diff options
| author | Antoine Tenart <atenart@kernel.org> | 2025-02-26 18:13:42 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-02-28 16:14:36 -0800 |
| commit | ee01b2f2d7d0010787c2343463965bbc283a497f (patch) | |
| tree | e0ac4e126506b56d3b4135bec7a09095938245b8 | |
| parent | 0fd7b2a432601997ad9f734e93125bc53ba20920 (diff) | |
net: gso: fix ownership in __udp_gso_segment
In __udp_gso_segment the skb destructor is removed before segmenting the
skb but the socket reference is kept as-is. This is an issue if the
original skb is later orphaned as we can hit the following bug:
kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan)
RIP: 0010:ip_rcv_core+0x8b2/0xca0
Call Trace:
ip_rcv+0xab/0x6e0
__netif_receive_skb_one_core+0x168/0x1b0
process_backlog+0x384/0x1100
__napi_poll.constprop.0+0xa1/0x370
net_rx_action+0x925/0xe50
The above can happen following a sequence of events when using
OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an
OVS_ACTION_ATTR_OUTPUT action:
1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb
goes through queue_gso_packets and then __udp_gso_segment, where its
destructor is removed.
2. The segments' data are copied and sent to userspace.
3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the
same original skb is sent to its path.
4. If it later hits skb_orphan, we hit the bug.
Fix this by also removing the reference to the socket in
__udp_gso_segment.
Fixes: ad405857b174 ("udp: better wmem accounting on gso")
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Link: https://patch.msgid.link/20250226171352.258045-1-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv4/udp_offload.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index a5be6e4ed326..ecfca59f31f1 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -321,13 +321,17 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, /* clear destructor to avoid skb_segment assigning it to tail */ copy_dtor = gso_skb->destructor == sock_wfree; - if (copy_dtor) + if (copy_dtor) { gso_skb->destructor = NULL; + gso_skb->sk = NULL; + } segs = skb_segment(gso_skb, features); if (IS_ERR_OR_NULL(segs)) { - if (copy_dtor) + if (copy_dtor) { gso_skb->destructor = sock_wfree; + gso_skb->sk = sk; + } return segs; } |