diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2013-10-05 13:15:30 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-10-07 15:57:56 -0400 |
| commit | 88ba09df236c618b5466d35a0165df0dc865eac5 (patch) | |
| tree | 76a1a70777d5be16ef1fd4b224cd44b71cb96969 /net | |
| parent | fe119a05f8ca481623a8d02efcc984332e612528 (diff) | |
| download | linux-88ba09df236c618b5466d35a0165df0dc865eac5.tar.bz2 | |
net: Update the sysctl permissions handler to test effective uid/gid
On Tue, 20 Aug 2013 11:40:04 -0500 Eric Sandeen <sandeen@redhat.com> wrote:
> This was brought up in a Red Hat bug (which may be marked private, I'm sorry):
>
> Bug 987055 - open O_WRONLY succeeds on some root owned files in /proc for process running with unprivileged EUID
>
> "On RHEL7 some of the files in /proc can be opened for writing by an unprivileged EUID."
>
> The flaw existed upstream as well last I checked.
>
> This commit in kernel v3.8 caused the regression:
>
> commit cff109768b2d9c03095848f4cd4b0754117262aa
> Author: Eric W. Biederman <ebiederm@xmission.com>
> Date: Fri Nov 16 03:03:01 2012 +0000
>
> net: Update the per network namespace sysctls to be available to the network namespace owner
>
> - Allow anyone with CAP_NET_ADMIN rights in the user namespace of the
> the netowrk namespace to change sysctls.
> - Allow anyone the uid of the user namespace root the same
> permissions over the network namespace sysctls as the global root.
> - Allow anyone with gid of the user namespace root group the same
> permissions over the network namespace sysctl as the global root group.
>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
> because it changed /sys/net's special permission handler to test current_uid, not
> current_euid; same for current_gid/current_egid.
>
> So in this case, root cannot drop privs via set[ug]id, and retains all privs
> in this codepath.
Modify the code to use current_euid(), and in_egroup_p, as in done
in fs/proc/proc_sysctl.c:test_perm()
Cc: stable@vger.kernel.org
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sysctl_net.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/sysctl_net.c b/net/sysctl_net.c index 9bc6db04be3e..e7000be321b0 100644 --- a/net/sysctl_net.c +++ b/net/sysctl_net.c @@ -47,12 +47,12 @@ static int net_ctl_permissions(struct ctl_table_header *head, /* Allow network administrator to have same access as root. */ if (ns_capable(net->user_ns, CAP_NET_ADMIN) || - uid_eq(root_uid, current_uid())) { + uid_eq(root_uid, current_euid())) { int mode = (table->mode >> 6) & 7; return (mode << 6) | (mode << 3) | mode; } /* Allow netns root group to have the same access as the root group */ - if (gid_eq(root_gid, current_gid())) { + if (in_egroup_p(root_gid)) { int mode = (table->mode >> 3) & 7; return (mode << 3) | mode; } |