linux-kernel - [PATCH 2/2] rsxx: Return -EFAULT if copy_to

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Date:   Wed, 10 Jun 2020 20:24:51 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Joshua Morris <josh.h.morris@...ibm.com>,
        Philip Kelleher <pjk1939@...ux.ibm.com>
Cc:     Jens Axboe <axboe@...nel.dk>, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH 2/2] rsxx: Return -EFAULT if copy_to_user() fails

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@...cle.com>
---
 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 6207449fa716f..558fa263acbc0 100644
--- a/drivers/block/rsxx/core.c
+++ b/drivers/block/rsxx/core.c
@@ -165,15 +165,17 @@ 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;
-- 
2.26.2