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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 4/7] rsxx: Return -EFAULT if copy_to_user() fails
Date:   Wed, 10 Mar 2021 14:25:17 +0100
Message-Id: <20210310132319.318920870@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 77516d25f54912a7baedeeac1b1b828b6f285152 ]

The copy_to_user() function returns the number of bytes remaining but
we want to return -EFAULT to the user if it can't complete the copy.
The "st" variable only holds zero on success or negative error codes on
failure so the type should be int.

Fixes: 36f988e978f8 ("rsxx: Adding in debugfs entries.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/block/rsxx/core.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/block/rsxx/core.c b/drivers/block/rsxx/core.c
index 620a3a67cdd5..0d9137408e3c 100644
--- a/drivers/block/rsxx/core.c
+++ b/drivers/block/rsxx/core.c
@@ -180,15 +180,17 @@ static ssize_t rsxx_cram_read(struct file *fp, char __user *ubuf,
 {
 	struct rsxx_cardinfo *card = file_inode(fp)->i_private;
 	char *buf;
-	ssize_t st;
+	int st;
 
 	buf = kzalloc(cnt, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
 	st = rsxx_creg_read(card, CREG_ADD_CRAM + (u32)*ppos, cnt, buf, 1);
-	if (!st)
-		st = copy_to_user(ubuf, buf, cnt);
+	if (!st) {
+		if (copy_to_user(ubuf, buf, cnt))
+			st = -EFAULT;
+	}
 	kfree(buf);
 	if (st)
 		return st;
-- 
2.30.1