52 lines
1.5 KiB
Diff
52 lines
1.5 KiB
Diff
From: Willem de Bruijn <willemb@google.com>
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Date: Thu, 10 Aug 2017 12:41:58 -0400
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Subject: packet: fix tp_reserve race in packet_set_ring
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Origin: https://git.kernel.org/linus/c27927e372f0785f3303e8fad94b85945e2c97b7
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Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-1000111
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Updates to tp_reserve can race with reads of the field in
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packet_set_ring. Avoid this by holding the socket lock during
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updates in setsockopt PACKET_RESERVE.
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This bug was discovered by syzkaller.
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Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt")
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Reported-by: Andrey Konovalov <andreyknvl@google.com>
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Signed-off-by: Willem de Bruijn <willemb@google.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/packet/af_packet.c | 13 +++++++++----
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1 file changed, 9 insertions(+), 4 deletions(-)
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diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
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index 0615c2a950fa..008a45ca3112 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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@@ -3700,14 +3700,19 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv
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if (optlen != sizeof(val))
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return -EINVAL;
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- if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
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- return -EBUSY;
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if (copy_from_user(&val, optval, sizeof(val)))
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return -EFAULT;
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if (val > INT_MAX)
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return -EINVAL;
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- po->tp_reserve = val;
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- return 0;
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+ lock_sock(sk);
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+ if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
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+ ret = -EBUSY;
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+ } else {
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+ po->tp_reserve = val;
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+ ret = 0;
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+ }
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+ release_sock(sk);
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+ return ret;
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}
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case PACKET_LOSS:
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{
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--
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2.11.0
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