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Commit 7ff4d90b authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

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: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 4fed655c

arch/s390/kernel/compat_linux.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -249,7 +249,7 @@ COMPAT_SYSCALL_DEFINE2(s390_setgroups16, int, gidsetsize, u16 __user *, grouplis 
	struct group_info *group_info;

	struct group_info *group_info;

	int retval;

	int retval;





	if (!capable(CAP_SETGID))

	if (!may_setgroups())

		return -EPERM;

		return -EPERM;

	if ((unsigned)gidsetsize > NGROUPS_MAX)

	if ((unsigned)gidsetsize > NGROUPS_MAX)

		return -EINVAL;

		return -EINVAL;

include/linux/cred.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -68,6 +68,7 @@ extern void groups_free(struct group_info *); 
extern int set_current_groups(struct group_info *);

extern int set_current_groups(struct group_info *);

extern void set_groups(struct cred *, struct group_info *);

extern void set_groups(struct cred *, struct group_info *);

extern int groups_search(const struct group_info *, kgid_t);

extern int groups_search(const struct group_info *, kgid_t);

extern bool may_setgroups(void);





/* access the groups "array" with this macro */

/* access the groups "array" with this macro */

#define GROUP_AT(gi, i) \

#define GROUP_AT(gi, i) \

kernel/groups.c

+8 −1
Original line number Original line Diff line number Diff line
@@ -213,6 +213,13 @@ SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist) 
	return i;

	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

 *	SMP: Our groups are copy-on-write. We can set them safely

 *	without another task interfering.

 *	without another task interfering.
@@ -223,7 +230,7 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist) 
	struct group_info *group_info;

	struct group_info *group_info;

	int retval;

	int retval;





	if (!ns_capable(current_user_ns(), CAP_SETGID))

	if (!may_setgroups())

		return -EPERM;

		return -EPERM;

	if ((unsigned)gidsetsize > NGROUPS_MAX)

	if ((unsigned)gidsetsize > NGROUPS_MAX)

		return -EINVAL;

		return -EINVAL;

kernel/uid16.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -176,7 +176,7 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist) 
	struct group_info *group_info;

	struct group_info *group_info;

	int retval;

	int retval;





	if (!ns_capable(current_user_ns(), CAP_SETGID))

	if (!may_setgroups())

		return -EPERM;

		return -EPERM;

	if ((unsigned)gidsetsize > NGROUPS_MAX)

	if ((unsigned)gidsetsize > NGROUPS_MAX)

		return -EINVAL;

		return -EINVAL;