Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b1cc4097 authored by Marc-André Lureau's avatar Marc-André Lureau Committed by Michael S. Tsirkin
Browse files

fw_cfg: handle fw_cfg_read_blob() error 



fw_cfg_read_blob() may fail, but does not return error. This may lead
to surprising behaviours, like populating zero file entries (in
register_file() or during read). Return an error if ACPI locking
failed. Also, the following DMA read/write extension will add more
error paths that should be handled appropriately.

Signed-off-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 59ecab18

drivers/firmware/qemu_fw_cfg.c

+22 −10
Original line number Diff line number Diff line
@@ -77,7 +77,7 @@ static void fw_cfg_sel_endianness(u16 key) 
}



/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */

static void fw_cfg_read_blob(u16 key,

static ssize_t fw_cfg_read_blob(u16 key,

				void *buf, loff_t pos, size_t count)

{

	u32 glk = -1U;
@@ -91,7 +91,7 @@ static void fw_cfg_read_blob(u16 key, 
		/* Should never get here */

		WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");

		memset(buf, 0, count);

		return;

		return -EINVAL;

	}



	mutex_lock(&fw_cfg_dev_lock);
@@ -102,6 +102,7 @@ static void fw_cfg_read_blob(u16 key, 
	mutex_unlock(&fw_cfg_dev_lock);



	acpi_release_global_lock(glk);

	return count;

}



/* clean up fw_cfg device i/o */
@@ -183,8 +184,9 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev) 
	}



	/* verify fw_cfg device signature */

	fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);

	if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {

	if (fw_cfg_read_blob(FW_CFG_SIGNATURE, sig,

				0, FW_CFG_SIG_SIZE) < 0 ||

		memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {

		fw_cfg_io_cleanup();

		return -ENODEV;

	}
@@ -344,8 +346,7 @@ static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj, 
	if (count > entry->size - pos)

		count = entry->size - pos;



	fw_cfg_read_blob(entry->select, buf, pos, count);

	return count;

	return fw_cfg_read_blob(entry->select, buf, pos, count);

}



static struct bin_attribute fw_cfg_sysfs_attr_raw = {
@@ -501,7 +502,11 @@ static int fw_cfg_register_dir_entries(void) 
	struct fw_cfg_file *dir;

	size_t dir_size;



	fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count, 0, sizeof(files_count));

	ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count,

			0, sizeof(files_count));

	if (ret < 0)

		return ret;



	count = be32_to_cpu(files_count);

	dir_size = count * sizeof(struct fw_cfg_file);
@@ -509,7 +514,10 @@ static int fw_cfg_register_dir_entries(void) 
	if (!dir)

		return -ENOMEM;



	fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(files_count), dir_size);

	ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, dir,

			sizeof(files_count), dir_size);

	if (ret < 0)

		goto end;



	for (i = 0; i < count; i++) {

		ret = fw_cfg_register_file(&dir[i]);
@@ -517,6 +525,7 @@ static int fw_cfg_register_dir_entries(void) 
			break;

	}



end:

	kfree(dir);

	return ret;

}
@@ -557,7 +566,10 @@ static int fw_cfg_sysfs_probe(struct platform_device *pdev) 
		goto err_probe;



	/* get revision number, add matching top-level attribute */

	fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev));

	err = fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev));

	if (err < 0)

		goto err_probe;



	fw_cfg_rev = le32_to_cpu(rev);

	err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);

	if (err)