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fix: reject invalid characters during ULID parsing #137

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fix: reject invalid characters during ULID parsing #137

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69 changes: 33 additions & 36 deletions ulid.go
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Original file line number Diff line number Diff line change
Expand Up @@ -155,58 +155,55 @@ func Make() (id ULID) {
// Parse parses an encoded ULID, returning an error in case of failure.
//
// ErrDataSize is returned if the len(ulid) is different from an encoded
// ULID's length. Invalid encodings produce undefined ULIDs. For a version that
// returns an error instead, see ParseStrict.
// ULID's length. Invalid encodings return ErrInvalidCharacters.
func Parse(ulid string) (id ULID, err error) {
return id, parse([]byte(ulid), false, &id)
return id, parse([]byte(ulid), &id)
}

// ParseStrict parses an encoded ULID, returning an error in case of failure.
//
// It is like Parse, but additionally validates that the parsed ULID consists
// only of valid base32 characters. It is slightly slower than Parse.
// It is equivalent to Parse.
//
// ErrDataSize is returned if the len(ulid) is different from an encoded
// ULID's length. Invalid encodings return ErrInvalidCharacters.
func ParseStrict(ulid string) (id ULID, err error) {
return id, parse([]byte(ulid), true, &id)
return Parse(ulid)
}

func parse(v []byte, strict bool, id *ULID) error {
func parse(v []byte, id *ULID) error {
// Check if a base32 encoded ULID is the right length.
if len(v) != EncodedSize {
return ErrDataSize
}

// Check if all the characters in a base32 encoded ULID are part of the
// expected base32 character set.
if strict &&
(dec[v[0]] == 0xFF ||
dec[v[1]] == 0xFF ||
dec[v[2]] == 0xFF ||
dec[v[3]] == 0xFF ||
dec[v[4]] == 0xFF ||
dec[v[5]] == 0xFF ||
dec[v[6]] == 0xFF ||
dec[v[7]] == 0xFF ||
dec[v[8]] == 0xFF ||
dec[v[9]] == 0xFF ||
dec[v[10]] == 0xFF ||
dec[v[11]] == 0xFF ||
dec[v[12]] == 0xFF ||
dec[v[13]] == 0xFF ||
dec[v[14]] == 0xFF ||
dec[v[15]] == 0xFF ||
dec[v[16]] == 0xFF ||
dec[v[17]] == 0xFF ||
dec[v[18]] == 0xFF ||
dec[v[19]] == 0xFF ||
dec[v[20]] == 0xFF ||
dec[v[21]] == 0xFF ||
dec[v[22]] == 0xFF ||
dec[v[23]] == 0xFF ||
dec[v[24]] == 0xFF ||
dec[v[25]] == 0xFF) {
if dec[v[0]] == 0xFF ||
dec[v[1]] == 0xFF ||
dec[v[2]] == 0xFF ||
dec[v[3]] == 0xFF ||
dec[v[4]] == 0xFF ||
dec[v[5]] == 0xFF ||
dec[v[6]] == 0xFF ||
dec[v[7]] == 0xFF ||
dec[v[8]] == 0xFF ||
dec[v[9]] == 0xFF ||
dec[v[10]] == 0xFF ||
dec[v[11]] == 0xFF ||
dec[v[12]] == 0xFF ||
dec[v[13]] == 0xFF ||
dec[v[14]] == 0xFF ||
dec[v[15]] == 0xFF ||
dec[v[16]] == 0xFF ||
dec[v[17]] == 0xFF ||
dec[v[18]] == 0xFF ||
dec[v[19]] == 0xFF ||
dec[v[20]] == 0xFF ||
dec[v[21]] == 0xFF ||
dec[v[22]] == 0xFF ||
dec[v[23]] == 0xFF ||
dec[v[24]] == 0xFF ||
dec[v[25]] == 0xFF {
return ErrInvalidCharacters
}

Expand Down Expand Up @@ -400,9 +397,9 @@ const EncodedSize = 26
// parsing the data as string encoded ULID.
//
// ErrDataSize is returned if the len(v) is different from an encoded
// ULID's length. Invalid encodings produce undefined ULIDs.
// ULID's length. Invalid encodings return ErrInvalidCharacters.
func (id *ULID) UnmarshalText(v []byte) error {
return parse(v, false, id)
return parse(v, id)
}

// Time returns the Unix time in milliseconds encoded in the ULID.
Expand Down
89 changes: 72 additions & 17 deletions ulid_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -121,7 +121,7 @@ func TestMustParse(t *testing.T) {
{"MustParse", ulid.MustParse},
{"MustParseStrict", ulid.MustParseStrict},
} {
t.Run(tc.name, func(t *testing.T) {
t.Run(tc.name+"/ErrDataSize", func(t *testing.T) {
defer func() {
if got, want := recover(), ulid.ErrDataSize; got != want {
t.Errorf("got panic %v, want %v", got, want)
Expand All @@ -130,6 +130,14 @@ func TestMustParse(t *testing.T) {
_ = tc.fn("")
})

t.Run(tc.name+"/ErrInvalidCharacters", func(t *testing.T) {
defer func() {
if got, want := recover(), ulid.ErrInvalidCharacters; got != want {
t.Errorf("got panic %v, want %v", got, want)
}
}()
_ = tc.fn("0LLLLLLLLLLLLLLLLLLLLLLLLL")
})
}
}

Expand Down Expand Up @@ -228,14 +236,71 @@ func TestParseStrictInvalidCharacters(t *testing.T) {

for _, tt := range testCases {
t.Run(tt.name, func(t *testing.T) {
_, err := ulid.ParseStrict(tt.input)
if err != ulid.ErrInvalidCharacters {
if _, err := ulid.ParseStrict(tt.input); err != ulid.ErrInvalidCharacters {
t.Errorf("ParseStrict(%q): got err %v, want %v", tt.input, err, ulid.ErrInvalidCharacters)
}
if _, err := ulid.Parse(tt.input); err != ulid.ErrInvalidCharacters {
t.Errorf("Parse(%q): got err %v, want %v", tt.input, err, ulid.ErrInvalidCharacters)
}
})
}
}

func TestParseInvalidCharacters(t *testing.T) {
t.Parallel()

// Crockford Base32 excludes I, L, O, U (and lowercase i, l, o, u).
// Strings containing them must be rejected with ErrInvalidCharacters.
issue69Cases := []struct {
name string
input string
}{
{"uppercase L", "0LLLLLLLLLLLLLLLLLLLLLLLLL"},
{"uppercase U", "0UUUUUUUUUUUUUUUUUUUUUUUUU"},
{"uppercase O", "0OOOOOOOOOOOOOOOOOOOOOOOOO"},
{"uppercase I", "0IIIIIIIIIIIIIIIIIIIIIIIII"},
{"lowercase l", "0lllllllllllllllllllllllll"},
{"lowercase u", "0uuuuuuuuuuuuuuuuuuuuuuuuu"},
{"lowercase o", "0ooooooooooooooooooooooooo"},
{"lowercase i", "0iiiiiiiiiiiiiiiiiiiiiiiii"},
{"first char I", "I0000000000000000000000000"},
{"first char L", "L0000000000000000000000000"},
{"first char O", "O0000000000000000000000000"},
{"first char U", "U0000000000000000000000000"},
{"symbol space", "0000XSNJG0MQJHBF4QX1EFD6Y "},
{"symbol hyphen", "0000XSNJG0MQ-HBF4QX1EFD6Y3"},
{"symbol at", "0000XSNJG0MQ@HBF4QX1EFD6Y3"},
}

for _, tc := range issue69Cases {
t.Run(tc.name, func(t *testing.T) {
if _, err := ulid.Parse(tc.input); err != ulid.ErrInvalidCharacters {
t.Errorf("Parse(%q): got err %v, want %v", tc.input, err, ulid.ErrInvalidCharacters)
}
if _, err := ulid.ParseStrict(tc.input); err != ulid.ErrInvalidCharacters {
t.Errorf("ParseStrict(%q): got err %v, want %v", tc.input, err, ulid.ErrInvalidCharacters)
}

var id ulid.ULID
if err := id.UnmarshalText([]byte(tc.input)); err != ulid.ErrInvalidCharacters {
t.Errorf("UnmarshalText(%q): got err %v, want %v", tc.input, err, ulid.ErrInvalidCharacters)
}
})
}

// Verify all positions 0..25 reject excluded Crockford Base32 characters.
base := "0000XSNJG0MQJHBF4QX1EFD6Y3"
excluded := []byte{'I', 'L', 'O', 'U', 'i', 'l', 'o', 'u'}
for i := 0; i < ulid.EncodedSize; i++ {
for _, ch := range excluded {
input := base[:i] + string(ch) + base[i+1:]
if _, err := ulid.Parse(input); err != ulid.ErrInvalidCharacters {
t.Errorf("Parse(%q) at index %d: got err %v, want %v", input, i, err, ulid.ErrInvalidCharacters)
}
}
}
}

func TestAlizainCompatibility(t *testing.T) {
t.Parallel()

Expand Down Expand Up @@ -324,8 +389,8 @@ func TestParseRobustness(t *testing.T) {
}

for _, tc := range cases {
if _, err := ulid.Parse(string(tc)); err != nil {
t.Error(err)
if _, err := ulid.Parse(string(tc)); err != ulid.ErrInvalidCharacters {
t.Errorf("got %v, want %v", err, ulid.ErrInvalidCharacters)
}
}

Expand All @@ -337,18 +402,8 @@ func TestParseRobustness(t *testing.T) {
}
}()

// quick.Check doesn't constrain input,
// so we need to do so artificially.
if s[0] > '7' {
s[0] %= '7'
}

var err error
if _, err = ulid.Parse(string(s[:])); err != nil {
t.Error(err)
}

return err == nil
_, _ = ulid.Parse(string(s[:]))
return true
}

err := quick.Check(prop, &quick.Config{MaxCount: 1e4})
Expand Down