From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 11F8C3B71C0; Tue, 13 Oct 2026 12:43:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791895398; cv=none; b=kCKSIxg9Pku/xAjM1oJGECyczGVcUzvmpw0zFfsf7OUZxz3YvZLxd9fZhi4hmEw2k4SkMBQMt7wAaYAPBiq/Cdvkdfb2dpw9lDQEqdIRw5nn4ccm+BahTaQiAlXqnUCWyB2qytmtXCRNG34eNjhZUSXEmpb4/UBb0zdRam8CSZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791895398; c=relaxed/simple; bh=Otq5usbpjA3dcFwhUixJtpvgPUgkDugwL3ai482AtU0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CMKIZ6OXpF4C+Rs6N6FwB4AhzHNLPP/67dwgtZOHTKIff0ewZ2eYHsyI+V+Kvxh2pNJ4A3v0et+8WQUMKDzrgT7gqgWPaWzYhknbw9eoHKkvHQjAZq7Gv7UFn2WN9kE7uhtw9iayO82bjngKIbiJR+zGHfV4qDSw95kdoU6lZlQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kuVIGVI3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="kuVIGVI3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 695351F000FF; Tue, 13 Oct 2026 12:43:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791895397; bh=zd6Fr6nt+DvUAVC9MHQdi/yvRtnyCFMn5fBMdMVcCC4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kuVIGVI3M/bjigd+UWfeVHWxjGCMT64GjskzPDqIySrz4HO32pTenrmsT+QugtSyj tYHaAphOrk6Q05eDcnlBCHYTPX+OdeXk4b6IVR4kSocf+iNSLPah75q9ZAtrH7xDNm glb+AuH0B4bQSQCKlJFaSWG4IM24IOKyr7Id+d4o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Jiri Slaby (SUSE)" , Sasha Levin Subject: [PATCH 6.12 260/497] tty/vt: use guard()s Date: Tue, 13 Oct 2026 13:37:07 +0200 Message-ID: <20261013112914.061793232@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112907.864180619@linuxfoundation.org> References: <20261013112907.864180619@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby (SUSE) [ Upstream commit e730c373b6ff16a177e132859bf6ea4dbb15105f ] Having all the new guards, use them in the vt code. This improves readability, makes error handling easier, and marks locked portions of code explicit. A local free_page_ptr __free guard is introduced for __get_free_page/free_page (with proper casts). This could be made public in include/. But I am not sure if there are more possible users, so keeping completely private here. Signed-off-by: "Jiri Slaby (SUSE)" Link: https://lore.kernel.org/r/20250814072456.182853-16-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Use scope-based console locking and buffer cleanup in vcs_write() so error paths can return directly while releasing both resources. Limit the conversion to the function needed by the follow-up console pointer reload fix. Omit the other guard conversions, including the selection changes whose context assumes bracketed-paste support. Allocate the page-sized copy buffer with kmalloc() and reuse the existing kfree cleanup guard instead of introducing a new cleanup helper. Declare the buffer before the console guard so the console is unlocked before the buffer is freed, preserving the original cleanup order. [ sashal: REDUCED BACKPORT of e730c373b6ff: carries 29/414 upstream changed lines; not carried: drivers/tty/vt/consolemap.c:con_set_trans_old(), drivers/tty/vt/consolemap.c:con_get_trans_old(), drivers/tty/vt/consolemap.c:con_set_trans_new(), drivers/tty/vt/consolemap.c:con_get_trans_new(), drivers/tty/vt/consolemap.c:con_clear_unimap(), drivers/tty/vt/selection.c:sel_loadlut(), drivers/tty/vt/selection.c:set_selection_kernel(), drivers/tty/vt/selection.c:paste_selection(), +28 more ] Stable-dep-of: 226bd5603371 ("vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF") Signed-off-by: Sasha Levin --- drivers/tty/vt/vc_screen.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c index 2536635153552..a59d2006b1a99 100644 --- a/drivers/tty/vt/vc_screen.c +++ b/drivers/tty/vt/vc_screen.c @@ -591,7 +591,6 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct inode *inode = file_inode(file); struct vc_data *vc; - char *con_buf; u16 *org0, *org; unsigned int written; int size; @@ -602,7 +601,7 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) if (use_unicode(inode)) return -EOPNOTSUPP; - con_buf = (char *) __get_free_page(GFP_KERNEL); + char *con_buf __free(kfree) = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!con_buf) return -ENOMEM; @@ -611,22 +610,18 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) /* Select the proper current console and verify * sanity of the situation under the console lock. */ - console_lock(); + guard(console_lock)(); attr = use_attributes(inode); - ret = -ENXIO; vc = vcs_vc(inode, &viewed); if (!vc) - goto unlock_out; + return -ENXIO; size = vcs_size(vc, attr, false); - if (size < 0) { - ret = size; - goto unlock_out; - } - ret = -EINVAL; + if (size < 0) + return size; if (pos < 0 || pos > size) - goto unlock_out; + return -EINVAL; if (count > size - pos) count = size - pos; written = 0; @@ -651,8 +646,7 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) */ if (written) break; - ret = -EFAULT; - goto unlock_out; + return -EFAULT; } } @@ -664,15 +658,13 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) if (!vc) { if (written) break; - ret = -ENXIO; - goto unlock_out; + return -ENXIO; } size = vcs_size(vc, attr, false); if (size < 0) { if (written) break; - ret = size; - goto unlock_out; + return size; } if (pos >= size) break; @@ -702,9 +694,6 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) if (written && vc) vcs_scr_updated(vc); -unlock_out: - console_unlock(); - free_page((unsigned long) con_buf); return ret; } -- 2.53.0