tree 26fbfd3dc6c2c40c25c88843e47f79b8e2e4e31e
parent ed8d19c2a5ff5579c92cd8612ee9360c21d75d9f
author Florian Westphal <fw@strlen.de> 1705787404 +0100
committer Nandhini Rengaraj <nrengaraj@google.com> 1707512379 +0000

netfilter: nf_tables: reject QUEUE/DROP verdict parameters

commit f342de4e2f33e0e39165d8639387aa6c19dff660 upstream.

This reverts commit e0abdadcc6e1.

core.c:nf_hook_slow assumes that the upper 16 bits of NF_DROP
verdicts contain a valid errno, i.e. -EPERM, -EHOSTUNREACH or similar,
or 0.

Due to the reverted commit, its possible to provide a positive
value, e.g. NF_ACCEPT (1), which results in use-after-free.

Its not clear to me why this commit was made.

NF_QUEUE is not used by nftables; "queue" rules in nftables
will result in use of "nft_queue" expression.

If we later need to allow specifiying errno values from userspace
(do not know why), this has to call NF_DROP_GETERR and check that
"err <= 0" holds true.

BUG=b/324041363
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-1086 in the linux kernel.

cos-patch: security-high
Fixes: e0abdadcc6e1 ("netfilter: nf_tables: accept QUEUE/DROP verdict parameters")
Cc: stable@vger.kernel.org
Reported-by: Notselwyn <notselwyn@pwning.tech>
Change-Id: I03a877e536402c5c02ee4a7a568c31f2cafdaab5
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Nandhini Rengaraj <nrengaraj@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/64770
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>