commit ea5ff5d351b520524019f7ff7f9ce418de2dad87 upstream.
Until VM_DONTEXPAND was added in commit 1c1914d6e8c6 ("dma-buf: heaps: Don't track CMA dma-buf pages under RssFile") it was possible to obtain a mapping larger than the buffer size via mremap and bypass the overflow check in dma_buf_mmap_internal. When using such a mapping to attempt to fault past the end of the buffer, the CMA heap fault handler also checks the fault offset against the buffer size, but gets the boundary wrong by 1. Fix the boundary check so that we don't read off the end of the pages array and insert an arbitrary page in the mapping.
Reported-by: Xingyu Jin xingyuj@google.com Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation") Cc: stable@vger.kernel.org # Applicable >= 5.10. Needs adjustments only for 5.10. Signed-off-by: T.J. Mercier tjmercier@google.com Acked-by: John Stultz jstultz@google.com Signed-off-by: Sumit Semwal sumit.semwal@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20240830192627.2546033-1-tjmer... [TJ: Backport to 5.10. On this kernel the bug is located in dma_heap_vm_fault which is used by both the CMA and system heaps.] Signed-off-by: T.J. Mercier tjmercier@google.com --- drivers/dma-buf/heaps/heap-helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c index d0696cf937af..a852b5e8122f 100644 --- a/drivers/dma-buf/heaps/heap-helpers.c +++ b/drivers/dma-buf/heaps/heap-helpers.c @@ -161,7 +161,7 @@ static vm_fault_t dma_heap_vm_fault(struct vm_fault *vmf) struct vm_area_struct *vma = vmf->vma; struct heap_helper_buffer *buffer = vma->vm_private_data;
- if (vmf->pgoff > buffer->pagecount) + if (vmf->pgoff >= buffer->pagecount) return VM_FAULT_SIGBUS;
vmf->page = buffer->pages[vmf->pgoff];
On Mon, Sep 16, 2024 at 04:34:41AM +0000, T.J. Mercier wrote:
commit ea5ff5d351b520524019f7ff7f9ce418de2dad87 upstream.
Until VM_DONTEXPAND was added in commit 1c1914d6e8c6 ("dma-buf: heaps: Don't track CMA dma-buf pages under RssFile") it was possible to obtain a mapping larger than the buffer size via mremap and bypass the overflow check in dma_buf_mmap_internal. When using such a mapping to attempt to fault past the end of the buffer, the CMA heap fault handler also checks the fault offset against the buffer size, but gets the boundary wrong by
- Fix the boundary check so that we don't read off the end of the pages
array and insert an arbitrary page in the mapping.
Reported-by: Xingyu Jin xingyuj@google.com Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation")
This commit is in 5.11, so why:
Cc: stable@vger.kernel.org # Applicable >= 5.10. Needs adjustments only for 5.10.
does this say 5.10?
thanks,
greg k-h
On Mon, Sep 16, 2024 at 12:02 AM Greg KH gregkh@linuxfoundation.org wrote:
On Mon, Sep 16, 2024 at 04:34:41AM +0000, T.J. Mercier wrote:
commit ea5ff5d351b520524019f7ff7f9ce418de2dad87 upstream.
Until VM_DONTEXPAND was added in commit 1c1914d6e8c6 ("dma-buf: heaps: Don't track CMA dma-buf pages under RssFile") it was possible to obtain a mapping larger than the buffer size via mremap and bypass the overflow check in dma_buf_mmap_internal. When using such a mapping to attempt to fault past the end of the buffer, the CMA heap fault handler also checks the fault offset against the buffer size, but gets the boundary wrong by
- Fix the boundary check so that we don't read off the end of the pages
array and insert an arbitrary page in the mapping.
Reported-by: Xingyu Jin xingyuj@google.com Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation")
This commit is in 5.11, so why:
Cc: stable@vger.kernel.org # Applicable >= 5.10. Needs adjustments only for 5.10.
does this say 5.10?
thanks,
greg k-h
a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation") moved the code from this heap-helpers.c file to cma_heap.c in 5.11, which is the only place it lives upstream now. The bug still exists in the original location in this heap-helpers.c file on 5.10.
On Mon, Sep 16, 2024 at 12:38:26AM -0700, T.J. Mercier wrote:
On Mon, Sep 16, 2024 at 12:02 AM Greg KH gregkh@linuxfoundation.org wrote:
On Mon, Sep 16, 2024 at 04:34:41AM +0000, T.J. Mercier wrote:
commit ea5ff5d351b520524019f7ff7f9ce418de2dad87 upstream.
Until VM_DONTEXPAND was added in commit 1c1914d6e8c6 ("dma-buf: heaps: Don't track CMA dma-buf pages under RssFile") it was possible to obtain a mapping larger than the buffer size via mremap and bypass the overflow check in dma_buf_mmap_internal. When using such a mapping to attempt to fault past the end of the buffer, the CMA heap fault handler also checks the fault offset against the buffer size, but gets the boundary wrong by
- Fix the boundary check so that we don't read off the end of the pages
array and insert an arbitrary page in the mapping.
Reported-by: Xingyu Jin xingyuj@google.com Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation")
This commit is in 5.11, so why:
Cc: stable@vger.kernel.org # Applicable >= 5.10. Needs adjustments only for 5.10.
does this say 5.10?
thanks,
greg k-h
a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation") moved the code from this heap-helpers.c file to cma_heap.c in 5.11, which is the only place it lives upstream now. The bug still exists in the original location in this heap-helpers.c file on 5.10.
Ah, then that was the wrong Fixes: tag :(
thanks, I'll go queue this up now.
greg k-h
On Mon, Sep 16, 2024 at 12:44 AM Greg KH gregkh@linuxfoundation.org wrote:
On Mon, Sep 16, 2024 at 12:38:26AM -0700, T.J. Mercier wrote:
On Mon, Sep 16, 2024 at 12:02 AM Greg KH gregkh@linuxfoundation.org wrote:
On Mon, Sep 16, 2024 at 04:34:41AM +0000, T.J. Mercier wrote:
commit ea5ff5d351b520524019f7ff7f9ce418de2dad87 upstream.
Until VM_DONTEXPAND was added in commit 1c1914d6e8c6 ("dma-buf: heaps: Don't track CMA dma-buf pages under RssFile") it was possible to obtain a mapping larger than the buffer size via mremap and bypass the overflow check in dma_buf_mmap_internal. When using such a mapping to attempt to fault past the end of the buffer, the CMA heap fault handler also checks the fault offset against the buffer size, but gets the boundary wrong by
- Fix the boundary check so that we don't read off the end of the pages
array and insert an arbitrary page in the mapping.
Reported-by: Xingyu Jin xingyuj@google.com Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation")
This commit is in 5.11, so why:
Cc: stable@vger.kernel.org # Applicable >= 5.10. Needs adjustments only for 5.10.
does this say 5.10?
thanks,
greg k-h
a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation") moved the code from this heap-helpers.c file to cma_heap.c in 5.11, which is the only place it lives upstream now. The bug still exists in the original location in this heap-helpers.c file on 5.10.
Ah, then that was the wrong Fixes: tag :(
thanks, I'll go queue this up now.
greg k-h
Ok sorry about that. Thanks.
linux-stable-mirror@lists.linaro.org
-
Greg KH -
T.J. Mercier