@@ -504,15 +504,18 @@ long __sys_setreuid(uid_t ruid, uid_t euid)
const struct cred *old;
struct cred *new;
int retval;
- kuid_t kruid, keuid;
+ kuid_t kruid, keuid, kfsuid;
kruid = make_kuid(ns, ruid);
keuid = make_kuid(ns, euid);
+ kfsuid = make_kfsuid(ns, euid);
if ((ruid != (uid_t) -1) && !uid_valid(kruid))
return -EINVAL;
if ((euid != (uid_t) -1) && !uid_valid(keuid))
return -EINVAL;
+ if ((euid != (uid_t) -1) && !uid_valid(kfsuid))
+ return -EINVAL;
new = prepare_creds();
if (!new)
@@ -535,6 +538,9 @@ long __sys_setreuid(uid_t ruid, uid_t euid)
!uid_eq(old->suid, keuid) &&
!ns_capable_setid(old->user_ns, CAP_SETUID))
goto error;
+ } else {
+ uid_t fsuid = from_kuid_munged(new->user_ns, new->euid);
+ kfsuid = make_kfsuid(ns, fsuid);
}
if (!uid_eq(new->uid, old->uid)) {
@@ -545,7 +551,7 @@ long __sys_setreuid(uid_t ruid, uid_t euid)
if (ruid != (uid_t) -1 ||
(euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
new->suid = new->euid;
- new->fsuid = new->euid;
+ new->fsuid = kfsuid;
retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
if (retval < 0)
Switch setreuid() 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 setreuid() 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. Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> --- kernel/sys.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)