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@xxxxxxxxxxxxx>
Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
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 c2489b463eb9..4f1c98502a09 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3978,6 +3978,7 @@ 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;
@@ -3991,7 +3992,8 @@ 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);
--
2.24.0
