tree a7361ded3c6c5f3793d607c6f58d86d526ea4e67
parent 4ab8438362e9c37338350984afb76b393769f998
author Christopher Faulet <cfaulet@haproxy.com> 1646058596 +0100
committer Christopher Faulet <cfaulet@haproxy.com> 1646065015 +0100

BUG/MEDIUM: htx: Fix a possible null derefs in htx_xfer_blks()

In htx_xfer_blks() function, when headers or trailers are partially
transferred, we rollback the copy by removing copied blocks. Internally, all
blocks between <dstref> and <dstblk> are removed. But if the transfer was
stopped because we failed to reserve a block, the variable <dstblk> is
NULL. Thus, we must not try to remove it. It is unexpected to call
htx_remove_blk() in this case.

htx_remove_blk() was updated to test <blk> variable inside the existing
BUG_ON(). The block must be defined.

For now, this bug may only be encountered when H2 trailers are copied. On H2
headers, the destination buffer is empty. Thus a swap is performed.

This patch should fix the issue #1578. It must be backported as far as 2.4.