linux-kernel - [PATCH 3/4] firmware: qemu_fw_cfg: fix sysfs information leak

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211201132528.30025-4-johan@kernel.org>
Date:   Wed,  1 Dec 2021 14:25:27 +0100
From:   Johan Hovold <johan@...nel.org>
To:     Gabriel Somlo <somlo@....edu>,
        "Michael S. Tsirkin" <mst@...hat.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kees Cook <keescook@...omium.org>, qemu-devel@...gnu.org,
        linux-kernel@...r.kernel.org, Johan Hovold <johan@...nel.org>,
        stable@...r.kernel.org
Subject: [PATCH 3/4] firmware: qemu_fw_cfg: fix sysfs information leak

Make sure to always NUL-terminate file names retrieved from the firmware
to avoid accessing data beyond the entry slab buffer and exposing it
through sysfs in case the firmware data is corrupt.

Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
Cc: stable@...r.kernel.org      # 4.6
Cc: Gabriel Somlo <somlo@....edu>
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/firmware/qemu_fw_cfg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index ccb7ed62452f..f08e056ed0ae 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -598,7 +598,7 @@ static int fw_cfg_register_file(const struct fw_cfg_file *f)
 	/* set file entry information */
 	entry->size = be32_to_cpu(f->size);
 	entry->select = be16_to_cpu(f->select);
-	memcpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH);
+	strscpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH);
 
 	/* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
 	err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
-- 
2.32.0