| Message ID | 20250319090839.3631424-1-donghua.liu@windriver.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [6.1.y] smb: prevent use-after-free due to open_cached_dir error paths | expand |
On Wed, Mar 19, 2025 at 05:08:39PM +0800, Cliff Liu wrote: > From: Paul Aurich <paul@darkrain42.org> > > If open_cached_dir() encounters an error parsing the lease from the > server, the error handling may race with receiving a lease break, > resulting in open_cached_dir() freeing the cfid while the queued work is > pending. > > Update open_cached_dir() to drop refs rather than directly freeing the > cfid. > > Have cached_dir_lease_break(), cfids_laundromat_worker(), and > invalidate_all_cached_dirs() clear has_lease immediately while still > holding cfids->cfid_list_lock, and then use this to also simplify the > reference counting in cfids_laundromat_worker() and > invalidate_all_cached_dirs(). > > Fixes this KASAN splat (which manually injects an error and lease break > in open_cached_dir()): > > ================================================================== > BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0 > Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65 > > CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87 > Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 > Workqueue: cifsiod smb2_cached_lease_break > Call Trace: > <TASK> > dump_stack_lvl+0x77/0xb0 > print_report+0xce/0x660 > kasan_report+0xd3/0x110 > smb2_cached_lease_break+0x27/0xb0 > process_one_work+0x50a/0xc50 > worker_thread+0x2ba/0x530 > kthread+0x17c/0x1c0 > ret_from_fork+0x34/0x60 > ret_from_fork_asm+0x1a/0x30 > </TASK> > > Allocated by task 2464: > kasan_save_stack+0x33/0x60 > kasan_save_track+0x14/0x30 > __kasan_kmalloc+0xaa/0xb0 > open_cached_dir+0xa7d/0x1fb0 > smb2_query_path_info+0x43c/0x6e0 > cifs_get_fattr+0x346/0xf10 > cifs_get_inode_info+0x157/0x210 > cifs_revalidate_dentry_attr+0x2d1/0x460 > cifs_getattr+0x173/0x470 > vfs_statx_path+0x10f/0x160 > vfs_statx+0xe9/0x150 > vfs_fstatat+0x5e/0xc0 > __do_sys_newfstatat+0x91/0xf0 > do_syscall_64+0x95/0x1a0 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > Freed by task 2464: > kasan_save_stack+0x33/0x60 > kasan_save_track+0x14/0x30 > kasan_save_free_info+0x3b/0x60 > __kasan_slab_free+0x51/0x70 > kfree+0x174/0x520 > open_cached_dir+0x97f/0x1fb0 > smb2_query_path_info+0x43c/0x6e0 > cifs_get_fattr+0x346/0xf10 > cifs_get_inode_info+0x157/0x210 > cifs_revalidate_dentry_attr+0x2d1/0x460 > cifs_getattr+0x173/0x470 > vfs_statx_path+0x10f/0x160 > vfs_statx+0xe9/0x150 > vfs_fstatat+0x5e/0xc0 > __do_sys_newfstatat+0x91/0xf0 > do_syscall_64+0x95/0x1a0 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > Last potentially related work creation: > kasan_save_stack+0x33/0x60 > __kasan_record_aux_stack+0xad/0xc0 > insert_work+0x32/0x100 > __queue_work+0x5c9/0x870 > queue_work_on+0x82/0x90 > open_cached_dir+0x1369/0x1fb0 > smb2_query_path_info+0x43c/0x6e0 > cifs_get_fattr+0x346/0xf10 > cifs_get_inode_info+0x157/0x210 > cifs_revalidate_dentry_attr+0x2d1/0x460 > cifs_getattr+0x173/0x470 > vfs_statx_path+0x10f/0x160 > vfs_statx+0xe9/0x150 > vfs_fstatat+0x5e/0xc0 > __do_sys_newfstatat+0x91/0xf0 > do_syscall_64+0x95/0x1a0 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > The buggy address belongs to the object at ffff88811cc24c00 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 16 bytes inside of > freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000) > > Cc: stable@vger.kernel.org > Signed-off-by: Paul Aurich <paul@darkrain42.org> > Signed-off-by: Steve French <stfrench@microsoft.com> > [ Do not apply the change for cfids_laundromat_worker() since there is no > this function and related feature on 6.1.y. Update open_cached_dir() > according to method of upstream patch. ] > Signed-off-by: Cliff Liu <donghua.liu@windriver.com> > Signed-off-by: He Zhe <Zhe.He@windriver.com> > --- > Verified the build test. > --- > fs/smb/client/cached_dir.c | 39 ++++++++++++++++---------------------- > 1 file changed, 16 insertions(+), 23 deletions(-) No upstream git id :(
Hi, There is upstream id in my local patch, but it is discarded by 'git shend-mail'. Please ignore this patch. I'll check the reason and send it later. So sorry for my mistake. Thanks, Cliff On 2025/3/19 22:03, Greg KH wrote: > CAUTION: This email comes from a non Wind River email account! > Do not click links or open attachments unless you recognize the sender and know the content is safe. > > On Wed, Mar 19, 2025 at 05:08:39PM +0800, Cliff Liu wrote: >> From: Paul Aurich <paul@darkrain42.org> >> >> If open_cached_dir() encounters an error parsing the lease from the >> server, the error handling may race with receiving a lease break, >> resulting in open_cached_dir() freeing the cfid while the queued work is >> pending. >> >> Update open_cached_dir() to drop refs rather than directly freeing the >> cfid. >> >> Have cached_dir_lease_break(), cfids_laundromat_worker(), and >> invalidate_all_cached_dirs() clear has_lease immediately while still >> holding cfids->cfid_list_lock, and then use this to also simplify the >> reference counting in cfids_laundromat_worker() and >> invalidate_all_cached_dirs(). >> >> Fixes this KASAN splat (which manually injects an error and lease break >> in open_cached_dir()): >> >> ================================================================== >> BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0 >> Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65 >> >> CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87 >> Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 >> Workqueue: cifsiod smb2_cached_lease_break >> Call Trace: >> <TASK> >> dump_stack_lvl+0x77/0xb0 >> print_report+0xce/0x660 >> kasan_report+0xd3/0x110 >> smb2_cached_lease_break+0x27/0xb0 >> process_one_work+0x50a/0xc50 >> worker_thread+0x2ba/0x530 >> kthread+0x17c/0x1c0 >> ret_from_fork+0x34/0x60 >> ret_from_fork_asm+0x1a/0x30 >> </TASK> >> >> Allocated by task 2464: >> kasan_save_stack+0x33/0x60 >> kasan_save_track+0x14/0x30 >> __kasan_kmalloc+0xaa/0xb0 >> open_cached_dir+0xa7d/0x1fb0 >> smb2_query_path_info+0x43c/0x6e0 >> cifs_get_fattr+0x346/0xf10 >> cifs_get_inode_info+0x157/0x210 >> cifs_revalidate_dentry_attr+0x2d1/0x460 >> cifs_getattr+0x173/0x470 >> vfs_statx_path+0x10f/0x160 >> vfs_statx+0xe9/0x150 >> vfs_fstatat+0x5e/0xc0 >> __do_sys_newfstatat+0x91/0xf0 >> do_syscall_64+0x95/0x1a0 >> entry_SYSCALL_64_after_hwframe+0x76/0x7e >> >> Freed by task 2464: >> kasan_save_stack+0x33/0x60 >> kasan_save_track+0x14/0x30 >> kasan_save_free_info+0x3b/0x60 >> __kasan_slab_free+0x51/0x70 >> kfree+0x174/0x520 >> open_cached_dir+0x97f/0x1fb0 >> smb2_query_path_info+0x43c/0x6e0 >> cifs_get_fattr+0x346/0xf10 >> cifs_get_inode_info+0x157/0x210 >> cifs_revalidate_dentry_attr+0x2d1/0x460 >> cifs_getattr+0x173/0x470 >> vfs_statx_path+0x10f/0x160 >> vfs_statx+0xe9/0x150 >> vfs_fstatat+0x5e/0xc0 >> __do_sys_newfstatat+0x91/0xf0 >> do_syscall_64+0x95/0x1a0 >> entry_SYSCALL_64_after_hwframe+0x76/0x7e >> >> Last potentially related work creation: >> kasan_save_stack+0x33/0x60 >> __kasan_record_aux_stack+0xad/0xc0 >> insert_work+0x32/0x100 >> __queue_work+0x5c9/0x870 >> queue_work_on+0x82/0x90 >> open_cached_dir+0x1369/0x1fb0 >> smb2_query_path_info+0x43c/0x6e0 >> cifs_get_fattr+0x346/0xf10 >> cifs_get_inode_info+0x157/0x210 >> cifs_revalidate_dentry_attr+0x2d1/0x460 >> cifs_getattr+0x173/0x470 >> vfs_statx_path+0x10f/0x160 >> vfs_statx+0xe9/0x150 >> vfs_fstatat+0x5e/0xc0 >> __do_sys_newfstatat+0x91/0xf0 >> do_syscall_64+0x95/0x1a0 >> entry_SYSCALL_64_after_hwframe+0x76/0x7e >> >> The buggy address belongs to the object at ffff88811cc24c00 >> which belongs to the cache kmalloc-1k of size 1024 >> The buggy address is located 16 bytes inside of >> freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000) >> >> Cc: stable@vger.kernel.org >> Signed-off-by: Paul Aurich <paul@darkrain42.org> >> Signed-off-by: Steve French <stfrench@microsoft.com> >> [ Do not apply the change for cfids_laundromat_worker() since there is no >> this function and related feature on 6.1.y. Update open_cached_dir() >> according to method of upstream patch. ] >> Signed-off-by: Cliff Liu <donghua.liu@windriver.com> >> Signed-off-by: He Zhe <Zhe.He@windriver.com> >> --- >> Verified the build test. >> --- >> fs/smb/client/cached_dir.c | 39 ++++++++++++++++---------------------- >> 1 file changed, 16 insertions(+), 23 deletions(-) > No upstream git id :(
Thanks for backporting this! I think you should pick up these patches as
pre-requisites for the one here:
- 5c86919455c1 ("smb: client: fix use-after-free in
smb2_query_info_compound()")
- 7afb86733685 ("smb: Don't leak cfid when reconnect races with
open_cached_dir")
All three of these patches touch on how the cached directory handling of the
'has_lease' field works, and my work was built on top of those.
On 2025-03-19 17:08:39 +0800, Cliff Liu wrote:
>From: Paul Aurich <paul@darkrain42.org>
>
>If open_cached_dir() encounters an error parsing the lease from the
>server, the error handling may race with receiving a lease break,
>resulting in open_cached_dir() freeing the cfid while the queued work is
>pending.
>
>Update open_cached_dir() to drop refs rather than directly freeing the
>cfid.
>
>Have cached_dir_lease_break(), cfids_laundromat_worker(), and
>invalidate_all_cached_dirs() clear has_lease immediately while still
>holding cfids->cfid_list_lock, and then use this to also simplify the
>reference counting in cfids_laundromat_worker() and
>invalidate_all_cached_dirs().
>
>Fixes this KASAN splat (which manually injects an error and lease break
>in open_cached_dir()):
>
>==================================================================
>BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0
>Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65
>
>CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87
>Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
>Workqueue: cifsiod smb2_cached_lease_break
>Call Trace:
> <TASK>
> dump_stack_lvl+0x77/0xb0
> print_report+0xce/0x660
> kasan_report+0xd3/0x110
> smb2_cached_lease_break+0x27/0xb0
> process_one_work+0x50a/0xc50
> worker_thread+0x2ba/0x530
> kthread+0x17c/0x1c0
> ret_from_fork+0x34/0x60
> ret_from_fork_asm+0x1a/0x30
> </TASK>
>
>Allocated by task 2464:
> kasan_save_stack+0x33/0x60
> kasan_save_track+0x14/0x30
> __kasan_kmalloc+0xaa/0xb0
> open_cached_dir+0xa7d/0x1fb0
> smb2_query_path_info+0x43c/0x6e0
> cifs_get_fattr+0x346/0xf10
> cifs_get_inode_info+0x157/0x210
> cifs_revalidate_dentry_attr+0x2d1/0x460
> cifs_getattr+0x173/0x470
> vfs_statx_path+0x10f/0x160
> vfs_statx+0xe9/0x150
> vfs_fstatat+0x5e/0xc0
> __do_sys_newfstatat+0x91/0xf0
> do_syscall_64+0x95/0x1a0
> entry_SYSCALL_64_after_hwframe+0x76/0x7e
>
>Freed by task 2464:
> kasan_save_stack+0x33/0x60
> kasan_save_track+0x14/0x30
> kasan_save_free_info+0x3b/0x60
> __kasan_slab_free+0x51/0x70
> kfree+0x174/0x520
> open_cached_dir+0x97f/0x1fb0
> smb2_query_path_info+0x43c/0x6e0
> cifs_get_fattr+0x346/0xf10
> cifs_get_inode_info+0x157/0x210
> cifs_revalidate_dentry_attr+0x2d1/0x460
> cifs_getattr+0x173/0x470
> vfs_statx_path+0x10f/0x160
> vfs_statx+0xe9/0x150
> vfs_fstatat+0x5e/0xc0
> __do_sys_newfstatat+0x91/0xf0
> do_syscall_64+0x95/0x1a0
> entry_SYSCALL_64_after_hwframe+0x76/0x7e
>
>Last potentially related work creation:
> kasan_save_stack+0x33/0x60
> __kasan_record_aux_stack+0xad/0xc0
> insert_work+0x32/0x100
> __queue_work+0x5c9/0x870
> queue_work_on+0x82/0x90
> open_cached_dir+0x1369/0x1fb0
> smb2_query_path_info+0x43c/0x6e0
> cifs_get_fattr+0x346/0xf10
> cifs_get_inode_info+0x157/0x210
> cifs_revalidate_dentry_attr+0x2d1/0x460
> cifs_getattr+0x173/0x470
> vfs_statx_path+0x10f/0x160
> vfs_statx+0xe9/0x150
> vfs_fstatat+0x5e/0xc0
> __do_sys_newfstatat+0x91/0xf0
> do_syscall_64+0x95/0x1a0
> entry_SYSCALL_64_after_hwframe+0x76/0x7e
>
>The buggy address belongs to the object at ffff88811cc24c00
> which belongs to the cache kmalloc-1k of size 1024
>The buggy address is located 16 bytes inside of
> freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000)
>
>Cc: stable@vger.kernel.org
>Signed-off-by: Paul Aurich <paul@darkrain42.org>
>Signed-off-by: Steve French <stfrench@microsoft.com>
>[ Do not apply the change for cfids_laundromat_worker() since there is no
> this function and related feature on 6.1.y. Update open_cached_dir()
> according to method of upstream patch. ]
>Signed-off-by: Cliff Liu <donghua.liu@windriver.com>
>Signed-off-by: He Zhe <Zhe.He@windriver.com>
>---
>Verified the build test.
>---
> fs/smb/client/cached_dir.c | 39 ++++++++++++++++----------------------
> 1 file changed, 16 insertions(+), 23 deletions(-)
>
>diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
>index d09226c1ac90..d65d5fe5b8fe 100644
>--- a/fs/smb/client/cached_dir.c
>+++ b/fs/smb/client/cached_dir.c
>@@ -320,17 +320,13 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
> /*
> * We are guaranteed to have two references at this point.
> * One for the caller and one for a potential lease.
>- * Release the Lease-ref so that the directory will be closed
>- * when the caller closes the cached handle.
>+ * Release one here, and the second below.
> */
> kref_put(&cfid->refcount, smb2_close_cached_fid);
> }
> if (rc) {
>- if (cfid->is_open)
>- SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
>- cfid->fid.volatile_fid);
>- free_cached_dir(cfid);
>- cfid = NULL;
>+ cfid->has_lease = false;
This should be cleared while holding cfids->cfid_list_lock, which is what the
upstream version of this backport (a9685b409a0) does, because of how this
error handling was adjusted in 5c86919455c1 ("smb: client: fix use-after-free
in smb2_query_info_compound()")
>+ kref_put(&cfid->refcount, smb2_close_cached_fid);
> }
>
> if (rc == 0) {
>@@ -462,25 +458,24 @@ void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
> cfids->num_entries--;
> cfid->is_open = false;
> cfid->on_list = false;
>- /* To prevent race with smb2_cached_lease_break() */
>- kref_get(&cfid->refcount);
>+ if (cfid->has_lease) {
>+ /*
>+ * The lease was never cancelled from the server,
>+ * so steal that reference.
>+ */
>+ cfid->has_lease = false;
>+ } else
>+ kref_get(&cfid->refcount);
> }
> spin_unlock(&cfids->cfid_list_lock);
>
> list_for_each_entry_safe(cfid, q, &entry, entry) {
> list_del(&cfid->entry);
> cancel_work_sync(&cfid->lease_break);
>- if (cfid->has_lease) {
>- /*
>- * We lease was never cancelled from the server so we
>- * need to drop the reference.
>- */
>- spin_lock(&cfids->cfid_list_lock);
>- cfid->has_lease = false;
>- spin_unlock(&cfids->cfid_list_lock);
>- kref_put(&cfid->refcount, smb2_close_cached_fid);
>- }
>- /* Drop the extra reference opened above*/
>+ /*
>+ * Drop the ref-count from above, either the lease-ref (if there
>+ * was one) or the extra one acquired.
>+ */
> kref_put(&cfid->refcount, smb2_close_cached_fid);
> }
> }
>@@ -491,9 +486,6 @@ smb2_cached_lease_break(struct work_struct *work)
> struct cached_fid *cfid = container_of(work,
> struct cached_fid, lease_break);
>
>- spin_lock(&cfid->cfids->cfid_list_lock);
>- cfid->has_lease = false;
>- spin_unlock(&cfid->cfids->cfid_list_lock);
> kref_put(&cfid->refcount, smb2_close_cached_fid);
> }
>
>@@ -511,6 +503,7 @@ int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
> !memcmp(lease_key,
> cfid->fid.lease_key,
> SMB2_LEASE_KEY_SIZE)) {
>+ cfid->has_lease = false;
> cfid->time = 0;
> /*
> * We found a lease remove it from the list
>--
>2.43.0
>
~Paul
Also would be good to see if we can isolate the umount race with freeing cached dentries which I can occasionally reproduce to Windows part way through a large XFS test (but never fails if directory leases disabled) On Wed, Mar 19, 2025 at 10:16 PM Paul Aurich <paul@darkrain42.org> wrote: > > Thanks for backporting this! I think you should pick up these patches as > pre-requisites for the one here: > > - 5c86919455c1 ("smb: client: fix use-after-free in > smb2_query_info_compound()") > - 7afb86733685 ("smb: Don't leak cfid when reconnect races with > open_cached_dir") > > All three of these patches touch on how the cached directory handling of the > 'has_lease' field works, and my work was built on top of those. > > On 2025-03-19 17:08:39 +0800, Cliff Liu wrote: > >From: Paul Aurich <paul@darkrain42.org> > > > >If open_cached_dir() encounters an error parsing the lease from the > >server, the error handling may race with receiving a lease break, > >resulting in open_cached_dir() freeing the cfid while the queued work is > >pending. > > > >Update open_cached_dir() to drop refs rather than directly freeing the > >cfid. > > > >Have cached_dir_lease_break(), cfids_laundromat_worker(), and > >invalidate_all_cached_dirs() clear has_lease immediately while still > >holding cfids->cfid_list_lock, and then use this to also simplify the > >reference counting in cfids_laundromat_worker() and > >invalidate_all_cached_dirs(). > > > >Fixes this KASAN splat (which manually injects an error and lease break > >in open_cached_dir()): > > > >================================================================== > >BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0 > >Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65 > > > >CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87 > >Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 > >Workqueue: cifsiod smb2_cached_lease_break > >Call Trace: > > <TASK> > > dump_stack_lvl+0x77/0xb0 > > print_report+0xce/0x660 > > kasan_report+0xd3/0x110 > > smb2_cached_lease_break+0x27/0xb0 > > process_one_work+0x50a/0xc50 > > worker_thread+0x2ba/0x530 > > kthread+0x17c/0x1c0 > > ret_from_fork+0x34/0x60 > > ret_from_fork_asm+0x1a/0x30 > > </TASK> > > > >Allocated by task 2464: > > kasan_save_stack+0x33/0x60 > > kasan_save_track+0x14/0x30 > > __kasan_kmalloc+0xaa/0xb0 > > open_cached_dir+0xa7d/0x1fb0 > > smb2_query_path_info+0x43c/0x6e0 > > cifs_get_fattr+0x346/0xf10 > > cifs_get_inode_info+0x157/0x210 > > cifs_revalidate_dentry_attr+0x2d1/0x460 > > cifs_getattr+0x173/0x470 > > vfs_statx_path+0x10f/0x160 > > vfs_statx+0xe9/0x150 > > vfs_fstatat+0x5e/0xc0 > > __do_sys_newfstatat+0x91/0xf0 > > do_syscall_64+0x95/0x1a0 > > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > >Freed by task 2464: > > kasan_save_stack+0x33/0x60 > > kasan_save_track+0x14/0x30 > > kasan_save_free_info+0x3b/0x60 > > __kasan_slab_free+0x51/0x70 > > kfree+0x174/0x520 > > open_cached_dir+0x97f/0x1fb0 > > smb2_query_path_info+0x43c/0x6e0 > > cifs_get_fattr+0x346/0xf10 > > cifs_get_inode_info+0x157/0x210 > > cifs_revalidate_dentry_attr+0x2d1/0x460 > > cifs_getattr+0x173/0x470 > > vfs_statx_path+0x10f/0x160 > > vfs_statx+0xe9/0x150 > > vfs_fstatat+0x5e/0xc0 > > __do_sys_newfstatat+0x91/0xf0 > > do_syscall_64+0x95/0x1a0 > > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > >Last potentially related work creation: > > kasan_save_stack+0x33/0x60 > > __kasan_record_aux_stack+0xad/0xc0 > > insert_work+0x32/0x100 > > __queue_work+0x5c9/0x870 > > queue_work_on+0x82/0x90 > > open_cached_dir+0x1369/0x1fb0 > > smb2_query_path_info+0x43c/0x6e0 > > cifs_get_fattr+0x346/0xf10 > > cifs_get_inode_info+0x157/0x210 > > cifs_revalidate_dentry_attr+0x2d1/0x460 > > cifs_getattr+0x173/0x470 > > vfs_statx_path+0x10f/0x160 > > vfs_statx+0xe9/0x150 > > vfs_fstatat+0x5e/0xc0 > > __do_sys_newfstatat+0x91/0xf0 > > do_syscall_64+0x95/0x1a0 > > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > >The buggy address belongs to the object at ffff88811cc24c00 > > which belongs to the cache kmalloc-1k of size 1024 > >The buggy address is located 16 bytes inside of > > freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000) > > > >Cc: stable@vger.kernel.org > >Signed-off-by: Paul Aurich <paul@darkrain42.org> > >Signed-off-by: Steve French <stfrench@microsoft.com> > >[ Do not apply the change for cfids_laundromat_worker() since there is no > > this function and related feature on 6.1.y. Update open_cached_dir() > > according to method of upstream patch. ] > >Signed-off-by: Cliff Liu <donghua.liu@windriver.com> > >Signed-off-by: He Zhe <Zhe.He@windriver.com> > >--- > >Verified the build test. > >--- > > fs/smb/client/cached_dir.c | 39 ++++++++++++++++---------------------- > > 1 file changed, 16 insertions(+), 23 deletions(-) > > > >diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c > >index d09226c1ac90..d65d5fe5b8fe 100644 > >--- a/fs/smb/client/cached_dir.c > >+++ b/fs/smb/client/cached_dir.c > >@@ -320,17 +320,13 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, > > /* > > * We are guaranteed to have two references at this point. > > * One for the caller and one for a potential lease. > >- * Release the Lease-ref so that the directory will be closed > >- * when the caller closes the cached handle. > >+ * Release one here, and the second below. > > */ > > kref_put(&cfid->refcount, smb2_close_cached_fid); > > } > > if (rc) { > >- if (cfid->is_open) > >- SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid, > >- cfid->fid.volatile_fid); > >- free_cached_dir(cfid); > >- cfid = NULL; > >+ cfid->has_lease = false; > > This should be cleared while holding cfids->cfid_list_lock, which is what the > upstream version of this backport (a9685b409a0) does, because of how this > error handling was adjusted in 5c86919455c1 ("smb: client: fix use-after-free > in smb2_query_info_compound()") > > >+ kref_put(&cfid->refcount, smb2_close_cached_fid); > > } > > > > if (rc == 0) { > >@@ -462,25 +458,24 @@ void invalidate_all_cached_dirs(struct cifs_tcon *tcon) > > cfids->num_entries--; > > cfid->is_open = false; > > cfid->on_list = false; > >- /* To prevent race with smb2_cached_lease_break() */ > >- kref_get(&cfid->refcount); > >+ if (cfid->has_lease) { > >+ /* > >+ * The lease was never cancelled from the server, > >+ * so steal that reference. > >+ */ > >+ cfid->has_lease = false; > >+ } else > >+ kref_get(&cfid->refcount); > > } > > spin_unlock(&cfids->cfid_list_lock); > > > > list_for_each_entry_safe(cfid, q, &entry, entry) { > > list_del(&cfid->entry); > > cancel_work_sync(&cfid->lease_break); > >- if (cfid->has_lease) { > >- /* > >- * We lease was never cancelled from the server so we > >- * need to drop the reference. > >- */ > >- spin_lock(&cfids->cfid_list_lock); > >- cfid->has_lease = false; > >- spin_unlock(&cfids->cfid_list_lock); > >- kref_put(&cfid->refcount, smb2_close_cached_fid); > >- } > >- /* Drop the extra reference opened above*/ > >+ /* > >+ * Drop the ref-count from above, either the lease-ref (if there > >+ * was one) or the extra one acquired. > >+ */ > > kref_put(&cfid->refcount, smb2_close_cached_fid); > > } > > } > >@@ -491,9 +486,6 @@ smb2_cached_lease_break(struct work_struct *work) > > struct cached_fid *cfid = container_of(work, > > struct cached_fid, lease_break); > > > >- spin_lock(&cfid->cfids->cfid_list_lock); > >- cfid->has_lease = false; > >- spin_unlock(&cfid->cfids->cfid_list_lock); > > kref_put(&cfid->refcount, smb2_close_cached_fid); > > } > > > >@@ -511,6 +503,7 @@ int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]) > > !memcmp(lease_key, > > cfid->fid.lease_key, > > SMB2_LEASE_KEY_SIZE)) { > >+ cfid->has_lease = false; > > cfid->time = 0; > > /* > > * We found a lease remove it from the list > >-- > >2.43.0 > > > > ~Paul > >
diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c index d09226c1ac90..d65d5fe5b8fe 100644 --- a/fs/smb/client/cached_dir.c +++ b/fs/smb/client/cached_dir.c @@ -320,17 +320,13 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, /* * We are guaranteed to have two references at this point. * One for the caller and one for a potential lease. - * Release the Lease-ref so that the directory will be closed - * when the caller closes the cached handle. + * Release one here, and the second below. */ kref_put(&cfid->refcount, smb2_close_cached_fid); } if (rc) { - if (cfid->is_open) - SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid, - cfid->fid.volatile_fid); - free_cached_dir(cfid); - cfid = NULL; + cfid->has_lease = false; + kref_put(&cfid->refcount, smb2_close_cached_fid); } if (rc == 0) { @@ -462,25 +458,24 @@ void invalidate_all_cached_dirs(struct cifs_tcon *tcon) cfids->num_entries--; cfid->is_open = false; cfid->on_list = false; - /* To prevent race with smb2_cached_lease_break() */ - kref_get(&cfid->refcount); + if (cfid->has_lease) { + /* + * The lease was never cancelled from the server, + * so steal that reference. + */ + cfid->has_lease = false; + } else + kref_get(&cfid->refcount); } spin_unlock(&cfids->cfid_list_lock); list_for_each_entry_safe(cfid, q, &entry, entry) { list_del(&cfid->entry); cancel_work_sync(&cfid->lease_break); - if (cfid->has_lease) { - /* - * We lease was never cancelled from the server so we - * need to drop the reference. - */ - spin_lock(&cfids->cfid_list_lock); - cfid->has_lease = false; - spin_unlock(&cfids->cfid_list_lock); - kref_put(&cfid->refcount, smb2_close_cached_fid); - } - /* Drop the extra reference opened above*/ + /* + * Drop the ref-count from above, either the lease-ref (if there + * was one) or the extra one acquired. + */ kref_put(&cfid->refcount, smb2_close_cached_fid); } } @@ -491,9 +486,6 @@ smb2_cached_lease_break(struct work_struct *work) struct cached_fid *cfid = container_of(work, struct cached_fid, lease_break); - spin_lock(&cfid->cfids->cfid_list_lock); - cfid->has_lease = false; - spin_unlock(&cfid->cfids->cfid_list_lock); kref_put(&cfid->refcount, smb2_close_cached_fid); } @@ -511,6 +503,7 @@ int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]) !memcmp(lease_key, cfid->fid.lease_key, SMB2_LEASE_KEY_SIZE)) { + cfid->has_lease = false; cfid->time = 0; /* * We found a lease remove it from the list