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Message-ID: <20240625013645.45034-4-kuniyu@amazon.com>
Date: Mon, 24 Jun 2024 18:36:37 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>
CC: Rao Shoaib <Rao.Shoaib@...cle.com>, Kuniyuki Iwashima <kuniyu@...zon.com>,
Kuniyuki Iwashima <kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net 03/11] af_unix: Stop recv(MSG_PEEK) at consumed OOB skb.
After consuming OOB data, recv() reading the preceding data must break at
the OOB skb regardless of MSG_PEEK.
Currently, MSG_PEEK does not stop recv() for AF_UNIX, and the behaviour is
not compliant with TCP.
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX)
>>> c1.send(b'hello', MSG_OOB)
5
>>> c1.send(b'world')
5
>>> c2.recv(1, MSG_OOB)
b'o'
>>> c2.recv(9, MSG_PEEK) # This should return b'hell'
b'hellworld' # even with enough buffer.
Let's fix it by returning NULL for consumed skb and unlinking it only if
MSG_PEEK is not specified.
This patch also adds test cases that add recv(MSG_PEEK) before each recv().
Without fix:
# RUN msg_oob.peek.oob_ahead_break ...
# msg_oob.c:134:oob_ahead_break:AF_UNIX :hellworld
# msg_oob.c:135:oob_ahead_break:Expected:hell
# msg_oob.c:137:oob_ahead_break:Expected ret[0] (9) == expected_len (4)
# oob_ahead_break: Test terminated by assertion
# FAIL msg_oob.peek.oob_ahead_break
not ok 13 msg_oob.peek.oob_ahead_break
With fix:
# RUN msg_oob.peek.oob_ahead_break ...
# OK msg_oob.peek.oob_ahead_break
ok 13 msg_oob.peek.oob_ahead_break
Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
net/unix/af_unix.c | 9 ++++---
tools/testing/selftests/net/af_unix/msg_oob.c | 25 +++++++++++++++++--
2 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 5e695a9a609c..2eaecf9d78a4 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2613,9 +2613,12 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
{
struct unix_sock *u = unix_sk(sk);
- if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) {
- skb_unlink(skb, &sk->sk_receive_queue);
- consume_skb(skb);
+ if (!unix_skb_len(skb)) {
+ if (!(flags & MSG_PEEK)) {
+ skb_unlink(skb, &sk->sk_receive_queue);
+ consume_skb(skb);
+ }
+
skb = NULL;
} else {
struct sk_buff *unlinked_skb = NULL;
diff --git a/tools/testing/selftests/net/af_unix/msg_oob.c b/tools/testing/selftests/net/af_unix/msg_oob.c
index d427d39d0806..de8d1fcde883 100644
--- a/tools/testing/selftests/net/af_unix/msg_oob.c
+++ b/tools/testing/selftests/net/af_unix/msg_oob.c
@@ -21,6 +21,21 @@ FIXTURE(msg_oob)
*/
};
+FIXTURE_VARIANT(msg_oob)
+{
+ bool peek;
+};
+
+FIXTURE_VARIANT_ADD(msg_oob, no_peek)
+{
+ .peek = false,
+};
+
+FIXTURE_VARIANT_ADD(msg_oob, peek)
+{
+ .peek = true
+};
+
static void create_unix_socketpair(struct __test_metadata *_metadata,
FIXTURE_DATA(msg_oob) *self)
{
@@ -156,8 +171,14 @@ static void __recvpair(struct __test_metadata *_metadata,
__sendpair(_metadata, self, buf, len, flags)
#define recvpair(expected_buf, expected_len, buf_len, flags) \
- __recvpair(_metadata, self, \
- expected_buf, expected_len, buf_len, flags)
+ do { \
+ if (variant->peek) \
+ __recvpair(_metadata, self, \
+ expected_buf, expected_len, \
+ buf_len, (flags) | MSG_PEEK); \
+ __recvpair(_metadata, self, \
+ expected_buf, expected_len, buf_len, flags); \
+ } while (0)
TEST_F(msg_oob, non_oob)
{
--
2.30.2
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