lib/tdb: maintain reference hashes with the hash function that's used at create time

If the hashes are available and the current hash function can't verify
them, we reject the open.

metze

diff --git a/lib/tdb/common/open.c b/lib/tdb/common/open.c
index 49b8e85f1264f00c57e874916972350712b8a437..ff0fd376017b5c3db6764b4d2ade71d65814f384 100644 (file)
--- a/lib/tdb/common/open.c
+++ b/lib/tdb/common/open.c
@@ -52,6 +52,7 @@ static int tdb_new_database(struct tdb_context *tdb, int hash_size)
        size_t size;
        int ret = -1;
        ssize_t written;
+       TDB_DATA hash_key;
 
        /* We make it up in memory, then write it out if not internal */
        size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);
@@ -61,6 +62,15 @@ 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;
+
+       hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_FOOD);
+       hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
+       newdb->magic_food_hash = tdb->hash_fn(&hash_key);
+
+       hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_HASH_VERIFY_KEY);
+       hash_key.dsize = sizeof(TDB_MAGIC_HASH_VERIFY_KEY);
+       newdb->verify_key_hash = tdb->hash_fn(&hash_key);
+
        if (tdb->flags & TDB_INTERNAL) {
                tdb->map_size = size;
                tdb->map_ptr = (char *)newdb;
@@ -153,6 +163,10 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
        unsigned char *vp;
        uint32_t vertest;
        unsigned v;
+       TDB_DATA hash_key;
+       uint32_t magic_food_hash;
+       uint32_t verify_key_hash;
+       const char *hash_alg;
 
        if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
                /* Can't log this */
@@ -171,7 +185,14 @@ 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();
@@ -270,6 +291,35 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
                goto fail;
        }
 
+       hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_FOOD);
+       hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
+       magic_food_hash = tdb->hash_fn(&hash_key);
+
+       hash_key.dptr = discard_const_p(uint8_t, TDB_MAGIC_HASH_VERIFY_KEY);
+       hash_key.dsize = sizeof(TDB_MAGIC_HASH_VERIFY_KEY);
+       verify_key_hash = tdb->hash_fn(&hash_key);
+
+       if ((tdb->header.magic_food_hash == 0) &&
+           (tdb->header.verify_key_hash == 0)) {
+               /* older TDB without magic hash references */
+       } else if ((tdb->header.magic_food_hash != magic_food_hash) ||
+                  (tdb->header.verify_key_hash != verify_key_hash)) {
+               TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: %s "
+                        "was created with a different hash function current[%s]"
+                        "magic_food_hash[0x%08X %s 0x%08X] "
+                        "verify_key_hash[0x%08X %s 0x%08X]\n",
+                        name,
+                        hash_alg,
+                        tdb->header.magic_food_hash,
+                        (tdb->header.magic_food_hash == magic_food_hash)?"==":"!=",
+                        magic_food_hash,
+                        tdb->header.verify_key_hash,
+                        (tdb->header.verify_key_hash == verify_key_hash)?"==":"!=",
+                        verify_key_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 562b813ff115c4002a16c771ca6ed1172322b074..226ace279c50fca9282a2e9fe246c7021b1acd97 100644 (file)
--- a/lib/tdb/common/tdb_private.h
+++ b/lib/tdb/common/tdb_private.h
@@ -48,6 +48,7 @@ typedef uint32_t tdb_off_t;
 #define TDB_FREE_MAGIC (~TDB_MAGIC)
 #define TDB_DEAD_MAGIC (0xFEE1DEAD)
 #define TDB_RECOVERY_MAGIC (0xf53bc0e7U)
+#define TDB_MAGIC_HASH_VERIFY_KEY "!TDB_MAGIC_HASH_VERIFY_KEY!"
 #define TDB_ALIGNMENT 4
 #define DEFAULT_HASH_SIZE 131
 #define FREELIST_TOP (sizeof(struct tdb_header))
@@ -114,7 +115,9 @@ 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 magic_food_hash;
+       uint32_t verify_key_hash;
+       tdb_off_t reserved[27];
 };
 
 struct tdb_lock_type {