From: Lee Jones Date: Wed, 13 Dec 2023 16:42:31 +0000 (+0000) Subject: usb: gadget: f_uac1: Replace snprintf() with the safer scnprintf() variant X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c1a371866db9c44ab3004b5fc06df066a1b96262;p=linux.git usb: gadget: f_uac1: 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: Ruslan Bilovol Cc: Julian Scheel Cc: Bryan Wu Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20231213164246.1021885-3-lee@kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/gadget/function/f_uac1.c b/drivers/usb/gadget/function/f_uac1.c index 78634ea7863a7..7de74a3dd3921 100644 --- a/drivers/usb/gadget/function/f_uac1.c +++ b/drivers/usb/gadget/function/f_uac1.c @@ -1634,7 +1634,7 @@ static ssize_t f_uac1_opts_##name##_show(struct config_item *item, \ int result; \ \ mutex_lock(&opts->lock); \ - result = snprintf(page, sizeof(opts->name), "%s", opts->name); \ + result = scnprintf(page, sizeof(opts->name), "%s", opts->name); \ mutex_unlock(&opts->lock); \ \ return result; \ @@ -1652,7 +1652,7 @@ static ssize_t f_uac1_opts_##name##_store(struct config_item *item, \ goto end; \ } \ \ - ret = snprintf(opts->name, min(sizeof(opts->name), len), \ + ret = scnprintf(opts->name, min(sizeof(opts->name), len), \ "%s", page); \ \ end: \ @@ -1758,7 +1758,7 @@ static struct usb_function_instance *f_audio_alloc_inst(void) opts->req_number = UAC1_DEF_REQ_NUM; - snprintf(opts->function_name, sizeof(opts->function_name), "AC Interface"); + scnprintf(opts->function_name, sizeof(opts->function_name), "AC Interface"); return &opts->func_inst; }