Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
netfilter: nft_meta: no longer acquire sk_callback_lock in nft_meta_get_eval_skugid()
After commit 983512f3a87f ("net: Drop the lock in skb_may_tx_timestamp()")
from Sebastian Andrzej Siewior, apply the same logic in
nft_meta_get_eval_skugid() to avoid touching sk->sk_callback_lock.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
authored by
Eric Dumazet
and committed by
Florian Westphal
afc2125d
cdec942a
+13
-10
+13
-10
net/netfilter/nft_meta.c
+13
-10
net/netfilter/nft_meta.c
···
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u32 *dest,
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const struct nft_pktinfo *pkt)
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{
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-
struct sock *sk = skb_to_full_sk(pkt->skb);
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-
struct socket *sock;
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+
const struct sock *sk = skb_to_full_sk(pkt->skb);
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+
const struct socket *sock;
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+
const struct file *file;
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if (!sk || !sk_fullsock(sk) || !net_eq(nft_net(pkt), sock_net(sk)))
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return false;
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-
read_lock_bh(&sk->sk_callback_lock);
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-
sock = sk->sk_socket;
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-
if (!sock || !sock->file) {
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read_unlock_bh(&sk->sk_callback_lock);
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+
/* The sk pointer remains valid as long as the skb is. The sk_socket and
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* file pointer may become NULL if the socket is closed. Both structures
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+
* (including file->cred) are RCU freed which means they can be accessed
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* within a RCU read section.
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+
*/
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+
sock = READ_ONCE(sk->sk_socket);
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+
file = sock ? READ_ONCE(sock->file) : NULL;
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+
if (!file)
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return false;
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-
}
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switch (key) {
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case NFT_META_SKUID:
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*dest = from_kuid_munged(sock_net(sk)->user_ns,
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-
sock->file->f_cred->fsuid);
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+
file->f_cred->fsuid);
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break;
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case NFT_META_SKGID:
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*dest = from_kgid_munged(sock_net(sk)->user_ns,
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-
sock->file->f_cred->fsgid);
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+
file->f_cred->fsgid);
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break;
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default:
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break;
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}
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-
read_unlock_bh(&sk->sk_callback_lock);
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return true;
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}
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