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drm/ttm: fix out-of-bounds read in ttm_put_pages() v2

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When ttm_put_pages() tries to figure out whether it's dealing with
transparent hugepages, it just reads past the bounds of the pages array
without a check.

v2: simplify the test if enough pages are left in the array (Christian).

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Fixes: 5c42c64f7d ("drm/ttm: fix the fix for huge compound pages")
Cc: stable@vger.kernel.org
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Christian König 2019-04-02 09:26:52 +02:00 committed by Alex Deucher
parent d47703d43e
commit a66477b0ef
1 changed files with 3 additions and 2 deletions
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5
drivers/gpu/drm/ttm/ttm_page_alloc.c
View file

@ -730,7 +730,8 @@ static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
if (!(flags & TTM_PAGE_FLAG_DMA32)) {
if (!(flags & TTM_PAGE_FLAG_DMA32) &&
(npages - i) >= HPAGE_PMD_NR) {
for (j = 0; j < HPAGE_PMD_NR; ++j)
if (p++ != pages[i + j])
break;
@ -759,7 +760,7 @@ static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
unsigned max_size, n2free;
spin_lock_irqsave(&huge->lock, irq_flags);
while (i < npages) {
while ((npages - i) >= HPAGE_PMD_NR) {
struct page *p = pages[i];
unsigned j;