[klibc] Add LUKS support to fstype, second version

[David Härdeman]

The attached patch adds support for detecting LUKS partitions (Linux 
Unified Key Setup - http://luks.endorphin.org/) to fstype. This makes it 
easier to automatically detect and activate encrypted (root) partitions 
from an initramfs image.

The patch is now against klibc's git tree instead of klibc-1.2.

Signed-off-by: David Härdeman <david at 2gen.com>

--

 fstype.c  |   17 ++++++++++++++++-
 luks_fs.h |   45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 1 deletion(-)

-------------- next part --------------
Index: klibc/usr/kinit/fstype/fstype.c
===================================================================
--- klibc.orig/usr/kinit/fstype/fstype.c	2006-02-05 10:53:51.000000000 +0100
+++ klibc/usr/kinit/fstype/fstype.c	2006-02-05 11:09:31.000000000 +0100
@@ -7,7 +7,7 @@
  *  FSSIZE - filesystem size (if known)
  *
  * We currently detect (in order):
- *  gzip, cramfs, romfs, xfs, minix, ext3, ext2, reiserfs, jfs
+ *  gzip, cramfs, romfs, xfs, luks, minix, ext3, ext2, reiserfs, jfs
  *
  * MINIX, ext3 and Reiserfs bits are currently untested.
  */
@@ -29,6 +29,7 @@
 #include "ext2_fs.h"
 #include "ext3_fs.h"
 #include "xfs_sb.h"
+#include "luks_fs.h"
 
 /*
  * Slightly cleaned up version of jfs_superblock to
@@ -168,6 +169,19 @@
 	return 0;
 }
 
+static int luks_image(const unsigned char *buf, unsigned long long *blocks)
+{
+	const struct luks_partition_header *lph =
+		(const struct luks_partition_header *)buf;
+
+	if (!memcmp(lph->magic, LUKS_MAGIC, LUKS_MAGIC_L)) {
+		/* FSSIZE is dictated by the underlying fs, not by LUKS */
+		*blocks = 0;
+		return 1;
+	}
+	return 0;
+}
+
 struct imagetype {
 	off_t		block;
 	const char	name[12];
@@ -179,6 +193,7 @@
 	{ 0,	"cramfs",	cramfs_image	},
 	{ 0,	"romfs",	romfs_image	},
 	{ 0,	"xfs",		xfs_image	},
+	{ 0,	"luks",		luks_image	},
 	{ 1,	"minix",	minix_image	},
 	{ 1,	"ext3",		ext3_image	},
 	{ 1,	"ext2",		ext2_image	},
Index: klibc/usr/kinit/fstype/luks_fs.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ klibc/usr/kinit/fstype/luks_fs.h	2006-02-05 10:57:52.000000000 +0100
@@ -0,0 +1,45 @@
+#ifndef __LINUX_LUKS_FS_H
+#define __LINUX_LUKS_FS_H
+
+/* The basic structures of the luks partition header */
+#define LUKS_MAGIC_L		6
+#define LUKS_CIPHERNAME_L	32
+#define LUKS_CIPHERMODE_L	32
+#define LUKS_HASHSPEC_L		32
+#define LUKS_UUID_STRING_L	40
+
+#define LUKS_MAGIC		"LUKS\xBA\xBE"
+#define LUKS_DIGESTSIZE		20
+#define LUKS_SALTSIZE		32
+#define LUKS_NUMKEYS		8
+#define LUKS_MKD_ITER		10
+#define LUKS_KEY_DISABLED	0x0000DEAD
+#define LUKS_KEY_ENABLED	0x00AC71F3
+#define LUKS_STRIPES		4000
+
+
+/* On-disk "super block" */
+struct luks_partition_header {
+	char	magic[LUKS_MAGIC_L];
+	__be16	version;
+	char	cipherName[LUKS_CIPHERNAME_L];
+	char	cipherMode[LUKS_CIPHERMODE_L];
+	char	hashSpec[LUKS_HASHSPEC_L];
+	__be32	payloadOffset;
+	__be32  keyBytes;
+	char	mkDigest[LUKS_DIGESTSIZE];
+	char	mkDigestSalt[LUKS_SALTSIZE];
+	__be32	mkDigestIterations;
+	char	uuid[LUKS_UUID_STRING_L];
+
+	struct {
+		__be32	active;
+		/* Parameters for PBKDF2 processing */
+		__be32	passwordIterations;
+		char	passwordSalt[LUKS_SALTSIZE];
+		__be32	keyMaterialOffset;
+		__be32	stripes;
+	} keyblock[LUKS_NUMKEYS];
+};
+
+#endif