MINIR: mux-h1: Return 414 or 431 when appropriate

When the request is too large to fit in a buffer a 414 or a 431 error
message is returned depending on the error state of the request parser. A
414 is returned if the URI is too long, otherwise a 431 is returned.

This patch should fix the issue #1309.

Author: capflam

include/haproxy/h1.h

@@ -131,6 +131,7 @@ struct h1m {
 	uint64_t curr_len;          // content-length or last chunk length
 	uint64_t body_len;          // total known size of the body length
 	uint32_t next;              // next byte to parse, relative to buffer's head
+	unsigned int err_code;      // the HTTP status code corresponding to the error, if it can be specified (0: unset)
 	int err_pos;                // position in the byte stream of the first error (H1 or H2)
 	int err_state;              // state where the first error was met (H1 or H2)
 };
@@ -358,6 +359,7 @@ static inline struct h1m *h1m_init_req(struct h1m *h1m)
 	h1m->flags = H1_MF_NONE;
 	h1m->curr_len = 0;
 	h1m->body_len = 0;
+	h1m->err_code = 0;
 	h1m->err_pos = -2;
 	h1m->err_state = 0;
 	return h1m;
@@ -371,6 +373,7 @@ static inline struct h1m *h1m_init_res(struct h1m *h1m)
 	h1m->flags = H1_MF_RESP;
 	h1m->curr_len = 0;
 	h1m->body_len = 0;
+	h1m->err_code = 0;
 	h1m->err_pos = -2;
 	h1m->err_state = 0;
 	return h1m;

src/h1_htx.c

@@ -163,8 +163,10 @@ static int h1_postparse_req_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx
 	 * size allowed.
 	 */
 	if (h1_eval_htx_size(meth, uri, vsn, hdrs) > max) {
-		if (htx_is_empty(htx))
+		if (htx_is_empty(htx)) {
+			h1m->err_code = 431;
 			goto error;
+		}
 		goto output_full;
 	}
 
@@ -364,8 +366,13 @@ int h1_parse_msg_hdrs(struct h1m *h1m, union h1_sl *h1sl, struct htx *dsthtx,
 		 * contains headers and is full, which is detected by it being
 		 * full and the offset to be zero, it's an error because
 		 * headers are too large to be handled by the parser. */
-		if (ret < 0 || (!ret && !ofs && !buf_room_for_htx_data(srcbuf)))
+		if (ret < 0)
+			goto error;
+		if (!ret && !ofs && !buf_room_for_htx_data(srcbuf)) {
+			if (!(h1m->flags & H1_MF_RESP))
+				h1m->err_code = (h1m->err_state < H1_MSG_HDR_FIRST) ? 414: 431;
 			goto error;
+		}
 		goto end;
 	}
 	total = ret;

src/mux_h1.c

@@ -1926,6 +1926,8 @@ static size_t h1_handle_headers(struct h1s *h1s, struct h1m *h1m, struct htx *ht
 		TRACE_DEVEL("leaving on missing data or error", H1_EV_RX_DATA|H1_EV_RX_HDRS, h1s->h1c->conn, h1s);
 		if (ret == -1) {
 			h1s->flags |= H1S_F_PARSING_ERROR;
+			if (h1m->err_code)
+				h1s->h1c->errcode = h1m->err_code;
 			TRACE_ERROR("parsing error, reject H1 message", H1_EV_RX_DATA|H1_EV_RX_HDRS|H1_EV_H1S_ERR, h1s->h1c->conn, h1s);
 			h1_capture_bad_message(h1s->h1c, h1s, h1m, buf);
 		}