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 <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index a733118..742b127 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);
--
1.8.4.rc3
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