diff options
| author | Yang Yang <yang.yang29@zte.com.cn> | 2021-07-19 18:43:28 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-07-20 07:15:22 -0700 |
| commit | 8292d7f6e8712381a828eac2a19a610ce680c4dd (patch) | |
| tree | 0ef685d728205720d2c4f58e95249788d1688b48 | |
| parent | b79c6fba6cd7c49a7dbea9999e182f74cca63e19 (diff) | |
net: ipv4: add capability check for net administration
Root in init user namespace can modify /proc/sys/net/ipv4/ip_forward
without CAP_NET_ADMIN, this doesn't follow the principle of
capabilities. For example, let's take a look at netdev_store(),
root can't modify netdev attribute without CAP_NET_ADMIN.
So let's keep the consistency of permission check logic.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/devinet.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index d38124bd1b94..94b648d9eaff 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -2424,11 +2424,15 @@ static int devinet_sysctl_forward(struct ctl_table *ctl, int write, int *valp = ctl->data; int val = *valp; loff_t pos = *ppos; - int ret = proc_dointvec(ctl, write, buffer, lenp, ppos); + struct net *net = ctl->extra2; + int ret; - if (write && *valp != val) { - struct net *net = ctl->extra2; + if (write && !ns_capable(net->user_ns, CAP_NET_ADMIN)) + return -EPERM; + + ret = proc_dointvec(ctl, write, buffer, lenp, ppos); + if (write && *valp != val) { if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) { if (!rtnl_trylock()) { /* Restore the original values before restarting */ |