Message ID | 1516842969.3715.41.camel@gmail.com |
---|---|
State | Awaiting Upstream, archived |
Delegated to: | David Miller |
Headers | show |
Series | [v2,net] netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target} | expand |
Eric Dumazet <eric.dumazet@gmail.com> wrote: > From: Eric Dumazet <edumazet@google.com> > > 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> Thanks a lot Eric! Acked-by: Florian Westphal <fw@strlen.de>
On Wed, Jan 24, 2018 at 05:16:09PM -0800, Eric Dumazet wrote: > From: Eric Dumazet <edumazet@google.com> > > 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. Applied, thanks Eric.
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 55802e97f906d1987ed78b4296584deb38e5f876..ecffc51ce83b07c063a0db67cdb33d9bf48a75ac 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -210,6 +210,9 @@ 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); @@ -252,6 +255,9 @@ 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);