Check frame length after packing a frame

If resultant length of a frame exceeds the maximum value (which is
2**24 - 1 for SPDY/2 and 3), SPDYLAY_ERR_FRAME_TOO_LARGE is used to
indicate this error. This error will be notified by
on_ctrl_not_send_callback.

lib/includes/spdylay/spdylay.h

@@ -167,6 +167,10 @@ typedef enum {
    * The user callback function failed due to the temporal error.
    */
   SPDYLAY_ERR_TEMPORAL_CALLBACK_FAILURE = -521,
+  /**
+   * The length of the frame is too large.
+   */
+  SPDYLAY_ERR_FRAME_TOO_LARGE = -522,
   /**
    * The errors < :enum:`SPDYLAY_ERR_FATAL` mean that the library is
    * under unexpected condition and cannot process any further data

lib/spdylay_frame.c

@@ -107,6 +107,11 @@ ssize_t spdylay_frame_alloc_pack_nv(uint8_t **buf_ptr,
     return framelen;
   }
   framelen += nv_offset;
+
+  if(framelen - SPDYLAY_FRAME_HEAD_LENGTH > SPDYLAY_LENGTH_MASK) {
+    /* In SPDY/2 and 3, Max frame size is 2**24 - 1. */
+    return SPDYLAY_ERR_FRAME_TOO_LARGE;
+  }
   return framelen;
 }
 

lib/spdylay_frame.h

@@ -35,6 +35,8 @@
 #include "spdylay_client_cert_vector.h"
 
 #define SPDYLAY_STREAM_ID_MASK 0x7fffffff
+/* This is actually the maximum length of a control frame in SPDY/2
+   and 3. */
 #define SPDYLAY_LENGTH_MASK 0xffffff
 #define SPDYLAY_VERSION_MASK 0x7fff
 #define SPDYLAY_DELTA_WINDOW_SIZE_MASK 0x7fffffff
@@ -124,6 +126,8 @@ size_t spdylay_frame_get_len_size(uint16_t version);
  *     The version is not supported.
  * SPDYLAY_ERR_ZLIB
  *     The deflate operation failed.
+ * SPDYLAY_ERR_FRAME_TOO_LARGE
+ *     The length of the frame is too large.
  * SPDYLAY_ERR_NOMEM
  *     Out of memory.
  */
@@ -201,6 +205,8 @@ int spdylay_frame_unpack_syn_stream_without_nv(spdylay_syn_stream *frame,
  *     The version is not supported.
  * SPDYLAY_ERR_ZLIB
  *     The deflate operation failed.
+ * SPDYLAY_ERR_FRAME_TOO_LARGE
+ *     The length of the frame is too large.
  * SPDYLAY_ERR_NOMEM
  *     Out of memory.
  */
@@ -335,6 +341,8 @@ int spdylay_frame_unpack_goaway(spdylay_goaway *frame,
  *     The version is not supported.
  * SPDYLAY_ERR_ZLIB
  *     The deflate operation failed.
+ * SPDYLAY_ERR_FRAME_TOO_LARGE
+ *     The length of the frame is too large.
  * SPDYLAY_ERR_NOMEM
  *     Out of memory.
  */
@@ -539,6 +547,8 @@ ssize_t spdylay_frame_pack_nv(uint8_t *buf, char **nv, size_t len_size);
  *
  * SPDYLAY_ERR_ZLIB
  *     The deflate operation failed.
+ * SPDYLAY_ERR_FRAME_TOO_LARGE
+ *     The length of the frame is too large.
  * SPDYLAY_ERR_NOMEM
  *     Out of memory.
  */

lib/spdylay_helper.c

@@ -119,6 +119,8 @@ const char* spdylay_strerror(int error_code)
     return "Gzip error";
   case SPDYLAY_ERR_TEMPORAL_CALLBACK_FAILURE:
     return "The user callback function failed due to the temporal error";
+  case SPDYLAY_ERR_FRAME_TOO_LARGE:
+    return "The length of the frame is too large";
   case SPDYLAY_ERR_NOMEM:
     return "Out of memory";
   case SPDYLAY_ERR_CALLBACK_FAILURE:

lib/spdylay_int.h

@@ -38,8 +38,7 @@ typedef int (*spdylay_compar)(const void *lhs, const void *rhs);
 /* Internal error code. They must be in the range [-499, -100],
    inclusive. */
 typedef enum {
-  SPDYLAY_ERR_CREDENTIAL_PENDING = -101,
-  SPDYLAY_ERR_FRAME_TOO_LARGE = -102
+  SPDYLAY_ERR_CREDENTIAL_PENDING = -101
 } spdylay_internal_error;
 
 #endif /* SPDYLAY_INT_H */

tests/main.c

@@ -186,6 +186,8 @@ int main(int argc, char* argv[])
                    test_spdylay_frame_pack_syn_stream_spdy2) ||
       !CU_add_test(pSuite, "frame_pack_syn_stream_spdy3",
                    test_spdylay_frame_pack_syn_stream_spdy3) ||
+      !CU_add_test(pSuite, "frame_pack_syn_stream_frame_too_large",
+                   test_spdylay_frame_pack_syn_stream_frame_too_large) ||
       !CU_add_test(pSuite, "frame_pack_syn_reply_spdy2",
                    test_spdylay_frame_pack_syn_reply_spdy2) ||
       !CU_add_test(pSuite, "frame_pack_syn_reply_spdy3",

tests/spdylay_frame_test.c

@@ -346,6 +346,35 @@ void test_spdylay_frame_pack_syn_stream_spdy3(void)
   test_spdylay_frame_pack_syn_stream_version(SPDYLAY_PROTO_SPDY3);
 }
 
+void test_spdylay_frame_pack_syn_stream_frame_too_large(void)
+{
+  spdylay_zlib deflater;
+  spdylay_frame frame;
+  uint8_t *buf = NULL, *nvbuf = NULL;
+  size_t buflen = 0, nvbuflen = 0;
+  ssize_t framelen;
+  size_t big_vallen = 16777215;
+  char *big_val = malloc(big_vallen + 1);
+  const char *big_hds[] = { "header", big_val, NULL };
+  memset(big_val, '0', big_vallen);
+  big_val[big_vallen] = '\0';
+
+  spdylay_zlib_deflate_hd_init(&deflater, SPDYLAY_PROTO_SPDY3);
+  spdylay_frame_syn_stream_init(&frame.syn_stream, SPDYLAY_PROTO_SPDY3,
+                                SPDYLAY_CTRL_FLAG_FIN, 65536, 1000000007, 3,
+                                spdylay_frame_nv_copy(big_hds));
+  framelen = spdylay_frame_pack_syn_stream(&buf, &buflen,
+                                           &nvbuf, &nvbuflen,
+                                           &frame.syn_stream, &deflater);
+  CU_ASSERT_EQUAL(SPDYLAY_ERR_FRAME_TOO_LARGE, framelen);
+
+  spdylay_frame_syn_stream_free(&frame.syn_stream);
+  free(buf);
+  free(nvbuf);
+  free(big_val);
+  spdylay_zlib_deflate_free(&deflater);
+}
+
 static void test_spdylay_frame_pack_syn_reply_version(uint16_t version)
 {
   spdylay_zlib deflater, inflater;

tests/spdylay_frame_test.h

@@ -35,6 +35,7 @@ void test_spdylay_frame_pack_goaway_spdy2(void);
 void test_spdylay_frame_pack_goaway_spdy3(void);
 void test_spdylay_frame_pack_syn_stream_spdy2(void);
 void test_spdylay_frame_pack_syn_stream_spdy3(void);
+void test_spdylay_frame_pack_syn_stream_frame_too_large(void);
 void test_spdylay_frame_pack_syn_reply_spdy2(void);
 void test_spdylay_frame_pack_syn_reply_spdy3(void);
 void test_spdylay_frame_pack_headers_spdy2(void);