diff options
| author | Andrew Kanner <andrew.kanner@gmail.com> | 2023-08-03 20:59:48 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-08-07 19:14:41 -0700 |
| commit | 59eeb232940515590de513b997539ef495faca9a (patch) | |
| tree | b7b965f7742632b0fab0a65e720e508f2a2bfb7c /drivers/net/tun.c | |
| parent | fa41884c1c6deb6774135390e5813a97184903e0 (diff) | |
drivers: net: prevent tun_build_skb() to exceed the packet size limit
Using the syzkaller repro with reduced packet size it was discovered
that XDP_PACKET_HEADROOM is not checked in tun_can_build_skb(),
although pad may be incremented in tun_build_skb(). This may end up
with exceeding the PAGE_SIZE limit in tun_build_skb().
Jason Wang <jasowang@redhat.com> proposed to count XDP_PACKET_HEADROOM
always (e.g. without rcu_access_pointer(tun->xdp_prog)) in
tun_can_build_skb() since there's a window during which XDP program
might be attached between tun_can_build_skb() and tun_build_skb().
Fixes: 7df13219d757 ("tun: reserve extra headroom only when XDP is set")
Link: https://syzkaller.appspot.com/bug?extid=f817490f5bd20541b90a
Signed-off-by: Andrew Kanner <andrew.kanner@gmail.com>
Link: https://lore.kernel.org/r/20230803185947.2379988-1-andrew.kanner@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 25f0191df00b..100339bc8b04 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1594,7 +1594,7 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, if (zerocopy) return false; - if (SKB_DATA_ALIGN(len + TUN_RX_PAD) + + if (SKB_DATA_ALIGN(len + TUN_RX_PAD + XDP_PACKET_HEADROOM) + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) return false; |