Commit 0c82bca7 authored by Mike Kravetz's avatar Mike Kravetz Committed by Greg Kroah-Hartman

hugetlbfs: fix bug in pgoff overflow checking

commit 5df63c2a149ae65a9ec239e7c2af44efa6f79beb upstream.

This is a fix for a regression in 32 bit kernels caused by an invalid
check for pgoff overflow in hugetlbfs mmap setup.  The check incorrectly
specified that the size of a loff_t was the same as the size of a long.
The regression prevents mapping hugetlbfs files at offsets greater than
4GB on 32 bit kernels.

On 32 bit kernels conversion from a page based unsigned long can not
overflow a loff_t byte offset.  Therefore, skip this check if
sizeof(unsigned long) != sizeof(loff_t).

Link: http://lkml.kernel.org/r/20180330145402.5053-1-mike.kravetz@oracle.com
Fixes: 63489f8e8211 ("hugetlbfs: check for pgoff value overflow")
Reported-by: default avatarDan Rue <dan.rue@linaro.org>
Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Tested-by: default avatarAnders Roxell <anders.roxell@linaro.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Nic Losby <blurbdust@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4ec44e98
......@@ -148,10 +148,14 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
/*
* page based offset in vm_pgoff could be sufficiently large to
* overflow a (l)off_t when converted to byte offset.
* overflow a loff_t when converted to byte offset. This can
* only happen on architectures where sizeof(loff_t) ==
* sizeof(unsigned long). So, only check in those instances.
*/
if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
return -EINVAL;
if (sizeof(unsigned long) == sizeof(loff_t)) {
if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
return -EINVAL;
}
/* must be huge page aligned */
if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
......
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