BUG/MEDIUM: mux-h2: make sure we don't emit TE headers with anything but "trailers"

While the H2 parser properly checks for the absence of anything but
"trailers" in the TE header field, we forget to check this when sending
the request to an H2 server. The problem is that an H2->H2 conversion
may keep "gzip" and fail on the next stage.

This patch makes sure that we only send "TE: trailers" if the TE header
contains the "trailers" token, otherwise it's dropped.

This fixes issue #464 and should be backported till 1.9.

diff --git a/src/mux_h2.c b/src/mux_h2.c
index 1a1d2ff53205303c4ba973a892dc88ec079d6fc0..df7a4e680dd35b6977993e3f7a2c3e145766a101 100644 (file)
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -5011,23 +5011,36 @@ static size_t h2s_bck_make_req_headers(struct h2s *h2s, struct htx *htx)
         * do not provide an authority.
         */
        for (hdr = 0; hdr < sizeof(list)/sizeof(list[0]); hdr++) {
+               struct ist n = list[hdr].n;
+               struct ist v = list[hdr].v;
+
                /* these ones do not exist in H2 and must be dropped. */
-               if (isteq(list[hdr].n, ist("connection")) ||
-                   (auth.len && isteq(list[hdr].n, ist("host"))) ||
-                   isteq(list[hdr].n, ist("proxy-connection")) ||
-                   isteq(list[hdr].n, ist("keep-alive")) ||
-                   isteq(list[hdr].n, ist("upgrade")) ||
-                   isteq(list[hdr].n, ist("transfer-encoding")))
+               if (isteq(n, ist("connection")) ||
+                   (auth.len && isteq(n, ist("host"))) ||
+                   isteq(n, ist("proxy-connection")) ||
+                   isteq(n, ist("keep-alive")) ||
+                   isteq(n, ist("upgrade")) ||
+                   isteq(n, ist("transfer-encoding")))
                        continue;
 
+               if (isteq(n, ist("te"))) {
+                       /* "te" may only be sent with "trailers" if this value
+                        * is present, otherwise it must be deleted.
+                        */
+                       v = istist(v, ist("trailers"));
+                       if (!v.ptr || (v.len > 8 && v.ptr[8] != ','))
+                               continue;
+                       v = ist("trailers");
+               }
+
                /* Skip all pseudo-headers */
-               if (*(list[hdr].n.ptr) == ':')
+               if (*(n.ptr) == ':')
                        continue;
 
-               if (isteq(list[hdr].n, ist("")))
+               if (isteq(n, ist("")))
                        break; // end
 
-               if (!hpack_encode_header(&outbuf, list[hdr].n, list[hdr].v)) {
+               if (!hpack_encode_header(&outbuf, n, v)) {
                        /* output full */
                        if (b_space_wraps(mbuf))
                                goto realign_again;