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| author |   Eric Dumazet <edumazet@google.com> | 2025-09-02 12:46:42 +0000 |
|---|---|---|
| committer |   Jakub Kicinski <kuba@kernel.org> | 2025-09-03 17:06:30 -0700 |
| commit | 8156210d36a43e76372312c87eb5ea3dbb405a85 (patch) | |
| tree | 8dfaffc31f53e369edfe449c646bbd85c5fbdb35 | |
| parent | mctp: return -ENOPROTOOPT for unknown getsockopt options (diff) | |
| download | wireguard-linux-8156210d36a43e76372312c87eb5ea3dbb405a85.tar.xz wireguard-linux-8156210d36a43e76372312c87eb5ea3dbb405a85.zip | |
ax25: properly unshare skbs in ax25_kiss_rcv()
Bernard Pidoux reported a regression apparently caused by commit
c353e8983e0d ("net: introduce per netns packet chains").
skb->dev becomes NULL and we crash in __netif_receive_skb_core().
Before above commit, different kind of bugs or corruptions could happen
without a major crash.
But the root cause is that ax25_kiss_rcv() can queue/mangle input skb
without checking if this skb is shared or not.
Many thanks to Bernard Pidoux for his help, diagnosis and tests.
We had a similar issue years ago fixed with commit 7aaed57c5c28
("phonet: properly unshare skbs in phonet_rcv()").
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Bernard Pidoux <f6bvp@free.fr>
Closes: https://lore.kernel.org/netdev/1713f383-c538-4918-bc64-13b3288cd542@free.fr/
Tested-by: Bernard Pidoux <f6bvp@free.fr>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Joerg Reuter <jreuter@yaina.de>
Cc: David Ranch <dranch@trinnet.net>
Cc: Folkert van Heusden <folkert@vanheusden.com>
Reviewed-by: Dan Cross <crossd@gmail.com>
Link: https://patch.msgid.link/20250902124642.212705-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ax25/ax25_in.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ax25/ax25_in.c b/net/ax25/ax25_in.c index 1cac25aca637..f2d66af86359 100644 --- a/net/ax25/ax25_in.c +++ b/net/ax25/ax25_in.c @@ -433,6 +433,10 @@ free: int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) { + skb = skb_share_check(skb, GFP_ATOMIC); + if (!skb) + return NET_RX_DROP; + skb_orphan(skb); if (!net_eq(dev_net(dev), &init_net)) { |