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From: Roberto Sassu <roberto.sassu@huawei.com>
To: <viro@zeniv.linux.org.uk>
Cc: <linux-security-module@vger.kernel.org>,
	<linux-integrity@vger.kernel.org>, <initramfs@vger.kernel.org>,
	<linux-api@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <bug-cpio@gnu.org>,
	<zohar@linux.vnet.ibm.com>, <silviu.vlasceanu@huawei.com>,
	<dmitry.kasatkin@huawei.com>, <takondra@cisco.com>,
	<kamensky@cisco.com>, <hpa@zytor.com>, <arnd@arndb.de>,
	<rob@landley.net>, <james.w.mcmechan@gmail.com>,
	<niveditas98@gmail.com>, Roberto Sassu <roberto.sassu@huawei.com>
Subject: [PATCH v4 2/3] initramfs: read metadata from special file METADATA!!!
Date: Thu, 23 May 2019 14:18:02 +0200	[thread overview]
Message-ID: <20190523121803.21638-3-roberto.sassu@huawei.com> (raw)
In-Reply-To: <20190523121803.21638-1-roberto.sassu@huawei.com>

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: Roberto Sassu <roberto.sassu@huawei.com>
Reported-by: kbuild test robot <lkp@intel.com>
---
 init/initramfs.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/init/initramfs.c b/init/initramfs.c
index 5de396a6aac0..862c03123de8 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -222,6 +222,7 @@ 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)
 {
@@ -400,6 +401,7 @@ static int __init __maybe_unused do_parse_metadata(char *pathname)
 }
 
 static __initdata int wfd;
+static __initdata int metadata;
 
 static int __init do_name(void)
 {
@@ -408,6 +410,10 @@ 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)) {
@@ -444,11 +450,47 @@ 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) {
 		if (xwrite(wfd, victim, body_len) != body_len)
 			error("write error");
+		if (metadata)
+			do_process_metadata(victim, body_len, true);
 		ksys_close(wfd);
 		do_utime(vcollected, mtime);
 		kfree(vcollected);
@@ -458,6 +500,8 @@ static int __init do_copy(void)
 	} else {
 		if (xwrite(wfd, victim, byte_count) != byte_count)
 			error("write error");
+		if (metadata)
+			do_process_metadata(victim, byte_count, false);
 		body_len -= byte_count;
 		eat(byte_count);
 		return 1;
@@ -467,6 +511,7 @@ 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);
 	ksys_symlink(collected + N_ALIGN(name_len), collected);
 	ksys_lchown(collected, uid, gid);
@@ -534,8 +579,9 @@ 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(N_ALIGN(PATH_MAX), 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;
@@ -580,6 +626,7 @@ 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);
-- 
2.17.1


  parent reply	other threads:[~2019-05-23 12:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23 12:18 [PATCH v4 0/3] initramfs: add support for xattrs in the initial ram disk Roberto Sassu
2019-05-23 12:18 ` [PATCH v4 1/3] initramfs: add file metadata Roberto Sassu
2019-05-23 12:18 ` Roberto Sassu [this message]
2019-07-01 12:54   ` [PATCH v4 2/3] initramfs: read metadata from special file METADATA!!! Mimi Zohar
2019-05-23 12:18 ` [PATCH v4 3/3] gen_init_cpio: add support for file metadata Roberto Sassu
2019-06-30 15:27   ` Mimi Zohar
2019-06-03  9:31 ` [PATCH v4 0/3] initramfs: add support for xattrs in the initial ram disk Roberto Sassu
2019-06-03 18:32   ` Rob Landley
2019-06-26  8:15     ` Roberto Sassu
2019-06-30 15:39       ` Mimi Zohar
2019-07-01 13:42         ` Roberto Sassu
2019-07-01 14:31           ` Mimi Zohar
2019-07-15 16:54             ` Roberto Sassu
2019-07-24 15:34               ` Roberto Sassu
2019-07-01 13:22 ` Mimi Zohar

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