From d888b7af7c149c115dd6ac772cc11c375da3e17c Mon Sep 17 00:00:00 2001 From: Zijian Zhang Date: Tue, 10 Dec 2024 01:20:39 +0000 Subject: tcp_bpf: Add sk_rmem_alloc related logic for tcp_bpf ingress redirection When we do sk_psock_verdict_apply->sk_psock_skb_ingress, an sk_msg will be created out of the skb, and the rmem accounting of the sk_msg will be handled by the skb. For skmsgs in __SK_REDIRECT case of tcp_bpf_send_verdict, when redirecting to the ingress of a socket, although we sk_rmem_schedule and add sk_msg to the ingress_msg of sk_redir, we do not update sk_rmem_alloc. As a result, except for the global memory limit, the rmem of sk_redir is nearly unlimited. Thus, add sk_rmem_alloc related logic to limit the recv buffer. Since the function sk_msg_recvmsg and __sk_psock_purge_ingress_msg are used in these two paths. We use "msg->skb" to test whether the sk_msg is skb backed up. If it's not, we shall do the memory accounting explicitly. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Zijian Zhang Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Link: https://lore.kernel.org/bpf/20241210012039.1669389-3-zijianzhang@bytedance.com --- net/core/skmsg.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'net/core/skmsg.c') diff --git a/net/core/skmsg.c b/net/core/skmsg.c index e90fbab703b2..8ad7e6755fd6 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -445,8 +445,10 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg, if (likely(!peek)) { sge->offset += copy; sge->length -= copy; - if (!msg_rx->skb) + if (!msg_rx->skb) { sk_mem_uncharge(sk, copy); + atomic_sub(copy, &sk->sk_rmem_alloc); + } msg_rx->sg.size -= copy; if (!sge->length) { @@ -772,6 +774,8 @@ static void __sk_psock_purge_ingress_msg(struct sk_psock *psock) list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) { list_del(&msg->list); + if (!msg->skb) + atomic_sub(msg->sg.size, &psock->sk->sk_rmem_alloc); sk_msg_free(psock->sk, msg); kfree(msg); } -- cgit