diff mbox series

[net,v3,4/4] tcp: handle pure FIN case correctly

Message ID 20220817195445.151609-5-xiyou.wangcong@gmail.com (mailing list archive)
State Accepted
Commit 2e23acd99efacfd2a63cb9725afbc65e4e964fb7
Delegated to: Netdev Maintainers
Headers show
Series tcp: some bug fixes for tcp_read_skb() | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 427 this patch: 427
netdev/cc_maintainers fail 1 blamed authors not CCed: daniel@iogearbox.net; 6 maintainers not CCed: yoshfuji@linux-ipv6.org davem@davemloft.net daniel@iogearbox.net dsahern@kernel.org kuba@kernel.org pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 427 this patch: 427
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 19 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Cong Wang Aug. 17, 2022, 7:54 p.m. UTC 
From: Cong Wang <cong.wang@bytedance.com>

When skb->len==0, the recv_actor() returns 0 too, but we also use 0
for error conditions. This patch amends this by propagating the errors
to tcp_read_skb() so that we can distinguish skb->len==0 case from
error cases.

Fixes: 04919bed948d ("tcp: Introduce tcp_read_skb()")
Reported-by: Eric Dumazet <edumazet@google.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 net/core/skmsg.c | 5 +++--
 net/ipv4/tcp.c   | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index f47338d89d5d..59e75ffcc1f4 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -1194,8 +1194,9 @@  static int sk_psock_verdict_recv(struct sock *sk, struct sk_buff *skb)
 		ret = bpf_prog_run_pin_on_cpu(prog, skb);
 		ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
 	}
-	if (sk_psock_verdict_apply(psock, skb, ret) < 0)
-		len = 0;
+	ret = sk_psock_verdict_apply(psock, skb, ret);
+	if (ret < 0)
+		len = ret;
 out:
 	rcu_read_unlock();
 	return len;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 56a554b49caa..bbe218753662 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1768,7 +1768,7 @@  int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
 	__skb_unlink(skb, &sk->sk_receive_queue);
 	WARN_ON(!skb_set_owner_sk_safe(skb, sk));
 	copied = recv_actor(sk, skb);
-	if (copied > 0) {
+	if (copied >= 0) {
 		seq += copied;
 		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 			++seq;