After commit 36008fe6e3 ("smb: client: don't try following DFS links
in cifs_tree_connect()"), TCP_Server_Info::leaf_fullpath will no
longer be changed, so there is no need to kstrdup() it.
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
TCP_Server_Info::leaf_fullpath is allocated in cifs_get_tcp_session()
and never changed afterwards, so there is no need to serialize its
access.
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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>
In some DFS setups, a single DFS share may contain hundreds of DFS
links and increasing the DFS cache to allow more referrals to be
cached improves DFS failover as the client will likely find a cached
DFS referral when reconnecting and then avoiding unnecessary remounts.
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Remove hard-coded strings by using the str_yes_no() helper function.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Steve French <stfrench@microsoft.com>
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) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Purge cached referrals that have a single target when reaching maximum
of cache size as the client won't need them to failover. Otherwise
remove oldest cache entry.
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Do not mark tcons for reconnect when current connection matches any of
the targets returned by new referral even when there is no cached
entry.
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Avoid refreshing DFS referral with refpath_lock acquired as the I/O
could block for a while due to a potentially disconnected or slow DFS
root server and then making other threads - that use same @server and
don't require a DFS root server - unable to make any progress.
Cc: stable@vger.kernel.org # 6.4+
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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 <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404021527.ZlRkIxgv-lkp@intel.com/
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
With current implementation, when a nested DFS link is found during
mount(2), the client follows the referral and then try to connect to
all of its targets. If all targets failed, the client bails out
rather than retrying remaining targets from previous referral.
Fix this by stacking all referrals and targets so the client can retry
remaining targets from previous referrals in case all targets of
current referral have failed.
Thanks to samba, this can be easily tested like below
* Run the following under dfs folder in samba server
$ ln -s "msdfs:srv\\bad-share" link1
$ ln -s "msdfs:srv\\dfs\\link1,srv\\good-share" link0
* Before patch
$ mount.cifs //srv/dfs/link0 /mnt -o ...
mount error(2): No such file or directory
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)...
* After patch
$ mount.cifs //srv/dfs/link0 /mnt -o ...
# ls /mnt
bar fileshare1 sub
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Add new helper which declares and initialises target list of a DFS
referral rather having to do both separately.
No functional changes.
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When having two DFS root mounts that are connected to same namespace,
same mount options but different prefix paths, we can't really use the
shared @server->origin_fullpath when chasing DFS links in them.
Move the origin_fullpath field to cifs_tcon structure so when having
shared DFS root mounts with different prefix paths, and we need to
chase any DFS links, dfs_get_automount_devname() will pick up the
correct full path out of the @tcon that will be used for the new
mount.
Before patch
mount.cifs //dom/dfs/dir /mnt/1 -o ...
mount.cifs //dom/dfs /mnt/2 -o ...
# shared server, ses, tcon
# server: origin_fullpath=//dom/dfs/dir
# @server->origin_fullpath + '/dir/link1'
$ ls /mnt/2/dir/link1
ls: cannot open directory '/mnt/2/dir/link1': No such file or directory
After patch
mount.cifs //dom/dfs/dir /mnt/1 -o ...
mount.cifs //dom/dfs /mnt/2 -o ...
# shared server & ses
# tcon_1: origin_fullpath=//dom/dfs/dir
# tcon_2: origin_fullpath=//dom/dfs
# @tcon_2->origin_fullpath + '/dir/link1'
$ ls /mnt/2/dir/link1
dir0 dir1 dir10 dir3 dir5 dir6 dir7 dir9 target2_file.txt tsub
Fixes: 8e3554150d ("cifs: fix sharing of DFS connections")
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:
fs/cifs --> fs/smb/client
fs/ksmbd --> fs/smb/server
fs/smbfs_common --> fs/smb/common
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
