From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Andrew Hendry" <andrew.hendry@gmail.com>,
"kiyin(尹亮)" <kiyin@tencent.com>,
"Martin Schiller" <ms@dev.tdt.de>
Cc: "security@kernel.org" <security@kernel.org>,
"linux-distros@vs.openwall.org" <linux-distros@vs.openwall.org>,
"huntchen(陈阳)" <huntchen@tencent.com>,
"dannywang(王宇)" <dannywang@tencent.com>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
linux-x25@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH net] net/x25: prevent a couple of overflows
Date: Mon, 30 Nov 2020 13:04:25 +0300 [thread overview]
Message-ID: <20201130100425.GB2789@kadam> (raw)
In-Reply-To: <61d3e7e75f704996bf312ef5d271bcea@tencent.com>
From: "kiyin(尹亮)" <kiyin@tencent.com>
The .x25_addr[] address comes from the user and is not necessarily
NUL terminated. This leads to a couple problems. The first problem is
that the strlen() in x25_bind() can read beyond the end of the buffer.
The second problem is more subtle and could result in memory corruption.
The call tree is:
x25_connect()
--> x25_write_internal()
--> x25_addr_aton()
The .x25_addr[] buffers are copied to the "addresses" buffer from
x25_write_internal() so it will lead to stack corruption.
The x25 protocol only allows 15 character addresses so putting a NUL
terminator as the 16th character is safe and obviously preferable to
reading out of bounds.
Signed-off-by: "kiyin(尹亮)" <kiyin@tencent.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
net/x25/af_x25.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index 0bbb283f23c9..3180f15942fe 100644
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -686,6 +686,8 @@ static int x25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
goto out;
}
+ addr->sx25_addr.x25_addr[X25_ADDR_LEN - 1] = '\0';
+
/* check for the null_x25_address */
if (strcmp(addr->sx25_addr.x25_addr, null_x25_address.x25_addr)) {
@@ -779,6 +781,7 @@ static int x25_connect(struct socket *sock, struct sockaddr *uaddr,
goto out;
rc = -ENETUNREACH;
+ addr->sx25_addr.x25_addr[X25_ADDR_LEN - 1] = '\0';
rt = x25_get_route(&addr->sx25_addr);
if (!rt)
goto out;
--
2.28.0
next parent reply other threads:[~2020-11-30 10:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <61d3e7e75f704996bf312ef5d271bcea@tencent.com>
2020-11-30 10:04 ` Dan Carpenter [this message]
2020-12-01 6:50 ` [PATCH net] net/x25: prevent a couple of overflows Martin Schiller
2020-12-01 15:15 ` [PATCH net v2] " Dan Carpenter
2020-12-02 7:43 ` [PATCH net v2] net/x25: prevent a couple of overflows(Internet mail) kiyin(尹亮)
2020-12-02 9:27 ` [PATCH net v2] net/x25: prevent a couple of overflows Martin Schiller
2020-12-03 1:27 ` Jakub Kicinski
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