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Properly parse nested proxy #10

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d06ea55
Properly parse nested proxy
whs Apr 10, 2019
1162d1d
Don't check whether IP is public or private
whs Apr 11, 2019
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22 changes: 17 additions & 5 deletions xff.go
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Original file line number Diff line number Diff line change
Expand Up @@ -49,13 +49,25 @@ func IsPublicIP(ip net.IP) bool {
}

// Parse parses the value of the X-Forwarded-For Header and returns the IP address.
func Parse(ipList string) string {
for _, ip := range strings.Split(ipList, ",") {
func Parse(ipList string, allowed func(sip string) bool) string {
ipSplit := strings.Split(ipList, ",")
var lastValidIP net.IP
for i := len(ipSplit) - 1; i >= 0; i-- {
ip := ipSplit[i]
ip = strings.TrimSpace(ip)
if IP := net.ParseIP(ip); IP != nil && IsPublicIP(IP) {
return ip
parsedIP := net.ParseIP(ip)
if parsedIP != nil {
lastValidIP = parsedIP
if !allowed(ip) {
break
}
} else {
break
}
}
if lastValidIP != nil {
return lastValidIP.String()
}
return ""
}

Expand All @@ -71,7 +83,7 @@ func GetRemoteAddrIfAllowed(r *http.Request, allowed func(sip string) bool) stri
if xffh := r.Header.Get("X-Forwarded-For"); xffh != "" {
if sip, sport, err := net.SplitHostPort(r.RemoteAddr); err == nil && sip != "" {
if allowed(sip) {
if xip := Parse(xffh); xip != "" {
if xip := Parse(xffh, allowed); xip != "" {
return net.JoinHostPort(xip, sport)
}
}
Expand Down
81 changes: 65 additions & 16 deletions xff_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -8,63 +8,86 @@ import (
"github.com/stretchr/testify/assert"
)

func allowAll(string) bool {
return true
}

func TestParse_none(t *testing.T) {
res := Parse("")
res := Parse("", allowAll)
assert.Equal(t, "", res)
}

func TestParse_localhost(t *testing.T) {
res := Parse("127.0.0.1")
assert.Equal(t, "", res)
res := Parse("127.0.0.1", allowAll)
assert.Equal(t, "127.0.0.1", res)
}

func TestParse_invalid(t *testing.T) {
res := Parse("invalid")
res := Parse("invalid", allowAll)
assert.Equal(t, "", res)
}

func TestParse_invalid_sioux(t *testing.T) {
res := Parse("123#1#2#3")
res := Parse("123#1#2#3", allowAll)
assert.Equal(t, "", res)
}

func TestParse_invalid_private_lookalike(t *testing.T) {
res := Parse("102.3.2.1")
res := Parse("102.3.2.1", allowAll)
assert.Equal(t, "102.3.2.1", res)
}

func TestParse_valid(t *testing.T) {
res := Parse("68.45.152.220")
res := Parse("68.45.152.220", allowAll)
assert.Equal(t, "68.45.152.220", res)
}

func TestParse_multi_first(t *testing.T) {
res := Parse("12.13.14.15, 68.45.152.220")
res := Parse("12.13.14.15, 68.45.152.220", allowAll)
assert.Equal(t, "12.13.14.15", res)
}

func TestParse_multi_last(t *testing.T) {
res := Parse("192.168.110.162, 190.57.149.90")
assert.Equal(t, "190.57.149.90", res)
res := Parse("192.168.110.162, 190.57.149.90", allowAll)
assert.Equal(t, "192.168.110.162", res)
}

func TestParse_multi_accept(t *testing.T) {
res := Parse("1.0.0.1, 1.0.0.2, 1.0.0.3", func(ip string) bool {
return ip == "1.0.0.3"
})
assert.Equal(t, "1.0.0.2", res)
}

func TestParse_multi_accept_intermediate_private(t *testing.T) {
res := Parse("1.0.0.1, 1.0.0.2, 10.0.0.1, 1.0.0.3", func(ip string) bool {
return ip == "1.0.0.3" || ip == "10.0.0.1"
})
assert.Equal(t, "1.0.0.2", res)
}

func TestParse_multi_accept_final_private(t *testing.T) {
res := Parse("10.0.0.1, 1.0.0.3", allowAll)
assert.Equal(t, "10.0.0.1", res)
}

func TestParse_multi_with_invalid(t *testing.T) {
res := Parse("192.168.110.162, invalid, 190.57.149.90")
res := Parse("192.168.110.162, invalid, 190.57.149.90", allowAll)
assert.Equal(t, "190.57.149.90", res)
}

func TestParse_multi_with_invalid2(t *testing.T) {
res := Parse("192.168.110.162, 190.57.149.90, invalid")
assert.Equal(t, "190.57.149.90", res)
res := Parse("192.168.110.162, 190.57.149.90, invalid", allowAll)
assert.Equal(t, "", res)
}

func TestParse_multi_with_invalid_sioux(t *testing.T) {
res := Parse("192.168.110.162, 190.57.149.90, 123#1#2#3")
assert.Equal(t, "190.57.149.90", res)
res := Parse("192.168.110.162, 190.57.149.90, 123#1#2#3", allowAll)
assert.Equal(t, "", res)
}

func TestParse_ipv6_with_port(t *testing.T) {
res := Parse("2604:2000:71a9:bf00:f178:a500:9a2d:670d")
res := Parse("2604:2000:71a9:bf00:f178:a500:9a2d:670d", allowAll)
assert.Equal(t, "2604:2000:71a9:bf00:f178:a500:9a2d:670d", res)
}

Expand Down Expand Up @@ -106,6 +129,32 @@ func TestGetRemoteAddr_ipv6_with_xff(t *testing.T) {
assert.Equal(t, "[2001:db8:0:1:1:1:1:1]:1234", ra)
}

func TestGetRemoteAddrIfAllowed_ipv4_with_xff(t *testing.T) {
r := &http.Request{
RemoteAddr: "1.2.3.4:1234",
Header: http.Header{
"X-Forwarded-For": []string{"100.1.0.1, 100.0.0.1"},
},
}
ra := GetRemoteAddrIfAllowed(r, func(ip string) bool {
return ip == "1.2.3.4" || ip == "100.0.0.1"
})
assert.Equal(t, "100.1.0.1:1234", ra)
}

func TestGetRemoteAddrIfAllowed_ipv6_with_xff(t *testing.T) {
r := &http.Request{
RemoteAddr: "1.2.3.4:1234",
Header: http.Header{
"X-Forwarded-For": []string{"2001:db8:cafe::17, 2001:db8:0:1:1:1:1:1"},
},
}
ra := GetRemoteAddrIfAllowed(r, func(ip string) bool {
return ip == "1.2.3.4" || ip == "2001:db8:0:1:1:1:1:1"
})
assert.Equal(t, "[2001:db8:cafe::17]:1234", ra)
}

func TestToMasks_empty(t *testing.T) {
ips := []string{}
masks, err := toMasks(ips)
Expand Down