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