From: Kees Cook Date: Tue, 12 Mar 2013 00:31:45 +0000 (-0700) Subject: drm/i915: bounds check execbuffer relocation count X-Git-Tag: v3.8.5~54 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5016d9ac0938789e7aaba86be3e6fbf24e7b7bee;p=karo-tx-linux.git drm/i915: bounds check execbuffer relocation count commit 3118a4f652c7b12c752f3222af0447008f9b2368 upstream. It is possible to wrap the counter used to allocate the buffer for relocation copies. This could lead to heap writing overflows. CVE-2013-0913 v3: collapse test, improve comment v2: move check into validate_exec_list Signed-off-by: Kees Cook Reported-by: Pinkie Pie Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index 26d08bb58218..7adf5a789e3d 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -706,15 +706,20 @@ validate_exec_list(struct drm_i915_gem_exec_object2 *exec, int count) { int i; + int relocs_total = 0; + int relocs_max = INT_MAX / sizeof(struct drm_i915_gem_relocation_entry); for (i = 0; i < count; i++) { char __user *ptr = (char __user *)(uintptr_t)exec[i].relocs_ptr; int length; /* limited by fault_in_pages_readable() */ - /* First check for malicious input causing overflow */ - if (exec[i].relocation_count > - INT_MAX / sizeof(struct drm_i915_gem_relocation_entry)) + /* First check for malicious input causing overflow in + * the worst case where we need to allocate the entire + * relocation tree as a single array. + */ + if (exec[i].relocation_count > relocs_max - relocs_total) return -EINVAL; + relocs_total += exec[i].relocation_count; length = exec[i].relocation_count * sizeof(struct drm_i915_gem_relocation_entry);