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scsi: target: tcmu: Fix possible page UAF
[ Upstream commit a6968f7a36
]
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@gmail.com>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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parent
c189745bb0
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1 changed files with 2 additions and 1 deletions
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@ -1820,6 +1820,7 @@ static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi)
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mutex_lock(&udev->cmdr_lock);
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page = xa_load(&udev->data_pages, dpi);
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if (likely(page)) {
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get_page(page);
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mutex_unlock(&udev->cmdr_lock);
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return page;
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}
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@ -1876,6 +1877,7 @@ static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf)
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/* For the vmalloc()ed cmd area pages */
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addr = (void *)(unsigned long)info->mem[mi].addr + offset;
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page = vmalloc_to_page(addr);
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get_page(page);
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} else {
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uint32_t dpi;
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@ -1886,7 +1888,6 @@ static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf)
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return VM_FAULT_SIGBUS;
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}
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get_page(page);
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vmf->page = page;
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return 0;
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}
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