tree 5482fe85c14efe346488f4d1be80392b908e745e
parent 9778968ebcf520e51b4807f2f93d946e30538ed1
author Tom Sepez <tsepez@chromium.org> 1634236172 +0000
committer Tom Sepez <tsepez@chromium.org> 1634236172 +0000

M94: Use more safe arithmetic in CFX_DIBBase

Most of the calculations are "safe" because we know that the DIB
has validated sizes before allocating a buffer, and that calculations
in terms of bytes won't overflow and will be within the buffer. But
calculations in terms of bits might create overflow in temporaries,
so use safe arithmetic there instead.

Re-arranging the order of operations thus converting to bytes first
might be one option, but we want to handle the 1 bpp case.

Test would require large images that might not be possible on
all platforms.

Bug: chromium:1253399
Change-Id: I3c6c5b8b1f1bf3f429c7d377a8a84c5ab53cafd9
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/85510
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
(cherry picked from commit a8b293732a0160d1bc1d5b0ad5744922f0f820d5)
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/85950