From 1ae292a2457cd692828da2be87cb967260993ad0 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 22 Aug 2016 15:01:03 +0200 Subject: [PATCH] net: ipconfig: Fix NULL pointer dereference on RARP/BOOTP/DHCP timeout 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 Fixes: 2647cffb2bc6fbed ("net: ipconfig: Support using "delayed" DHCP replies") Signed-off-by: David S. Miller --- 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 ba9cbea..071a785 100644 --- a/net/ipv4/ipconfig.c +++ b/net/ipv4/ipconfig.c @@ -306,7 +306,7 @@ 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); } -- 2.7.4