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).
Fixes: 63489f8e8211 ("hugetlbfs: check for pgoff value overflow") Cc: stable@vger.kernel.org Reported-by: Dan Rue dan.rue@linaro.org Signed-off-by: Mike Kravetz mike.kravetz@oracle.com --- fs/hugetlbfs/inode.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index b9a254dcc0e7..d508c7844681 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -138,10 +138,14 @@ 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))
On 30 March 2018 at 16:54, Mike Kravetz mike.kravetz@oracle.com wrote:
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).
Fixes: 63489f8e8211 ("hugetlbfs: check for pgoff value overflow") Cc: stable@vger.kernel.org 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
fs/hugetlbfs/inode.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index b9a254dcc0e7..d508c7844681 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -138,10 +138,14 @@ 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))-- 2.13.6
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