[PATCH v2 24/28] commoncap: cap_task_fix_setuid(): handle fsid mappings

Christian Brauner
2020-02-14T18:40:25Z

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@ubuntu.com>
---
/* v2 */
unchanged
---
security/commoncap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/commoncap.c b/security/commoncap.c
index 9641695d8383..0581c6aa8bdc 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
@@ -1061,7 +1062,7 @@ 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