| From: Mike Kravetz <mike.kravetz@oracle.com> |
| Date: Thu, 5 Apr 2018 16:18:21 -0700 |
| Subject: 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: Dan Rue <dan.rue@linaro.org> |
| Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> |
| Tested-by: Anders 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> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| fs/hugetlbfs/inode.c | 10 +++++++--- |
| 1 file changed, 7 insertions(+), 3 deletions(-) |
| |
| --- a/fs/hugetlbfs/inode.c |
| +++ b/fs/hugetlbfs/inode.c |
| @@ -127,10 +127,14 @@ static int hugetlbfs_file_mmap(struct fi |
| |
| /* |
| * 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)) |
