commit 52131680c42ddbfa6f2b5d109ffc79c28f44e42a
Author: Christopher Faulet <cfaulet@haproxy.com>
Date:   Thu Jun 27 17:40:14 2019 +0200

    BUG/MINOR: mux-h1: Skip trailers for non-chunked outgoing messages
    
    Unlike H1, H2 messages may contains trailers while the header "Content-Length"
    is set. Indeed, because of the framed structure of HTTP/2, it is no longer
    necessary to use the chunked transfer encoding. So Trailing HEADERS frames,
    after all DATA frames, may be added on messages with an explicit content length.
    
    But in H1, it is impossible to have trailers on non-chunked messages. So when
    outgoing messages are formatted by the H1 multiplexer, if the message is not
    chunked, all trailers must be dropped.
    
    This patch must be backported to 2.0 and 1.9. However, the patch will have to be
    adapted for the 1.9.
    
    (cherry picked from commit 5433a0b0215c791b4165bddd360a254fa141c6e9)
    Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>

diff --git a/src/mux_h1.c b/src/mux_h1.c
index e497e6f6..e7d769b4 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -1696,7 +1696,9 @@ static size_t h1_process_output(struct h1c *h1c, struct buffer *buf, size_t coun
 					goto done;
 				}
 				else if (type == HTX_BLK_EOT || type == HTX_BLK_TLR) {
-					if (!chunk_memcat(&tmp, "0\r\n", 3))
+					/* If the message is not chunked, never
+					 * add the last chunk. */
+					if ((h1m->flags & H1_MF_CHNK) && !chunk_memcat(&tmp, "0\r\n", 3))
 						goto copy;
 					goto trailers;
 				}
@@ -1715,6 +1717,11 @@ static size_t h1_process_output(struct h1c *h1c, struct buffer *buf, size_t coun
 					goto error;
 			  trailers:
 				h1m->state = H1_MSG_TRAILERS;
+				/* If the message is not chunked, ignore
+				 * trailers. It may happen with H2 messages. */
+				if (!(h1m->flags & H1_MF_CHNK))
+					break;
+
 				if (type == HTX_BLK_EOT) {
 					if (!chunk_memcat(&tmp, "\r\n", 2))
 						goto copy;