On Thu, Aug 17, 2017 at 09:23:10AM +0300, Dan Carpenter wrote: > There are some potential integer overflows here on 64 bit systems. > > The condition "if (nfences > SIZE_MAX / sizeof(*fences))" can only be > true on 32 bit systems, it's a no-op on 64 bit, so let's ignore the > check for now and look a couple lines after: > > if (!access_ok(VERIFY_READ, user, nfences * 2 * sizeof(u32))) > ^^^^^^^^^^^ > "nfences" is an unsigned int, so if we set it to UINT_MAX and multiply > by two, it's going to have an integer overflow.
AFAICS it wouldn't overflow due the promotion to unsigned long by '* sizeof(u32)'. > The "args->buffer_count" > is also an unsigned int so it could overflow if it's set to UINT_MAX > when we do: > > exec2_list = kvmalloc_array(args->buffer_count + 1, sz, > ^^^^^^^^^^^^^^^^^^^^^^ Yes, this could overflow. > Fixes: 2889caa92321 ("drm/i915: Eliminate lots of iterations over the > execobjects array") > Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com> > > diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c > b/drivers/gpu/drm/i915/i915_gem_execbuffer.c > index 15ab3e6792f9..f569721aad1a 100644 > --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c > +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c > @@ -2152,7 +2152,7 @@ get_fence_array(struct drm_i915_gem_execbuffer2 *args, > if (!(args->flags & I915_EXEC_FENCE_ARRAY)) > return NULL; > > - if (nfences > SIZE_MAX / sizeof(*fences)) > + if (nfences > UINT_MAX / sizeof(*fences)) > return ERR_PTR(-EINVAL); > > user = u64_to_user_ptr(args->cliprects_ptr); > @@ -2520,7 +2520,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data, > unsigned int i; > int err; > > - if (args->buffer_count < 1 || args->buffer_count > SIZE_MAX / sz - 1) { > + if (args->buffer_count < 1 || args->buffer_count > UINT_MAX / sz - 1) { > DRM_DEBUG("execbuf2 with %d buffers\n", args->buffer_count); > return -EINVAL; > } > @@ -2609,7 +2609,7 @@ i915_gem_execbuffer2(struct drm_device *dev, void *data, > struct drm_syncobj **fences = NULL; > int err; > > - if (args->buffer_count < 1 || args->buffer_count > SIZE_MAX / sz - 1) { > + if (args->buffer_count < 1 || args->buffer_count > UINT_MAX / sz - 1) { > DRM_DEBUG("execbuf2 with %d buffers\n", args->buffer_count); > return -EINVAL; > } > _______________________________________________ > dri-devel mailing list > dri-de...@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx