Commit 4b09791b authored Jun 26, 2018 by Ondrej Mosnáček Committed by Paul Moore Jun 28, 2018

cred: conditionally declare groups-related functions

The groups-related functions declared in include/linux/cred.h are
defined in kernel/groups.c, which is compiled only when
CONFIG_MULTIUSER=y. Move all these function declarations under #ifdef
CONFIG_MULTIUSER to help avoid accidental usage in contexts where
CONFIG_MULTIUSER might be disabled.

This patch also adds a fallback for groups_search(). Currently this
function is only called from kernel/groups.c itself and
security/keys/permissions.c, where the call is (by coincidence)
optimized away in case CONFIG_MULTIUSER=n. However, the audit subsystem
(which does not depend on CONFIG_MULTIUSER) calls this function in
-next, so the fallback will be needed to avoid compilation errors or
ugly workarounds.

See also:
https://lkml.org/lkml/2018/6/20/670
https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git/commit/?h=next&id=af85d1772e31fed34165a1b3decef340cf4080c0



Reported-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

parent f7859590

include/linux/cred.h

+10 −5

Original line number	Diff line number	Diff line
		@@ -65,6 +65,12 @@ extern void groups_free(struct group_info *);

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

		extern int set_current_groups(struct group_info *);
		extern void set_groups(struct cred , struct group_info );
		extern bool may_setgroups(void);
		extern void groups_sort(struct group_info *);
		#else
		static inline void groups_free(struct group_info *group_info)
		{
		@@ -78,12 +84,11 @@ static inline int in_egroup_p(kgid_t grp)
		{
		return 1;
		}
		static inline int groups_search(const struct group_info *group_info, kgid_t grp)
		{
		return 1;
		}
		#endif
		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);
		extern void groups_sort(struct group_info *);

		/*
		* The security context of a task

Admin message