userns: Use kgids for sysctl_ping_group_range
- Store sysctl_ping_group_range as a paire of kgid_t values
instead of a pair of gid_t values.
- Move the kgid conversion work from ping_init_sock into ipv4_ping_group_range
- For invalid cases reset to the default disabled state.
With the kgid_t conversion made part of the original value sanitation
from userspace understand how the code will react becomes clearer
and it becomes possible to set the sysctl ping group range from
something other than the initial user namespace.
Cc: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 1b5ce96..3e78c79 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -76,9 +76,9 @@
}
-static void inet_get_ping_group_range_table(struct ctl_table *table, gid_t *low, gid_t *high)
+static void inet_get_ping_group_range_table(struct ctl_table *table, kgid_t *low, kgid_t *high)
{
- gid_t *data = table->data;
+ kgid_t *data = table->data;
unsigned int seq;
do {
seq = read_seqbegin(&sysctl_local_ports.lock);
@@ -89,12 +89,12 @@
}
/* Update system visible IP port range */
-static void set_ping_group_range(struct ctl_table *table, gid_t range[2])
+static void set_ping_group_range(struct ctl_table *table, kgid_t low, kgid_t high)
{
- gid_t *data = table->data;
+ kgid_t *data = table->data;
write_seqlock(&sysctl_local_ports.lock);
- data[0] = range[0];
- data[1] = range[1];
+ data[0] = low;
+ data[1] = high;
write_sequnlock(&sysctl_local_ports.lock);
}
@@ -103,21 +103,33 @@
void __user *buffer,
size_t *lenp, loff_t *ppos)
{
+ struct user_namespace *user_ns = current_user_ns();
int ret;
- gid_t range[2];
+ gid_t urange[2];
+ kgid_t low, high;
ctl_table tmp = {
- .data = &range,
- .maxlen = sizeof(range),
+ .data = &urange,
+ .maxlen = sizeof(urange),
.mode = table->mode,
.extra1 = &ip_ping_group_range_min,
.extra2 = &ip_ping_group_range_max,
};
- inet_get_ping_group_range_table(table, range, range + 1);
+ inet_get_ping_group_range_table(table, &low, &high);
+ urange[0] = from_kgid_munged(user_ns, low);
+ urange[1] = from_kgid_munged(user_ns, high);
ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
- if (write && ret == 0)
- set_ping_group_range(table, range);
+ if (write && ret == 0) {
+ low = make_kgid(user_ns, urange[0]);
+ high = make_kgid(user_ns, urange[1]);
+ if (!gid_valid(low) || !gid_valid(high) ||
+ (urange[1] < urange[0]) || gid_lt(high, low)) {
+ low = make_kgid(&init_user_ns, 1);
+ high = make_kgid(&init_user_ns, 0);
+ }
+ set_ping_group_range(table, low, high);
+ }
return ret;
}
@@ -786,7 +798,7 @@
{
.procname = "ping_group_range",
.data = &init_net.ipv4.sysctl_ping_group_range,
- .maxlen = sizeof(init_net.ipv4.sysctl_ping_group_range),
+ .maxlen = sizeof(gid_t)*2,
.mode = 0644,
.proc_handler = ipv4_ping_group_range,
},
@@ -830,8 +842,8 @@
* Sane defaults - nobody may create ping sockets.
* Boot scripts should set this to distro-specific group.
*/
- net->ipv4.sysctl_ping_group_range[0] = 1;
- net->ipv4.sysctl_ping_group_range[1] = 0;
+ net->ipv4.sysctl_ping_group_range[0] = make_kgid(&init_user_ns, 1);
+ net->ipv4.sysctl_ping_group_range[1] = make_kgid(&init_user_ns, 0);
tcp_init_mem(net);