tdb2: make sure records with extra padding have a 0 byte.
[ccan] / ccan / tdb2 / check.c
index 9bbd12645f199ba6a5a62708caccc79d08cf16d1..b602d80d64777030aeb08fab853b1df9561561d2 100644 (file)
@@ -30,7 +30,8 @@ static bool append(tdb_off_t **arr, size_t *num, tdb_off_t off)
        return true;
 }
 
-static enum TDB_ERROR check_header(struct tdb_context *tdb, tdb_off_t *recovery)
+static enum TDB_ERROR check_header(struct tdb_context *tdb, tdb_off_t *recovery,
+                                  uint64_t *features)
 {
        uint64_t hash_test;
        struct tdb_header hdr;
@@ -59,6 +60,16 @@ static enum TDB_ERROR check_header(struct tdb_context *tdb, tdb_off_t *recovery)
                                  hdr.magic_food);
        }
 
+       /* Features which are used must be a subset of features offered. */
+       if (hdr.features_used & ~hdr.features_offered) {
+               return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+                                 "check: features used (0x%llx) which"
+                                 " are not offered (0x%llx)",
+                                 (long long)hdr.features_used,
+                                 (long long)hdr.features_offered);
+       }
+
+       *features = hdr.features_offered;
        *recovery = hdr.recovery;
        if (*recovery) {
                if (*recovery < sizeof(hdr) || *recovery > tdb->map_size) {
@@ -568,7 +579,7 @@ tdb_off_t dead_space(struct tdb_context *tdb, tdb_off_t off)
 static enum TDB_ERROR check_linear(struct tdb_context *tdb,
                                   tdb_off_t **used, size_t *num_used,
                                   tdb_off_t **fr, size_t *num_free,
-                                  tdb_off_t recovery)
+                                  uint64_t features, tdb_off_t recovery)
 {
        tdb_off_t off;
        tdb_len_t len;
@@ -697,6 +708,28 @@ static enum TDB_ERROR check_linear(struct tdb_context *tdb,
                                                  (long long)len,
                                                  (long long)off);
                        }
+
+                       /* Check that records have correct 0 at end (but may
+                        * not in future). */
+                       if (extra && !features) {
+                               const char *p;
+                               char c;
+                               p = tdb_access_read(tdb, off + sizeof(rec.u)
+                                                   + klen + dlen, 1, false);
+                               if (TDB_PTR_IS_ERR(p))
+                                       return TDB_PTR_ERR(p);
+                               c = *p;
+                               tdb_access_release(tdb, p);
+
+                               if (c != '\0') {
+                                       return tdb_logerr(tdb, TDB_ERR_CORRUPT,
+                                                         TDB_LOG_ERROR,
+                                                         "tdb_check:"
+                                                         " non-zero extra"
+                                                         " at %llu",
+                                                         (long long)off);
+                               }
+                       }
                } else {
                        return tdb_logerr(tdb, TDB_ERR_CORRUPT,
                                          TDB_LOG_ERROR,
@@ -724,6 +757,7 @@ enum TDB_ERROR tdb_check_(struct tdb_context *tdb,
 {
        tdb_off_t *fr = NULL, *used = NULL, ft, recovery;
        size_t num_free = 0, num_used = 0, num_found = 0, num_ftables = 0;
+       uint64_t features;
        enum TDB_ERROR ecode;
 
        ecode = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
@@ -737,12 +771,13 @@ enum TDB_ERROR tdb_check_(struct tdb_context *tdb,
                return ecode;
        }
 
-       ecode = check_header(tdb, &recovery);
+       ecode = check_header(tdb, &recovery, &features);
        if (ecode != TDB_SUCCESS)
                goto out;
 
        /* First we do a linear scan, checking all records. */
-       ecode = check_linear(tdb, &used, &num_used, &fr, &num_free, recovery);
+       ecode = check_linear(tdb, &used, &num_used, &fr, &num_free, features,
+                            recovery);
        if (ecode != TDB_SUCCESS)
                goto out;