From: Daniel Vetter Date: Thu, 19 Sep 2013 12:00:11 +0000 (+0200) Subject: drm/i915: Use unsigned for overflow checks in execbuf X-Git-Tag: next-20131017~58^2~1^2~89 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b205ca572159ab9a617fc96e4659bc138064ca8e;p=karo-tx-linux.git drm/i915: Use unsigned for overflow checks in execbuf There's actually no real risk since we already check for stricter constraints earlier (using UINT_MAX / sizeof (struct drm_i915_gem_exec_object2) as the limit). But in eb_create we use signed integers, which steals a factor of 2. Luckily struct drm_i915_gem_exec_object2 for this to not matter. Still, be consistent and use unsigned integers. Similar use unsinged integers when checking for overflows in the relocation entry processing. I've also added a new subtests to igt/gem_reloc_overflow to also test for overflowing args->buffer_count values. v2: Give the variables again tighter scope to make it clear that the computation is purely local and doesn't leak out to the 2nd block. Requested by Chris Wilson. Cc: Chris Wilson Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index b87107e73c05..da23cfe3902b 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -48,15 +48,15 @@ eb_create(struct drm_i915_gem_execbuffer2 *args, struct i915_address_space *vm) struct eb_vmas *eb = NULL; if (args->flags & I915_EXEC_HANDLE_LUT) { - int size = args->buffer_count; + unsigned size = args->buffer_count; size *= sizeof(struct i915_vma *); size += sizeof(struct eb_vmas); eb = kmalloc(size, GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY); } if (eb == NULL) { - int size = args->buffer_count; - int count = PAGE_SIZE / sizeof(struct hlist_head) / 2; + unsigned size = args->buffer_count; + unsigned count = PAGE_SIZE / sizeof(struct hlist_head) / 2; BUILD_BUG_ON_NOT_POWER_OF_2(PAGE_SIZE / sizeof(struct hlist_head)); while (count > 2*size) count >>= 1; @@ -667,7 +667,7 @@ i915_gem_execbuffer_relocate_slow(struct drm_device *dev, bool need_relocs; int *reloc_offset; int i, total, ret; - int count = args->buffer_count; + unsigned count = args->buffer_count; if (WARN_ON(list_empty(&eb->vmas))) return 0; @@ -818,8 +818,8 @@ 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); + unsigned relocs_total = 0; + unsigned relocs_max = UINT_MAX / sizeof(struct drm_i915_gem_relocation_entry); for (i = 0; i < count; i++) { char __user *ptr = to_user_ptr(exec[i].relocs_ptr);