From: Christopher Faulet <cfaulet@haproxy.com>
Date: Mon, 2 Mar 2020 15:20:05 +0000 (+0100)
Subject: BUG/MEDIUM: compression/filters: Fix loop on HTX blocks compressing the payload
X-Git-Tag: v2.2-dev4~39
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e6a62bf79655623da0ecd7e412175bf38c99ab9d;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: compression/filters: Fix loop on HTX blocks compressing the payload

During the payload filtering, the offset is relative to the head of the HTX
message and not its first index. This index is the position of the first block
to (re)start the HTTP analysis. It must be used during HTTP analysis but not
during the payload forwarding.

So, from the compression filter point of view, when we loop on the HTX blocks to
compress the response payload, we must start from the head of the HTX
message. To ease the loop, we use the function htx_find_offset().

This patch must be backported as far as 2.0. It depends on the commit "MINOR:
htx: Add a function to return a block at a specific an offset". So this one must
be backported first.
---

diff --git a/src/flt_http_comp.c b/src/flt_http_comp.c
index 574b937349..b456fcd7a4 100644
--- a/src/flt_http_comp.c
+++ b/src/flt_http_comp.c
@@ -177,19 +177,17 @@ comp_http_payload(struct stream *s, struct filter *filter, struct http_msg *msg,
 {
 	struct comp_state *st = filter->ctx;
 	struct htx *htx = htxbuf(&msg->chn->buf);
+	struct htx_ret htxret = htx_find_offset(htx, offset);
 	struct htx_blk *blk;
 	int ret, consumed = 0, to_forward = 0;
 
-	for (blk = htx_get_first_blk(htx); blk && len; blk = htx_get_next_blk(htx, blk)) {
+	blk = htxret.blk;
+	offset = htxret.ret;
+	for (; blk && len; blk = htx_get_next_blk(htx, blk)) {
 		enum htx_blk_type type = htx_get_blk_type(blk);
 		uint32_t sz = htx_get_blksz(blk);
 		struct ist v;
 
-		if (offset >= sz) {
-			offset -= sz;
-			continue;
-		}
-
 		switch (type) {
 			case HTX_BLK_UNUSED:
 				break;