[PATCH 4.10 24/62] ipv6: sr: fix out-of-bounds access in SRH validation

[Greg Kroah-Hartman]

4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Lebrun <david.lebrun@xxxxxxxxxxxx>


[ Upstream commit 2f3bb64247b5b083d05ccecad9c2e139bbfdc294 ]

This patch fixes an out-of-bounds access in seg6_validate_srh() when the
trailing data is less than sizeof(struct sr6_tlv).

Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: David Lebrun <david.lebrun@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/seg6.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/ipv6/seg6.c
+++ b/net/ipv6/seg6.c
@@ -53,6 +53,9 @@ bool seg6_validate_srh(struct ipv6_sr_hd
 		struct sr6_tlv *tlv;
 		unsigned int tlv_len;
 
+		if (trailing < sizeof(*tlv))
+			return false;
+
 		tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
 		tlv_len = sizeof(*tlv) + tlv->len;