[PATCH RESEND bpf 2/4] bpf, sockmap: Fix missing BPF_F_INGRESS flag when using apply_bytes

Pengcheng Yang
2022-11-22T01:59:28Z

When redirecting, we use sk_msg_to_ingress() to get the BPF_F_INGRESS
flag from the msg->flags. If apply_bytes is used and it is larger than
the current data being processed, sk_psock_msg_verdict() will not be
called when sendmsg() is called again. At this time, the msg->flags is 0,
and we lost the BPF_F_INGRESS flag.

So we need to save the BPF_F_INGRESS flag in sk_psock and assign it to
msg->flags before redirection.

Fixes: 8934ce2fd081 ("bpf: sockmap redirect ingress support")
Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
---
include/linux/skmsg.h | 1 +
net/core/skmsg.c | 1 +
net/ipv4/tcp_bpf.c | 1 +
net/tls/tls_sw.c | 1 +
4 files changed, 4 insertions(+)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 48f4b64..e1d463f 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -82,6 +82,7 @@ struct sk_psock {
u32 apply_bytes;
u32 cork_bytes;
u32 eval;
+ u32 flags;
struct sk_msg *cork;
struct sk_psock_progs progs;
#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 188f855..ab2f8f3 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -888,6 +888,7 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
if (psock->sk_redir)
sock_put(psock->sk_redir);
psock->sk_redir = msg->sk_redir;
+ psock->flags = msg->flags;
if (!psock->sk_redir) {
ret = __SK_DROP;
goto out;
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index ef5de4f..1390d72 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -323,6 +323,7 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
break;
case __SK_REDIRECT:
sk_redir = psock->sk_redir;
+ msg->flags = psock->flags;
sk_msg_apply_bytes(psock, tosend);
if (!psock->apply_bytes) {
/* Clean up before releasing the sock lock. */
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index fe27241..49e424d 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -838,6 +838,7 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk,
break;
case __SK_REDIRECT:
sk_redir = psock->sk_redir;
+ msg->flags = psock->flags;
memcpy(&msg_redir, msg, sizeof(*msg));
if (msg->apply_bytes < send)
msg->apply_bytes = 0;
--
1.8.3.1