diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2019-12-07 22:26:44 +0000 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2019-12-09 09:57:57 +0000 |
| commit | 8d65859a4cbae92f441b9aec8780055a361cc3d0 (patch) | |
| tree | bb858257a58cff33034cce7cb17f203e1a5c1777 /drivers/gpu/drm/i915/gem/i915_gem_mman.c | |
| parent | d63411000741ebca84b147b3e79cb6b298ee07e9 (diff) | |
drm/i915/gem: Comment on inability to check args.pad for MMAP_OFFSET
Since we didn't check and insist that args.pad must be zero for MMAP_GTT
historically, we cannot insert a check now as old userspace may be
feeding in garbage. As such the lack of check is enshrined into the ABI,
so add a comment to remind us we cannot add the check later.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191207222644.2830129-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/gem/i915_gem_mman.c')
| -rw-r--r-- | drivers/gpu/drm/i915/gem/i915_gem_mman.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c index 3a3f30bc8ac7..879fff8adc48 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c @@ -620,6 +620,15 @@ i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data, enum i915_mmap_type type; int err; + /* + * Historically we failed to check args.pad and args.offset + * and so we cannot use those fields for user input and we cannot + * add -EINVAL for them as the ABI is fixed, i.e. old userspace + * may be feeding in garbage in those fields. + * + * if (args->pad) return -EINVAL; is verbotten! + */ + err = i915_user_extensions(u64_to_user_ptr(args->extensions), NULL, 0, NULL); if (err) |