Messages in this thread Patch in this message |  | | From | Tvrtko Ursulin <> | Subject | [PATCH 6/6] lib/scatterlist: Fix overflow check in sgl_alloc_order | Date | Wed, 26 Sep 2018 15:16:25 +0100 |
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From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
It is necessary to ensure types on both sides of the comparison are of the same width. Otherwise the check overflows sooner than expect due left hand side being an unsigned long length, and the right hand side unsigned int number of elements multiplied by element size.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Jens Axboe <axboe@kernel.dk> --- lib/scatterlist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 581a2e91e515..c87243d46f10 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -485,7 +485,7 @@ struct scatterlist *sgl_alloc_order(unsigned long length, unsigned int order, nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); /* Check for integer overflow */ - if (length > (nent << (PAGE_SHIFT + order))) + if (length > ((unsigned long)nent << (PAGE_SHIFT + order))) return NULL; nalloc = nent; if (chainable) { -- 2.17.1
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