[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: Jesper Juhl <jesper.juhl@gmail.com>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index 1751990..26e4672 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -2536,6 +2536,11 @@
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) {