From ce9d419dbecc292cc3e06e8b1d6d123d3fa813a4 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 26 Sep 2010 20:50:05 +0100 Subject: [PATCH 1/2] drm/i915: Sanity check pread/pwrite Move the access control up from the fast paths, which are no longer universally taken first, up into the caller. This then duplicates some sanity checking along the slow paths, but is much simpler. Tracked as CVE-2010-2962. Reported-by: Kees Cook Signed-off-by: Chris Wilson Cc: stable@kernel.org --- drivers/gpu/drm/i915/i915_gem.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index cfe597865f5d..7749e78a7300 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -477,8 +477,15 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data, */ if (args->offset > obj->size || args->size > obj->size || args->offset + args->size > obj->size) { - drm_gem_object_unreference_unlocked(obj); - return -EINVAL; + ret = -EINVAL; + goto err; + } + + if (!access_ok(VERIFY_WRITE, + (char __user *)(uintptr_t)args->data_ptr, + args->size)) { + ret = -EFAULT; + goto err; } if (i915_gem_object_needs_bit17_swizzle(obj)) { @@ -490,8 +497,8 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data, file_priv); } +err: drm_gem_object_unreference_unlocked(obj); - return ret; } @@ -580,8 +587,6 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev, struct drm_gem_object *obj, user_data = (char __user *) (uintptr_t) args->data_ptr; remain = args->size; - if (!access_ok(VERIFY_READ, user_data, remain)) - return -EFAULT; mutex_lock(&dev->struct_mutex); @@ -940,8 +945,15 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data, */ if (args->offset > obj->size || args->size > obj->size || args->offset + args->size > obj->size) { - drm_gem_object_unreference_unlocked(obj); - return -EINVAL; + ret = -EINVAL; + goto err; + } + + if (!access_ok(VERIFY_READ, + (char __user *)(uintptr_t)args->data_ptr, + args->size)) { + ret = -EFAULT; + goto err; } /* We can only do the GTT pwrite on untiled buffers, as otherwise @@ -975,8 +987,8 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data, DRM_INFO("pwrite failed %d\n", ret); #endif +err: drm_gem_object_unreference_unlocked(obj); - return ret; } From 7dcd2499deab8f10011713c40bc2f309c9b65077 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 26 Sep 2010 20:21:44 +0100 Subject: [PATCH 2/2] drm/i915: Rephrase pwrite bounds checking to avoid any potential overflow ... and do the same for pread. Signed-off-by: Chris Wilson Cc: stable@kernel.org --- drivers/gpu/drm/i915/i915_gem.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 7749e78a7300..aa959c4a1836 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -471,12 +471,8 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data, return -ENOENT; obj_priv = to_intel_bo(obj); - /* Bounds check source. - * - * XXX: This could use review for overflow issues... - */ - if (args->offset > obj->size || args->size > obj->size || - args->offset + args->size > obj->size) { + /* Bounds check source. */ + if (args->offset > obj->size || args->size > obj->size - args->offset) { ret = -EINVAL; goto err; } @@ -939,12 +935,8 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data, return -ENOENT; obj_priv = to_intel_bo(obj); - /* Bounds check destination. - * - * XXX: This could use review for overflow issues... - */ - if (args->offset > obj->size || args->size > obj->size || - args->offset + args->size > obj->size) { + /* Bounds check destination. */ + if (args->offset > obj->size || args->size > obj->size - args->offset) { ret = -EINVAL; goto err; }