Add support for authenticated file systems using HMAC(SHA256) as checksumming algorithm.
Example: mkfs.btrfs --csum hmac-sha256 --auth-key 0123456789 -f test.img Not-yet-signed-off-by: Johannes Thumshirn <[email protected]> --- Makefile.inc.in | 2 +- cmds/inspect-dump-super.c | 5 ++++- configure.ac | 7 +++++++ crypto/hash.c | 16 ++++++++++++++++ crypto/hash.h | 2 ++ ctree.c | 1 + ctree.h | 3 +++ disk-io.c | 9 ++++++++- mkfs/common.c | 10 ++++++++++ mkfs/common.h | 3 +++ mkfs/main.c | 25 ++++++++++++++++++++++++- 11 files changed, 79 insertions(+), 4 deletions(-) diff --git a/Makefile.inc.in b/Makefile.inc.in index a86c528ed0a5..34191fa0a381 100644 --- a/Makefile.inc.in +++ b/Makefile.inc.in @@ -25,7 +25,7 @@ PYTHON_CFLAGS = @PYTHON_CFLAGS@ SUBST_CFLAGS = @CFLAGS@ SUBST_LDFLAGS = @LDFLAGS@ -LIBS_BASE = @UUID_LIBS@ @BLKID_LIBS@ -L. -pthread +LIBS_BASE = @UUID_LIBS@ @BLKID_LIBS@ @LIBGCRYPT_LIBS@ -L. -pthread LIBS_COMP = @ZLIB_LIBS@ @LZO2_LIBS@ @ZSTD_LIBS@ LIBS_PYTHON = @PYTHON_LIBS@ STATIC_LIBS_BASE = @UUID_LIBS_STATIC@ @BLKID_LIBS_STATIC@ -L. -pthread diff --git a/cmds/inspect-dump-super.c b/cmds/inspect-dump-super.c index 1a2ef4d4822c..5bf5a6bc6f27 100644 --- a/cmds/inspect-dump-super.c +++ b/cmds/inspect-dump-super.c @@ -318,6 +318,7 @@ static bool is_valid_csum_type(u16 csum_type) case BTRFS_CSUM_TYPE_XXHASH: case BTRFS_CSUM_TYPE_SHA256: case BTRFS_CSUM_TYPE_BLAKE2: + case BTRFS_CSUM_TYPE_HMAC_SHA256: return true; default: return false; @@ -351,7 +352,9 @@ static void dump_superblock(struct btrfs_super_block *sb, int full) printf("csum\t\t\t0x"); for (i = 0, p = sb->csum; i < csum_size; i++) printf("%02x", p[i]); - if (!is_valid_csum_type(csum_type)) + if (csum_type == BTRFS_CSUM_TYPE_HMAC_SHA256) + printf(" [NO KEY FOR HMAC]"); + else if (!is_valid_csum_type(csum_type)) printf(" [UNKNOWN CSUM TYPE OR SIZE]"); else if (check_csum_sblock(sb, csum_size, csum_type)) printf(" [match]"); diff --git a/configure.ac b/configure.ac index cf792eb5488b..32b3f41e70d9 100644 --- a/configure.ac +++ b/configure.ac @@ -267,6 +267,13 @@ AC_SUBST([LZO2_LIBS]) AC_SUBST([LZO2_LIBS_STATIC]) AC_SUBST([LZO2_CFLAGS]) +dnl gcrypt library for HMAC(SHA256) +AM_PATH_LIBGCRYPT([1.0.0], [ + AC_SUBST(LIBGCRYPT_LIBS) + AC_SUBST(LIBGCRYPT_CFLAGS) + ], [ + AC_MSG_ERROR([cannot find gcrypt library]) +]) dnl library stuff AC_SUBST([LIBBTRFS_MAJOR]) diff --git a/crypto/hash.c b/crypto/hash.c index 48623c798739..c507a007d4d6 100644 --- a/crypto/hash.c +++ b/crypto/hash.c @@ -1,3 +1,7 @@ +#include <gcrypt.h> + +#include "ctree.h" + #include "crypto/hash.h" #include "crypto/crc32c.h" #include "crypto/xxhash.h" @@ -49,3 +53,15 @@ int hash_blake2b(const u8 *buf, size_t len, u8 *out) return 0; } + +int hash_hmac_sha256(struct btrfs_fs_info *fs_info, const u8 *buf, + size_t length, u8 *out) +{ + gcry_mac_hd_t mac; + gcry_mac_open(&mac, GCRY_MAC_HMAC_SHA256, 0, NULL); + gcry_mac_setkey(mac, fs_info->auth_key, strlen(fs_info->auth_key)); + gcry_mac_write(mac, buf, length); + gcry_mac_read(mac, out, &length); + + return 0; +} diff --git a/crypto/hash.h b/crypto/hash.h index fefccbd59a09..252ce9f94f72 100644 --- a/crypto/hash.h +++ b/crypto/hash.h @@ -9,5 +9,7 @@ int hash_crc32c(const u8 *buf, size_t length, u8 *out); int hash_xxhash(const u8 *buf, size_t length, u8 *out); int hash_sha256(const u8 *buf, size_t length, u8 *out); int hash_blake2b(const u8 *buf, size_t length, u8 *out); +int hash_hmac_sha256(struct btrfs_fs_info *fs_info, const u8 *buf, + size_t length, u8 *out); #endif diff --git a/ctree.c b/ctree.c index 97b44d48dc85..a22ad0bfe3fd 100644 --- a/ctree.c +++ b/ctree.c @@ -46,6 +46,7 @@ static const struct btrfs_csum { [BTRFS_CSUM_TYPE_XXHASH] = { 8, "xxhash64" }, [BTRFS_CSUM_TYPE_SHA256] = { 32, "sha256" }, [BTRFS_CSUM_TYPE_BLAKE2] = { 32, "blake2" }, + [BTRFS_CSUM_TYPE_HMAC_SHA256] = { 32, "hmac-sha256" }, }; u16 btrfs_super_csum_size(const struct btrfs_super_block *sb) diff --git a/ctree.h b/ctree.h index b99ba11279ad..bb64d54c5894 100644 --- a/ctree.h +++ b/ctree.h @@ -170,6 +170,7 @@ enum btrfs_csum_type { BTRFS_CSUM_TYPE_XXHASH = 1, BTRFS_CSUM_TYPE_SHA256 = 2, BTRFS_CSUM_TYPE_BLAKE2 = 3, + BTRFS_CSUM_TYPE_HMAC_SHA256 = 32, // XXX dummy value for now }; #define BTRFS_EMPTY_DIR_SIZE 0 @@ -1190,6 +1191,8 @@ struct btrfs_fs_info { u32 nodesize; u32 sectorsize; u32 stripesize; + + char *auth_key; }; /* diff --git a/disk-io.c b/disk-io.c index 5de6daf1563a..ef43521d0dcf 100644 --- a/disk-io.c +++ b/disk-io.c @@ -153,6 +153,12 @@ int btrfs_csum_data(struct btrfs_fs_info *fs_info, u16 csum_type, return hash_sha256(data, len, out); case BTRFS_CSUM_TYPE_BLAKE2: return hash_blake2b(data, len, out); + case BTRFS_CSUM_TYPE_HMAC_SHA256: + if (!fs_info || !fs_info->auth_key) { + fprintf(stderr, "ERROR: no key for HMAC(SHA256)\n"); + return 0; + } + return hash_hmac_sha256(fs_info, data, len, out); default: fprintf(stderr, "ERROR: unknown csum type: %d\n", csum_type); ASSERT(0); @@ -817,6 +823,7 @@ struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr, fs_info->data_alloc_profile = (u64)-1; fs_info->metadata_alloc_profile = (u64)-1; fs_info->system_alloc_profile = fs_info->metadata_alloc_profile; + fs_info->auth_key = auth_key; return fs_info; free_all: btrfs_free_fs_info(fs_info); @@ -1393,7 +1400,7 @@ int btrfs_check_super(struct btrfs_super_block *sb, unsigned sbflags) btrfs_csum_data(NULL, csum_type, (u8 *)sb + BTRFS_CSUM_SIZE, result, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE); - if (memcmp(result, sb->csum, csum_size)) { + if (memcmp(result, sb->csum, csum_size) && csum_type != BTRFS_CSUM_TYPE_HMAC_SHA256) { error("superblock checksum mismatch"); return -EIO; } diff --git a/mkfs/common.c b/mkfs/common.c index 469b88d6a8d3..81d0b5c12a52 100644 --- a/mkfs/common.c +++ b/mkfs/common.c @@ -160,6 +160,13 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg) if (!buf) return -ENOMEM; + buf->fs_info = calloc(1, sizeof(struct btrfs_fs_info)); + if (!buf->fs_info) { + free(buf); + return -ENOMEM; + } + + first_free = BTRFS_SUPER_INFO_OFFSET + cfg->sectorsize * 2 - 1; first_free &= ~((u64)cfg->sectorsize - 1); @@ -224,6 +231,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg) btrfs_header_chunk_tree_uuid(buf), BTRFS_UUID_SIZE); + buf->fs_info->auth_key = cfg->auth_key; + ret = btrfs_create_tree_root(fd, cfg, buf); if (ret < 0) goto out; @@ -474,6 +483,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg) ret = 0; out: + free(buf->fs_info); free(buf); return ret; } diff --git a/mkfs/common.h b/mkfs/common.h index 1ca71a4fcce5..161221d849ec 100644 --- a/mkfs/common.h +++ b/mkfs/common.h @@ -65,6 +65,9 @@ struct btrfs_mkfs_config { /* Superblock offset after make_btrfs */ u64 super_bytenr; + + /* authentication key */ + char *auth_key; }; int make_btrfs(int fd, struct btrfs_mkfs_config *cfg); diff --git a/mkfs/main.c b/mkfs/main.c index aca104a4bd57..5ba57c923359 100644 --- a/mkfs/main.c +++ b/mkfs/main.c @@ -343,6 +343,7 @@ static void print_usage(int ret) printf(" features:\n"); printf("\t--csum TYPE\n"); printf("\t--checksum TYPE checksum algorithm to use (default: crc32c)\n"); + printf("\t--auth-key KEY authentication key to use for authenticated file-systems\n"); printf("\t-n|--nodesize SIZE size of btree nodes\n"); printf("\t-s|--sectorsize SIZE data block size (may not be mountable by current kernel)\n"); printf("\t-O|--features LIST comma separated list of filesystem features (use '-O list-all' to list features)\n"); @@ -400,6 +401,9 @@ static enum btrfs_csum_type parse_csum_type(const char *s) } else if (strcasecmp(s, "blake2b") == 0 || strcasecmp(s, "blake2") == 0) { return BTRFS_CSUM_TYPE_BLAKE2; + } else if (strcasecmp(s, "hmac-sha256") == 0 || + strcasecmp(s, "hmac(sha256)") == 0) { + return BTRFS_CSUM_TYPE_HMAC_SHA256; } else { error("unknown csum type %s", s); exit(1); @@ -855,14 +859,21 @@ int BOX_MAIN(mkfs)(int argc, char **argv) struct mkfs_allocation allocation = { 0 }; struct btrfs_mkfs_config mkfs_cfg; enum btrfs_csum_type csum_type = BTRFS_CSUM_TYPE_CRC32; + char *auth_key = NULL; crc32c_optimization_init(); while(1) { int c; - enum { GETOPT_VAL_SHRINK = 257, GETOPT_VAL_CHECKSUM }; + enum { + GETOPT_VAL_SHRINK = 257, + GETOPT_VAL_CHECKSUM, + GETOPT_VAL_AUTHKEY, + }; static const struct option long_options[] = { { "alloc-start", required_argument, NULL, 'A'}, + { "auth-key", required_argument, NULL, + GETOPT_VAL_AUTHKEY }, { "byte-count", required_argument, NULL, 'b' }, { "csum", required_argument, NULL, GETOPT_VAL_CHECKSUM }, @@ -968,6 +979,9 @@ int BOX_MAIN(mkfs)(int argc, char **argv) case GETOPT_VAL_CHECKSUM: csum_type = parse_csum_type(optarg); break; + case GETOPT_VAL_AUTHKEY: + auth_key = strdup(optarg); + break; case GETOPT_VAL_HELP: default: print_usage(c != GETOPT_VAL_HELP); @@ -995,6 +1009,12 @@ int BOX_MAIN(mkfs)(int argc, char **argv) goto error; } + if ((auth_key && csum_type != BTRFS_CSUM_TYPE_HMAC_SHA256) || + (csum_type == BTRFS_CSUM_TYPE_HMAC_SHA256 && !auth_key)) { + error("the option --auth-key must be used with --csum hmac(sha256)"); + goto error; + } + if (*fs_uuid) { uuid_t dummy_uuid; @@ -1208,6 +1228,7 @@ int BOX_MAIN(mkfs)(int argc, char **argv) mkfs_cfg.stripesize = stripesize; mkfs_cfg.features = features; mkfs_cfg.csum_type = csum_type; + mkfs_cfg.auth_key = auth_key; ret = make_btrfs(fd, &mkfs_cfg); if (ret) { @@ -1424,6 +1445,7 @@ out: btrfs_close_all_devices(); free(label); + free(auth_key); return !!ret; error: @@ -1431,6 +1453,7 @@ error: close(fd); free(label); + free(auth_key); exit(1); success: exit(0); -- 2.16.4
