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Proper stamps length check

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This commit is contained in:
Frank Denis 2018-02-04 11:04:29 +01:00
parent cfeb25a4c2
commit 9ee7e522b1
1 changed files with 10 additions and 8 deletions
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18
dnscrypt-proxy/stamps.go
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@ -85,15 +85,15 @@ func NewServerStampFromString(stampStr string) (ServerStamp, error) {
func newDNSCryptServerStamp(bin []byte) (ServerStamp, error) {
stamp := ServerStamp{proto: StampProtoTypeDNSCrypt}
if len(bin) < 24 {
return stamp, errors.New("Stamp is too short")
if len(bin) < 66 {
return stamp, fmt.Errorf("Stamp is too short", bin)
}
stamp.props = ServerInformalProperties(binary.LittleEndian.Uint64(bin[1:9]))
binLen := len(bin)
pos := 9
len := int(bin[pos])
if len >= binLen-pos {
if 1+len >= binLen-pos {
return stamp, errors.New("Invalid stamp")
}
pos++
@ -104,7 +104,7 @@ func newDNSCryptServerStamp(bin []byte) (ServerStamp, error) {
}
len = int(bin[pos])
if len >= binLen-pos {
if 1+len >= binLen-pos {
return stamp, errors.New("Invalid stamp")
}
pos++
@ -129,13 +129,15 @@ func newDNSCryptServerStamp(bin []byte) (ServerStamp, error) {
func newDoHServerStamp(bin []byte) (ServerStamp, error) {
stamp := ServerStamp{proto: StampProtoTypeDoH, hashes: [][]byte{}}
if len(bin) < 22 {
return stamp, fmt.Errorf("Stamp is too short", bin)
}
stamp.props = ServerInformalProperties(binary.LittleEndian.Uint64(bin[1:9]))
binLen := len(bin)
pos := 9
len := int(bin[pos])
if len >= binLen-pos {
if 1+len >= binLen-pos {
return stamp, errors.New("Invalid stamp")
}
pos++
@ -148,7 +150,7 @@ func newDoHServerStamp(bin []byte) (ServerStamp, error) {
for {
vlen := int(bin[pos])
len = vlen & ^0x80
if len >= binLen-pos {
if 1+len >= binLen-pos {
return stamp, errors.New("Invalid stamp")
}
pos++
@ -160,7 +162,7 @@ func newDoHServerStamp(bin []byte) (ServerStamp, error) {
}
len = int(bin[pos])
if len >= binLen-pos {
if 1+len >= binLen-pos {
return stamp, errors.New("Invalid stamp")
}
pos++