This is a note to let you know that I've just added the patch titled
groups: Consolidate the setgroups permission checks
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
groups-consolidate-the-setgroups-permission-checks.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 7ff4d90b4c24a03666f296c3d4878cd39001e81e Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <[email protected]>
Date: Fri, 5 Dec 2014 17:19:27 -0600
Subject: groups: Consolidate the setgroups permission checks
From: "Eric W. Biederman" <[email protected]>
commit 7ff4d90b4c24a03666f296c3d4878cd39001e81e upstream.
Today there are 3 instances of setgroups and due to an oversight their
permission checking has diverged. Add a common function so that
they may all share the same permission checking code.
This corrects the current oversight in the current permission checks
and adds a helper to avoid this in the future.
A user namespace security fix will update this new helper, shortly.
Signed-off-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/s390/kernel/compat_linux.c | 2 +-
include/linux/cred.h | 1 +
kernel/groups.c | 9 ++++++++-
kernel/uid16.c | 2 +-
4 files changed, 11 insertions(+), 3 deletions(-)
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -249,7 +249,7 @@ COMPAT_SYSCALL_DEFINE2(s390_setgroups16,
struct group_info *group_info;
int retval;
- if (!capable(CAP_SETGID))
+ if (!may_setgroups())
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -68,6 +68,7 @@ extern void groups_free(struct group_inf
extern int set_current_groups(struct group_info *);
extern void set_groups(struct cred *, struct group_info *);
extern int groups_search(const struct group_info *, kgid_t);
+extern bool may_setgroups(void);
/* access the groups "array" with this macro */
#define GROUP_AT(gi, i) \
--- a/kernel/groups.c
+++ b/kernel/groups.c
@@ -213,6 +213,13 @@ out:
return i;
}
+bool may_setgroups(void)
+{
+ struct user_namespace *user_ns = current_user_ns();
+
+ return ns_capable(user_ns, CAP_SETGID);
+}
+
/*
* SMP: Our groups are copy-on-write. We can set them safely
* without another task interfering.
@@ -223,7 +230,7 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsi
struct group_info *group_info;
int retval;
- if (!ns_capable(current_user_ns(), CAP_SETGID))
+ if (!may_setgroups())
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
--- a/kernel/uid16.c
+++ b/kernel/uid16.c
@@ -176,7 +176,7 @@ SYSCALL_DEFINE2(setgroups16, int, gidset
struct group_info *group_info;
int retval;
- if (!ns_capable(current_user_ns(), CAP_SETGID))
+ if (!may_setgroups())
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
Patches currently in stable-queue which might be from [email protected] are
queue-3.18/mnt-update-unprivileged-remount-test.patch
queue-3.18/mnt-fix-a-memory-stomp-in-umount.patch
queue-3.18/userns-check-euid-no-fsuid-when-establishing-an-unprivileged-uid-mapping.patch
queue-3.18/mnt-implicitly-add-mnt_nodev-on-remount-when-it-was-implicitly-added-by-mount.patch
queue-3.18/userns-don-t-allow-unprivileged-creation-of-gid-mappings.patch
queue-3.18/userns-rename-id_map_mutex-to-userns_state_mutex.patch
queue-3.18/userns-add-a-knob-to-disable-setgroups-on-a-per-user-namespace-basis.patch
queue-3.18/userns-allow-setting-gid_maps-without-privilege-when-setgroups-is-disabled.patch
queue-3.18/userns-don-t-allow-setgroups-until-a-gid-mapping-has-been-setablished.patch
queue-3.18/groups-consolidate-the-setgroups-permission-checks.patch
queue-3.18/userns-only-allow-the-creator-of-the-userns-unprivileged-mappings.patch
queue-3.18/userns-document-what-the-invariant-required-for-safe-unprivileged-mappings.patch
queue-3.18/umount-disallow-unprivileged-mount-force.patch
queue-3.18/userns-unbreak-the-unprivileged-remount-tests.patch
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