Commit d81269fe authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: fix provide_buffers sign extension 



io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
problems. Not a huge problem as it's only used for access_ok() and
increases the checked length, but better to keep typing right.

Reported-by: default avatarColin Ian King <colin.king@canonical.com>
Fixes: efe68c1c ("io_uring: validate the full range of provided buffers for access")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarColin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/562376a39509e260d8532186a06226e56eb1f594.1616149233.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b65c128f

fs/io_uring.c

+3 −1
Original line number Diff line number Diff line
@@ -3977,6 +3977,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags) 
static int io_provide_buffers_prep(struct io_kiocb *req,

				   const struct io_uring_sqe *sqe)

{

	unsigned long size;

	struct io_provide_buf *p = &req->pbuf;

	u64 tmp;
@@ -3990,7 +3991,8 @@ static int io_provide_buffers_prep(struct io_kiocb *req, 
	p->addr = READ_ONCE(sqe->addr);

	p->len = READ_ONCE(sqe->len);



	if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))

	size = (unsigned long)p->len * p->nbufs;

	if (!access_ok(u64_to_user_ptr(p->addr), size))

		return -EFAULT;



	p->bgid = READ_ONCE(sqe->buf_group);