@@ -654,7 +654,7 @@ long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
const struct cred *old;
struct cred *new;
int retval;
- kuid_t kruid, keuid, ksuid;
+ kuid_t kruid, keuid, ksuid, kfsuid;
kruid = make_kuid(ns, ruid);
keuid = make_kuid(ns, euid);
@@ -696,11 +696,21 @@ long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
goto error;
}
}
- if (euid != (uid_t) -1)
+ if (euid != (uid_t) -1) {
new->euid = keuid;
+ kfsuid = make_kfsuid(ns, euid);
+ } else {
+ kfsuid = kuid_to_kfsuid(new->user_ns, new->euid);
+ }
+ if (!uid_valid(kfsuid)) {
+ return -EINVAL;
+ goto error;
+ }
+
if (suid != (uid_t) -1)
new->suid = ksuid;
- new->fsuid = new->euid;
+ new->kfsuid = new->euid;
+ new->fsuid = kfsuid;
retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
if (retval < 0)
Switch setresuid() 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. During setresuid() the kfsuid is set to the keuid corresponding the euid that is requested by userspace. If the requested euid is -1 the kfsuid is reset to the current keuid. For the latter case this means we need to lookup the corresponding userspace euid corresponding to the current keuid in the id mappings and translate this euid into the corresponding kfsuid in the fsid mappings. The kfsid to cleanly handle userns visible filesystem is set as before. We require that a user must have a valid fsid mapping for the target id. This is consistent with how the setid calls work today without fsid mappings. Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> --- /* v2 */ - Christian Brauner <christian.brauner@ubuntu.com>: - set kfsid which is used when dealing with proc permission checking --- kernel/sys.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)