[2.6.20.17 review 19/58] drm/i915: Fix i965 secured batchbuffer usage (CVE-2007-3851)

Willy Tarreau
2007-08-22T08:57:30Z

[-- Attachment #1: 0019-drm-i915-Fix-i965-secured-batchbuffer-usage-CVE-20.patch --]
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This 965G and above chipsets moved the batch buffer non-secure bits to
another place. This means that previous drm's allowed in-secure batchbuffers
to be submitted to the hardware from non-privileged users who are logged
into X and and have access to direct rendering.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/char/drm/i915_dma.c | 14 +++++++++++---
drivers/char/drm/i915_drv.h | 1 +
2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/char/drm/i915_dma.c b/drivers/char/drm/i915_dma.c
index 9354ce3..ab1a1d0 100644
--- a/drivers/char/drm/i915_dma.c
+++ b/drivers/char/drm/i915_dma.c
@@ -172,6 +172,8 @@ static int i915_initialize(drm_device_t * dev,
* private backbuffer/depthbuffer usage.
*/
dev_priv->use_mi_batchbuffer_start = 0;
+ if (IS_I965G(dev)) /* 965 doesn't support older method */
+ dev_priv->use_mi_batchbuffer_start = 1;

/* Allow hardware batchbuffers unless told otherwise.
*/
@@ -504,8 +506,13 @@ static int i915_dispatch_batchbuffer(drm_device_t * dev,

if (dev_priv->use_mi_batchbuffer_start) {
BEGIN_LP_RING(2);
- OUT_RING(MI_BATCH_BUFFER_START | (2 << 6));
- OUT_RING(batch->start | MI_BATCH_NON_SECURE);
+ if (IS_I965G(dev)) {
+ OUT_RING(MI_BATCH_BUFFER_START | (2 << 6) | MI_BATCH_NON_SECURE_I965);
+ OUT_RING(batch->start);
+ } else {
+ OUT_RING(MI_BATCH_BUFFER_START | (2 << 6));
+ OUT_RING(batch->start | MI_BATCH_NON_SECURE);
+ }
ADVANCE_LP_RING();
} else {
BEGIN_LP_RING(4);
@@ -722,7 +729,8 @@ static int i915_setparam(DRM_IOCTL_ARGS)

switch (param.param) {
case I915_SETPARAM_USE_MI_BATCHBUFFER_START:
- dev_priv->use_mi_batchbuffer_start = param.value;
+ if (!IS_I965G(dev))
+ dev_priv->use_mi_batchbuffer_start = param.value;
break;
case I915_SETPARAM_TEX_LRU_LOG_GRANULARITY:
dev_priv->tex_lru_log_granularity = param.value;
diff --git a/drivers/char/drm/i915_drv.h b/drivers/char/drm/i915_drv.h
index 93cdcfe..30022c8 100644
--- a/drivers/char/drm/i915_drv.h
+++ b/drivers/char/drm/i915_drv.h
@@ -280,6 +280,7 @@ extern int i915_wait_ring(drm_device_t * dev, int n, const char *caller);
#define MI_BATCH_BUFFER_START (0x31<<23)
#define MI_BATCH_BUFFER_END (0xA<<23)
#define MI_BATCH_NON_SECURE (1)
+#define MI_BATCH_NON_SECURE_I965 (1<<8)

#define MI_WAIT_FOR_EVENT ((0x3<<23))
#define MI_WAIT_FOR_PLANE_A_FLIP (1<<2)
--
1.5.2.5

--