From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Subject: [PATCH net] AX.25: Prevent integer overflows in connect and sendmsg Date: Thu, 23 Jul 2020 17:49:57 +0300 Message-ID: <20200723144957.GA293102@mwanda> References: <20200722.175714.1713497446730685740.davem@davemloft.net> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=jykVeaaj1de3HdC9bQbpFC12yVlqXQBg90kokCdh8VM=; b=OFlBu+ZyA5PUaIeiOHa/OCO2esXfYFSgbTbN/iF6x97HEwumrDf9+IkqKtNqXm/GYFv5 e8ugZFFlFLyXTwGS+s2/86DvWT+5baDMN0wmlm0U5VUKOUjH+oCXl5hLdJfOvIkPTWcf TSB1DboGbimlTcmNuiJNxfR+nuNVh35WU4yYWGfg+MYkHsz/O75pjf548HXsDnmaZhYr 5m1QJa+aP7FOOaGmDIuisacRMNHHOfKAwxxMFVwAezt+53XE13aUNLg71ouzVwJriKJf xyAmSX7cj8uSsyrSO9/ZEtOViSQTmaYVay+M9qtnWjcSVdvwFEbepHt9sp0dmdfzC4xK ew== Content-Disposition: inline In-Reply-To: <20200722.175714.1713497446730685740.davem@davemloft.net> Sender: linux-hams-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Joerg Reuter , Peilin Ye Cc: Ralf Baechle , "David S. Miller" , Jakub Kicinski , linux-hams@vger.kernel.org, netdev@vger.kernel.org, gregkh@linuxfoundation.org, syzkaller-bugs@googlegroups.com, linux-kernel-mentees@lists.linuxfoundation.org We recently added some bounds checking in ax25_connect() and ax25_sendmsg() and we so we removed the AX25_MAX_DIGIS checks because they were no longer required. Unfortunately, I believe they are required to prevent integer overflows so I have added them back. Fixes: 8885bb0621f0 ("AX.25: Prevent out-of-bounds read in ax25_sendmsg()") Fixes: 2f2a7ffad5c6 ("AX.25: Fix out-of-bounds read in ax25_connect()") Signed-off-by: Dan Carpenter --- >From code review. Not tested. It should be harmless though. net/ax25/af_ax25.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index 0862fe49d434..dec3f35467c9 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -1188,6 +1188,7 @@ static int __must_check ax25_connect(struct socket *sock, fsa->fsa_ax25.sax25_ndigis != 0) { /* Valid number of digipeaters ? */ if (fsa->fsa_ax25.sax25_ndigis < 1 || + fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS || addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * fsa->fsa_ax25.sax25_ndigis) { err = -EINVAL; @@ -1509,7 +1510,9 @@ 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 || addr_len < sizeof(struct sockaddr_ax25) + + if (usax->sax25_ndigis < 1 || + usax->sax25_ndigis > AX25_MAX_DIGIS || + addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * usax->sax25_ndigis) { err = -EINVAL; goto out; -- 2.27.0