[PATCH 14/24] commoncap: cap_task_fix_setuid(): handle fsid mappings

[Christian Brauner]

Switch cap_task_fix_setuid() to lookup fsids in the fsid mappings. If no fsid
mappings are setup the behavior is unchanged, i.e. fsids are looked up in the
id mappings.

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 security/commoncap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/commoncap.c b/security/commoncap.c
index f4ee0ae106b2..ecfa0d0c250e 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -24,6 +24,7 @@
 #include <linux/user_namespace.h>
 #include <linux/binfmts.h>
 #include <linux/personality.h>
+#include <linux/fsuidgid.h>
 
 /*
  * If a non-root user executes a setuid-root binary in
@@ -1051,7 +1052,7 @@ int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
 		 *          if not, we might be a bit too harsh here.
 		 */
 		if (!issecure(SECURE_NO_SETUID_FIXUP)) {
-			kuid_t root_uid = make_kuid(old->user_ns, 0);
+			kuid_t root_uid = make_kfsuid(old->user_ns, 0);
 			if (uid_eq(old->fsuid, root_uid) && !uid_eq(new->fsuid, root_uid))
 				new->cap_effective =
 					cap_drop_fs_set(new->cap_effective);
-- 
2.25.0