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author | David S. Miller <davem@davemloft.net> | 2022-02-09 14:41:48 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2022-02-09 14:41:48 +0300 |
commit | 676b49366a70ea91997585ba8e4577290f5172a5 (patch) | |
tree | 5ddb6e2fe01cc4820bc36c63dc3383c698dfd708 | |
parent | 7db788ad627aabff2b74d4f1a3b68516d0fee0d7 (diff) | |
parent | 9eeabdf17fa0ab75381045c867c370f4cc75a613 (diff) | |
download | linux-676b49366a70ea91997585ba8e4577290f5172a5.tar.xz |
Merge branch 'net-fix-skb-unclone-issues'
Antoine Tenart says:
====================
net: fix issues when uncloning an skb dst+metadata
This fixes two issues when uncloning an skb dst+metadata in
tun_dst_unclone; this was initially reported by Vlad Buslov[1]. Because
of the memory leak fixed by patch 2, the issue in patch 1 never happened
in practice.
tun_dst_unclone is called from two different places, one in geneve/vxlan
to handle PMTU and one in net/openvswitch/actions.c where it is used to
retrieve tunnel information. While both Vlad and I tested the former, we
could not for the latter. I did spend quite some time trying to, but
that code path is not easy to trigger. Code inspection shows this should
be fine, the tunnel information (dst+metadata) is uncloned and the skb
it is referenced from is only consumed after all accesses to the tunnel
information are done:
do_execute_actions
output_userspace
dev_fill_metadata_dst <- dst+metadata is uncloned
ovs_dp_upcall
queue_userspace_packet
ovs_nla_put_tunnel_info <- metadata (tunnel info) is accessed
consume_skb <- dst+metadata is freed
Thanks!
Antoine
[1] https://lore.kernel.org/all/ygnhh79yluw2.fsf@nvidia.com/T/#m2f814614a4f5424cea66bbff7297f692b59b69a0
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r-- | include/net/dst_metadata.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h index 14efa0ded75d..adab27ba1ecb 100644 --- a/include/net/dst_metadata.h +++ b/include/net/dst_metadata.h @@ -123,8 +123,20 @@ static inline struct metadata_dst *tun_dst_unclone(struct sk_buff *skb) memcpy(&new_md->u.tun_info, &md_dst->u.tun_info, sizeof(struct ip_tunnel_info) + md_size); +#ifdef CONFIG_DST_CACHE + /* Unclone the dst cache if there is one */ + if (new_md->u.tun_info.dst_cache.cache) { + int ret; + + ret = dst_cache_init(&new_md->u.tun_info.dst_cache, GFP_ATOMIC); + if (ret) { + metadata_dst_free(new_md); + return ERR_PTR(ret); + } + } +#endif + skb_dst_drop(skb); - dst_hold(&new_md->dst); skb_dst_set(skb, &new_md->dst); return new_md; } |