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authorAntoine Tenart <atenart@kernel.org>2025-02-26 18:13:42 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-03-13 13:07:54 +0100
commitc32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b (patch)
tree0c20a9eae281e0e348e677ac93f0a6e2601f05e9 /net
parent882ddfb1808f2e3317517da6592fc780ead6ddb6 (diff)
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net: gso: fix ownership in __udp_gso_segment
[ Upstream commit ee01b2f2d7d0010787c2343463965bbc283a497f ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/udp_offload.c8
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;
}