diff options
Diffstat (limited to 'vendor/github.com/miekg/dns/msg.go')
| -rw-r--r-- | vendor/github.com/miekg/dns/msg.go | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/vendor/github.com/miekg/dns/msg.go b/vendor/github.com/miekg/dns/msg.go index 57262a10c..a348f7c9d 100644 --- a/vendor/github.com/miekg/dns/msg.go +++ b/vendor/github.com/miekg/dns/msg.go @@ -14,13 +14,17 @@ package dns import ( crand "crypto/rand" "encoding/binary" + "fmt" "math/big" "math/rand" "strconv" "sync" ) -const maxCompressionOffset = 2 << 13 // We have 14 bits for the compression pointer +const ( + maxCompressionOffset = 2 << 13 // We have 14 bits for the compression pointer + maxDomainNameWireOctets = 255 // See RFC 1035 section 2.3.4 +) var ( ErrAlg error = &Error{err: "bad algorithm"} // ErrAlg indicates an error with the (DNSSEC) algorithm. @@ -33,6 +37,7 @@ var ( ErrKeyAlg error = &Error{err: "bad key algorithm"} // ErrKeyAlg indicates that the algorithm in the key is not valid. ErrKey error = &Error{err: "bad key"} ErrKeySize error = &Error{err: "bad key size"} + ErrLongDomain error = &Error{err: fmt.Sprintf("domain name exceeded %d wire-format octets", maxDomainNameWireOctets)} ErrNoSig error = &Error{err: "no signature found"} ErrPrivKey error = &Error{err: "bad private key"} ErrRcode error = &Error{err: "bad rcode"} @@ -329,6 +334,7 @@ func UnpackDomainName(msg []byte, off int) (string, int, error) { s := make([]byte, 0, 64) off1 := 0 lenmsg := len(msg) + maxLen := maxDomainNameWireOctets ptr := 0 // number of pointers followed Loop: for { @@ -353,8 +359,10 @@ Loop: fallthrough case '"', '\\': s = append(s, '\\', b) + // presentation-format \X escapes add an extra byte + maxLen += 1 default: - if b < 32 || b >= 127 { // unprintable use \DDD + if b < 32 || b >= 127 { // unprintable, use \DDD var buf [3]byte bufs := strconv.AppendInt(buf[:0], int64(b), 10) s = append(s, '\\') @@ -364,6 +372,8 @@ Loop: for _, r := range bufs { s = append(s, r) } + // presentation-format \DDD escapes add 3 extra bytes + maxLen += 3 } else { s = append(s, b) } @@ -388,6 +398,9 @@ Loop: if ptr++; ptr > 10 { return "", lenmsg, &Error{err: "too many compression pointers"} } + // pointer should guarantee that it advances and points forwards at least + // but the condition on previous three lines guarantees that it's + // at least loop-free off = (c^0xC0)<<8 | int(c1) default: // 0x80 and 0x40 are reserved @@ -399,6 +412,9 @@ Loop: } if len(s) == 0 { s = []byte(".") + } else if len(s) >= maxLen { + // error if the name is too long, but don't throw it away + return string(s), lenmsg, ErrLongDomain } return string(s), off1, nil } |