From 78b41148cfea2a3f04d87adf3a71b21735820a37 Mon Sep 17 00:00:00 2001 From: Xinyu Liu <1171169449@qq.com> Date: Wed, 9 Jul 2025 11:55:33 +0800 Subject: [PATCH] usb: gadget: configfs: Fix OOB read on empty string write commit 3014168731b7930300aab656085af784edc861f6 upstream. When writing an empty string to either 'qw_sign' or 'landingPage' sysfs attributes, the store functions attempt to access page[l - 1] before validating that the length 'l' is greater than zero. This patch fixes the vulnerability by adding a check at the beginning of os_desc_qw_sign_store() and webusb_landingPage_store() to handle the zero-length input case gracefully by returning immediately. Signed-off-by: Xinyu Liu Cc: stable Link: https://lore.kernel.org/r/tencent_B1C9481688D0E95E7362AB2E999DE8048207@qq.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/configfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index 87657e0ca5fc..476a22728e8d 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -824,6 +824,8 @@ static ssize_t os_desc_qw_sign_store(struct config_item *item, const char *page, struct gadget_info *gi = os_desc_item_to_gadget_info(item); int res, l; + if (!len) + return len; l = min((int)len, OS_STRING_QW_SIGN_LEN >> 1); if (page[l - 1] == '\n') --l;