From d1d788302e8c76e5138dfa61f4a5eee4f72a748f Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 21 Nov 2010 09:23:48 +0000 Subject: [PATCH] drm/i915: Prevent integer overflow when validating the execbuffer Commit 2549d6c2 removed the vmalloc used for temporary storage of the relocation lists used during execbuffer. However, our use of vmalloc was being protected by an integer overflow check which we do want to preserve! Reported-by: Dan Carpenter Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/i915_gem.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 17b1cba3b5f1..bc4164590054 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -3630,8 +3630,15 @@ validate_exec_list(struct drm_i915_gem_exec_object2 *exec, for (i = 0; i < count; i++) { char __user *ptr = (char __user *)(uintptr_t)exec[i].relocs_ptr; - size_t length = exec[i].relocation_count * sizeof(struct drm_i915_gem_relocation_entry); + 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)) + return -EINVAL; + + length = exec[i].relocation_count * + sizeof(struct drm_i915_gem_relocation_entry); if (!access_ok(VERIFY_READ, ptr, length)) return -EFAULT; -- 2.20.1