Commit edd47826 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe

io_uring/rsrc: disallow multi-source reg buffers

If two or more mappings go back to back to each other they can be passed
into io_uring to be registered as a single registered buffer. That would
even work if mappings came from different sources, e.g. it's possible to
mix in this way anon pages and pages from shmem or hugetlb. That is not
a problem but it'd rather be less prone if we forbid such mixing.

Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9a1563d1
......@@ -1162,14 +1162,17 @@ struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
pages, vmas);
if (pret == nr_pages) {
struct file *file = vmas[0]->vm_file;
/* don't support file backed memory */
for (i = 0; i < nr_pages; i++) {
struct vm_area_struct *vma = vmas[i];
if (vma_is_shmem(vma))
if (vmas[i]->vm_file != file) {
ret = -EINVAL;
break;
}
if (!file)
continue;
if (vma->vm_file &&
!is_file_hugepages(vma->vm_file)) {
if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
ret = -EOPNOTSUPP;
break;
}
......
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