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authorEric Dumazet <edumazet@google.com>2018-01-24 17:16:09 -0800
committerPablo Neira Ayuso <pablo@netfilter.org>2018-01-25 12:31:34 +0100
commitda17c73b6eb74aad3c3c0654394635675b623b3e (patch)
tree18783216423e8a3bbf86391b2e940424c0b2dba4 /net
parent889c604fd0b5f6d3b8694ade229ee44124de1127 (diff)
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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: 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>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/x_tables.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index e02a21549c99..d7070d18db20 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -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);