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authorVladimir Oltean <vladimir.oltean@nxp.com>2021-03-22 03:26:37 +0300
committerDavid S. Miller <davem@davemloft.net>2021-03-22 22:57:51 +0300
commita50a151e311bd3a793ebe4e5f233db8bfad0b78f (patch)
treed81a9fcf75885e0ff423382d1c03be500fe38a8c /net
parent6debc0fd71b947b03c1a39cc100f52b8238259d4 (diff)
downloadlinux-a50a151e311bd3a793ebe4e5f233db8bfad0b78f.tar.xz
net: ipconfig: ic_dev can be NULL in ic_close_devs
ic_close_dev contains a generalization of the logic to not close a network interface if it's the host port for a DSA switch. This logic is disguised behind an iteration through the lowers of ic_dev in ic_close_dev. When no interface for ipconfig can be found, ic_dev is NULL, and ic_close_dev: - dereferences a NULL pointer when assigning selected_dev - would attempt to search through the lower interfaces of a NULL net_device pointer So we should protect against that case. The "lower_dev" iterator variable was shortened to "lower" in order to keep the 80 character limit. Fixes: f68cbaed67cb ("net: ipconfig: avoid use-after-free in ic_close_devs") Fixes: 46acf7bdbc72 ("Revert "net: ipv4: handle DSA enabled master network devices"") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Tested-by: Heiko Thiery <heiko.thiery@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ipconfig.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 47db1bfdaaa0..bc2f6ca97152 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -309,7 +309,7 @@ have_carrier:
*/
static void __init ic_close_devs(void)
{
- struct net_device *selected_dev = ic_dev->dev;
+ struct net_device *selected_dev = ic_dev ? ic_dev->dev : NULL;
struct ic_device *d, *next;
struct net_device *dev;
@@ -317,16 +317,18 @@ static void __init ic_close_devs(void)
next = ic_first_dev;
while ((d = next)) {
bool bring_down = (d != ic_dev);
- struct net_device *lower_dev;
+ struct net_device *lower;
struct list_head *iter;
next = d->next;
dev = d->dev;
- netdev_for_each_lower_dev(selected_dev, lower_dev, iter) {
- if (dev == lower_dev) {
- bring_down = false;
- break;
+ if (selected_dev) {
+ netdev_for_each_lower_dev(selected_dev, lower, iter) {
+ if (dev == lower) {
+ bring_down = false;
+ break;
+ }
}
}
if (bring_down) {