From: Pavel Begunkov asml.silence@gmail.com
[ Upstream commit d81269fecb8ce16eb07efafc9ff5520b2a31c486 ]
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: efe68c1ca8f49 ("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/562376a39509e260d8532186a06226e56eb1f594.161614923... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- fs/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 06e9c2181995..dde290eb7dd0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -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);