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From 5db86df6a849684fda6a7ee53978a1ba931848cb Mon Sep 17 00:00:00 2001
Message-Id: <5db86df6a849684fda6a7ee53978a1ba931848cb.1495014490.git.davide.caratti@gmail.com>
From: Davide Caratti <davide.caratti@gmail.com>
Date: Fri, 24 Mar 2017 10:25:24 +0100
Subject: [PATCH] macsec_linux: Fix NULL pointer dereference on error cases
In case wpa_supplicant is using driver_macsec_linux, but macsec module
is not (yet) loaded in the kernel, nl_socket_alloc() fails and drv->sk
is NULL. In this case, don't call libnl functions rntl_link_add() or
rtnl_link_change() using such NULL pointer, to prevent program from
getting segmentation faults like:
Program received signal SIGSEGV, Segmentation fault.
nl_socket_get_local_port (sk=sk@entry=0x0) at socket.c:365
365 if (sk->s_local.nl_pid == 0) {
(gdb) p sk
$1 = (const struct nl_sock *) 0x0
(gdb) bt
#0 nl_socket_get_local_port (sk=sk@entry=0x0) at socket.c:365
#1 0x00007ffff79c56a0 in nl_complete_msg (sk=sk@entry=0x0,
msg=msg@entry=0x55555595a1f0) at nl.c:491
#2 0x00007ffff79c56d1 in nl_send_auto (sk=sk@entry=0x0,
msg=msg@entry=0x55555595a1f0) at nl.c:522
#3 0x00007ffff79c652f in nl_send_sync (sk=sk@entry=0x0,
msg=0x55555595a1f0) at nl.c:556
#4 0x00007ffff755faf5 in rtnl_link_add (sk=0x0,
link=link@entry=0x55555595b0f0, flags=flags@entry=1024) at route/link.c:1548
#5 0x000055555567a298 in macsec_drv_create_transmit_sc (priv=0x55555593b130,
sc=0x55555593b320, conf_offset=<optimized out>) at ../src/drivers/driver_macsec_linux.c:998
Signed-off-by: Davide Caratti <davide.caratti@gmail.com>
---
src/drivers/driver_macsec_linux.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/src/drivers/driver_macsec_linux.c b/src/drivers/driver_macsec_linux.c
index 5dab77a..0694e60 100644
--- a/src/drivers/driver_macsec_linux.c
+++ b/src/drivers/driver_macsec_linux.c
@@ -168,6 +168,9 @@ static int try_commit(struct macsec_drv_data *drv)
{
int err;
+ if (!drv->sk)
+ return 0;
+
if (!drv->link)
return 0;
@@ -982,6 +985,11 @@ static int macsec_drv_create_transmit_sc(
wpa_printf(MSG_DEBUG, "%s", __func__);
+ if (!drv->sk) {
+ wpa_printf(MSG_ERROR, DRV_PREFIX "NULL rtnl socket");
+ return -1;
+ }
+
link = rtnl_link_macsec_alloc();
if (!link) {
wpa_printf(MSG_ERROR, DRV_PREFIX "couldn't allocate link");
@@ -1048,6 +1056,9 @@ static int macsec_drv_delete_transmit_sc(void *priv, struct transmit_sc *sc)
wpa_printf(MSG_DEBUG, "%s", __func__);
+ if (!drv->sk)
+ return 0;
+
if (!drv->created_link) {
rtnl_link_put(drv->link);
drv->link = NULL;
--
2.7.4