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net/stun: Fix STUN attribute padding (#710) 

net/stun: fix STUN attribute padding

Signed-off-by: RenThraysk <renthraysk@gmail.com>
reviewable/pr711/r1
renthraysk 2020-08-24 20:52:13 +01:00 committed by GitHub
parent 9be1917c5b
commit 10cad39abd
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 38 additions and 3 deletions
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6
net/stun/stun.go
View File

@ -137,15 +137,15 @@ func foreachAttr(b []byte, fn func(attrType uint16, a []byte) error) error {
} }
attrType := binary.BigEndian.Uint16(b[:2]) attrType := binary.BigEndian.Uint16(b[:2])
attrLen := int(binary.BigEndian.Uint16(b[2:4])) attrLen := int(binary.BigEndian.Uint16(b[2:4]))
attrLenPad := attrLen % 4 attrLenWithPad := (attrLen + 3) &^ 3
b = b[4:] b = b[4:]
if attrLen+attrLenPad > len(b) { if attrLenWithPad > len(b) {
return ErrMalformedAttrs return ErrMalformedAttrs
} }
if err := fn(attrType, b[:attrLen]); err != nil { if err := fn(attrType, b[:attrLen]); err != nil {
return err return err
} }
b = b[attrLen+attrLenPad:] b = b[attrLenWithPad:]
} }
return nil return nil
} }

35
net/stun/stun_test.go
View File

@ -140,6 +140,41 @@ var responseTests = []struct {
wantAddr: net.ParseIP("2602:d1:b4cf:c100:38b2:31ff:feef:96f6"), wantAddr: net.ParseIP("2602:d1:b4cf:c100:38b2:31ff:feef:96f6"),
wantPort: 37070, wantPort: 37070,
}, },
// Testing STUN attribute padding rules using STUN software attribute
// with values of 1 & 3 length respectively before the XorMappedAddress attribute
{
name: "software-a",
data: []byte{
0x01, 0x01, 0x00, 0x14, 0x21, 0x12, 0xa4, 0x42,
0xeb, 0xc2, 0xd3, 0x6e, 0xf4, 0x71, 0x21, 0x7c,
0x4f, 0x3e, 0x30, 0x8e, 0x80, 0x22, 0x00, 0x01,
0x61, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x08,
0x00, 0x01, 0xce, 0x66, 0x5e, 0x12, 0xa4, 0x43,
},
wantTID: []byte{
0xeb, 0xc2, 0xd3, 0x6e, 0xf4, 0x71, 0x21, 0x7c,
0x4f, 0x3e, 0x30, 0x8e,
},
wantAddr: []byte{127, 0, 0, 1},
wantPort: 61300,
},
{
name: "software-abc",
data: []byte{
0x01, 0x01, 0x00, 0x14, 0x21, 0x12, 0xa4, 0x42,
0xeb, 0xc2, 0xd3, 0x6e, 0xf4, 0x71, 0x21, 0x7c,
0x4f, 0x3e, 0x30, 0x8e, 0x80, 0x22, 0x00, 0x03,
0x61, 0x62, 0x63, 0x00, 0x00, 0x20, 0x00, 0x08,
0x00, 0x01, 0xce, 0x66, 0x5e, 0x12, 0xa4, 0x43,
},
wantTID: []byte{
0xeb, 0xc2, 0xd3, 0x6e, 0xf4, 0x71, 0x21, 0x7c,
0x4f, 0x3e, 0x30, 0x8e,
},
wantAddr: []byte{127, 0, 0, 1},
wantPort: 61300,
},
} }
func TestParseResponse(t *testing.T) { func TestParseResponse(t *testing.T) {