum-test bndiv-test conf-test crl-test server-test x509-test
+  PROGRAMS_NO_INST=asn1-test asn1parse-test bignum-test bndiv-test client-test conf-test crl-test server-test x509-test
 
   IF[{- !$disabled{"cms"} -}]
     PROGRAMS_NO_INST=cms-test
@@ -87,6 +91,10 @@ IF[{- !$disabled{tests} -}]
   INCLUDE[bndiv-test]=../include
   DEPEND[bndiv-test]=../libcrypto
 
+  SOURCE[client-test]=client.c test-corpus.c
+  INCLUDE[client-test]=../include
+  DEPEND[client-test]=../libcrypto ../libssl
+
   SOURCE[cms-test]=cms.c test-corpus.c
   INCLUDE[cms-test]=../include
   DEPEND[cms-test]=../libcrypto
diff --git a/fuzz/client.c b/fuzz/client.c
new file mode 100644
index 0000000000..391e0cce9f
--- /dev/null
+++ b/fuzz/client.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL licenses, (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * https://www.openssl.org/source/license.html
+ * or in the file LICENSE in the source distribution.
+ */
+
+#include <openssl/rand.h>
+#include <openssl/ssl.h>
+#include <openssl/rsa.h>
+#include <openssl/err.h>
+#include "fuzzer.h"
+
+#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+extern int rand_predictable;
+#endif
+#define ENTROPY_NEEDED 32
+
+/* unused, to avoid warning. */
+static int idx;
+
+int FuzzerInitialize(int *argc, char ***argv)
+{
+    STACK_OF(SSL_COMP) *comp_methods;
+
+    OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS | OPENSSL_INIT_ASYNC, NULL);
+    OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS, NULL);
+    ERR_get_state();
+    CRYPTO_free_ex_index(0, -1);
+    idx = SSL_get_ex_data_X509_STORE_CTX_idx();
+    RAND_add("", 1, ENTROPY_NEEDED);
+    RAND_status();
+    RSA_get_default_method();
+    comp_methods = SSL_COMP_get_compression_methods();
+    OPENSSL_sk_sort((OPENSSL_STACK *)comp_methods);
+
+
+#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+    rand_predictable = 1;
+#endif
+
+    return 1;
+}
+
+int FuzzerTestOneInput(const uint8_t *buf, size_t len)
+{
+    SSL *client;
+    BIO *in;
+    BIO *out;
+    SSL_CTX *ctx;
+
+    if (len == 0)
+        return 0;
+
+    /*
+     * TODO: use the ossltest engine (optionally?) to disable crypto checks.
+     */
+
+    /* This only fuzzes the initial flow from the client so far. */
+    ctx = SSL_CTX_new(SSLv23_method());
+
+    client = SSL_new(ctx);
+    in = BIO_new(BIO_s_mem());
+    out = BIO_new(BIO_s_mem());
+    SSL_set_bio(client, in, out);
+    SSL_set_connect_state(client);
+    OPENSSL_assert((size_t)BIO_write(in, buf, len) == len);
+    if (SSL_do_handshake(client) == 1) {
+        /* Keep reading application data until error or EOF. */
+        uint8_t tmp[1024];
+        for (;;) {
+            if (SSL_read(client, tmp, sizeof(tmp)) <= 0) {
+                break;
+            }
+        }
+    }
+    SSL_free(client);
+    ERR_clear_error();
+    SSL_CTX_free(ctx);
+
+    return 0;
+}
+
+void FuzzerCleanup(void)
+{
+}