drm/i915/cmdparser: Do not check past the cmd length.
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Web: https://git.kernel.org/torvalds/c/b3ad99ed45917f42884fee731fa3cf9b8229a26c Commit: b3ad99ed45917f42884fee731fa3cf9b8229a26c Parent: b18224e95cb13ef7517aa26e6b47c85117327f11 Refname: refs/heads/master Author: Michal Srb <[email protected]> AuthorDate: Mon Feb 5 16:04:38 2018 +0000 Committer: Rodrigo Vivi <[email protected]> CommitDate: Tue Feb 6 11:41:40 2018 -0800 drm/i915/cmdparser: Do not check past the cmd length. 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] (cherry picked from commit 3aec7f871c65eb5f76b4125fda432593c834a6f2) Signed-off-by: Rodrigo Vivi <[email protected]> --- drivers/gpu/drm/i915/i915_cmd_parser.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c index ab4c8b0ec886..95478db9998b 100644 --- a/drivers/gpu/drm/i915/i915_cmd_parser.c +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c @@ -1212,6 +1212,12 @@ static bool check_cmd(const struct intel_engine_cs *engine, continue; } + if (desc->bits[i].offset >= length) { + DRM_DEBUG_DRIVER("CMD: Rejected command 0x%08X, too short to check bitmask (%s)\n", + *cmd, engine->name); + return false; + } + dword = cmd[desc->bits[i].offset] & desc->bits[i].mask; -- To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html