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fix open redirect vulnerability with AddTrailingSlashWithConfig and RemoveTrailingSlashWithConfig #1775

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Merged
merged 3 commits into from
Feb 11, 2021
Merged

fix open redirect vulnerability with AddTrailingSlashWithConfig and RemoveTrailingSlashWithConfig #1775

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c526e11
fix open redirect vulnerability with AddTrailingSlashWithConfig and R…
aldas Feb 11, 2021
5c4cb06
rename trimMultipleSlashes to sanitzeUrl
aldas Feb 11, 2021
e3ef5ac
rename trimMultipleSlashes to sanitizeURI
aldas Feb 11, 2021
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13 changes: 11 additions & 2 deletions middleware/slash.go
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ func AddTrailingSlashWithConfig(config TrailingSlashConfig) echo.MiddlewareFunc

// Redirect
if config.RedirectCode != 0 {
return c.Redirect(config.RedirectCode, uri)
return c.Redirect(config.RedirectCode, sanitizeURI(uri))
}

// Forward
Expand Down Expand Up @@ -108,7 +108,7 @@ func RemoveTrailingSlashWithConfig(config TrailingSlashConfig) echo.MiddlewareFu

// Redirect
if config.RedirectCode != 0 {
return c.Redirect(config.RedirectCode, uri)
return c.Redirect(config.RedirectCode, sanitizeURI(uri))
}

// Forward
Expand All @@ -119,3 +119,12 @@ func RemoveTrailingSlashWithConfig(config TrailingSlashConfig) echo.MiddlewareFu
}
}
}

func sanitizeURI(uri string) string {
// double slash `\\`, `//` or even `\/` is absolute uri for browsers and by redirecting request to that uri
// we are vulnerable to open redirect attack. so replace all slashes from the beginning with single slash
if len(uri) > 1 && (uri[0] == '\\' || uri[0] == '/') && (uri[1] == '\\' || uri[1] == '/') {
uri = "/" + strings.TrimLeft(uri, `/\`)
}
return uri
}
342 changes: 262 additions & 80 deletions middleware/slash_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -9,88 +9,270 @@ import (
"github.com/stretchr/testify/assert"
)

func TestAddTrailingSlashWithConfig(t *testing.T) {
var testCases = []struct {
whenURL string
whenMethod string
expectPath string
expectLocation []string
expectStatus int
}{
{
whenURL: "/add-slash",
whenMethod: http.MethodGet,
expectPath: "/add-slash",
expectLocation: []string{`/add-slash/`},
},
{
whenURL: "/add-slash?key=value",
whenMethod: http.MethodGet,
expectPath: "/add-slash",
expectLocation: []string{`/add-slash/?key=value`},
},
{
whenURL: "/",
whenMethod: http.MethodConnect,
expectPath: "/",
expectLocation: nil,
expectStatus: http.StatusOK,
},
// cases for open redirect vulnerability
{
whenURL: "http://localhost:1323/%5Cexample.com",
expectPath: `/\example.com`,
expectLocation: []string{`/example.com/`},
},
{
whenURL: `http://localhost:1323/\example.com`,
expectPath: `/\example.com`,
expectLocation: []string{`/example.com/`},
},
{
whenURL: `http://localhost:1323/\\%5C////%5C\\\example.com`,
expectPath: `/\\\////\\\\example.com`,
expectLocation: []string{`/example.com/`},
},
{
whenURL: "http://localhost:1323//example.com",
expectPath: `//example.com`,
expectLocation: []string{`/example.com/`},
},
{
whenURL: "http://localhost:1323/%5C%5C",
expectPath: `/\\`,
expectLocation: []string{`/`},
},
}
for _, tc := range testCases {
t.Run(tc.whenURL, func(t *testing.T) {
e := echo.New()

mw := AddTrailingSlashWithConfig(TrailingSlashConfig{
RedirectCode: http.StatusMovedPermanently,
})
h := mw(func(c echo.Context) error {
return nil
})

rec := httptest.NewRecorder()
req := httptest.NewRequest(tc.whenMethod, tc.whenURL, nil)
c := e.NewContext(req, rec)

err := h(c)
assert.NoError(t, err)

assert.Equal(t, tc.expectPath, req.URL.Path)
assert.Equal(t, tc.expectLocation, rec.Header()[echo.HeaderLocation])
if tc.expectStatus == 0 {
assert.Equal(t, http.StatusMovedPermanently, rec.Code)
} else {
assert.Equal(t, tc.expectStatus, rec.Code)
}
})
}
}

func TestAddTrailingSlash(t *testing.T) {
is := assert.New(t)
e := echo.New()
req := httptest.NewRequest(http.MethodGet, "/add-slash", nil)
rec := httptest.NewRecorder()
c := e.NewContext(req, rec)
h := AddTrailingSlash()(func(c echo.Context) error {
return nil
})
is.NoError(h(c))
is.Equal("/add-slash/", req.URL.Path)
is.Equal("/add-slash/", req.RequestURI)

// Method Connect must not fail:
req = httptest.NewRequest(http.MethodConnect, "", nil)
rec = httptest.NewRecorder()
c = e.NewContext(req, rec)
h = AddTrailingSlash()(func(c echo.Context) error {
return nil
})
is.NoError(h(c))
is.Equal("/", req.URL.Path)
is.Equal("/", req.RequestURI)

// With config
req = httptest.NewRequest(http.MethodGet, "/add-slash?key=value", nil)
rec = httptest.NewRecorder()
c = e.NewContext(req, rec)
h = AddTrailingSlashWithConfig(TrailingSlashConfig{
RedirectCode: http.StatusMovedPermanently,
})(func(c echo.Context) error {
return nil
})
is.NoError(h(c))
is.Equal(http.StatusMovedPermanently, rec.Code)
is.Equal("/add-slash/?key=value", rec.Header().Get(echo.HeaderLocation))
var testCases = []struct {
whenURL string
whenMethod string
expectPath string
expectLocation []string
}{
{
whenURL: "/add-slash",
whenMethod: http.MethodGet,
expectPath: "/add-slash/",
},
{
whenURL: "/add-slash?key=value",
whenMethod: http.MethodGet,
expectPath: "/add-slash/",
},
{
whenURL: "/",
whenMethod: http.MethodConnect,
expectPath: "/",
expectLocation: nil,
},
}
for _, tc := range testCases {
t.Run(tc.whenURL, func(t *testing.T) {
e := echo.New()

h := AddTrailingSlash()(func(c echo.Context) error {
return nil
})

rec := httptest.NewRecorder()
req := httptest.NewRequest(tc.whenMethod, tc.whenURL, nil)
c := e.NewContext(req, rec)

err := h(c)
assert.NoError(t, err)

assert.Equal(t, tc.expectPath, req.URL.Path)
assert.Equal(t, []string(nil), rec.Header()[echo.HeaderLocation])
assert.Equal(t, http.StatusOK, rec.Code)
})
}
}

func TestRemoveTrailingSlashWithConfig(t *testing.T) {
var testCases = []struct {
whenURL string
whenMethod string
expectPath string
expectLocation []string
expectStatus int
}{
{
whenURL: "/remove-slash/",
whenMethod: http.MethodGet,
expectPath: "/remove-slash/",
expectLocation: []string{`/remove-slash`},
},
{
whenURL: "/remove-slash/?key=value",
whenMethod: http.MethodGet,
expectPath: "/remove-slash/",
expectLocation: []string{`/remove-slash?key=value`},
},
{
whenURL: "/",
whenMethod: http.MethodConnect,
expectPath: "/",
expectLocation: nil,
expectStatus: http.StatusOK,
},
{
whenURL: "http://localhost",
whenMethod: http.MethodGet,
expectPath: "",
expectLocation: nil,
expectStatus: http.StatusOK,
},
// cases for open redirect vulnerability
{
whenURL: "http://localhost:1323/%5Cexample.com/",
expectPath: `/\example.com/`,
expectLocation: []string{`/example.com`},
},
{
whenURL: `http://localhost:1323/\example.com/`,
expectPath: `/\example.com/`,
expectLocation: []string{`/example.com`},
},
{
whenURL: `http://localhost:1323/\\%5C////%5C\\\example.com/`,
expectPath: `/\\\////\\\\example.com/`,
expectLocation: []string{`/example.com`},
},
{
whenURL: "http://localhost:1323//example.com/",
expectPath: `//example.com/`,
expectLocation: []string{`/example.com`},
},
{
whenURL: "http://localhost:1323/%5C%5C/",
expectPath: `/\\/`,
expectLocation: []string{`/`},
},
}
for _, tc := range testCases {
t.Run(tc.whenURL, func(t *testing.T) {
e := echo.New()

mw := RemoveTrailingSlashWithConfig(TrailingSlashConfig{
RedirectCode: http.StatusMovedPermanently,
})
h := mw(func(c echo.Context) error {
return nil
})

rec := httptest.NewRecorder()
req := httptest.NewRequest(tc.whenMethod, tc.whenURL, nil)
c := e.NewContext(req, rec)

err := h(c)
assert.NoError(t, err)

assert.Equal(t, tc.expectPath, req.URL.Path)
assert.Equal(t, tc.expectLocation, rec.Header()[echo.HeaderLocation])
if tc.expectStatus == 0 {
assert.Equal(t, http.StatusMovedPermanently, rec.Code)
} else {
assert.Equal(t, tc.expectStatus, rec.Code)
}
})
}
}

func TestRemoveTrailingSlash(t *testing.T) {
is := assert.New(t)
e := echo.New()
req := httptest.NewRequest(http.MethodGet, "/remove-slash/", nil)
rec := httptest.NewRecorder()
c := e.NewContext(req, rec)
h := RemoveTrailingSlash()(func(c echo.Context) error {
return nil
})
is.NoError(h(c))
is.Equal("/remove-slash", req.URL.Path)
is.Equal("/remove-slash", req.RequestURI)

// Method Connect must not fail:
req = httptest.NewRequest(http.MethodConnect, "", nil)
rec = httptest.NewRecorder()
c = e.NewContext(req, rec)
h = RemoveTrailingSlash()(func(c echo.Context) error {
return nil
})
is.NoError(h(c))
is.Equal("", req.URL.Path)
is.Equal("", req.RequestURI)

// With config
req = httptest.NewRequest(http.MethodGet, "/remove-slash/?key=value", nil)
rec = httptest.NewRecorder()
c = e.NewContext(req, rec)
h = RemoveTrailingSlashWithConfig(TrailingSlashConfig{
RedirectCode: http.StatusMovedPermanently,
})(func(c echo.Context) error {
return nil
})
is.NoError(h(c))
is.Equal(http.StatusMovedPermanently, rec.Code)
is.Equal("/remove-slash?key=value", rec.Header().Get(echo.HeaderLocation))

// With bare URL
req = httptest.NewRequest(http.MethodGet, "http://localhost", nil)
rec = httptest.NewRecorder()
c = e.NewContext(req, rec)
h = RemoveTrailingSlash()(func(c echo.Context) error {
return nil
})
is.NoError(h(c))
is.Equal("", req.URL.Path)
var testCases = []struct {
whenURL string
whenMethod string
expectPath string
}{
{
whenURL: "/remove-slash/",
whenMethod: http.MethodGet,
expectPath: "/remove-slash",
},
{
whenURL: "/remove-slash/?key=value",
whenMethod: http.MethodGet,
expectPath: "/remove-slash",
},
{
whenURL: "/",
whenMethod: http.MethodConnect,
expectPath: "/",
},
{
whenURL: "http://localhost",
whenMethod: http.MethodGet,
expectPath: "",
},
}
for _, tc := range testCases {
t.Run(tc.whenURL, func(t *testing.T) {
e := echo.New()

h := RemoveTrailingSlash()(func(c echo.Context) error {
return nil
})

rec := httptest.NewRecorder()
req := httptest.NewRequest(tc.whenMethod, tc.whenURL, nil)
c := e.NewContext(req, rec)

err := h(c)
assert.NoError(t, err)

assert.Equal(t, tc.expectPath, req.URL.Path)
assert.Equal(t, []string(nil), rec.Header()[echo.HeaderLocation])
assert.Equal(t, http.StatusOK, rec.Code)
})
}
}