diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index cc4b0959faf6..b452b8c5f641 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -503,6 +503,20 @@ static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) } } +/* + * clone_private_mount() checks CAP_SYS_ADMIN in current->cred. + * ovl_fill_super_creds() runs under the stashed creator cred, which + * override_creds may have dropped. + * The task that issued FSCONFIG_CMD_CREATE is still current->real_cred, so + * use that only for the clone. creator_cred stays in effect for every other + * backing-fs operation. + */ +static struct vfsmount *ovl_clone_private_mount(const struct path *path) +{ + scoped_with_creds(current_real_cred()) + return clone_private_mount(path); +} + static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, struct ovl_layer *upper_layer, const struct path *upperpath) @@ -526,7 +540,7 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, if (err) goto out; - upper_mnt = clone_private_mount(upperpath); + upper_mnt = ovl_clone_private_mount(upperpath); err = PTR_ERR(upper_mnt); if (IS_ERR(upper_mnt)) { pr_err("failed to clone upperpath\n"); @@ -1104,7 +1118,7 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, } } - mnt = clone_private_mount(&l->path); + mnt = ovl_clone_private_mount(&l->path); err = PTR_ERR(mnt); if (IS_ERR(mnt)) { pr_err("failed to clone lowerpath\n");