On Wed, Mar 19, 2025 at 05:08:39PM +0800, Cliff Liu wrote: > From: Paul Aurich <paul@xxxxxxxxxxxxxx> > > 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@xxxxxxxxxxxxxxx > Signed-off-by: Paul Aurich <paul@xxxxxxxxxxxxxx> > Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx> > [ 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@xxxxxxxxxxxxx> > Signed-off-by: He Zhe <Zhe.He@xxxxxxxxxxxxx> > --- > Verified the build test. > --- > fs/smb/client/cached_dir.c | 39 ++++++++++++++++---------------------- > 1 file changed, 16 insertions(+), 23 deletions(-) No upstream git id :(
