Allow RRSIG algorithm mnemonics (#1456)

* Allow RRSIG algorithm mnemonics

Java outputs these *and* the RFC says we should parse them, so parse
them. We'll never output them though. Throwback to the "be lenient to
what you accept, but strict with what you output". Anyhow the diff is
tiny and it helps interop.

Fixes: #1447

Signed-off-by: Miek Gieben <[email protected]>

* Check parsed algorithm

Signed-off-by: Miek Gieben <[email protected]>

---------

Signed-off-by: Miek Gieben <[email protected]>

Author: miekg

parse_test.go

@@ -1975,3 +1975,26 @@ func TestParseOPENPGPKEY(t *testing.T) {
 		}
 	}
 }
+
+func TestParseRRSIGAlgNames(t *testing.T) {
+	tests := map[string]uint8{
+		`miek.nl.  IN RRSIG SOA RSASHA1 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`:         RSASHA1,
+		`miek.nl.  IN RRSIG SOA RSAMD5 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`:          RSAMD5,
+		`miek.nl.  IN RRSIG SOA ECC-GOST 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`:        ECCGOST,
+		`miek.nl.  IN RRSIG SOA ED448 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`:           ED448,
+		`miek.nl.  IN RRSIG SOA ECDSAP256SHA256 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`: ECDSAP256SHA256,
+		`miek.nl.  IN RRSIG SOA INDIRECT 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`:        INDIRECT,
+		`miek.nl.  IN RRSIG SOA BLA 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`:             0,
+		`miek.nl.  IN RRSIG SOA - 2 43200 20140210031301 20140111031301 12051 miek.nl. MVZUyrYwq0iZhMFDDnVXD2Bvu7pcBoc=`:               0,
+	}
+	for r, alg := range tests {
+		rr, err := NewRR(r)
+		if alg != 0 && err != nil {
+			t.Error(err)
+			continue
+		}
+		if alg != 0 && rr.(*RRSIG).Algorithm != alg {
+			t.Errorf("expecting alg %d, got %d", alg, rr.(*RRSIG).Algorithm)
+		}
+	}
+}

scan_rr.go

@@ -904,11 +904,18 @@ func (rr *RRSIG) parse(c *zlexer, o string) *ParseError {
 
 	c.Next() // zBlank
 	l, _ = c.Next()
-	i, e := strconv.ParseUint(l.token, 10, 8)
-	if e != nil || l.err {
+	if l.err {
 		return &ParseError{"", "bad RRSIG Algorithm", l}
 	}
-	rr.Algorithm = uint8(i)
+	i, e := strconv.ParseUint(l.token, 10, 8)
+	rr.Algorithm = uint8(i) // if 0 we'll check the mnemonic in the if
+	if e != nil {
+		v, ok := StringToAlgorithm[l.token]
+		if !ok {
+			return &ParseError{"", "bad RRSIG Algorithm", l}
+		}
+		rr.Algorithm = v
+	}
 
 	c.Next() // zBlank
 	l, _ = c.Next()