@@ -756,7 +756,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
const struct cred *old;
struct cred *new;
int retval;
- kgid_t krgid, kegid, ksgid;
+ kgid_t krgid, kegid, ksgid, kfsgid;
krgid = make_kgid(ns, rgid);
kegid = make_kgid(ns, egid);
@@ -789,11 +789,21 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
if (rgid != (gid_t) -1)
new->gid = krgid;
- if (egid != (gid_t) -1)
+ if (egid != (gid_t) -1) {
new->egid = kegid;
+ kfsgid = make_kfsgid(ns, egid);
+ } else {
+ kfsgid = kgid_to_kfsgid(new->user_ns, new->egid);
+ }
+ if (!gid_valid(kfsgid)) {
+ retval = -EINVAL;
+ goto error;
+ }
+
if (sgid != (gid_t) -1)
new->sgid = ksgid;
- new->fsgid = new->egid;
+ new->kfsgid = new->egid;
+ new->fsgid = kfsgid;
return commit_creds(new);
Switch setresgid() 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 setresgid() the kfsgid is set to the kegid corresponding the egid that is requested by userspace. If the requested egid is -1 the kfsgid is reset to the current kegid. For the latter case this means we need to lookup the corresponding userspace egid corresponding to the current kegid in the id mappings and translate this egid into the corresponding kfsgid 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(-)