summaryrefslogtreecommitdiffstats
path: root/net/core
diff options
context:
space:
mode:
authorJakub Kicinski <kuba@kernel.org>2022-03-09 10:29:14 -0800
committerJakub Kicinski <kuba@kernel.org>2022-03-10 20:15:23 -0800
commit155fb43b70b5fce341347a77d1af2765d1e8fbb8 (patch)
treef2284583cd179aa85c97b4f0439c6af6d4414387 /net/core
parent5d26cff5bdbebdf98ba48217c078ff102536f134 (diff)
downloadlinux-155fb43b70b5fce341347a77d1af2765d1e8fbb8.tar.bz2
net: limit altnames to 64k total
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@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/rtnetlink.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index aa05e89cc47c..159c9c61e6af 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3652,12 +3652,23 @@ 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;