io_uring/memmap: cast nr_pages to size_t before shifting

If the allocated size exceeds UINT_MAX, then it's necessary to cast
the mr->nr_pages value to size_t to prevent it from overflowing. In
practice this isn't much of a concern as the required memory size will
have been validated upfront, and accounted to the user. And > 4GB sizes
will be necessary to make the lack of a cast a problem, which greatly
exceeds normal user locked_vm settings that are generally in the kb to
mb range. However, if root is used, then accounting isn't done, and
then it's possible to hit this issue.

Link: https://lore.kernel.org/all/[email protected]/
Cc: [email protected]
Reported-by: [email protected]
Fixes: 087f997870a9 ("io_uring/memmap: implement mmap for regions")
Signed-off-by: Jens Axboe <[email protected]>

0 files changed, 0 insertions, 0 deletions