[Mesa-dev] [PATCHv2 0/2] Fix some invalid pointer modifications

[Ilia Mirkin]

It looks like a lot of offsets in gallium are really not ready for >32-bit
buffer sizes. For example, pipe_buffer->width0 is an unsigned int. However in
these cases, there are some semi-legitimate use-cases where a 64-bit offset is
still computed, as tested by the draw-elements-base-vertex-neg piglit
test. This series fixes up a few instances that need the 64-bit multiplication
(on 64-bit platforms). There are probably more, but would be annoying to
change without many API changes.

Perhaps an alternative is to make nouveau comply with the broken 32-bit
truncation-on-multiply logic, but this was a _giant pain_ to debug, and when
64-bit-sized buffers do come in, or some other similar use-case occurs, I
would hate for the person doing that to go through this again. As such I think
it makes sense to assume that stuff _can_ be 64-bit even though in practice it
usually isn't. [Also it's not exactly fun to try to account for bugs in one
piece of code by introducing the exactly-inverse bugs in another piece of
code. For example, I do seem to recall that I tried to nuke the ptrdiff_t cast
in the nouveau code and that was insufficient.]

Ilia Mirkin (2):
  translate: deal with size overflows by casting to ptrdiff_t
  util/u_vbuf: correct map offset calculation for crazy offsets

 src/gallium/auxiliary/translate/translate_generic.c | 2 +-
 src/gallium/auxiliary/translate/translate_sse.c     | 8 ++++++--
 src/gallium/auxiliary/util/u_vbuf.c                 | 2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

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1.8.3.2