From: Christopher Faulet <cfaulet@haproxy.com>
Date: Mon, 2 Mar 2020 15:19:50 +0000 (+0100)
Subject: BUG/MEDIUM: cache/filters: Fix loop on HTX blocks caching the response payload
X-Git-Tag: v2.2-dev4~40
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=497c7595588371e8ac85c322825455d7c7d4e407;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: cache/filters: Fix loop on HTX blocks caching the response 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 cache point of view, when we loop on the HTX blocks to cache 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/cache.c b/src/cache.c
index b0be2094d6..4a0051f00a 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -314,6 +314,7 @@ cache_store_http_payload(struct stream *s, struct filter *filter, struct http_ms
 	struct htx *htx = htxbuf(&msg->chn->buf);
 	struct htx_blk *blk;
 	struct shared_block *fb;
+	struct htx_ret htxret;
 	unsigned int orig_len, to_forward;
 	int ret;
 
@@ -328,16 +329,15 @@ cache_store_http_payload(struct stream *s, struct filter *filter, struct http_ms
 	chunk_reset(&trash);
 	orig_len = len;
 	to_forward = 0;
-	for (blk = htx_get_first_blk(htx); blk && len; blk = htx_get_next_blk(htx, blk)) {
+
+	htxret = htx_find_offset(htx, offset);
+	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 info, sz = htx_get_blksz(blk);
 		struct ist v;
 
-		if (offset >= sz) {
-			offset -= sz;
-			continue;
-		}
-
 		switch (type) {
 			case HTX_BLK_UNUSED:
 				break;