diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2014-12-05 17:19:27 -0600 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2014-12-05 17:19:27 -0600 |
| commit | 7ff4d90b4c24a03666f296c3d4878cd39001e81e (patch) | |
| tree | 757293c98c93eec1c5b7caae149c34e49bb824c5 | |
| parent | 4fed655c410cc56add64c7b1f7c85c7c56066ac2 (diff) | |
| download | lwn-7ff4d90b4c24a03666f296c3d4878cd39001e81e.tar.gz lwn-7ff4d90b4c24a03666f296c3d4878cd39001e81e.zip | |
groups: Consolidate the setgroups permission checks
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.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| -rw-r--r-- | arch/s390/kernel/compat_linux.c | 2 | ||||
| -rw-r--r-- | include/linux/cred.h | 1 | ||||
| -rw-r--r-- | kernel/groups.c | 9 | ||||
| -rw-r--r-- | kernel/uid16.c | 2 |
4 files changed, 11 insertions, 3 deletions
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c index ca38139423ae..437e61159279 100644 --- a/arch/s390/kernel/compat_linux.c +++ b/arch/s390/kernel/compat_linux.c @@ -249,7 +249,7 @@ COMPAT_SYSCALL_DEFINE2(s390_setgroups16, int, gidsetsize, u16 __user *, grouplis struct group_info *group_info; int retval; - if (!capable(CAP_SETGID)) + if (!may_setgroups()) return -EPERM; if ((unsigned)gidsetsize > NGROUPS_MAX) return -EINVAL; diff --git a/include/linux/cred.h b/include/linux/cred.h index b2d0820837c4..2fb2ca2127ed 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -68,6 +68,7 @@ extern void groups_free(struct group_info *); 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) \ diff --git a/kernel/groups.c b/kernel/groups.c index 451698f86cfa..02d8a251c476 100644 --- 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, gidsetsize, gid_t __user *, grouplist) 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; diff --git a/kernel/uid16.c b/kernel/uid16.c index 602e5bbbceff..d58cc4d8f0d1 100644 --- a/kernel/uid16.c +++ b/kernel/uid16.c @@ -176,7 +176,7 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist) 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; |