kernel/linux.git/fs/smb/client/dfs.c, branch linux-7.0.y

smb: client: don't trust DFSREF_STORAGE_SERVER bit

2025-02-06T03:09:00+00:00

Some servers don't respect the DFSREF_STORAGE_SERVER bit, so unconditionally tree connect to DFS link target and then decide whether or not continue chasing DFS referrals for DFS interlinks. Otherwise the client would fail to mount such shares. Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

smb: client: optimize referral walk on failed link targets

2025-01-20T01:34:00+00:00

If a link referral request sent to root server was successful but client failed to connect to all link targets, there is no need to retry same link referral on a different root server. Set an end marker for the DFS root referral so the client will not attempt to re-send link referrals to different root servers on failures. Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

smb: client: provide dns_resolve_{unc,name} helpers

2025-01-20T01:34:00+00:00

Some places pass hostnames rather than UNC paths to resolve them to ip addresses, so provide helpers to handle both cases and then stop converting hostnames to UNC paths by inserting path delimiters into them. Also kill @expiry parameter as it's not used anywhere. Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

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

2025-01-20T01:34:00+00:00

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) Signed-off-by: Steve French

smb: client: don't try following DFS links in cifs_tree_connect()

2024-11-27T00:46:35+00:00

We can't properly support chasing DFS links in cifs_tree_connect() because (1) We don't support creating new sessions while we're reconnecting, which would be required for DFS interlinks. (2) ->is_path_accessible() can't be called from cifs_tree_connect() as it would deadlock with smb2_reconnect(). This is required for checking if new DFS target is a nested DFS link. By unconditionally trying to get an DFS referral from new DFS target isn't correct because if the new DFS target (interlink) is an DFS standalone namespace, then we would end up getting -ELOOP and then potentially leaving tcon disconnected. Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

smb: client: get rid of @nlsc param in cifs_tree_connect()

2024-11-27T00:46:19+00:00

We can access local_nls directly from @tcon->ses, so there is no need to pass it as parameter in cifs_tree_connect(). Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

smb: client: fix DFS interlink failover

2024-09-25T02:51:48+00:00

The DFS interlinks point to different DFS namespaces so make sure to use the correct DFS root server to chase any DFS links under it by storing the SMB session in dfs_ref_walk structure and then using it on every referral walk. Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

smb: client: guarantee refcounted children from parent session

2024-04-02T15:09:57+00:00

Avoid potential use-after-free bugs when walking DFS referrals, mounting and performing DFS failover by ensuring that all children from parent @tcon->ses are also refcounted. They're all needed across the entire DFS mount. Get rid of @tcon->dfs_ses_list while we're at it, too. Cc: stable@vger.kernel.org # 6.4+ Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202404021527.ZlRkIxgv-lkp@intel.com/ Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French

cifs: change tcon status when need_reconnect is set on it

2024-02-09T20:43:23+00:00

When a tcon is marked for need_reconnect, the intention is to have it reconnected. This change adjusts tcon->status in cifs_tree_connect when need_reconnect is set. Also, this change has a minor correction in resetting need_reconnect on success. It makes sure that it is done with tc_lock held. Signed-off-by: Shyam Prasad N Signed-off-by: Steve French

smb: client: fix mount when dns_resolver key is not available

2023-11-09T18:59:36+00:00

There was a wrong assumption that with CONFIG_CIFS_DFS_UPCALL=y there would always be a dns_resolver key set up so we could unconditionally upcall to resolve UNC hostname rather than using the value provided by mount(2). Only require it when performing automount of junctions within a DFS share so users that don't have dns_resolver key still can mount their regular shares with server hostname resolved by mount.cifs(8). Fixes: 348a04a8d113 ("smb: client: get rid of dfs code dep in namespace.c") Cc: stable@vger.kernel.org Tested-by: Eduard Bachmakov Reported-by: Eduard Bachmakov Closes: https://lore.kernel.org/all/CADCRUiNvZuiUZ0VGZZO9HRyPyw6x92kiA7o7Q4tsX5FkZqUkKg@mail.gmail.com/ Signed-off-by: Paulo Alcantara (SUSE) Signed-off-by: Steve French