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Message-Id: <20220412005042.351105-7-sashal@kernel.org>
Date: Mon, 11 Apr 2022 20:50:26 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Xiaoguang Wang <xiaoguang.wang@...ux.alibaba.com>,
Bodo Stroesser <bostroesser@...il.com>,
"Martin K . Petersen" <martin.petersen@...cle.com>,
Sasha Levin <sashal@...nel.org>, linux-scsi@...r.kernel.org,
target-devel@...r.kernel.org
Subject: [PATCH AUTOSEL 5.4 07/21] scsi: target: tcmu: Fix possible page UAF
From: Xiaoguang Wang <xiaoguang.wang@...ux.alibaba.com>
[ Upstream commit a6968f7a367f128d120447360734344d5a3d5336 ]
tcmu_try_get_data_page() looks up pages under cmdr_lock, but it does not
take refcount properly and just returns page pointer. When
tcmu_try_get_data_page() returns, the returned page may have been freed by
tcmu_blocks_release().
We need to get_page() under cmdr_lock to avoid concurrent
tcmu_blocks_release().
Link: https://lore.kernel.org/r/20220311132206.24515-1-xiaoguang.wang@linux.alibaba.com
Reviewed-by: Bodo Stroesser <bostroesser@...il.com>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@...ux.alibaba.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/target/target_core_user.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 71144e33272a..077c56cbed4e 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -1488,6 +1488,7 @@ static struct page *tcmu_try_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
mutex_lock(&udev->cmdr_lock);
page = tcmu_get_block_page(udev, dbi);
if (likely(page)) {
+ get_page(page);
mutex_unlock(&udev->cmdr_lock);
return page;
}
@@ -1526,6 +1527,7 @@ static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf)
/* For the vmalloc()ed cmd area pages */
addr = (void *)(unsigned long)info->mem[mi].addr + offset;
page = vmalloc_to_page(addr);
+ get_page(page);
} else {
uint32_t dbi;
@@ -1536,7 +1538,6 @@ static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
}
- get_page(page);
vmf->page = page;
return 0;
}
--
2.35.1
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