Commit 4f2d99b0 authored by Kees Cook's avatar Kees Cook Committed by Greg Kroah-Hartman
Browse files

firmware_loader: Use security_post_load_data() 



Now that security_post_load_data() is wired up, use it instead
of the NULL file argument style of security_post_read_file(),
and update the security_kernel_load_data() call to indicate that a
security_kernel_post_load_data() call is expected.

Wire up the IMA check to match earlier logic. Perhaps a generalized
change to ima_post_load_data() might look something like this:

    return process_buffer_measurement(buf, size,
                                      kernel_load_data_id_str(load_id),
                                      read_idmap[load_id] ?: FILE_CHECK,
                                      0, NULL);

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarMimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-10-keescook@chromium.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b64fcae7

drivers/base/firmware_loader/fallback.c

+4 −4
Original line number Diff line number Diff line
@@ -272,9 +272,9 @@ static ssize_t firmware_loading_store(struct device *dev, 
				dev_err(dev, "%s: map pages failed\n",

					__func__);

			else

				rc = security_kernel_post_read_file(NULL,

						fw_priv->data, fw_priv->size,

						READING_FIRMWARE);

				rc = security_kernel_post_load_data(fw_priv->data,

						fw_priv->size,

						LOADING_FIRMWARE, "blob");



			/*

			 * Same logic as fw_load_abort, only the DONE bit
@@ -613,7 +613,7 @@ static bool fw_run_sysfs_fallback(u32 opt_flags) 
		return false;



	/* Also permit LSMs and IMA to fail firmware sysfs fallback */

	ret = security_kernel_load_data(LOADING_FIRMWARE, false);

	ret = security_kernel_load_data(LOADING_FIRMWARE, true);

	if (ret < 0)

		return false;

drivers/base/firmware_loader/fallback_platform.c

+7 −1
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags) 
	if (!(opt_flags & FW_OPT_FALLBACK_PLATFORM))

		return -ENOENT;



	rc = security_kernel_load_data(LOADING_FIRMWARE, false);

	rc = security_kernel_load_data(LOADING_FIRMWARE, true);

	if (rc)

		return rc;
@@ -27,6 +27,12 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags) 


	if (fw_priv->data && size > fw_priv->allocated_size)

		return -ENOMEM;



	rc = security_kernel_post_load_data((u8 *)data, size, LOADING_FIRMWARE,

						"platform");

	if (rc)

		return rc;



	if (!fw_priv->data)

		fw_priv->data = vmalloc(size);

	if (!fw_priv->data)

security/integrity/ima/ima_main.c

+10 −10
Original line number Diff line number Diff line
@@ -648,15 +648,6 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, 
	enum ima_hooks func;

	u32 secid;



	if (!file && read_id == READING_FIRMWARE) {

		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&

		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {

			pr_err("Prevent firmware loading_store.\n");

			return -EACCES;	/* INTEGRITY_UNKNOWN */

		}

		return 0;

	}



	/* permit signed certs */

	if (!file && read_id == READING_X509_CERTIFICATE)

		return 0;
@@ -706,7 +697,7 @@ int ima_load_data(enum kernel_load_data_id id, bool contents) 
		}

		break;

	case LOADING_FIRMWARE:

		if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE)) {

		if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) {

			pr_err("Prevent firmware sysfs fallback loading.\n");

			return -EACCES;	/* INTEGRITY_UNKNOWN */

		}
@@ -742,6 +733,15 @@ int ima_post_load_data(char *buf, loff_t size, 
		       enum kernel_load_data_id load_id,

		       char *description)

{

	if (load_id == LOADING_FIRMWARE) {

		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&

		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {

			pr_err("Prevent firmware loading_store.\n");

			return -EACCES; /* INTEGRITY_UNKNOWN */

		}

		return 0;

	}



	return 0;

}

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