From: Eric Dumazet Date: Thu, 25 Jan 2018 01:16:09 +0000 (-0800) Subject: netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target} X-Git-Tag: C0P2-H0.0--20200415~5175 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=b39f3f381bf3ba387d62655539a8979085cb6ff6;p=linux.git netfilter: x_tables: avoid out-of-bounds reads in xt_request_find_{match|target} 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 Reported-by: syzbot Acked-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 3de763aa143d..e47ade305a46 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -207,6 +207,9 @@ 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); @@ -249,6 +252,9 @@ 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);