Commit f6e2cdc8 authored by Jesper Juhl's avatar Jesper Juhl Committed by Linus Torvalds
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[PATCH] ISDN: Avoid a potential NULL ptr deref in ippp 



There's a potential problem in isdn_ppp.c::isdn_ppp_decompress().
dev_alloc_skb() may fail and return NULL. If it does we will be passing a
NULL skb_out to ipc->decompress() and may also end up
dereferencing a NULL pointer at

    *proto = isdn_ppp_strip_proto(skb_out);

Correct this by testing 'skb_out' against NULL early and bail out.

Signed-off-by: default avatarJesper Juhl <jesper.juhl@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ba6d14af

drivers/isdn/i4l/isdn_ppp.c

+5 −0
Original line number Diff line number Diff line
@@ -2536,6 +2536,11 @@ static struct sk_buff *isdn_ppp_decompress(struct sk_buff *skb,struct ippp_struc 
  		rsparm.maxdlen = IPPP_RESET_MAXDATABYTES;

  

  		skb_out = dev_alloc_skb(is->mru + PPP_HDRLEN);

  		if (!skb_out) {

  			kfree_skb(skb);

  			printk(KERN_ERR "ippp: decomp memory allocation failure\n");

			return NULL;

  		}

		len = ipc->decompress(stat, skb, skb_out, &rsparm);

		kfree_skb(skb);

		if (len <= 0) {