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path: root/fs/cifs/dfs.c
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2023-05-25smb: move client and server files to common directory fs/smbSteve French1-643/+0
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>
2023-05-25cifs: fix smb1 mount regressionPaulo Alcantara1-1/+1
cifs.ko maps NT_STATUS_NOT_FOUND to -EIO when SMB1 servers couldn't resolve referral paths. Proceed to tree connect when we get -EIO from dfs_get_referral() as well. Reported-by: Kris Karas (Bug Reporting) <bugs-a21@moonlit-rail.com> Tested-by: Woody Suwalski <terraluna977@gmail.com> Fixes: 8e3554150d6c ("cifs: fix sharing of DFS connections") Cc: stable@vger.kernel.org # v6.2+ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-05-05cifs: fix sharing of DFS connectionsPaulo Alcantara1-19/+43
When matching DFS connections, we can't rely on the values set in cifs_sb_info::prepath and cifs_tcon::tree_name as they might change during DFS failover. The DFS referrals related to a specific DFS tcon are already matched earlier in match_server(), therefore we can safely skip those checks altogether as the connection is guaranteed to be unique for the DFS tcon. Besides, when creating or finding an SMB session, make sure to also refcount any DFS root session related to it (cifs_ses::dfs_root_ses), so if a new DFS mount ends up reusing the connection from the old mount while there was an umount(2) still in progress (e.g. umount(2) -> cifs_umount() -> reconnect -> cifs_put_tcon()), the connection could potentially be put right after the umount(2) finished. Patch has minor update to include fix for unused variable issue noted by the kernel test robot Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/oe-kbuild-all/202305041040.j7W2xQSy-lkp@intel.com/ Cc: stable@vger.kernel.org # v6.2+ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-05-04cifs: avoid potential races when handling multiple dfs tconsPaulo Alcantara1-0/+4
Now that a DFS tcon manages its own list of DFS referrals and sessions, there is no point in having a single worker to refresh referrals of all DFS tcons. Make it faster and less prone to race conditions when having several mounts by queueing a worker per DFS tcon that will take care of refreshing only the DFS referrals related to it. Cc: stable@vger.kernel.org # v6.2+ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-05-04cifs: protect access of TCP_Server_Info::{origin,leaf}_fullpathPaulo Alcantara1-6/+8
Protect access of TCP_Server_Info::{origin,leaf}_fullpath when matching DFS connections, and get rid of TCP_Server_Info::current_fullpath while we're at it. Cc: stable@vger.kernel.org # v6.2+ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-05-04cifs: fix potential race when tree connecting ipcPaulo Alcantara1-7/+50
Protect access of TCP_Server_Info::hostname when building the ipc tree name as it might get freed in cifsd thread and thus causing an use-after-free bug in __tree_connect_dfs_target(). Also, while at it, update status of IPC tcon on success and then avoid any extra tree connects. Cc: stable@vger.kernel.org # v6.2+ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-03-17cifs: check only tcon status on tcon related functionsShyam Prasad N1-3/+7
We had a couple of checks for session in cifs_tree_connect and cifs_mark_open_files_invalid, which were unnecessary. And that was done with ses_lock. Changed that to tc_lock too. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-03-15cifs: fix use-after-free bug in refresh_cache_worker()Paulo Alcantara1-13/+39
The UAF bug occurred because we were putting DFS root sessions in cifs_umount() while DFS cache refresher was being executed. Make DFS root sessions have same lifetime as DFS tcons so we can avoid the use-after-free bug is DFS cache refresher and other places that require IPCs to get new DFS referrals on. Also, get rid of mount group handling in DFS cache as we no longer need it. This fixes below use-after-free bug catched by KASAN [ 379.946955] BUG: KASAN: use-after-free in __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.947642] Read of size 8 at addr ffff888018f57030 by task kworker/u4:3/56 [ 379.948096] [ 379.948208] CPU: 0 PID: 56 Comm: kworker/u4:3 Not tainted 6.2.0-rc7-lku #23 [ 379.948661] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552-rebuilt.opensuse.org 04/01/2014 [ 379.949368] Workqueue: cifs-dfscache refresh_cache_worker [cifs] [ 379.949942] Call Trace: [ 379.950113] <TASK> [ 379.950260] dump_stack_lvl+0x50/0x67 [ 379.950510] print_report+0x16a/0x48e [ 379.950759] ? __virt_addr_valid+0xd8/0x160 [ 379.951040] ? __phys_addr+0x41/0x80 [ 379.951285] kasan_report+0xdb/0x110 [ 379.951533] ? __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.952056] ? __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.952585] __refresh_tcon.isra.0+0x10b/0xc10 [cifs] [ 379.953096] ? __pfx___refresh_tcon.isra.0+0x10/0x10 [cifs] [ 379.953637] ? __pfx___mutex_lock+0x10/0x10 [ 379.953915] ? lock_release+0xb6/0x720 [ 379.954167] ? __pfx_lock_acquire+0x10/0x10 [ 379.954443] ? refresh_cache_worker+0x34e/0x6d0 [cifs] [ 379.954960] ? __pfx_wb_workfn+0x10/0x10 [ 379.955239] refresh_cache_worker+0x4ad/0x6d0 [cifs] [ 379.955755] ? __pfx_refresh_cache_worker+0x10/0x10 [cifs] [ 379.956323] ? __pfx_lock_acquired+0x10/0x10 [ 379.956615] ? read_word_at_a_time+0xe/0x20 [ 379.956898] ? lockdep_hardirqs_on_prepare+0x12/0x220 [ 379.957235] process_one_work+0x535/0x990 [ 379.957509] ? __pfx_process_one_work+0x10/0x10 [ 379.957812] ? lock_acquired+0xb7/0x5f0 [ 379.958069] ? __list_add_valid+0x37/0xd0 [ 379.958341] ? __list_add_valid+0x37/0xd0 [ 379.958611] worker_thread+0x8e/0x630 [ 379.958861] ? __pfx_worker_thread+0x10/0x10 [ 379.959148] kthread+0x17d/0x1b0 [ 379.959369] ? __pfx_kthread+0x10/0x10 [ 379.959630] ret_from_fork+0x2c/0x50 [ 379.959879] </TASK> Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Cc: stable@vger.kernel.org # 6.2 Signed-off-by: Steve French <stfrench@microsoft.com>
2023-03-15cifs: set DFS root session in cifs_get_smb_ses()Paulo Alcantara1-11/+8
Set the DFS root session pointer earlier when creating a new SMB session to prevent racing with smb2_reconnect(), cifs_reconnect_tcon() and DFS cache refresher. Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Cc: stable@vger.kernel.org # 6.2 Signed-off-by: Steve French <stfrench@microsoft.com>
2023-01-04cifs: protect access of TCP_Server_Info::{dstaddr,hostname}Paulo Alcantara1-11/+11
Use the appropriate locks to protect access of hostname and dstaddr fields in cifs_tree_connect() as they might get changed by other tasks. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-01-04cifs: ignore ipc reconnect failures during dfs failoverPaulo Alcantara1-2/+1
If it failed to reconnect ipc used for getting referrals, we can just ignore it as it is not required for reconnecting the share. The worst case would be not being able to detect or chase nested links as long as dfs root server is unreachable. Before patch: $ mount.cifs //root/dfs/link /mnt -o echo_interval=10,... -> target share: /fs0/share disconnect root & fs0 $ ls /mnt ls: cannot access '/mnt': Host is down connect fs0 $ ls /mnt ls: cannot access '/mnt': Resource temporarily unavailable After patch: $ mount.cifs //root/dfs/link /mnt -o echo_interval=10,... -> target share: /fs0/share disconnect root & fs0 $ ls /mnt ls: cannot access '/mnt': Host is down connect fs0 $ ls /mnt bar.rtf dir1 foo Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-12-19cifs: optimize reconnect of nested linksPaulo Alcantara1-5/+4
There is no point going all the way back to the original dfs full path if reconnect of tcon did not finish due a nested link found as newly resolved target for the current referral. So, just mark current server for reconnect as we already set @current_fullpath to the new dfs referral in update_server_fullpath(). Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-12-19cifs: don't block in dfs_cache_noreq_update_tgthint()Paulo Alcantara1-0/+259
Avoid blocking in dfs_cache_noreq_update_tgthint() while reconnecting servers or tcons as the cache refresh worker or new mounts might already be updating their targets. Move some more dfs related code out of connect.c while at it. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-12-19cifs: fix refresh of cached referralsPaulo Alcantara1-0/+6
We can't rely on cifs_tcon::ses to refresh cached referral as the server target might not respond to referrals, e.g. share is not hosted in a DFS root server. Consider the following mount //dom/dfs/link -> /root1/dfs/link -> /fs0/share where fs0 can't get a referral for "/root1/dfs/link". To simplify and fix the access of dfs root sessions, store the dfs root session pointer directly to new sessions so making it easier to select the appropriate ipc connection and use it for failover or cache refresh. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-12-19cifs: share dfs connections and supersPaulo Alcantara1-0/+226
When matching DFS superblocks we can't rely on either the server's address or tcon's UNC name from mount(2) as the existing servers and tcons might be connected to somewhere else. Instead, check if superblock is dfs, and if so, match its original source pathname with the new mount's source pathname. For DFS connections, instead of checking server's address, match its referral path as it could be connected to different targets. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-12-19cifs: set resolved ip in sockaddrPaulo Alcantara1-23/+1
All callers from dns_resolve_server_name_to_ip() used to convert the ip addr string back to sockaddr, so do that inside dns_resolve_server_name_to_ip() and avoid duplicating code. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-12-19cifs: get rid of mount options string parsingPaulo Alcantara1-0/+76
After switching to filesystem context support, we no longer need to handle mount options string when chasing dfs referrals. Now, we set the new values directly into smb3_fs_context. Start working on a separate source file to handle most dfs related mount functions as connect.c has already became too big. The remaining functions will be moved gradually in follow-up patches. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
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