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.
Signed-off-by: Michal Srb <m...@suse.com>
---
v2: Return false instead of continuing - reject the command instead of
ignoring.
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 de7ec59433d1..ef7ad016d67c 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -1218,6 +1218,12 @@ 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;
--
2.13.6
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