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Message-Id: <20220321133216.895955622@linuxfoundation.org>
Date: Mon, 21 Mar 2022 14:51:38 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
John Fastabend <john.fastabend@...il.com>,
Jakub Sitnicki <jakub@...udflare.com>,
Daniel Borkmann <daniel@...earbox.net>,
Jakub Kicinski <kuba@...nel.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 08/16] tcp: make tcp_read_sock() more robust
From: Eric Dumazet <edumazet@...gle.com>
[ Upstream commit e3d5ea2c011ecb16fb94c56a659364e6b30fac94 ]
If recv_actor() returns an incorrect value, tcp_read_sock()
might loop forever.
Instead, issue a one time warning and make sure to make progress.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Acked-by: John Fastabend <john.fastabend@...il.com>
Acked-by: Jakub Sitnicki <jakub@...udflare.com>
Acked-by: Daniel Borkmann <daniel@...earbox.net>
Link: https://lore.kernel.org/r/20220302161723.3910001-2-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
net/ipv4/tcp.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index aeda018e4c49..6dfb964e1ad8 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1561,11 +1561,13 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
if (!copied)
copied = used;
break;
- } else if (used <= len) {
- seq += used;
- copied += used;
- offset += used;
}
+ if (WARN_ON_ONCE(used > len))
+ used = len;
+ seq += used;
+ copied += used;
+ offset += used;
+
/* If recv_actor drops the lock (e.g. TCP splice
* receive) the skb pointer might be invalid when
* getting here: tcp_collapse might have deleted it
--
2.34.1
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