[PATCH 5.14 285/849] memstick: r592: Fix a UAF bug when removing the driver

Greg Kroah-Hartman
2021-11-15T22:42:17Z

From: Zheyu Ma <zheyuma97@gmail.com>

[ Upstream commit 738216c1953e802aa9f930c5d15b8f9092c847ff ]

In r592_remove(), the driver will free dma after freeing the host, which
may cause a UAF bug.

The following log reveals it:

[ 45.361796 ] BUG: KASAN: use-after-free in r592_remove+0x269/0x350 [r592]
[ 45.364286 ] Call Trace:
[ 45.364472 ] dump_stack_lvl+0xa8/0xd1
[ 45.364751 ] print_address_description+0x87/0x3b0
[ 45.365137 ] kasan_report+0x172/0x1c0
[ 45.365415 ] ? r592_remove+0x269/0x350 [r592]
[ 45.365834 ] ? r592_remove+0x269/0x350 [r592]
[ 45.366168 ] __asan_report_load8_noabort+0x14/0x20
[ 45.366531 ] r592_remove+0x269/0x350 [r592]
[ 45.378785 ]
[ 45.378903 ] Allocated by task 4674:
[ 45.379162 ] ____kasan_kmalloc+0xb5/0xe0
[ 45.379455 ] __kasan_kmalloc+0x9/0x10
[ 45.379730 ] __kmalloc+0x150/0x280
[ 45.379984 ] memstick_alloc_host+0x2a/0x190
[ 45.380664 ]
[ 45.380781 ] Freed by task 5509:
[ 45.381014 ] kasan_set_track+0x3d/0x70
[ 45.381293 ] kasan_set_free_info+0x23/0x40
[ 45.381635 ] ____kasan_slab_free+0x10b/0x140
[ 45.381950 ] __kasan_slab_free+0x11/0x20
[ 45.382241 ] slab_free_freelist_hook+0x81/0x150
[ 45.382575 ] kfree+0x13e/0x290
[ 45.382805 ] memstick_free+0x1c/0x20
[ 45.383070 ] device_release+0x9c/0x1d0
[ 45.383349 ] kobject_put+0x2ef/0x4c0
[ 45.383616 ] put_device+0x1f/0x30
[ 45.383865 ] memstick_free_host+0x24/0x30
[ 45.384162 ] r592_remove+0x242/0x350 [r592]
[ 45.384473 ] pci_device_remove+0xa9/0x250

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/1634383581-11055-1-git-send-email-zheyuma97@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/memstick/host/r592.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
index 615a83782e55d..7aba0fdeba177 100644
--- a/drivers/memstick/host/r592.c
+++ b/drivers/memstick/host/r592.c
@@ -839,15 +839,15 @@ static void r592_remove(struct pci_dev *pdev)
}
memstick_remove_host(dev->host);

+ if (dev->dummy_dma_page)
+ dma_free_coherent(&pdev->dev, PAGE_SIZE, dev->dummy_dma_page,
+ dev->dummy_dma_page_physical_address);
+
free_irq(dev->irq, dev);
iounmap(dev->mmio);
pci_release_regions(pdev);
pci_disable_device(pdev);
memstick_free_host(dev->host);
-
- if (dev->dummy_dma_page)
- dma_free_coherent(&pdev->dev, PAGE_SIZE, dev->dummy_dma_page,
- dev->dummy_dma_page_physical_address);
}

#ifdef CONFIG_PM_SLEEP
--
2.33.0