initramfs: read metadata from special file METADATA!!!

hulk inclusion
category: feature
feature: IMA Digest Lists extension
bugzilla: 46797

-------------------------------------------------

Instead of changing the CPIO format, metadata are parsed from regular files
with special name 'METADATA!!!'. This file immediately follows the file
metadata are added to.

This patch checks if the file being extracted has the special name and, if
yes, creates a buffer with the content of that file and calls
do_parse_metadata() to parse metadata from the buffer.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NTianxing Zhang <zhangtianxing3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

init/initramfs.c

@@ -223,6 +223,7 @@ static void __init read_into(char *buf, unsigned size, enum state next)
 }
 
 static __initdata char *header_buf, *symlink_buf, *name_buf, *metadata_buf;
+static __initdata char *metadata_buf_ptr, *previous_name_buf;
 
 static int __init do_start(void)
 {
@@ -404,6 +405,7 @@ static int __init __maybe_unused do_parse_metadata(char *pathname)
 
 static __initdata struct file *wfile;
 static __initdata loff_t wfile_pos;
+static int metadata __initdata;
 
 static int __init do_name(void)
 {
@@ -412,6 +414,10 @@ static int __init do_name(void)
 	if (strcmp(collected, "TRAILER!!!") == 0) {
 		free_hash();
 		return 0;
+	} else if (strcmp(collected, METADATA_FILENAME) == 0) {
+		metadata = 1;
+	} else {
+		memcpy(previous_name_buf, collected, strlen(collected) + 1);
 	}
 	clean_path(collected, mode);
 	if (S_ISREG(mode)) {
@@ -448,12 +454,48 @@ static int __init do_name(void)
 	return 0;
 }
 
+static int __init do_process_metadata(char *buf, int len, bool last)
+{
+	int ret = 0;
+
+	if (!metadata_buf) {
+		metadata_buf_ptr = metadata_buf = kmalloc(body_len, GFP_KERNEL);
+		if (!metadata_buf_ptr) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		metadata_len = body_len;
+	}
+
+	if (metadata_buf_ptr + len > metadata_buf + metadata_len) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	memcpy(metadata_buf_ptr, buf, len);
+	metadata_buf_ptr += len;
+
+	if (last)
+		do_parse_metadata(previous_name_buf);
+out:
+	if (ret < 0 || last) {
+		kfree(metadata_buf);
+		metadata_buf = NULL;
+		metadata = 0;
+	}
+
+	return ret;
+}
+
 static int __init do_copy(void)
 {
 	if (byte_count >= body_len) {
 		struct timespec64 t[2] = { };
 		if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
 			error("write error");
+		if (metadata)
+			do_process_metadata(victim, body_len, true);
 
 		t[0].tv_sec = mtime;
 		t[1].tv_sec = mtime;
@@ -466,6 +508,8 @@ static int __init do_copy(void)
 	} else {
 		if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
 			error("write error");
+		if (metadata)
+			do_process_metadata(victim, byte_count, false);
 		body_len -= byte_count;
 		eat(byte_count);
 		return 1;
@@ -475,6 +519,7 @@ static int __init do_copy(void)
 static int __init do_symlink(void)
 {
 	collected[N_ALIGN(name_len) + body_len] = '\0';
+	memcpy(previous_name_buf, collected, strlen(collected) + 1);
 	clean_path(collected, 0);
 	init_symlink(collected + N_ALIGN(name_len), collected);
 	init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
@@ -542,8 +587,10 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 	header_buf = kmalloc(110, GFP_KERNEL);
 	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
+	previous_name_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1,
+				    GFP_KERNEL);
 
-	if (!header_buf || !symlink_buf || !name_buf)
+	if (!header_buf || !symlink_buf || !name_buf || !previous_name_buf)
 		panic("can't allocate buffers");
 
 	state = Start;
@@ -588,6 +635,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 		len -= my_inptr;
 	}
 	dir_utime();
+	kfree(previous_name_buf);
 	kfree(name_buf);
 	kfree(symlink_buf);
 	kfree(header_buf);