netfilter: nf_log: avoid oops in (un)bind with invalid nfproto values
Like many other places, we have to check that the array index is
within allowed limits, or otherwise, a kernel oops and other nastiness
can ensue when we access memory beyond the end of the array.
[ 5954.115381] BUG: unable to handle kernel paging request at 0000004000000000
[ 5954.120014] IP: __find_logger+0x6f/0xa0
[ 5954.123979] nf_log_bind_pf+0x2b/0x70
[ 5954.123979] nfulnl_recv_config+0xc0/0x4a0 [nfnetlink_log]
[ 5954.123979] nfnetlink_rcv_msg+0x12c/0x1b0 [nfnetlink]
...
The problem goes back to v2.6.30-rc1~1372~1342~31 where nf_log_bind
was decoupled from nf_log_register.
Reported-by: Miguel Di Ciurcio Filho <miguel.filho@gmail.com>,
via irc.freenode.net/#netfilter
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index b07393e..9181699 100644
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -85,6 +85,8 @@
int nf_log_bind_pf(u_int8_t pf, const struct nf_logger *logger)
{
+ if (pf >= ARRAY_SIZE(nf_loggers))
+ return -EINVAL;
mutex_lock(&nf_log_mutex);
if (__find_logger(pf, logger->name) == NULL) {
mutex_unlock(&nf_log_mutex);
@@ -98,6 +100,8 @@
void nf_log_unbind_pf(u_int8_t pf)
{
+ if (pf >= ARRAY_SIZE(nf_loggers))
+ return;
mutex_lock(&nf_log_mutex);
rcu_assign_pointer(nf_loggers[pf], NULL);
mutex_unlock(&nf_log_mutex);