From 2d1803ada2e021b9333b8a784c55fe828ab2b985 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 16 Nov 2023 11:14:52 -0800 Subject: [PATCH] usb: gadget: f_midi: Replace strlcpy() with strscpy() strlcpy() reads the entire source buffer first. This read may exceed the destination size limit. This is both inefficient and can lead to linear read overflows if a source string is not NUL-terminated[1]. Additionally, it returns the size of the source string, not the resulting size of the destination string. In an effort to remove strlcpy() completely[2], replace strlcpy() here with strscpy(). In the unlikely (impossible?) case where opts->id was larger than PAGE_SIZE, this will now correctly report truncation errors. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [1] Link: https://github.com/KSPP/linux/issues/89 [2] Cc: Greg Kroah-Hartman Cc: Will McVicker Cc: "Gustavo A. R. Silva" Cc: Peter Chen Cc: Davidlohr Bueso Cc: Zhang Qilong Cc: Linyu Yuan Cc: John Keeping Cc: Azeem Shaikh Cc: linux-usb@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20231116191452.work.902-kees@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_midi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 5335845d697b5..20c6fbd94f32d 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -1177,11 +1177,11 @@ F_MIDI_OPT(out_ports, true, MAX_PORTS); static ssize_t f_midi_opts_id_show(struct config_item *item, char *page) { struct f_midi_opts *opts = to_f_midi_opts(item); - int result; + ssize_t result; mutex_lock(&opts->lock); if (opts->id) { - result = strlcpy(page, opts->id, PAGE_SIZE); + result = strscpy(page, opts->id, PAGE_SIZE); } else { page[0] = 0; result = 0; -- 2.30.2