Port early callback support to CBS.
Resolve one of the TODOs since it's quick. Adjust the
-expect-server-name test to assert it both in the normal codepath and
in the early callback, to provide test coverage for
SSL_early_callback_ctx_extension_get.
Change-Id: I4d71158b9fd2f4fbb54d3e51184bd25d117bdc91
Reviewed-on: https://boringssl-review.googlesource.com/1120
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 86914dc..2fa4101 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -296,102 +296,64 @@
char ssl_early_callback_init(struct ssl_early_callback_ctx *ctx)
{
- size_t len = ctx->client_hello_len;
- const unsigned char *p = ctx->client_hello;
- CBS extensions;
+ CBS client_hello, session_id, cipher_suites, compression_methods, extensions;
+
+ CBS_init(&client_hello, ctx->client_hello, ctx->client_hello_len);
/* Skip client version. */
- if (len < 2)
+ if (!CBS_skip(&client_hello, 2))
return 0;
- len -= 2; p += 2;
/* Skip client nonce. */
- if (len < 32)
+ if (!CBS_skip(&client_hello, 32))
return 0;
- len -= 32; p += 32;
- /* Get length of session id. */
- if (len < 1)
+ /* Extract session_id. */
+ if (!CBS_get_u8_length_prefixed(&client_hello, &session_id))
return 0;
- ctx->session_id_len = *p;
- p++; len--;
-
- ctx->session_id = p;
- if (len < ctx->session_id_len)
- return 0;
- p += ctx->session_id_len; len -= ctx->session_id_len;
+ ctx->session_id = CBS_data(&session_id);
+ ctx->session_id_len = CBS_len(&session_id);
/* Skip past DTLS cookie */
if (ctx->ssl->version == DTLS1_VERSION || ctx->ssl->version == DTLS1_BAD_VER)
{
- unsigned cookie_len;
+ CBS cookie;
- if (len < 1)
+ if (!CBS_get_u8_length_prefixed(&client_hello, &cookie))
return 0;
- cookie_len = *p;
- p++; len--;
- if (len < cookie_len)
- return 0;
- p += cookie_len; len -= cookie_len;
}
- /* Skip cipher suites. */
- if (len < 2)
+ /* Extract cipher_suites. */
+ if (!CBS_get_u16_length_prefixed(&client_hello, &cipher_suites) ||
+ CBS_len(&cipher_suites) < 2 ||
+ (CBS_len(&cipher_suites) & 1) != 0)
return 0;
- n2s(p, ctx->cipher_suites_len);
- len -= 2;
+ ctx->cipher_suites = CBS_data(&cipher_suites);
+ ctx->cipher_suites_len = CBS_len(&cipher_suites);
- if ((ctx->cipher_suites_len & 1) != 0)
+ /* Extract compression_methods. */
+ if (!CBS_get_u8_length_prefixed(&client_hello, &compression_methods) ||
+ CBS_len(&compression_methods) < 1)
return 0;
-
- ctx->cipher_suites = p;
- if (len < ctx->cipher_suites_len)
- return 0;
- p += ctx->cipher_suites_len; len -= ctx->cipher_suites_len;
-
- /* Skip compression methods. */
- if (len < 1)
- return 0;
- ctx->compression_methods_len = *p;
- p++; len--;
-
- ctx->compression_methods = p;
- if (len < ctx->compression_methods_len)
- return 0;
- p += ctx->compression_methods_len; len -= ctx->compression_methods_len;
+ ctx->compression_methods = CBS_data(&compression_methods);
+ ctx->compression_methods_len = CBS_len(&compression_methods);
/* If the ClientHello ends here then it's valid, but doesn't have any
* extensions. (E.g. SSLv3.) */
- if (len == 0)
+ if (CBS_len(&client_hello) == 0)
{
ctx->extensions = NULL;
ctx->extensions_len = 0;
return 1;
}
- if (len < 2)
+ /* Extract extensions and check it is valid. */
+ if (!CBS_get_u16_length_prefixed(&client_hello, &extensions) ||
+ !tls1_check_duplicate_extensions(&extensions) ||
+ CBS_len(&client_hello) != 0)
return 0;
- n2s(p, ctx->extensions_len);
- len -= 2;
-
- if (ctx->extensions_len == 0 && len == 0)
- {
- ctx->extensions = NULL;
- return 1;
- }
-
- ctx->extensions = p;
- if (len != ctx->extensions_len)
- return 0;
-
- /* Verify that the extensions have valid lengths and that there are
- * no duplicates.
- *
- * TODO(fork): Port the rest of this processing to CBS.
- */
- CBS_init(&extensions, ctx->extensions, ctx->extensions_len);
- if (!tls1_check_duplicate_extensions(&extensions))
- return 0;
+ ctx->extensions = CBS_data(&extensions);
+ ctx->extensions_len = CBS_len(&extensions);
return 1;
}
@@ -402,29 +364,26 @@
const unsigned char **out_data,
size_t *out_len)
{
- size_t len = ctx->extensions_len;
- const unsigned char *p = ctx->extensions;
+ CBS extensions;
- while (len != 0)
+ CBS_init(&extensions, ctx->extensions, ctx->extensions_len);
+
+ while (CBS_len(&extensions) != 0)
{
- uint16_t ext_type, ext_len;
+ uint16_t type;
+ CBS extension;
- if (len < 4)
+ /* Decode the next extension. */
+ if (!CBS_get_u16(&extensions, &type) ||
+ !CBS_get_u16_length_prefixed(&extensions, &extension))
return 0;
- n2s(p, ext_type);
- n2s(p, ext_len);
- len -= 4;
- if (len < ext_len)
- return 0;
- if (ext_type == extension_type)
+ if (type == extension_type)
{
- *out_data = p;
- *out_len = ext_len;
+ *out_data = CBS_data(&extension);
+ *out_len = CBS_len(&extension);
return 1;
}
-
- p += ext_len; len -= ext_len;
}
return 0;
diff --git a/ssl/test/bssl_shim.cc b/ssl/test/bssl_shim.cc
index 1dde819..d0117da 100644
--- a/ssl/test/bssl_shim.cc
+++ b/ssl/test/bssl_shim.cc
@@ -16,10 +16,51 @@
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
+#include <unistd.h>
#include <openssl/ssl.h>
#include <openssl/bio.h>
+#include <openssl/bytestring.h>
+const char *expected_server_name = NULL;
+int early_callback_called = 0;
+
+int select_certificate_callback(const struct ssl_early_callback_ctx *ctx) {
+ early_callback_called = 1;
+
+ if (expected_server_name) {
+ const unsigned char *extension_data;
+ size_t extension_len;
+ CBS extension, server_name_list, host_name;
+ uint8_t name_type;
+
+ if (!SSL_early_callback_ctx_extension_get(ctx, TLSEXT_TYPE_server_name,
+ &extension_data,
+ &extension_len)) {
+ fprintf(stderr, "Could not find server_name extension.");
+ return -1;
+ }
+
+ CBS_init(&extension, extension_data, extension_len);
+ if (!CBS_get_u16_length_prefixed(&extension, &server_name_list) ||
+ CBS_len(&extension) != 0 ||
+ !CBS_get_u8(&server_name_list, &name_type) ||
+ name_type != TLSEXT_NAMETYPE_host_name ||
+ !CBS_get_u16_length_prefixed(&server_name_list, &host_name) ||
+ CBS_len(&server_name_list) != 0) {
+ fprintf(stderr, "Could not decode server_name extension.");
+ return -1;
+ }
+
+ if (CBS_len(&host_name) != strlen(expected_server_name) ||
+ memcmp(expected_server_name,
+ CBS_data(&host_name), CBS_len(&host_name)) != 0) {
+ fprintf(stderr, "Server name mismatch.");
+ }
+ }
+
+ return 1;
+}
SSL *setup_test(int is_server) {
if (!SSL_library_init()) {
@@ -44,6 +85,8 @@
goto err;
}
+ ssl_ctx->select_certificate_cb = select_certificate_callback;
+
ssl = SSL_new(ssl_ctx);
if (ssl == NULL) {
goto err;
@@ -74,7 +117,6 @@
int main(int argc, char **argv) {
int i, is_server, ret;
- const char *expected_server_name = NULL;
if (argc < 2) {
fprintf(stderr, "Usage: %s (client|server) [flags...]\n", argv[0]);
@@ -153,6 +195,11 @@
server_name, expected_server_name);
return 2;
}
+
+ if (!early_callback_called) {
+ fprintf(stderr, "early callback not called\n");
+ return 2;
+ }
}
for (;;) {
