From: Peilin Ye <yepeilin.cs@gmail.com>
To: Joerg Reuter <jreuter@yaina.de>, Ralf Baechle <ralf@linux-mips.org>
Cc: syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org,
Peilin Ye <yepeilin.cs@gmail.com>,
netdev@vger.kernel.org, linux-hams@vger.kernel.org,
Jakub Kicinski <kuba@kernel.org>,
linux-kernel-mentees@lists.linuxfoundation.org,
"David S . Miller" <davem@davemloft.net>
Subject: [Linux-kernel-mentees] [PATCH net] AX.25: Prevent out-of-bounds read in ax25_sendmsg()
Date: Wed, 22 Jul 2020 12:05:12 -0400 [thread overview]
Message-ID: <20200722160512.370802-1-yepeilin.cs@gmail.com> (raw)
Checks on `addr_len` and `usax->sax25_ndigis` are insufficient.
ax25_sendmsg() can go out of bounds when `usax->sax25_ndigis` equals to 7
or 8. Fix it.
It is safe to remove `usax->sax25_ndigis > AX25_MAX_DIGIS`, since
`addr_len` is guaranteed to be less than or equal to
`sizeof(struct full_sockaddr_ax25)`
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
net/ax25/af_ax25.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index ef5bf116157a..0862fe49d434 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1509,7 +1509,8 @@ static int ax25_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)usax;
/* Valid number of digipeaters ? */
- if (usax->sax25_ndigis < 1 || usax->sax25_ndigis > AX25_MAX_DIGIS) {
+ if (usax->sax25_ndigis < 1 || addr_len < sizeof(struct sockaddr_ax25) +
+ sizeof(ax25_address) * usax->sax25_ndigis) {
err = -EINVAL;
goto out;
}
--
2.25.1
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next reply other threads:[~2020-07-22 16:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 16:05 Peilin Ye [this message]
2020-07-23 1:07 ` [Linux-kernel-mentees] [PATCH net] AX.25: Prevent out-of-bounds read in ax25_sendmsg() David Miller
2020-07-24 22:25 ` David Ranch
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