Patch "netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target}" has been added to the 4.9-stable tree

Patch "netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target}" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target}

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netfilter-x_tables-avoid-out-of-bounds-reads-in-xt_request_find_-match-target.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From da17c73b6eb74aad3c3c0654394635675b623b3e Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 24 Jan 2018 17:16:09 -0800
Subject: netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target}

From: Eric Dumazet <edumazet@google.com>

commit da17c73b6eb74aad3c3c0654394635675b623b3e upstream.

It looks like syzbot found its way into netfilter territory.

Issue here is that @name comes from user space and might
not be null terminated.

Out-of-bound reads happen, KASAN is not happy.

v2 added similar fix for xt_request_find_target(),
as Florian advised.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/netfilter/x_tables.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -207,6 +207,9 @@ xt_request_find_match(uint8_t nfproto, c
 {
 	struct xt_match *match;
 
+	if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
+		return ERR_PTR(-EINVAL);
+
 	match = xt_find_match(nfproto, name, revision);
 	if (IS_ERR(match)) {
 		request_module("%st_%s", xt_prefix[nfproto], name);
@@ -249,6 +252,9 @@ struct xt_target *xt_request_find_target
 {
 	struct xt_target *target;
 
+	if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
+		return ERR_PTR(-EINVAL);
+
 	target = xt_find_target(af, name, revision);
 	if (IS_ERR(target)) {
 		request_module("%st_%s", xt_prefix[af], name);


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.9/kcm-check-if-sk_user_data-already-set-in-kcm_attach.patch
queue-4.9/netfilter-x_tables-avoid-out-of-bounds-reads-in-xt_request_find_-match-target.patch
queue-4.9/kcm-only-allow-tcp-sockets-to-be-attached-to-a-kcm-mux.patch
queue-4.9/netfilter-xt_rateest-acquire-xt_rateest_mutex-for-hash-insert.patch