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| author | Rohith Surabattula <rohiths@microsoft.com> | 2021-05-20 18:45:01 +0200 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2021-05-20 19:20:42 +0200 |
| commit | 9687c85dfbf84a6a37522626b4d5c5191a695e6c (patch) | |
| tree | a3cbd160d03e94dd486cf0d4c2c5e29734f1e18b /fs/cifs/misc.c | |
| parent | Defer close only when lease is enabled. (diff) | |
| download | linux-9687c85dfbf84a6a37522626b4d5c5191a695e6c.tar.xz linux-9687c85dfbf84a6a37522626b4d5c5191a695e6c.zip | |
Fix KASAN identified use-after-free issue.
[ 612.157429] ==================================================================
[ 612.158275] BUG: KASAN: use-after-free in process_one_work+0x90/0x9b0
[ 612.158801] Read of size 8 at addr ffff88810a31ca60 by task kworker/2:9/2382
[ 612.159611] CPU: 2 PID: 2382 Comm: kworker/2:9 Tainted: G
OE 5.13.0-rc2+ #98
[ 612.159623] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.14.0-1.fc33 04/01/2014
[ 612.159640] Workqueue: 0x0 (deferredclose)
[ 612.159669] Call Trace:
[ 612.159685] dump_stack+0xbb/0x107
[ 612.159711] print_address_description.constprop.0+0x18/0x140
[ 612.159733] ? process_one_work+0x90/0x9b0
[ 612.159743] ? process_one_work+0x90/0x9b0
[ 612.159754] kasan_report.cold+0x7c/0xd8
[ 612.159778] ? lock_is_held_type+0x80/0x130
[ 612.159789] ? process_one_work+0x90/0x9b0
[ 612.159812] kasan_check_range+0x145/0x1a0
[ 612.159834] process_one_work+0x90/0x9b0
[ 612.159877] ? pwq_dec_nr_in_flight+0x110/0x110
[ 612.159914] ? spin_bug+0x90/0x90
[ 612.159967] worker_thread+0x3b6/0x6c0
[ 612.160023] ? process_one_work+0x9b0/0x9b0
[ 612.160038] kthread+0x1dc/0x200
[ 612.160051] ? kthread_create_worker_on_cpu+0xd0/0xd0
[ 612.160092] ret_from_fork+0x1f/0x30
[ 612.160399] Allocated by task 2358:
[ 612.160757] kasan_save_stack+0x1b/0x40
[ 612.160768] __kasan_kmalloc+0x9b/0xd0
[ 612.160778] cifs_new_fileinfo+0xb0/0x960 [cifs]
[ 612.161170] cifs_open+0xadf/0xf20 [cifs]
[ 612.161421] do_dentry_open+0x2aa/0x6b0
[ 612.161432] path_openat+0xbd9/0xfa0
[ 612.161441] do_filp_open+0x11d/0x230
[ 612.161450] do_sys_openat2+0x115/0x240
[ 612.161460] __x64_sys_openat+0xce/0x140
When mod_delayed_work is called to modify the delay of pending work,
it might return false and queue a new work when pending work is
already scheduled or when try to grab pending work failed.
So, Increase the reference count when new work is scheduled to
avoid use-after-free.
Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to '')
| -rw-r--r-- | fs/cifs/misc.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 34f2a7e80c58..7207a63819cb 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -674,6 +674,8 @@ cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink, /* * Critical section which runs after acquiring deferred_lock. + * As there is no reference count on cifs_deferred_close, pdclose + * should not be used outside deferred_lock. */ bool cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose) @@ -752,8 +754,14 @@ cifs_close_all_deferred_files(struct cifs_tcon *tcon) spin_lock(&tcon->open_file_lock); list_for_each(tmp, &tcon->openFileList) { cfile = list_entry(tmp, struct cifsFileInfo, tlist); - if (delayed_work_pending(&cfile->deferred)) - mod_delayed_work(deferredclose_wq, &cfile->deferred, 0); + if (delayed_work_pending(&cfile->deferred)) { + /* + * If there is no pending work, mod_delayed_work queues new work. + * So, Increase the ref count to avoid use-after-free. + */ + if (!mod_delayed_work(deferredclose_wq, &cfile->deferred, 0)) + cifsFileInfo_get(cfile); + } } spin_unlock(&tcon->open_file_lock); } |