From 0348dcd98af3b9bf3ddf4785e74b335bdc65bc4d Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Thu, 5 Jul 2018 18:49:23 +0000 Subject: [PATCH] ipv4: Return EINVAL when ping_group_range sysctl doesn't map to user ns [ Upstream commit 70ba5b6db96ff7324b8cfc87e0d0383cf59c9677 ] The low and high values of the net.ipv4.ping_group_range sysctl were being silently forced to the default disabled state when a write to the sysctl contained GIDs that didn't map to the associated user namespace. Confusingly, the sysctl's write operation would return success and then a subsequent read of the sysctl would indicate that the low and high values are the overflowgid. This patch changes the behavior by clearly returning an error when the sysctl write operation receives a GID range that doesn't map to the associated user namespace. In such a situation, the previous value of the sysctl is preserved and that range will be returned in a subsequent read of the sysctl. Signed-off-by: Tyler Hicks Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/sysctl_net_ipv4.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 5a29dc5083a3..d82e8344fc54 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -186,8 +186,9 @@ static int ipv4_ping_group_range(struct ctl_table *table, int write, 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)) { + if (!gid_valid(low) || !gid_valid(high)) + return -EINVAL; + if (urange[1] < urange[0] || gid_lt(high, low)) { low = make_kgid(&init_user_ns, 1); high = make_kgid(&init_user_ns, 0); }