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author | Daniel Verkamp <dverkamp@chromium.org> | 2019-10-14 15:21:50 -0700 |
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committer | Commit Bot <commit-bot@chromium.org> | 2019-10-25 17:49:40 +0000 |
commit | 7f64f5030b40acded00631465cc3f8b122317b04 (patch) | |
tree | e618b69017caf335d30411f810b908de7270912c /devices/src/virtio/block.rs | |
parent | 67bdbc1a57a6e62a5d162d8eb43508b20fd0acda (diff) | |
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descriptor_utils: check for size overflow in new()
Move the check for length overflow that was in available_bytes() into Reader::new() and Writer::new(). This simplifies callers, since they can assume that once a valid Reader or Writer has been constructed, available_bytes() cannot fail. Since we are walking the descriptor chain during new() anyway, this extra check should be essentially free. BUG=None TEST=cargo test -p devices descriptor_utils Change-Id: Ibeb1defd3728e7b71356650094b0885f3419ed47 Signed-off-by: Daniel Verkamp <dverkamp@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1873142 Reviewed-by: Dylan Reid <dgreid@chromium.org> Reviewed-by: Zach Reizner <zachr@chromium.org> Tested-by: kokoro <noreply+kokoro@google.com> Commit-Queue: Stephen Barber <smbarber@chromium.org>
Diffstat (limited to 'devices/src/virtio/block.rs')
-rw-r--r-- | devices/src/virtio/block.rs | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/devices/src/virtio/block.rs b/devices/src/virtio/block.rs index 554898c..58e00d7 100644 --- a/devices/src/virtio/block.rs +++ b/devices/src/virtio/block.rs @@ -293,9 +293,7 @@ impl Worker { ) -> result::Result<usize, ExecuteError> { let mut status_writer = Writer::new(mem, avail_desc.clone()).map_err(ExecuteError::Descriptor)?; - let available_bytes = status_writer - .available_bytes() - .map_err(ExecuteError::Descriptor)?; + let available_bytes = status_writer.available_bytes(); let status_offset = available_bytes .checked_sub(1) .ok_or(ExecuteError::MissingStatus)?; @@ -616,7 +614,6 @@ impl Block { // The last byte of writer is virtio_blk_req::status, so subtract it from data_len. let data_len = writer .available_bytes() - .map_err(ExecuteError::Descriptor)? .checked_sub(1) .ok_or(ExecuteError::MissingStatus)?; let offset = sector @@ -641,7 +638,7 @@ impl Block { } } VIRTIO_BLK_T_OUT => { - let data_len = reader.available_bytes().map_err(ExecuteError::Descriptor)?; + let data_len = reader.available_bytes(); let offset = sector .checked_shl(u32::from(SECTOR_SHIFT)) .ok_or(ExecuteError::OutOfRange)?; @@ -671,9 +668,7 @@ impl Block { } } VIRTIO_BLK_T_DISCARD | VIRTIO_BLK_T_WRITE_ZEROES => { - while reader.available_bytes().map_err(ExecuteError::Descriptor)? - >= size_of::<virtio_blk_discard_write_zeroes>() - { + while reader.available_bytes() >= size_of::<virtio_blk_discard_write_zeroes>() { let seg: virtio_blk_discard_write_zeroes = reader.read_obj().map_err(ExecuteError::Read)?; |