linux-stable.git/fs/cifs/dfs_cache.c, branch linux-6.2.y Linux kernel stable tree cifs: avoid potential races when handling multiple dfs tcons 2023-05-17T11:58:56+00:00 Paulo Alcantara pc@manguebit.com 2023-04-27T07:40:08+00:00 a9e3d4ad71a3ca8e4e576e36afab38426a26d31a [ Upstream commit 6be2ea33a4093402252724a00c4af8033725184c ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 6be2ea33a4093402252724a00c4af8033725184c ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cifs: check only tcon status on tcon related functions 2023-05-17T11:58:55+00:00 Shyam Prasad N sprasad@microsoft.com 2023-03-16T10:45:12+00:00 f184f153b1e0c7e14b574cc2e3ac59e809aa789b [ Upstream commit 2f0e4f0342201fe2228fcc2301cc2b42ae04b8e3 ] 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> Stable-dep-of: 6be2ea33a409 ("cifs: avoid potential races when handling multiple dfs tcons") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 2f0e4f0342201fe2228fcc2301cc2b42ae04b8e3 ]

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>
Stable-dep-of: 6be2ea33a409 ("cifs: avoid potential races when handling multiple dfs tcons")
Signed-off-by: Sasha Levin <sashal@kernel.org>
cifs: protect access of TCP_Server_Info::{origin,leaf}_fullpath 2023-05-11T14:11:36+00:00 Paulo Alcantara pc@manguebit.com 2023-04-26T16:43:53+00:00 6dbd709df900f80f687737954b2b8298c48c6747 commit 3dc9c433c9dde15477d02b609ccb4328e2adb6dc upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3dc9c433c9dde15477d02b609ccb4328e2adb6dc upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cifs: fix use-after-free bug in refresh_cache_worker() 2023-03-22T12:38:01+00:00 Paulo Alcantara pc@manguebit.com 2023-03-14T23:32:54+00:00 5a89d81c1a3c152837ea204fd29572228e54ce0b commit 396935de145589c8bfe552fa03a5e38604071829 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 396935de145589c8bfe552fa03a5e38604071829 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cifs: remove unused function 2023-01-18T20:49:51+00:00 Paulo Alcantara pc@cjr.nz 2023-01-18T16:55:01+00:00 a1b7c8457ecc062f612a1aca174c2e1c21f9ac10 Remove dfs_cache_update_tgthint() as it is not used anywhere. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com> 
Remove dfs_cache_update_tgthint() as it is not used anywhere.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs: fix return of uninitialized rc in dfs_cache_update_tgthint() 2023-01-18T17:24:20+00:00 Paulo Alcantara pc@cjr.nz 2023-01-18T16:36:31+00:00 d6a49e8c4ca4d399ed65ac219585187fc8c2e2b1 Fix this by initializing rc to 0 as cache_refresh_path() would not set it in case of success. Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/all/202301190004.bEHvbKG6-lkp@intel.com/ Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com> 
Fix this by initializing rc to 0 as cache_refresh_path() would not set
it in case of success.

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202301190004.bEHvbKG6-lkp@intel.com/
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs: handle cache lookup errors different than -ENOENT 2023-01-18T16:45:58+00:00 Paulo Alcantara pc@cjr.nz 2023-01-17T22:00:41+00:00 3deddb77fdd932df92f3b6a27a9cffed82c4fe1a lookup_cache_entry() might return an error different than -ENOENT (e.g. from ->char2uni), so handle those as well in cache_refresh_path(). Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com> 
lookup_cache_entry() might return an error different than -ENOENT
(e.g. from ->char2uni), so handle those as well in
cache_refresh_path().

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs: remove duplicate code in __refresh_tcon() 2023-01-18T16:45:58+00:00 Paulo Alcantara pc@cjr.nz 2023-01-17T22:00:40+00:00 8064f711c6a4614a848009b5a773e8d7f055a4c5 The logic for creating or updating a cache entry in __refresh_tcon() could be simply done with cache_refresh_path(), so use it instead. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com> 
The logic for creating or updating a cache entry in __refresh_tcon()
could be simply done with cache_refresh_path(), so use it instead.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs: don't take exclusive lock for updating target hints 2023-01-18T16:45:58+00:00 Paulo Alcantara pc@cjr.nz 2023-01-17T22:00:39+00:00 11c8b3f8493cb5253da42fcd178d9b4630063f96 Avoid contention while updating dfs target hints. This should be perfectly fine to update them under shared locks. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com> 
Avoid contention while updating dfs target hints.  This should be
perfectly fine to update them under shared locks.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs: avoid re-lookups in dfs_cache_find() 2023-01-18T16:45:58+00:00 Paulo Alcantara pc@cjr.nz 2023-01-17T22:00:38+00:00 48d240bf00af943db6f069a53f090e444e85f760 Simply downgrade the write lock on cache updates from cache_refresh_path() and avoid unnecessary re-lookup in dfs_cache_find(). Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com> 
Simply downgrade the write lock on cache updates from
cache_refresh_path() and avoid unnecessary re-lookup in
dfs_cache_find().

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>