From 5125cfdff13a4da4c34a053cd67e99083aece028 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Fri, 7 Sep 2018 14:36:30 +0200 Subject: 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: Sascha Hauer Signed-off-by: Richard Weinberger --- fs/ubifs/debug.c | 6 ++++++ fs/ubifs/super.c | 1 + fs/ubifs/ubifs-media.h | 46 +++++++++++++++++++++++++++++++++++++++++++--- 3 files changed, 50 insertions(+), 3 deletions(-) (limited to 'fs/ubifs') diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c index 564e330d05b1..c49ff50fdceb 100644 --- a/fs/ubifs/debug.c +++ b/fs/ubifs/debug.c @@ -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); diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c index 70a64e00f0a8..0194e3c0853f 100644 --- a/fs/ubifs/super.c +++ b/fs/ubifs/super.c @@ -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; diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h index e8c23c9d4f4a..8b7c1844014f 100644 --- a/fs/ubifs/ubifs-media.h +++ b/fs/ubifs/ubifs-media.h @@ -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; -- cgit v1.2.3-58-ga151