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| author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2021-03-22 03:26:37 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-03-22 22:57:51 +0300 |
| commit | a50a151e311bd3a793ebe4e5f233db8bfad0b78f (patch) | |
| tree | d81a9fcf75885e0ff423382d1c03be500fe38a8c /net/ipv4 | |
| parent | 6debc0fd71b947b03c1a39cc100f52b8238259d4 (diff) | |
| download | linux-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/ipv4')
| -rw-r--r-- | net/ipv4/ipconfig.c | 14 |
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) { |