From: Dan Carpenter dan.carpenter@oracle.com
[ Upstream commit 4b408c74ee5a0b74fc9265c2fe39b0e7dec7c056 ]
The concern here is that "gup->size" is a u64 and "nr_pages" is unsigned long. On 32 bit systems we could trick the kernel into allocating fewer pages than expected.
Link: http://lkml.kernel.org/r/20181025061546.hnhkv33diogf2uis@kili.mountain Fixes: 64c349f4ae78 ("mm: add infrastructure for get_user_pages_fast() benchmarking") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Reviewed-by: Andrew Morton akpm@linux-foundation.org Cc: Stephen Rothwell sfr@canb.auug.org.au Cc: Keith Busch keith.busch@intel.com Cc: "Michael S. Tsirkin" mst@redhat.com Cc: Kees Cook keescook@chromium.org Cc: YueHaibing yuehaibing@huawei.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/gup_benchmark.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c index 7405c9d89d651..7e6f2d2dafb55 100644 --- a/mm/gup_benchmark.c +++ b/mm/gup_benchmark.c @@ -23,6 +23,9 @@ static int __gup_benchmark_ioctl(unsigned int cmd, int nr; struct page **pages;
+ if (gup->size > ULONG_MAX) + return -EINVAL; + nr_pages = gup->size / PAGE_SIZE; pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL); if (!pages)