Commit 5125cfdf authored by Sascha Hauer's avatar Sascha Hauer Committed by Richard Weinberger
Browse files

ubifs: Format changes for authentication support 



This patch adds the changes to the on disk format needed for
authentication support. We'll add:

* a HMAC covering super block node
* a HMAC covering the master node
* a hash over the root index node to the master node
* a hash over the LPT to the master node
* a flag to the filesystem flag indicating the filesystem is
  authenticated
* an authentication node necessary to authenticate the nodes written
  to the journal heads while they are written.
* a HMAC of a well known message to the super block node to be able
  to check if the correct key is provided

And finally, not visible in this patch, nevertheless explained here:

* hashes over the referenced child nodes in each branch of a index node

Signed-off-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent fd615005

fs/ubifs/debug.c

+6 −0
Original line number Diff line number Diff line
@@ -165,6 +165,8 @@ const char *dbg_ntype(int type) 
		return "commit start node";

	case UBIFS_ORPH_NODE:

		return "orphan node";

	case UBIFS_AUTH_NODE:

		return "auth node";

	default:

		return "unknown node";

	}
@@ -542,6 +544,10 @@ void ubifs_dump_node(const struct ubifs_info *c, const void *node) 
			       (unsigned long long)le64_to_cpu(orph->inos[i]));

		break;

	}

	case UBIFS_AUTH_NODE:

	{

		break;

	}

	default:

		pr_err("node type %d was not recognized\n",

		       (int)ch->node_type);

fs/ubifs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -579,6 +579,7 @@ static int init_constants_early(struct ubifs_info *c) 
	c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;

	c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;

	c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;

	c->ranges[UBIFS_AUTH_NODE].len = UBIFS_AUTH_NODE_SZ;



	c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;

	c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;

fs/ubifs/ubifs-media.h

+43 −3
Original line number Diff line number Diff line
@@ -286,6 +286,7 @@ enum { 
#define UBIFS_IDX_NODE_SZ  sizeof(struct ubifs_idx_node)

#define UBIFS_CS_NODE_SZ   sizeof(struct ubifs_cs_node)

#define UBIFS_ORPH_NODE_SZ sizeof(struct ubifs_orph_node)

#define UBIFS_AUTH_NODE_SZ sizeof(struct ubifs_auth_node)

/* Extended attribute entry nodes are identical to directory entry nodes */

#define UBIFS_XENT_NODE_SZ UBIFS_DENT_NODE_SZ

/* Only this does not have to be multiple of 8 bytes */
@@ -300,6 +301,12 @@ enum { 
/* The largest UBIFS node */

#define UBIFS_MAX_NODE_SZ UBIFS_MAX_INO_NODE_SZ



/* The maxmimum size of a hash, enough for sha512 */

#define UBIFS_MAX_HASH_LEN 64



/* The maxmimum size of a hmac, enough for hmac(sha512) */

#define UBIFS_MAX_HMAC_LEN 64



/*

 * xattr name of UBIFS encryption context, we don't use a prefix

 * nor a long name to not waste space on the flash.
@@ -365,6 +372,7 @@ enum { 
 * UBIFS_IDX_NODE: index node

 * UBIFS_CS_NODE: commit start node

 * UBIFS_ORPH_NODE: orphan node

 * UBIFS_AUTH_NODE: authentication node

 * UBIFS_NODE_TYPES_CNT: count of supported node types

 *

 * Note, we index arrays by these numbers, so keep them low and contiguous.
@@ -384,6 +392,7 @@ enum { 
	UBIFS_IDX_NODE,

	UBIFS_CS_NODE,

	UBIFS_ORPH_NODE,

	UBIFS_AUTH_NODE,

	UBIFS_NODE_TYPES_CNT,

};
@@ -421,15 +430,19 @@ enum { 
 * UBIFS_FLG_DOUBLE_HASH: store a 32bit cookie in directory entry nodes to

 *			  support 64bit cookies for lookups by hash

 * UBIFS_FLG_ENCRYPTION: this filesystem contains encrypted files

 * UBIFS_FLG_AUTHENTICATION: this filesystem contains hashes for authentication

 */

enum {

	UBIFS_FLG_BIGLPT = 0x02,

	UBIFS_FLG_SPACE_FIXUP = 0x04,

	UBIFS_FLG_DOUBLE_HASH = 0x08,

	UBIFS_FLG_ENCRYPTION = 0x10,

	UBIFS_FLG_AUTHENTICATION = 0x20,

};



#define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT|UBIFS_FLG_SPACE_FIXUP|UBIFS_FLG_DOUBLE_HASH|UBIFS_FLG_ENCRYPTION)

#define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT | UBIFS_FLG_SPACE_FIXUP | \

		UBIFS_FLG_DOUBLE_HASH | UBIFS_FLG_ENCRYPTION | \

		UBIFS_FLG_AUTHENTICATION)



/**

 * struct ubifs_ch - common header node.
@@ -633,6 +646,10 @@ struct ubifs_pad_node { 
 * @time_gran: time granularity in nanoseconds

 * @uuid: UUID generated when the file system image was created

 * @ro_compat_version: UBIFS R/O compatibility version

 * @hmac: HMAC to authenticate the superblock node

 * @hmac_wkm: HMAC of a well known message (the string "UBIFS") as a convenience

 *            to the user to check if the correct key is passed.

 * @hash_algo: The hash algo used for this filesystem (one of enum hash_algo)

 */

struct ubifs_sb_node {

	struct ubifs_ch ch;
@@ -660,7 +677,10 @@ struct ubifs_sb_node { 
	__le32 time_gran;

	__u8 uuid[16];

	__le32 ro_compat_version;

	__u8 padding2[3968];

	__u8 hmac[UBIFS_MAX_HMAC_LEN];

	__u8 hmac_wkm[UBIFS_MAX_HMAC_LEN];

	__le16 hash_algo;

	__u8 padding2[3838];

} __packed;



/**
@@ -695,6 +715,9 @@ struct ubifs_sb_node { 
 * @empty_lebs: number of empty logical eraseblocks

 * @idx_lebs: number of indexing logical eraseblocks

 * @leb_cnt: count of LEBs used by file-system

 * @hash_root_idx: the hash of the root index node

 * @hash_lpt: the hash of the LPT

 * @hmac: HMAC to authenticate the master node

 * @padding: reserved for future, zeroes

 */

struct ubifs_mst_node {
@@ -727,7 +750,10 @@ struct ubifs_mst_node { 
	__le32 empty_lebs;

	__le32 idx_lebs;

	__le32 leb_cnt;

	__u8 padding[344];

	__u8 hash_root_idx[UBIFS_MAX_HASH_LEN];

	__u8 hash_lpt[UBIFS_MAX_HASH_LEN];

	__u8 hmac[UBIFS_MAX_HMAC_LEN];

	__u8 padding[152];

} __packed;



/**
@@ -746,12 +772,26 @@ struct ubifs_ref_node { 
	__u8 padding[28];

} __packed;



/**

 * struct ubifs_auth_node - node for authenticating other nodes

 * @ch: common header

 * @hmac: The HMAC

 */

struct ubifs_auth_node {

	struct ubifs_ch ch;

	__u8 hmac[];

} __packed;



/**

 * struct ubifs_branch - key/reference/length branch

 * @lnum: LEB number of the target node

 * @offs: offset within @lnum

 * @len: target node length

 * @key: key

 *

 * In an authenticated UBIFS we have the hash of the referenced node after @key.

 * This can't be added to the struct type definition because @key is a

 * dynamically sized element already.

 */

struct ubifs_branch {

	__le32 lnum;

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