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From: Johan Hovold <johan@kernel.org>
To: Gabriel Somlo <somlo@cmu.edu>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kees Cook <keescook@chromium.org>,
	qemu-devel@nongnu.org, linux-kernel@vger.kernel.org,
	Johan Hovold <johan@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH 3/4] firmware: qemu_fw_cfg: fix sysfs information leak
Date: Wed,  1 Dec 2021 14:25:27 +0100	[thread overview]
Message-ID: <20211201132528.30025-4-johan@kernel.org> (raw)
In-Reply-To: <20211201132528.30025-1-johan@kernel.org>

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@vger.kernel.org      # 4.6
Cc: Gabriel Somlo <somlo@cmu.edu>
Signed-off-by: Johan Hovold <johan@kernel.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


WARNING: multiple messages have this Message-ID (diff)
From: Johan Hovold <johan@kernel.org>
To: Gabriel Somlo <somlo@cmu.edu>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: Kees Cook <keescook@chromium.org>,
	qemu-devel@nongnu.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Johan Hovold <johan@kernel.org>,
	stable@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 3/4] firmware: qemu_fw_cfg: fix sysfs information leak
Date: Wed,  1 Dec 2021 14:25:27 +0100	[thread overview]
Message-ID: <20211201132528.30025-4-johan@kernel.org> (raw)
In-Reply-To: <20211201132528.30025-1-johan@kernel.org>

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@vger.kernel.org      # 4.6
Cc: Gabriel Somlo <somlo@cmu.edu>
Signed-off-by: Johan Hovold <johan@kernel.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



  parent reply	other threads:[~2021-12-01 13:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-01 13:25 [PATCH 0/4] firmware: qemu_fw_cfg: misc bug fixes Johan Hovold
2021-12-01 13:25 ` Johan Hovold
2021-12-01 13:25 ` [PATCH 1/4] firmware: qemu_fw_cfg: fix NULL-pointer deref on duplicate entries Johan Hovold
2021-12-01 13:25   ` Johan Hovold
2021-12-01 13:25 ` [PATCH 2/4] firmware: qemu_fw_cfg: fix kobject leak in probe error path Johan Hovold
2021-12-01 13:25   ` Johan Hovold
2021-12-01 13:25 ` Johan Hovold [this message]
2021-12-01 13:25   ` [PATCH 3/4] firmware: qemu_fw_cfg: fix sysfs information leak Johan Hovold
2021-12-01 13:25 ` [PATCH 4/4] firmware: qemu_fw_cfg: remove sysfs entries explicitly Johan Hovold
2021-12-01 13:25   ` Johan Hovold

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