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authorShiraz Hashim <shashim@codeaurora.org>2016-11-10 10:46:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-11-11 08:12:37 -0800
commit6b36ba599d602d8a73920fb5c470fe272fac49c1 (patch)
tree013d0a9d0eb45539fe656545edcfded22e2ee37f /mm/cma.c
parenteef06b82f16c78dc0197e3e9d5b2230647a890ff (diff)
downloadlinux-stericsson-6b36ba599d602d8a73920fb5c470fe272fac49c1.tar.gz
mm/cma.c: check the max limit for cma allocation
CMA allocation request size is represented by size_t that gets truncated when same is passed as int to bitmap_find_next_zero_area_off. We observe that during fuzz testing when cma allocation request is too high, bitmap_find_next_zero_area_off still returns success due to the truncation. This leads to kernel crash, as subsequent code assumes that requested memory is available. Fail cma allocation in case the request breaches the corresponding cma region size. Link: http://lkml.kernel.org/r/1478189211-3467-1-git-send-email-shashim@codeaurora.org Signed-off-by: Shiraz Hashim <shashim@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/cma.c')
-rw-r--r--mm/cma.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/cma.c b/mm/cma.c
index 384c2cb51b56..c960459eda7e 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -385,6 +385,9 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
bitmap_maxno = cma_bitmap_maxno(cma);
bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+ if (bitmap_count > bitmap_maxno)
+ return NULL;
+
for (;;) {
mutex_lock(&cma->lock);
bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,