ksmbd: handle channel binding with a different user

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When an authenticated user tries to bind a channel to a session owned by a
different user, ksmbd returns STATUS_LOGON_FAILURE. Windows instead rejects
this attempt with STATUS_ACCESS_DENIED. The supplied credentials are valid
but cannot be used with the existing session.

Use a distinct internal error for a user mismatch in both NTLM and Kerberos
authentication and map it to STATUS_ACCESS_DENIED during SESSION_SETUP.
Keep ordinary authentication failures mapped to STATUS_LOGON_FAILURE.

A failed SMB 3.1.1 binding also leaves its preauthentication context on the
connection. A subsequent binding attempt for the same session reuses the
stale hash and derives an incorrect channel signing key. Remove the binding
preauthentication context on failure so a valid retry starts with a fresh
hash.

This fixes smb2.session.bind_different_user.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

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Namjae Jeon 2026-07-02 20:07:25 +09:00 • committed by Steve French

parent faf8578c77

commit 1c5daa2ea9

2 changed files with 16 additions and 3 deletions

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2

fs/smb/server/auth.c

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17

fs/smb/server/smb2pdu.c

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