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-rw-r--r--SOURCES/net-packet-fix-overflow-in-tpacket_rcv.patch59
1 files changed, 59 insertions, 0 deletions
diff --git a/SOURCES/net-packet-fix-overflow-in-tpacket_rcv.patch b/SOURCES/net-packet-fix-overflow-in-tpacket_rcv.patch
new file mode 100644
index 0000000..6c6868f
--- /dev/null
+++ b/SOURCES/net-packet-fix-overflow-in-tpacket_rcv.patch
@@ -0,0 +1,59 @@
+From 00c393ea14d12a4ef490a6aedf0fa6bfc2bfe8c3 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Thu, 3 Sep 2020 21:05:28 -0700
+Subject: net/packet: fix overflow in tpacket_rcv
+
+From: Or Cohen <orcohen@paloaltonetworks.com>
+
+[ Upstream commit acf69c946233259ab4d64f8869d4037a198c7f06 ]
+
+Using tp_reserve to calculate netoff can overflow as
+tp_reserve is unsigned int and netoff is unsigned short.
+
+This may lead to macoff receving a smaller value then
+sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr
+is set, an out-of-bounds write will occur when
+calling virtio_net_hdr_from_skb.
+
+The bug is fixed by converting netoff to unsigned int
+and checking if it exceeds USHRT_MAX.
+
+This addresses CVE-2020-14386
+
+Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt")
+Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com>
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ net/packet/af_packet.c | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
+index 301f41d4929bd..82f7802983797 100644
+--- a/net/packet/af_packet.c
++++ b/net/packet/af_packet.c
+@@ -2170,7 +2170,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
+ int skb_len = skb->len;
+ unsigned int snaplen, res;
+ unsigned long status = TP_STATUS_USER;
+- unsigned short macoff, netoff, hdrlen;
++ unsigned short macoff, hdrlen;
++ unsigned int netoff;
+ struct sk_buff *copy_skb = NULL;
+ struct timespec64 ts;
+ __u32 ts_status;
+@@ -2239,6 +2240,10 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
+ }
+ macoff = netoff - maclen;
+ }
++ if (netoff > USHRT_MAX) {
++ atomic_inc(&po->tp_drops);
++ goto drop_n_restore;
++ }
+ if (po->tp_version <= TPACKET_V2) {
+ if (macoff + snaplen > po->rx_ring.frame_size) {
+ if (po->copy_thresh &&
+--
+2.25.1
+