3.16.60-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Michal Srb <[email protected]> commit 3aec7f871c65eb5f76b4125fda432593c834a6f2 upstream. The command MEDIA_VFE_STATE checks bits at offset +2 dwords. However, it is possible to have MEDIA_VFE_STATE command with length = 0 + LENGTH_BIAS = 2. In that case check_cmd will read bits from the following command, or even past the end of the buffer. If the offset ends up outside of the command length, reject the command. Fixes: 351e3db2b363 ("drm/i915: Implement command buffer parsing logic") Signed-off-by: Michal Srb <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] Reviewed-by: Chris Wilson <[email protected]> Signed-off-by: Chris Wilson <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] [bwh: Backported to 3.16: Log ring->id rather than engine->name] Signed-off-by: Ben Hutchings <[email protected]> --- drivers/gpu/drm/i915/i915_cmd_parser.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/gpu/drm/i915/i915_cmd_parser.c +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c @@ -941,6 +941,12 @@ static bool check_cmd(const struct intel continue; } + if (desc->bits[i].offset >= length) { + DRM_DEBUG_DRIVER("CMD: Rejected command 0x%08X, too short to check bitmask (ring=%d)\n", + *cmd, ring->id); + return false; + } + dword = cmd[desc->bits[i].offset] & desc->bits[i].mask;
