5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Bommarito [ Upstream commit f63edb54d8f738f9c21e2068c777ae1c097df6b7 ] os_desc_qw_sign_show() passes OS_STRING_QW_SIGN_LEN as the input length to utf16s_to_utf8s(), but that argument counts UTF-16 code units while OS_STRING_QW_SIGN_LEN (14) is the byte size of qw_sign[]. The array holds only OS_STRING_QW_SIGN_LEN / 2 (7) code units, so the conversion reads up to 7 units (14 bytes) past the end of qw_sign[] into the following members of struct gadget_info when the stored signature fills the array without a NUL terminator, exposing those bytes through the configfs attribute. The store path halves the count for its input bound but passes the full byte count as the utf8s_to_utf16s() output limit; use the destination code-unit count in both directions. Fixes: 76180d716f91 ("usb: gadget: configfs: make qw_sign attribute symmetric") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/20260618005043.1581707-1-michael.bommarito@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/configfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index 4256b1d09380f..e00762efd6da2 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -842,7 +842,7 @@ static ssize_t os_desc_qw_sign_show(struct config_item *item, char *page) struct gadget_info *gi = os_desc_item_to_gadget_info(item); int res; - res = utf16s_to_utf8s((wchar_t *) gi->qw_sign, OS_STRING_QW_SIGN_LEN, + res = utf16s_to_utf8s((wchar_t *) gi->qw_sign, OS_STRING_QW_SIGN_LEN / 2, UTF16_LITTLE_ENDIAN, page, PAGE_SIZE - 1); page[res++] = '\n'; @@ -864,7 +864,7 @@ static ssize_t os_desc_qw_sign_store(struct config_item *item, const char *page, mutex_lock(&gi->lock); res = utf8s_to_utf16s(page, l, UTF16_LITTLE_ENDIAN, (wchar_t *) gi->qw_sign, - OS_STRING_QW_SIGN_LEN); + OS_STRING_QW_SIGN_LEN / 2); if (res > 0) res = len; mutex_unlock(&gi->lock); -- 2.53.0