From d32dcb0659bcb3b68878a985280024ec92d0db5b Mon Sep 17 00:00:00 2001 From: Lee Jones Date: Wed, 13 Dec 2023 16:42:34 +0000 Subject: [PATCH] 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 Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20231213164246.1021885-6-lee@kernel.org Signed-off-by: Greg Kroah-Hartman --- 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;