patch "Staging: comedi: Return -EFAULT if copy_to_user() fails" added to staging-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    Staging: comedi: Return -EFAULT if copy_to_user() fails

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From cab36da4bf1a35739b091b73714a39a1bbd02b05 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 2 Dec 2020 09:43:49 +0300
Subject: Staging: comedi: Return -EFAULT if copy_to_user() fails

Return -EFAULT on error instead of the number of bytes remaining to be
copied.

Fixes: bac42fb21259 ("comedi: get rid of compat_alloc_user_space() mess in COMEDI_CMD{,TEST} compat")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/X8c3pfwFy2jpy4BP@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/comedi/comedi_fops.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index d99231c737fb..80d74cce2a01 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2987,7 +2987,9 @@ static int put_compat_cmd(struct comedi32_cmd_struct __user *cmd32,
 	v32.chanlist_len = cmd->chanlist_len;
 	v32.data = ptr_to_compat(cmd->data);
 	v32.data_len = cmd->data_len;
-	return copy_to_user(cmd32, &v32, sizeof(v32));
+	if (copy_to_user(cmd32, &v32, sizeof(v32)))
+		return -EFAULT;
+	return 0;
 }
 
 /* Handle 32-bit COMEDI_CMD ioctl. */
-- 
2.29.2