ksmbd does not preserve supplementary groups

[bol-van]

Ksmbd 3.4.8 does not allow access to the file system based on supplimentary group
In the same scenario if samba4-server used instead of ksmbd - all works as expected.

For example, i am "user" with main group "user" and extra group "sftp"
There's dir "dir" and some content inside.
"NO ACCESS" means i cant see anything inside "dir" when connected as "user"
"OK" means I can see content inside "dir"

chown dir sftp:sftp
chmod dir 770
NO ACCESS
chown dir sftp:sftp
chmod dir 775
OK
chown dir sftp:user
chmod dir 770
OK

[namjaejeon]

Can you elaborate more ? Where did you command chown/chmod ? through smb client ? or on local share directory ?
So my questions are:

1. Where did you command chown/chmod ? through smb client ? or on local share directory ?
2. NO ACCESS => Where did you access file ? through smb client ?
3. if you use cifs.ko(mount -t cifs) as smb client, Let me know your mount options.

[bol-van]

I did chown/chmod on the systems where ksmbd runs.
SMB client is windows. net use X: \ksmbd-server\share /user:user

ksmbd-server is openwrt. just install samba4-server instead of ksmbd and it works