leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

net: limit altnames to 64k total

Browse Source 
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>
This commit is contained in:
Jakub Kicinski
2022-03-09 10:29:14 -08:00
parent 5d26cff5bd
commit 155fb43b70
1 changed files with 11 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
net/core/rtnetlink.c
View File

@@ -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;