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. 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,
^^^^^^^^^^^^^^^^^^^^^^
Fixes: 2889caa92321 ("drm/i915: Eliminate lots of iterations over the execobjects array")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
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;
}
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