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Commit da17c73b authored by Eric Dumazet's avatar Eric Dumazet Committed by Pablo Neira Ayuso
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netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target} 



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: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
Acked-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 889c604f

net/netfilter/x_tables.c

+6 −0
Original line number Diff line number Diff line
@@ -209,6 +209,9 @@ xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision) 
{

	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);
@@ -251,6 +254,9 @@ struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision) 
{

	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);