io_uring: fix provide_buffers sign extension

[ Upstream commit d81269fecb ]

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: Colin Ian King <colin.king@canonical.com>
Fixes: efe68c1ca8 ("io_uring: validate the full range of provided buffers for access")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/562376a39509e260d8532186a06226e56eb1f594.1616149233.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Pavel Begunkov 2021-03-19 10:21:19 +00:00 committed by Greg Kroah-Hartman
parent efb334c4e5
commit dcf2dfc161

View file

@ -3996,6 +3996,7 @@ static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock,
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;
@ -4009,7 +4010,8 @@ 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);