smb: client: fix uid/gid override in getattr with posix extensions

When mounting with 'multiuser,posix' options, cifs_getattr() overrides
the server-provided uid/gid with the current process's fsuid/fsgid.
This is because the condition only checks for unix extensions
(tcon->unix_ext) but not posix extensions (tcon->posix_extensions).

With SMB3 POSIX extensions, the server provides real uid/gid values
just like with unix extensions, so they should be preserved rather
than replaced with the caller's credentials.

Add a tcon->posix_extensions check to the condition so that uid/gid
from the server are properly reported in stat results.

Reported-by: Arthur Lesuisse <arthur.lesuisse@ulb.be>
Closes: https://lore.kernel.org/r/DB9P190MB2012266F6B8DECBE5D26A1798DB52@DB9P190MB2012.EURP190.PROD.OUTLOOK.COM
Suggested-by: Arthur Lesuisse <arthur.lesuisse@ulb.be>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Paulo Alcantara 2026-09-06 14:39:44 -03:00
commit cf4d358966