patch "usb: gadget: udc: atmel: Replace snprintf() with the safer" added to usb-next

patch "usb: gadget: udc: atmel: Replace snprintf() with the safer" added to usb-next

[gregkh]

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

    usb: gadget: udc: atmel: Replace snprintf() with the safer

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next 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 also be merged in the next major kernel release
during the merge window.

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


From d32dcb0659bcb3b68878a985280024ec92d0db5b Mon Sep 17 00:00:00 2001
From: Lee Jones <lee@kernel.org>
Date: Wed, 13 Dec 2023 16:42:34 +0000
Subject: usb: gadget: udc: atmel: Replace snprintf() with the safer
 scnprintf() variant

There is a general misunderstanding amongst engineers that {v}snprintf()
returns the length of the data *actually* encoded into the destination
array.  However, as per the C99 standard {v}snprintf() really returns
the length of the data that *would have been* written if there were
enough space for it.  This misunderstanding has led to buffer-overruns
in the past.  It's generally considered safer to use the {v}scnprintf()
variants in their place (or even sprintf() in simple cases).  So let's
do that.

Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Cc: Cristian Birsan <cristian.birsan@microchip.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Cc:  <linux-arm-kernel@lists.infradead.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20231213164246.1021885-6-lee@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/gadget/udc/atmel_usba_udc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index 02b1bef5e22e..b76885d78e8a 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -94,7 +94,7 @@ static ssize_t queue_dbg_read(struct file *file, char __user *buf,
 
 	inode_lock(file_inode(file));
 	list_for_each_entry_safe(req, tmp_req, queue, queue) {
-		len = snprintf(tmpbuf, sizeof(tmpbuf),
+		len = scnprintf(tmpbuf, sizeof(tmpbuf),
 				"%8p %08x %c%c%c %5d %c%c%c\n",
 				req->req.buf, req->req.length,
 				req->req.no_interrupt ? 'i' : 'I',
@@ -104,7 +104,6 @@ static ssize_t queue_dbg_read(struct file *file, char __user *buf,
 				req->submitted ? 'F' : 'f',
 				req->using_dma ? 'D' : 'd',
 				req->last_transaction ? 'L' : 'l');
-		len = min(len, sizeof(tmpbuf));
 		if (len > nbytes)
 			break;
 
-- 
2.43.0



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