[PATCH] Fix slab-out-of-bounds in nvme_dbbuf_set

[Sungwoo Kim]

dev->online_queues is a count incremented in nvme_init_queue.
Thus, valid indices are 0 through dev->online_queues − 1.

This patch fixes the loop condition to ensure the index stays
within the valid range.
Index 0 is excluded because it is the admin queue.

KASAN splat:

==================================================================
BUG: KASAN: slab-out-of-bounds in nvme_dbbuf_free drivers/nvme/host/pci.c:377 [inline]
BUG: KASAN: slab-out-of-bounds in nvme_dbbuf_set+0x39c/0x400 drivers/nvme/host/pci.c:404
Read of size 2 at addr ffff88800592a574 by task kworker/u8:5/74

CPU: 0 UID: 0 PID: 74 Comm: kworker/u8:5 Not tainted 6.19.0-dirty #10 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
Workqueue: nvme-reset-wq nvme_reset_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xea/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xce/0x5d0 mm/kasan/report.c:482
 kasan_report+0xdc/0x110 mm/kasan/report.c:595
 __asan_report_load2_noabort+0x18/0x20 mm/kasan/report_generic.c:379
 nvme_dbbuf_free drivers/nvme/host/pci.c:377 [inline]
 nvme_dbbuf_set+0x39c/0x400 drivers/nvme/host/pci.c:404
 nvme_reset_work+0x36b/0x8c0 drivers/nvme/host/pci.c:3252
 process_one_work+0x956/0x1aa0 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x65c/0xe60 kernel/workqueue.c:3421
 kthread+0x41a/0x930 kernel/kthread.c:463
 ret_from_fork+0x6f8/0x8c0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 34 on cpu 1 at 4.241550s:
 kasan_save_stack+0x2c/0x60 mm/kasan/common.c:57
 kasan_save_track+0x1c/0x70 mm/kasan/common.c:78
 kasan_save_alloc_info+0x3c/0x50 mm/kasan/generic.c:570
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xb5/0xc0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_node_noprof+0x2bf/0x8d0 mm/slub.c:5663
 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline]
 nvme_pci_alloc_dev drivers/nvme/host/pci.c:3479 [inline]
 nvme_probe+0x2f1/0x1820 drivers/nvme/host/pci.c:3534
 local_pci_probe+0xef/0x1c0 drivers/pci/pci-driver.c:324
 pci_call_probe drivers/pci/pci-driver.c:392 [inline]
 __pci_device_probe drivers/pci/pci-driver.c:417 [inline]
 pci_device_probe+0x743/0x920 drivers/pci/pci-driver.c:451
 call_driver_probe drivers/base/dd.c:583 [inline]
 really_probe+0x29b/0xb70 drivers/base/dd.c:661
 __driver_probe_device+0x3b0/0x4a0 drivers/base/dd.c:803
 driver_probe_device+0x56/0x1f0 drivers/base/dd.c:833
 __driver_attach_async_helper+0x155/0x340 drivers/base/dd.c:1159
 async_run_entry_fn+0xa6/0x4b0 kernel/async.c:129
 process_one_work+0x956/0x1aa0 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x65c/0xe60 kernel/workqueue.c:3421
 kthread+0x41a/0x930 kernel/kthread.c:463
 ret_from_fork+0x6f8/0x8c0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

The buggy address belongs to the object at ffff88800592a000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 244 bytes to the right of
 allocated 1152-byte region [ffff88800592a000, ffff88800592a480)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5928
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfffffc0000040(head|node=0|zone=1|lastcpupid=0x1fffff)
page_type: f5(slab)
raw: 000fffffc0000040 ffff888001042000 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 000fffffc0000040 ffff888001042000 0000000000000000 dead000000000001
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 000fffffc0000003 ffffea0000164a01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88800592a400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88800592a480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88800592a500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                             ^
 ffff88800592a580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88800592a600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Fixes: 0f0d2c876c96 (nvme: free sq/cq dbbuf pointers when dbbuf set
fails)
Acked-by: Chao Shi <cshi008@xxxxxxx>
Acked-by: Weidong Zhu <weizhu@xxxxxxx>
Acked-by: Dave Tian <daveti@xxxxxxxxxx>
Signed-off-by: Sungwoo Kim <iam@xxxxxxxxxxxx>
---
 drivers/nvme/host/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index a7fb88aa8..3c83076a5 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -400,7 +400,7 @@ static void nvme_dbbuf_set(struct nvme_dev *dev)
 		/* Free memory and continue on */
 		nvme_dbbuf_dma_free(dev);
 
-		for (i = 1; i <= dev->online_queues; i++)
+		for (i = 1; i < dev->online_queues; i++)
 			nvme_dbbuf_free(&dev->queues[i]);
 	}
 }
-- 
2.47.3