From f48b6274ca933bf0066271e4e8f1903a25c5bdae Mon Sep 17 00:00:00 2001
From: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Date: Thu, 4 Jun 2020 18:01:52 -0700
Subject: [PATCH 1541/2944] io_uring: validate the full range of provided
 buffers for access

to #28736503

commit efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff upstream

Account for the number of provided buffers when validating the address
range.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
---
 fs/io_uring.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index c87f05d..d6c1107 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3174,7 +3174,8 @@ 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(VERIFY_WRITE, u64_to_user_ptr(p->addr), p->len))
+	if (!access_ok(VERIFY_WRITE, u64_to_user_ptr(p->addr),
+	    p->len * p->nbufs))
 		return -EFAULT;
 
 	p->bgid = READ_ONCE(sqe->buf_group);
-- 
1.8.3.1