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drm: fd.o Bug #7595: Avoid u32 overflows in radeon_check_and_fixup_offset().

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The overflows could cause valid offsets to get rejected under some
circumstances, e.g. when the framebuffer resides at the very end of the card's
address space.

Signed-off-by: Dave Airlie <airlied@linux.ie>
This commit is contained in:
Michel Daenzer 2006-09-22 04:12:11 +10:00 committed by Dave Airlie
parent 47cc140931
commit 214ff13d9e
1 changed files with 12 additions and 13 deletions
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25
drivers/char/drm/radeon_state.c
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@ -42,7 +42,11 @@ static __inline__ int radeon_check_and_fixup_offset(drm_radeon_private_t *
drm_file_t * filp_priv,
u32 *offset)
{
u32 off = *offset;
u64 off = *offset;
u32 fb_start = dev_priv->fb_location;
u32 fb_end = fb_start + dev_priv->fb_size - 1;
u32 gart_start = dev_priv->gart_vm_start;
u32 gart_end = gart_start + dev_priv->gart_size - 1;
struct drm_radeon_driver_file_fields *radeon_priv;
/* Hrm ... the story of the offset ... So this function converts
@ -62,10 +66,8 @@ static __inline__ int radeon_check_and_fixup_offset(drm_radeon_private_t *
/* First, the best case, the offset already lands in either the
* framebuffer or the GART mapped space
*/
if ((off >= dev_priv->fb_location &&
off < (dev_priv->fb_location + dev_priv->fb_size)) ||
(off >= dev_priv->gart_vm_start &&
off < (dev_priv->gart_vm_start + dev_priv->gart_size)))
if ((off >= fb_start && off <= fb_end) ||
(off >= gart_start && off <= gart_end))
return 0;
/* Ok, that didn't happen... now check if we have a zero based
@ -78,16 +80,13 @@ static __inline__ int radeon_check_and_fixup_offset(drm_radeon_private_t *
}
/* Finally, assume we aimed at a GART offset if beyond the fb */
if (off > (dev_priv->fb_location + dev_priv->fb_size))
off = off - (dev_priv->fb_location + dev_priv->fb_size) +
dev_priv->gart_vm_start;
if (off > fb_end)
off = off - fb_end - 1 + gart_start;
/* Now recheck and fail if out of bounds */
if ((off >= dev_priv->fb_location &&
off < (dev_priv->fb_location + dev_priv->fb_size)) ||
(off >= dev_priv->gart_vm_start &&
off < (dev_priv->gart_vm_start + dev_priv->gart_size))) {
DRM_DEBUG("offset fixed up to 0x%x\n", off);
if ((off >= fb_start && off <= fb_end) ||
(off >= gart_start && off <= gart_end)) {
DRM_DEBUG("offset fixed up to 0x%x\n", (unsigned int)off);
*offset = off;
return 0;
}