From 63c582c99128c3623e270e8425966cab7744fb2f Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 13 Sep 2010 20:05:59 +0930 Subject: [PATCH] tdb: put example hashes into header, so we notice incorrect hash_fn. This is Stefan Metzmacher 's patch with minor changes: 1) Use the TDB_MAGIC constant so both hashes aren't of strings. 2) Check the hash in tdb_check (paranoia, really). 3) Additional check in the (unlikely!) case where both examples hash to 0. 4) Cosmetic changes to var names and complaint message. Signed-off-by: Rusty Russell --- lib/tdb/common/check.c | 6 ++++ lib/tdb/common/open.c | 55 +++++++++++++++++++++++++++++++++++- lib/tdb/common/tdb_private.h | 6 +++- 3 files changed, 65 insertions(+), 2 deletions(-) diff --git a/lib/tdb/common/check.c b/lib/tdb/common/check.c index fd3c0a91..b1b98d4f 100644 --- a/lib/tdb/common/check.c +++ b/lib/tdb/common/check.c @@ -28,6 +28,7 @@ static bool tdb_check_header(struct tdb_context *tdb, tdb_off_t *recovery) { struct tdb_header hdr; + uint32_t h1, h2; if (tdb->methods->tdb_read(tdb, 0, &hdr, sizeof(hdr), 0) == -1) return false; @@ -41,6 +42,11 @@ static bool tdb_check_header(struct tdb_context *tdb, tdb_off_t *recovery) if (hdr.rwlocks != 0) goto corrupt; + tdb_header_hash(tdb, &h1, &h2); + if (hdr.magic1_hash && hdr.magic2_hash && + (hdr.magic1_hash != h1 || hdr.magic2_hash != h2)) + goto corrupt; + if (hdr.hash_size == 0) goto corrupt; diff --git a/lib/tdb/common/open.c b/lib/tdb/common/open.c index 7687ff6e..401fa74a 100644 --- a/lib/tdb/common/open.c +++ b/lib/tdb/common/open.c @@ -44,6 +44,25 @@ static unsigned int default_tdb_hash(TDB_DATA *key) return (1103515243 * value + 12345); } +/* We use two hashes to double-check they're using the right hash function. */ +void tdb_header_hash(struct tdb_context *tdb, + uint32_t *magic1_hash, uint32_t *magic2_hash) +{ + TDB_DATA hash_key; + uint32_t tdb_magic = TDB_MAGIC; + + hash_key.dptr = (unsigned char *)TDB_MAGIC_FOOD; + hash_key.dsize = sizeof(TDB_MAGIC_FOOD); + *magic1_hash = tdb->hash_fn(&hash_key); + + hash_key.dptr = CONVERT(tdb_magic); + hash_key.dsize = sizeof(tdb_magic); + *magic2_hash = tdb->hash_fn(&hash_key); + + /* Make sure at least one hash is non-zero! */ + if (*magic1_hash == 0 && *magic2_hash == 0) + *magic1_hash = 1; +} /* initialise a new database with a specified hash size */ static int tdb_new_database(struct tdb_context *tdb, int hash_size) @@ -62,6 +81,9 @@ static int tdb_new_database(struct tdb_context *tdb, int hash_size) /* Fill in the header */ newdb->version = TDB_VERSION; newdb->hash_size = hash_size; + + tdb_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash); + if (tdb->flags & TDB_INTERNAL) { tdb->map_size = size; tdb->map_ptr = (char *)newdb; @@ -140,6 +162,9 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags, unsigned char *vp; uint32_t vertest; unsigned v; + uint32_t magic1_hash; + uint32_t magic2_hash; + const char *hash_alg; if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) { /* Can't log this */ @@ -161,7 +186,14 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags, tdb->log.log_fn = null_log_fn; tdb->log.log_private = NULL; } - tdb->hash_fn = hash_fn ? hash_fn : default_tdb_hash; + + if (hash_fn) { + tdb->hash_fn = hash_fn; + hash_alg = "user defined"; + } else { + tdb->hash_fn = default_tdb_hash; + hash_alg = "default"; + } /* cache the page size */ tdb->page_size = getpagesize(); @@ -279,6 +311,27 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags, goto fail; } + tdb_header_hash(tdb, &magic1_hash, &magic2_hash); + + if ((tdb->header.magic1_hash == 0) && (tdb->header.magic2_hash == 0)) { + /* older TDB without magic hash references */ + } else if ((tdb->header.magic1_hash != magic1_hash) || + (tdb->header.magic2_hash != magic2_hash)) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "%s was not created with the %s hash function we are using\n" + "magic1_hash[0x%08X %s 0x%08X] " + "magic2_hash[0x%08X %s 0x%08X]\n", + name, hash_alg, + tdb->header.magic1_hash, + (tdb->header.magic1_hash == magic1_hash) ? "==" : "!=", + magic1_hash, + tdb->header.magic2_hash, + (tdb->header.magic2_hash == magic2_hash) ? "==" : "!=", + magic2_hash)); + errno = EINVAL; + goto fail; + } + /* Is it already in the open list? If so, fail. */ if (tdb_already_open(st.st_dev, st.st_ino)) { TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h index 9d0f3bcd..eccd6880 100644 --- a/lib/tdb/common/tdb_private.h +++ b/lib/tdb/common/tdb_private.h @@ -147,7 +147,9 @@ struct tdb_header { tdb_off_t rwlocks; /* obsolete - kept to detect old formats */ tdb_off_t recovery_start; /* offset of transaction recovery region */ tdb_off_t sequence_number; /* used when TDB_SEQNUM is set */ - tdb_off_t reserved[29]; + uint32_t magic1_hash; /* hash of TDB_MAGIC_FOOD. */ + uint32_t magic2_hash; /* hash of TDB_MAGIC. */ + tdb_off_t reserved[27]; }; struct tdb_lock_type { @@ -268,3 +270,5 @@ int tdb_rec_free_read(struct tdb_context *tdb, tdb_off_t off, struct tdb_record *rec); bool tdb_write_all(int fd, const void *buf, size_t count); int tdb_transaction_recover(struct tdb_context *tdb); +void tdb_header_hash(struct tdb_context *tdb, + uint32_t *magic1_hash, uint32_t *magic2_hash); -- 2.34.1