From: Mickaël Salaün <mic@digikod.net> mainline inclusion from mainline-6.1-rc1 commit 7c88c1e0ab1704bacb751341ee6431c3be34b834 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I60T7G CVE: NA Reference: https://git.kernel.org/torvalds/linux/c/7c88c1e0ab17 ------------------------------- A kernel daemon should not rely on the current thread, which is unknown and might be malicious. Before this security fix, ksmbd_override_fsids() didn't correctly override FS UID/GID which means that arbitrary user space threads could trick the kernel to impersonate arbitrary users or groups for file system access checks, leading to file system access bypass. This was found while investigating truncate support for Landlock: https://lore.kernel.org/r/CAKYAXd8fpMJ7guizOjHgxEyyjoUwPsx3jLOPZP=wPYcbhkVXq... Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: Hyunchul Lee <hyc.lee@gmail.com> Cc: Steve French <smfrench@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün <mic@digikod.net> Link: https://lore.kernel.org/r/20220929100447.108468-1-mic@digikod.net Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com> --- fs/ksmbd/smb_common.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c index 2476ba92b475..8ea2cdda0984 100644 --- a/fs/ksmbd/smb_common.c +++ b/fs/ksmbd/smb_common.c @@ -4,6 +4,8 @@ * Copyright (C) 2018 Namjae Jeon <linkinjeon@kernel.org> */ +#include <linux/user_namespace.h> + #include "smb_common.h" #include "server.h" #include "misc.h" @@ -621,8 +623,8 @@ int ksmbd_override_fsids(struct ksmbd_work *work) if (!cred) return -ENOMEM; - cred->fsuid = make_kuid(current_user_ns(), uid); - cred->fsgid = make_kgid(current_user_ns(), gid); + cred->fsuid = make_kuid(&init_user_ns, uid); + cred->fsgid = make_kgid(&init_user_ns, gid); gi = groups_alloc(0); if (!gi) { -- 2.31.1