From 8bf529571cca60fb8af65d6d034bdbbc99a9127c Mon Sep 17 00:00:00 2001 From: Armin Wolf Date: Mon, 25 May 2026 01:55:53 +0200 Subject: [PATCH] leds: uleds: Fix potential buffer overread commit c19fe864f667afc49d1391d764e20b66555bcf7a upstream. The name string supplied by userspace is not guaranteed to be null-terminated, so using strchr() on it might result in a buffer overread. The same thing will happen when said string is used by the LED class device. Fix this by using strnchr() instead and explicitly check that the name string is properly null-terminated. Cc: stable@vger.kernel.org Fixes: e381322b0190 ("leds: Introduce userspace LED class driver") Signed-off-by: Armin Wolf Link: https://patch.msgid.link/20260524235553.189134-1-W_Armin@gmx.de Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman --- drivers/leds/uleds.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/leds/uleds.c b/drivers/leds/uleds.c index 3d361c920030..d69e1febc79f 100644 --- a/drivers/leds/uleds.c +++ b/drivers/leds/uleds.c @@ -102,7 +102,8 @@ static ssize_t uleds_write(struct file *file, const char __user *buffer, name = udev->user_dev.name; if (!name[0] || !strcmp(name, ".") || !strcmp(name, "..") || - strchr(name, '/')) { + strnchr(name, sizeof(udev->user_dev.name), '/') || + !strnchr(name, sizeof(udev->user_dev.name), '\0')) { ret = -EINVAL; goto out; }