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Commit 6593d924 authored by Kees Cook's avatar Kees Cook
Browse files

firmware_class: perform new LSM checks 



This attaches LSM hooks to the existing firmware loading interfaces:
filesystem-found firmware and demand-loaded blobs. On errors, loads
are aborted and the failure code is returned to userspace.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarTakashi Iwai <tiwai@suse.de>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 13752fe2

drivers/base/firmware_class.c

+26 −4
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/suspend.h>

#include <linux/syscore_ops.h>

#include <linux/reboot.h>

#include <linux/security.h>



#include <generated/utsrelease.h>
@@ -308,12 +309,17 @@ static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf) 
	if (rc != size) {

		if (rc > 0)

			rc = -EIO;

		vfree(buf);

		return rc;

		goto fail;

	}

	rc = security_kernel_fw_from_file(file, buf, size);

	if (rc)

		goto fail;

	fw_buf->data = buf;

	fw_buf->size = size;

	return 0;

fail:

	vfree(buf);

	return rc;

}



static int fw_get_filesystem_firmware(struct device *device,
@@ -617,6 +623,7 @@ static ssize_t firmware_loading_store(struct device *dev, 
{

	struct firmware_priv *fw_priv = to_firmware_priv(dev);

	struct firmware_buf *fw_buf;

	ssize_t written = count;

	int loading = simple_strtol(buf, NULL, 10);

	int i;
@@ -640,6 +647,8 @@ static ssize_t firmware_loading_store(struct device *dev, 
		break;

	case 0:

		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {

			int rc;



			set_bit(FW_STATUS_DONE, &fw_buf->status);

			clear_bit(FW_STATUS_LOADING, &fw_buf->status);
@@ -649,10 +658,23 @@ static ssize_t firmware_loading_store(struct device *dev, 
			 * see the mapped 'buf->data' once the loading

			 * is completed.

			 * */

			if (fw_map_pages_buf(fw_buf))

			rc = fw_map_pages_buf(fw_buf);

			if (rc)

				dev_err(dev, "%s: map pages failed\n",

					__func__);

			else

				rc = security_kernel_fw_from_file(NULL,

						fw_buf->data, fw_buf->size);



			/*

			 * Same logic as fw_load_abort, only the DONE bit

			 * is ignored and we set ABORT only on failure.

			 */

			list_del_init(&fw_buf->pending_list);

			if (rc) {

				set_bit(FW_STATUS_ABORT, &fw_buf->status);

				written = rc;

			}

			complete_all(&fw_buf->completion);

			break;

		}
@@ -666,7 +688,7 @@ static ssize_t firmware_loading_store(struct device *dev, 
	}

out:

	mutex_unlock(&fw_lock);

	return count;

	return written;

}



static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);