netdev - [PATCH AUTOSEL 5.10 56/65] net: limit altnames to 64k total

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:   Fri,  1 Apr 2022 10:41:57 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Jakub Kicinski <kuba@...nel.org>,
        George Shuklin <george.shuklin@...il.com>,
        David Ahern <dsahern@...nel.org>,
        Sasha Levin <sashal@...nel.org>, davem@...emloft.net,
        pabeni@...hat.com, idosch@...dia.com, petrm@...dia.com,
        edumazet@...gle.com, yajun.deng@...ux.dev, johannes.berg@...el.com,
        cong.wang@...edance.com, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 5.10 56/65] net: limit altnames to 64k total

From: Jakub Kicinski <kuba@...nel.org>

[ Upstream commit 155fb43b70b5fce341347a77d1af2765d1e8fbb8 ]

Property list (altname is a link "property") is wrapped
in a nlattr. nlattrs length is 16bit so practically
speaking the list of properties can't be longer than
that, otherwise user space would have to interpret
broken netlink messages.

Prevent the problem from occurring by checking the length
of the property list before adding new entries.

Reported-by: George Shuklin <george.shuklin@...il.com>
Reviewed-by: David Ahern <dsahern@...nel.org>
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/core/rtnetlink.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 77b3d9cc08a1..873081cda950 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3626,12 +3626,23 @@ static int rtnl_alt_ifname(int cmd, struct net_device *dev, struct nlattr *attr,
 			   bool *changed, struct netlink_ext_ack *extack)
 {
 	char *alt_ifname;
+	size_t size;
 	int err;
 
 	err = nla_validate(attr, attr->nla_len, IFLA_MAX, ifla_policy, extack);
 	if (err)
 		return err;
 
+	if (cmd == RTM_NEWLINKPROP) {
+		size = rtnl_prop_list_size(dev);
+		size += nla_total_size(ALTIFNAMSIZ);
+		if (size >= U16_MAX) {
+			NL_SET_ERR_MSG(extack,
+				       "effective property list too long");
+			return -EINVAL;
+		}
+	}
+
 	alt_ifname = nla_strdup(attr, GFP_KERNEL_ACCOUNT);
 	if (!alt_ifname)
 		return -ENOMEM;
-- 
2.34.1