From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A4D340F8E6 for ; Mon, 2 Mar 2026 15:33:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772465611; cv=none; b=WpiQkCy/Fl5AzBSKwL6zohFmT9BxK7mRTYx9jxPHpIHlGA8CvZmyYpWYd5QSGeHzJhK0ShYkii4GdLhhbiNVLgNqt9fOaD6/D2dhLQKZrBVzOEhYIut4hBKZWNztlS0aOOdTV2fZnT8+9r/GEoHTyvws622sGxgqL9vxdcuogS0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772465611; c=relaxed/simple; bh=MNNJW2hRro9P65HIlDA8urdHBCBxnBx2+T6R000SmPA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=fCOhwSWcv3eDQCBzZ3wht42YBi2rsWBcARj3h3pvhwJVfkmhdZAhiTXucInSERm0h2H2YiOvU4wUf913z85YBGHkugHvCQ9B7oFrfdJAFTFmUoA2GSc3XfGdyUgQ9erHPblRZAJtaS2HWd5LroIkbaPS3KQ2ZTSt/1e8ECH80HU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=nYbV9COL; arc=none smtp.client-ip=91.218.175.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="nYbV9COL" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1772465606; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=VqZ/SnJ6Zhkv9bCWgs5o2lPKwZpFSb8Xw8sTXDIFygY=; b=nYbV9COLHWj0r73nw4qdAGbqG+R9eLgUEPYpjb4/rosTTfMbXjpwmWYomrEIwTawMQ5zFy w3wUAJuqap27Cvn944wxh19Hh75yRQeb1zeqF2gInHrxxhI+C/tbeYnfHO6Trkz8dakadX VFeArTgq2NF8S+n4U49m4Ye94ItEkx4= From: Thorsten Blum To: Greg Kroah-Hartman , Jiri Slaby , Alexey Gladkov , Nathan Chancellor , Myrrh Periwinkle , Thomas Gleixner Cc: Thorsten Blum , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org Subject: [PATCH v2] tty: vt/keyboard: Hoist and reuse variable in vt_do_kdgkb_ioctl Date: Mon, 2 Mar 2026 16:32:52 +0100 Message-ID: <20260302153255.6278-2-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Hoist 'len' and use it in both cases. Add a comment explaining why reassigning 'kbs' is intentional. Signed-off-by: Thorsten Blum --- Changes in v2: - Keep 'kbs' reassignment and add a comment why it's required (Jiri) - Link to v1: https://lore.kernel.org/lkml/20260226123419.737669-1-thorsten.blum@linux.dev/ --- drivers/tty/vt/keyboard.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c index 13bc048f45e8..88fd4ef2634a 100644 --- a/drivers/tty/vt/keyboard.c +++ b/drivers/tty/vt/keyboard.c @@ -2000,17 +2000,18 @@ static char *vt_kdskbsent(char *kbs, unsigned char cur) int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm) { unsigned char kb_func; + ssize_t len; if (get_user(kb_func, &user_kdgkb->kb_func)) return -EFAULT; kb_func = array_index_nospec(kb_func, MAX_NR_FUNC); + /* size should have been a struct member */ + len = sizeof(user_kdgkb->kb_string); + switch (cmd) { case KDGKBSENT: { - /* size should have been a struct member */ - ssize_t len = sizeof(user_kdgkb->kb_string); - char __free(kfree) *kbs = kmalloc(len, GFP_KERNEL); if (!kbs) return -ENOMEM; @@ -2031,11 +2032,16 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm) return -EPERM; char __free(kfree) *kbs = strndup_user(user_kdgkb->kb_string, - sizeof(user_kdgkb->kb_string)); + len); if (IS_ERR(kbs)) return PTR_ERR(kbs); guard(spinlock_irqsave)(&func_buf_lock); + + /* + * Ownership transfer: vt_kdskbsent() returns a pointer + * that must be freed (new buffer, old buffer, or NULL). + */ kbs = vt_kdskbsent(kbs, kb_func); return 0; -- Thorsten Blum GPG: 1D60 735E 8AEF 3BE4 73B6 9D84 7336 78FD 8DFE EAD4