From: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Subject: hugetlbfs: fix bug in pgoff overflow checking 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@xxxxxxxxxx Fixes: 63489f8e8211 ("hugetlbfs: check for pgoff value overflow") Reported-by: Dan Rue <dan.rue@xxxxxxxxxx> Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Tested-by: Anders Roxell <anders.roxell@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Yisheng Xie <xieyisheng1@xxxxxxxxxx> Cc: "Kirill A . Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Nic Losby <blurbdust@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/hugetlbfs/inode.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff -puN fs/hugetlbfs/inode.c~hugetlbfs-fix-bug-in-pgoff-overflow-checking fs/hugetlbfs/inode.c --- a/fs/hugetlbfs/inode.c~hugetlbfs-fix-bug-in-pgoff-overflow-checking +++ a/fs/hugetlbfs/inode.c @@ -138,10 +138,14 @@ 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)) _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
