H2 cookie header field (#219)

TingDaoK · web-flow · commit 7f65818c786b · 2020-04-06T17:53:47.000-07:00
Compressing the cookie header field (RFC 7540 8.1.2.5)
diff --git a/include/aws/http/private/http_impl.h b/include/aws/http/private/http_impl.h
@@ -51,6 +51,7 @@ enum aws_http_header_name {
     AWS_HTTP_HEADER_CONTENT_LENGTH,
     AWS_HTTP_HEADER_EXPECT,
     AWS_HTTP_HEADER_TRANSFER_ENCODING,
+    AWS_HTTP_HEADER_COOKIE,
 
     AWS_HTTP_HEADER_COUNT, /* Number of enums */
 };
diff --git a/source/h2_decoder.c b/source/h2_decoder.c
@@ -36,6 +36,9 @@ static const size_t s_scratch_space_size = 9;
 /* Stream ids & dependencies should only write the bottom 31 bits */
 static const uint32_t s_31_bit_mask = UINT32_MAX >> 1;
 
+/* initial size for cookie buffer, buffer will grow if needed */
+static const size_t s_decoder_cookie_buffer_initial_size = 512;
+
 #define DECODER_LOGF(level, decoder, text, ...)                                                                        \
     AWS_LOGF_##level(AWS_LS_HTTP_DECODER, "id=%p " text, (decoder)->logging_id, __VA_ARGS__)
 #define DECODER_LOG(level, decoder, text) DECODER_LOGF(level, decoder, "%s", text)
@@ -245,6 +248,12 @@ struct aws_h2_decoder {
          * A malformed header-block is not a connection error, it's a Stream Error (RFC-7540 5.4.2).
          * We continue decoding and report that it's malformed in on_headers_end(). */
         bool malformed;
+
+        /* Buffer up cookie header fields to concatenate separate ones */
+        struct aws_byte_buf cookies;
+        /* If separate cookie fields have different compression types, the concatenated cookie uses the strictest type.
+         */
+        enum aws_http_header_compression cookie_header_compression_type;
     } header_block_in_progress;
 
     /* Settings for decoder, which is based on the settings sent to the peer and ACKed by peer */
@@ -280,7 +289,7 @@ struct aws_h2_decoder *aws_h2_decoder_new(struct aws_h2_decoder_params *params)
     void *allocation = aws_mem_acquire_many(
         params->alloc, 2, &decoder, sizeof(struct aws_h2_decoder), &scratch_buf, s_scratch_space_size);
     if (!allocation) {
-        goto failed_alloc;
+        goto error;
     }
 
     AWS_ZERO_STRUCT(*decoder);
@@ -295,7 +304,7 @@ struct aws_h2_decoder *aws_h2_decoder_new(struct aws_h2_decoder_params *params)
 
     decoder->hpack = aws_hpack_context_new(params->alloc, AWS_LS_HTTP_DECODER, decoder);
     if (!decoder->hpack) {
-        goto failed_new_hpack;
+        goto error;
     }
 
     if (decoder->is_server && !params->skip_connection_preface) {
@@ -311,23 +320,34 @@ struct aws_h2_decoder *aws_h2_decoder_new(struct aws_h2_decoder_params *params)
 
     if (aws_array_list_init_dynamic(
             &decoder->settings_buffer_list, decoder->alloc, 0, sizeof(struct aws_h2_frame_setting))) {
-        goto array_list_failed;
+        goto error;
+    }
+
+    if (aws_byte_buf_init(
+            &decoder->header_block_in_progress.cookies, decoder->alloc, s_decoder_cookie_buffer_initial_size)) {
+        goto error;
     }
 
     return decoder;
 
-failed_new_hpack:
-array_list_failed:
+error:
+    if (decoder) {
+        aws_hpack_context_destroy(decoder->hpack);
+        aws_array_list_clean_up(&decoder->settings_buffer_list);
+        aws_byte_buf_clean_up(&decoder->header_block_in_progress.cookies);
+    }
     aws_mem_release(params->alloc, allocation);
-failed_alloc:
     return NULL;
 }
 
 static void s_reset_header_block_in_progress(struct aws_h2_decoder *decoder) {
     for (size_t i = 0; i < PSEUDOHEADER_COUNT; ++i) {
         aws_string_destroy(decoder->header_block_in_progress.pseudoheader_values[i]);
     }
+    struct aws_byte_buf cookie_backup = decoder->header_block_in_progress.cookies;
     AWS_ZERO_STRUCT(decoder->header_block_in_progress);
+    decoder->header_block_in_progress.cookies = cookie_backup;
+    aws_byte_buf_reset(&decoder->header_block_in_progress.cookies, false);
 }
 
 void aws_h2_decoder_destroy(struct aws_h2_decoder *decoder) {
@@ -337,6 +357,7 @@ void aws_h2_decoder_destroy(struct aws_h2_decoder *decoder) {
     aws_array_list_clean_up(&decoder->settings_buffer_list);
     aws_hpack_context_destroy(decoder->hpack);
     s_reset_header_block_in_progress(decoder);
+    aws_byte_buf_clean_up(&decoder->header_block_in_progress.cookies);
     aws_mem_release(decoder->alloc, decoder);
 }
 
@@ -1263,11 +1284,35 @@ static int s_process_header_field(struct aws_h2_decoder *decoder, const struct a
 
         /* #TODO Validate characters used in header_field->value */
 
-        /* Deliver header-field via callback */
-        if (current_block->is_push_promise) {
-            DECODER_CALL_VTABLE_STREAM_ARGS(decoder, on_push_promise_i, header_field, name_enum);
-        } else {
-            DECODER_CALL_VTABLE_STREAM_ARGS(decoder, on_headers_i, header_field, name_enum, current_block->block_type);
+        switch (name_enum) {
+            case AWS_HTTP_HEADER_COOKIE:
+                /* for a header cookie, we will not fire callback until we concatenate them all, let's store it at the
+                 * buffer */
+                if (header_field->compression > current_block->cookie_header_compression_type) {
+                    current_block->cookie_header_compression_type = header_field->compression;
+                }
+
+                if (current_block->cookies.len) {
+                    /* add a delimiter */
+                    struct aws_byte_cursor delimiter = AWS_BYTE_CUR_INIT_FROM_STRING_LITERAL("; ");
+                    if (aws_byte_buf_append_dynamic(&current_block->cookies, &delimiter)) {
+                        return AWS_OP_ERR;
+                    }
+                }
+                if (aws_byte_buf_append_dynamic(&current_block->cookies, &header_field->value)) {
+                    return AWS_OP_ERR;
+                }
+                break;
+
+            default:
+                /* Deliver header-field via callback */
+                if (current_block->is_push_promise) {
+                    DECODER_CALL_VTABLE_STREAM_ARGS(decoder, on_push_promise_i, header_field, name_enum);
+                } else {
+                    DECODER_CALL_VTABLE_STREAM_ARGS(
+                        decoder, on_headers_i, header_field, name_enum, current_block->block_type);
+                }
+                break;
         }
     }
 
@@ -1282,6 +1327,29 @@ static int s_process_header_field(struct aws_h2_decoder *decoder, const struct a
     return AWS_OP_SUCCESS;
 }
 
+static int s_flush_cookie_header(struct aws_h2_decoder *decoder) {
+    struct aws_header_block_in_progress *current_block = &decoder->header_block_in_progress;
+    if (current_block->malformed) {
+        return AWS_OP_SUCCESS;
+    }
+    if (current_block->cookies.len == 0) {
+        /* Nothing to flush */
+        return AWS_OP_SUCCESS;
+    }
+    struct aws_http_header concatenated_cookie;
+    struct aws_byte_cursor header_name = AWS_BYTE_CUR_INIT_FROM_STRING_LITERAL("cookie");
+    concatenated_cookie.name = header_name;
+    concatenated_cookie.value = aws_byte_cursor_from_buf(&current_block->cookies);
+    concatenated_cookie.compression = current_block->cookie_header_compression_type;
+    if (current_block->is_push_promise) {
+        DECODER_CALL_VTABLE_STREAM_ARGS(decoder, on_push_promise_i, &concatenated_cookie, AWS_HTTP_HEADER_COOKIE);
+    } else {
+        DECODER_CALL_VTABLE_STREAM_ARGS(
+            decoder, on_headers_i, &concatenated_cookie, AWS_HTTP_HEADER_COOKIE, current_block->block_type);
+    }
+    return AWS_OP_SUCCESS;
+}
+
 /* This state checks whether we've consumed the current frame's entire header-block fragment.
  * We revisit this state after each entry is decoded.
  * This state consumes no data. */
@@ -1297,6 +1365,10 @@ static int s_state_fn_header_block_loop(struct aws_h2_decoder *decoder, struct a
             if (s_flush_pseudoheaders(decoder)) {
                 return AWS_OP_ERR;
             }
+            /* flush the concatenated cookie header */
+            if (s_flush_cookie_header(decoder)) {
+                return AWS_OP_ERR;
+            }
 
             bool malformed = decoder->header_block_in_progress.malformed;
             DECODER_LOGF(TRACE, decoder, "Done decoding header-block, malformed=%d", malformed);
@@ -1389,8 +1461,6 @@ static int s_state_fn_header_block_entry(struct aws_h2_decoder *decoder, struct
      * If dynamic table size changed via SETTINGS frame, next header-block must start with DYNAMIC_TABLE_RESIZE entry.
      * Is it illegal to receive a resize entry at other times? */
 
-    /* #TODO Cookie headers must be concatenated into single delivery RFC-7540 8.1.2.5 */
-
     /* #TODO The TE header field ... MUST NOT contain any value other than "trailers" */
 
     if (result.type == AWS_HPACK_DECODE_T_HEADER_FIELD) {
diff --git a/source/http.c b/source/http.c
@@ -253,6 +253,7 @@ static void s_headers_init(struct aws_allocator *alloc) {
     s_header_enum_to_str[AWS_HTTP_HEADER_AUTHORITY] = aws_byte_cursor_from_c_str(":authority");
     s_header_enum_to_str[AWS_HTTP_HEADER_PATH] = aws_byte_cursor_from_c_str(":path");
     s_header_enum_to_str[AWS_HTTP_HEADER_STATUS] = aws_byte_cursor_from_c_str(":status");
+    s_header_enum_to_str[AWS_HTTP_HEADER_COOKIE] = aws_byte_cursor_from_c_str("cookie");
     s_header_enum_to_str[AWS_HTTP_HEADER_CONNECTION] = aws_byte_cursor_from_c_str("connection");
     s_header_enum_to_str[AWS_HTTP_HEADER_CONTENT_LENGTH] = aws_byte_cursor_from_c_str("content-length");
     s_header_enum_to_str[AWS_HTTP_HEADER_EXPECT] = aws_byte_cursor_from_c_str("expect");
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
@@ -246,6 +246,7 @@ add_h2_decoder_test_set(h2_decoder_headers_priority)
 add_h2_decoder_test_set(h2_decoder_headers_ignores_unknown_flags)
 add_h2_decoder_test_set(h2_decoder_headers_response_informational)
 add_h2_decoder_test_set(h2_decoder_headers_request)
+add_h2_decoder_test_set(h2_decoder_headers_cookies)
 add_h2_decoder_test_set(h2_decoder_headers_trailer)
 add_h2_decoder_test_set(h2_decoder_headers_empty_trailer)
 add_h2_decoder_test_set(h2_decoder_err_headers_requires_stream_id)
diff --git a/tests/test_h2_decoder.c b/tests/test_h2_decoder.c
@@ -634,6 +634,51 @@ H2_DECODER_ON_SERVER_TEST(h2_decoder_headers_request) {
     return AWS_OP_SUCCESS;
 }
 
+H2_DECODER_ON_SERVER_TEST(h2_decoder_headers_cookies) {
+    (void)allocator;
+    struct fixture *fixture = ctx;
+
+    /* clang-format off */
+    uint8_t input[] = {
+        /* HEADERS FRAME*/
+        0x00, 0x00, 0x06,           /* Length (24) */
+        AWS_H2_FRAME_T_HEADERS,     /* Type (8) */
+        AWS_H2_FRAME_F_END_STREAM,  /* Flags (8) */
+        0x76, 0x54, 0x32, 0x10,     /* Reserved (1) | Stream Identifier (31) */
+        /* HEADERS */
+        0x82,                       /* ":method: GET" - indexed */
+        0x60, 0x03, 'a', '=', 'b',  /* "cache: a=b" - indexed name, uncompressed value */
+
+        /* CONTINUATION FRAME*/
+        0x00, 0x00, 16,             /* Length (24) */
+        AWS_H2_FRAME_T_CONTINUATION,/* Type (8) */
+        AWS_H2_FRAME_F_END_HEADERS, /* Flags (8) */
+        0x76, 0x54, 0x32, 0x10,     /* Reserved (1) | Stream Identifier (31) */
+        /* PAYLOAD */
+        0x7a, 0x04, 't', 'e', 's', 't',  /* "user-agent: test" - indexed name, uncompressed value */
+        0x60, 0x03, 'c', '=', 'd',  /* "cache: c=d" - indexed name, uncompressed value */
+        0x60, 0x03, 'e', '=', 'f',  /* "cache: e=f" - indexed name, uncompressed value */
+    };
+    /* clang-format on */
+
+    /* Decode */
+    ASSERT_SUCCESS(s_decode_all(fixture, aws_byte_cursor_from_array(input, sizeof(input))));
+
+    /* Validate */
+    struct h2_decoded_frame *frame = h2_decode_tester_latest_frame(&fixture->decode);
+    ASSERT_SUCCESS(h2_decoded_frame_check_finished(frame, AWS_H2_FRAME_T_HEADERS, 0x76543210 /*stream_id*/));
+    ASSERT_FALSE(frame->headers_malformed);
+    /* two sepaprate cookie headers are concatenated and moved as the last header*/
+    ASSERT_UINT_EQUALS(3, aws_http_headers_count(frame->headers));
+    ASSERT_SUCCESS(s_check_header(frame, 0, ":method", "GET", AWS_HTTP_HEADER_COMPRESSION_USE_CACHE));
+    ASSERT_SUCCESS(s_check_header(frame, 1, "user-agent", "test", AWS_HTTP_HEADER_COMPRESSION_USE_CACHE));
+    ASSERT_SUCCESS(s_check_header(frame, 2, "cookie", "a=b; c=d; e=f", AWS_HTTP_HEADER_COMPRESSION_USE_CACHE));
+    ASSERT_INT_EQUALS(AWS_HTTP_HEADER_BLOCK_MAIN, frame->header_block_type);
+    ASSERT_TRUE(frame->end_stream);
+
+    return AWS_OP_SUCCESS;
+}
+
 /* A trailing header has no psuedo-headers, and always ends the stream */
 H2_DECODER_ON_CLIENT_TEST(h2_decoder_headers_trailer) {
     (void)allocator;
