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authorBen Hutchings <ben@decadent.org.uk>2015-11-01 16:22:53 +0000
committerDavid S. Miller <davem@davemloft.net>2015-11-02 16:25:00 -0500
commit4ab42d78e37a294ac7bc56901d563c642e03c4ae (patch)
treeeed185aafd345a302f05711c3e6d5d80fca7c3f9 /drivers/isdn
parent0baa57d8dc32db78369d8b5176ef56c5e2e18ab3 (diff)
downloadlinux-4ab42d78e37a294ac7bc56901d563c642e03c4ae.tar.gz
ppp, slip: Validate VJ compression slot parameters completely
Currently slhc_init() treats out-of-range values of rslots and tslots
as equivalent to 0, except that if tslots is too large it will
dereference a null pointer (CVE-2015-7799).

Add a range-check at the top of the function and make it return an
ERR_PTR() on error instead of NULL.  Change the callers accordingly.

Compile-tested only.

Reported-by: 郭永刚 <guoyonggang@360.cn>
References: http://article.gmane.org/gmane.comp.security.oss.general/17908
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn')
-rw-r--r--drivers/isdn/i4l/isdn_ppp.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index 86f9abebcb72..9c1e8adaf4fc 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -322,9 +322,9 @@ isdn_ppp_open(int min, struct file *file)
 	 * VJ header compression init
 	 */
 	is->slcomp = slhc_init(16, 16);	/* not necessary for 2. link in bundle */
-	if (!is->slcomp) {
+	if (IS_ERR(is->slcomp)) {
 		isdn_ppp_ccp_reset_free(is);
-		return -ENOMEM;
+		return PTR_ERR(is->slcomp);
 	}
 #endif
 #ifdef CONFIG_IPPP_FILTER
@@ -573,10 +573,8 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
 			is->maxcid = val;
 #ifdef CONFIG_ISDN_PPP_VJ
 			sltmp = slhc_init(16, val);
-			if (!sltmp) {
-				printk(KERN_ERR "ippp, can't realloc slhc struct\n");
-				return -ENOMEM;
-			}
+			if (IS_ERR(sltmp))
+				return PTR_ERR(sltmp);
 			if (is->slcomp)
 				slhc_free(is->slcomp);
 			is->slcomp = sltmp;