diff options
Diffstat (limited to 'dns/rdtypes/dsbase.py')
| -rw-r--r-- | dns/rdtypes/dsbase.py | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/dns/rdtypes/dsbase.py b/dns/rdtypes/dsbase.py index 38c9548..d125db2 100644 --- a/dns/rdtypes/dsbase.py +++ b/dns/rdtypes/dsbase.py @@ -24,6 +24,15 @@ import dns.rdata import dns.rdatatype +# Digest types registry: https://www.iana.org/assignments/ds-rr-types/ds-rr-types.xhtml +_digest_length_by_type = { + 1: 20, # SHA-1, RFC 3658 Sec. 2.4 + 2: 32, # SHA-256, RFC 4509 Sec. 2.2 + 3: 32, # GOST R 34.11-94, RFC 5933 Sec. 4 in conjunction with RFC 4490 Sec. 2.1 + 4: 48, # SHA-384, RFC 6605 Sec. 2 +} + + @dns.immutable.immutable class DSBase(dns.rdata.Rdata): @@ -39,6 +48,15 @@ class DSBase(dns.rdata.Rdata): self.digest_type = self._as_uint8(digest_type) self.digest = self._as_bytes(digest) + try: + if self.digest_type == 0: # reserved, RFC 3658 Sec. 2.4 + raise ValueError('digest type 0 is reserved') + expected_length = _digest_length_by_type[self.digest_type] + except KeyError: + raise ValueError('unknown digest type') + if len(self.digest) != expected_length: + raise ValueError('digest length inconsistent with digest type') + def to_text(self, origin=None, relativize=True, **kw): kw = kw.copy() chunksize = kw.pop('chunksize', 128) |