From: Geert Uytterhoeven geert+renesas@glider.be
commit 1ae292a2457cd692828da2be87cb967260993ad0 upstream.
If no RARP, BOOTP, or DHCP response is received, ic_dev is never set, causing a NULL pointer dereference in ic_close_devs():
Sending DHCP requests ...... timed out! Unable to handle kernel NULL pointer dereference at virtual address 00000004
To fix this, add a check to avoid dereferencing ic_dev if it is still NULL.
Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be Fixes: 2647cffb2bc6fbed ("net: ipconfig: Support using "delayed" DHCP replies") Signed-off-by: David S. Miller davem@davemloft.net [Patryk: cherry-picked to 4.4] Signed-off-by: Patryk Mungai patryk.mungai-ndungu.kx@renesas.com --- net/ipv4/ipconfig.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c index 6b78590..ca658af 100644 --- a/net/ipv4/ipconfig.c +++ b/net/ipv4/ipconfig.c @@ -313,7 +313,7 @@ static void __init ic_close_devs(void) while ((d = next)) { next = d->next; dev = d->dev; - if (dev != ic_dev->dev && !netdev_uses_dsa(dev)) { + if ((!ic_dev || dev != ic_dev->dev) && !netdev_uses_dsa(dev)) { pr_debug("IP-Config: Downing %s\n", dev->name); dev_change_flags(dev, d->flags); }