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authorMichal Srb <msrb@suse.com>2018-02-05 16:04:38 +0000
committerChris Wilson <chris@chris-wilson.co.uk>2018-02-05 20:49:24 +0000
commit3aec7f871c65eb5f76b4125fda432593c834a6f2 (patch)
treefbcd9dfa91c91c5ebe4a48a5bdffbe1d2c8611ce
parent2f265fad9756a40c09e3f4dcc62d5d7fa73a9fb2 (diff)
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 <msrb@suse.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180205151745.29292-1-msrb@suse.com Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20180205160438.3267-2-chris@chris-wilson.co.uk
-rw-r--r--drivers/gpu/drm/i915/i915_cmd_parser.c6
1 files changed, 6 insertions, 0 deletions
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;