smb: client: fix DFS mount against old servers with NTLMSSP

Old Windows servers will return not fully qualified DFS targets by
default as specified in

  MS-DFSC 3.2.5.5 Receiving a Root Referral Request or Link Referral
  Request

    | Servers SHOULD<30> return fully qualified DNS host names of
    | targets in responses to root referral requests and link referral
    | requests.
    | ...
    | <30> Section 3.2.5.5: By default, Windows Server 2003, Windows
    | Server 2008, Windows Server 2008 R2, Windows Server 2012, and
    | Windows Server 2012 R2 return DNS host names that are not fully
    | qualified for targets.

Fix this by converting all NetBIOS host names from DFS targets to
FQDNs and try resolving them first if DNS domain name was provided in
NTLMSSP CHALLENGE_MESSAGE message from previous SMB2_SESSION_SETUP.
This also prevents the client from translating the DFS target
hostnames to another domain depending on the network domain search
order.

Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara
2025-01-03 16:58:12 -03:00
committed by Steve French
parent 0e8ae9b953
commit ad46faff1a
9 changed files with 105 additions and 50 deletions

View File

@@ -1189,7 +1189,8 @@ int match_target_ip(struct TCP_Server_Info *server,
cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
rc = dns_resolve_server_name_to_ip(target, (struct sockaddr *)&ss, NULL);
rc = dns_resolve_server_name_to_ip(server->dns_dom, target,
(struct sockaddr *)&ss, NULL);
kfree(target);
if (rc < 0)