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Message-ID: <20241023191757.56735-1-kuniyu@amazon.com>
Date: Wed, 23 Oct 2024 12:17:57 -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: Ignat Korchagin <ignat@...udflare.com>, Kuniyuki Iwashima
<kuniyu@...zon.com>, Kuniyuki Iwashima <kuni1840@...il.com>,
<netdev@...r.kernel.org>
Subject: [PATCH v1 net-next] socket: Print pf->create() when it does not clear sock->sk on failure.
I suggested to put DEBUG_NET_WARN_ON_ONCE() in __sock_create() to
catch possible use-after-free.
But the warning itself was not useful because our interest is in
the callee than the caller.
Let's define DEBUG_NET_WARN_ONCE() and print the name of pf->create()
and the socket identifier.
While at it, we enclose DEBUG_NET_WARN_ON_ONCE() in parentheses too
to avoid a checkpatch error.
Note that %pf or %pF were obsoleted and later removed as per comment
in lib/vsprintf.c.
Link: https://lore.kernel.org/netdev/202410231427.633734b3-lkp@intel.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
include/net/net_debug.h | 4 +++-
net/socket.c | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/include/net/net_debug.h b/include/net/net_debug.h
index 1e74684cbbdb..9fecb1496be3 100644
--- a/include/net/net_debug.h
+++ b/include/net/net_debug.h
@@ -149,9 +149,11 @@ do { \
#if defined(CONFIG_DEBUG_NET)
-#define DEBUG_NET_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
+#define DEBUG_NET_WARN_ON_ONCE(cond) ((void)WARN_ON_ONCE(cond))
+#define DEBUG_NET_WARN_ONCE(cond, format...) ((void)WARN_ONCE(cond, format))
#else
#define DEBUG_NET_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
+#define DEBUG_NET_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
#endif
#endif /* _LINUX_NET_DEBUG_H */
diff --git a/net/socket.c b/net/socket.c
index 9a8e4452b9b2..da00db3824e3 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1578,7 +1578,9 @@ int __sock_create(struct net *net, int family, int type, int protocol,
/* ->create should release the allocated sock->sk object on error
* and make sure sock->sk is set to NULL to avoid use-after-free
*/
- DEBUG_NET_WARN_ON_ONCE(sock->sk);
+ DEBUG_NET_WARN_ONCE(sock->sk,
+ "%pS must clear sock->sk on failure, family: %d, type: %d, protocol: %d\n",
+ pf->create, family, type, protocol);
goto out_module_put;
}
--
2.39.5 (Apple Git-154)
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