/usr/share/gocode/src/golang.org/x/text/secure/precis/profile.go is in golang-golang-x-text-dev 0.0~git20170627.0.6353ef0-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 | // Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package precis
import (
"bytes"
"errors"
"unicode/utf8"
"golang.org/x/text/cases"
"golang.org/x/text/language"
"golang.org/x/text/runes"
"golang.org/x/text/secure/bidirule"
"golang.org/x/text/transform"
"golang.org/x/text/width"
)
var (
errDisallowedRune = errors.New("precis: disallowed rune encountered")
)
var dpTrie = newDerivedPropertiesTrie(0)
// A Profile represents a set of rules for normalizing and validating strings in
// the PRECIS framework.
type Profile struct {
options
class *class
}
// NewIdentifier creates a new PRECIS profile based on the Identifier string
// class. Profiles created from this class are suitable for use where safety is
// prioritized over expressiveness like network identifiers, user accounts, chat
// rooms, and file names.
func NewIdentifier(opts ...Option) *Profile {
return &Profile{
options: getOpts(opts...),
class: identifier,
}
}
// NewFreeform creates a new PRECIS profile based on the Freeform string class.
// Profiles created from this class are suitable for use where expressiveness is
// prioritized over safety like passwords, and display-elements such as
// nicknames in a chat room.
func NewFreeform(opts ...Option) *Profile {
return &Profile{
options: getOpts(opts...),
class: freeform,
}
}
// NewTransformer creates a new transform.Transformer that performs the PRECIS
// preparation and enforcement steps on the given UTF-8 encoded bytes.
func (p *Profile) NewTransformer() *Transformer {
var ts []transform.Transformer
// These transforms are applied in the order defined in
// https://tools.ietf.org/html/rfc7564#section-7
if p.options.foldWidth {
ts = append(ts, width.Fold)
}
for _, f := range p.options.additional {
ts = append(ts, f())
}
if p.options.cases != nil {
ts = append(ts, p.options.cases)
}
ts = append(ts, p.options.norm)
if p.options.bidiRule {
ts = append(ts, bidirule.New())
}
ts = append(ts, &checker{p: p, allowed: p.Allowed()})
// TODO: Add the disallow empty rule with a dummy transformer?
return &Transformer{transform.Chain(ts...)}
}
var errEmptyString = errors.New("precis: transformation resulted in empty string")
type buffers struct {
src []byte
buf [2][]byte
next int
}
func (b *buffers) apply(t transform.SpanningTransformer) (err error) {
n, err := t.Span(b.src, true)
if err != transform.ErrEndOfSpan {
return err
}
x := b.next & 1
if b.buf[x] == nil {
b.buf[x] = make([]byte, 0, 8+len(b.src)+len(b.src)>>2)
}
span := append(b.buf[x][:0], b.src[:n]...)
b.src, _, err = transform.Append(t, span, b.src[n:])
b.buf[x] = b.src
b.next++
return err
}
// Pre-allocate transformers when possible. In some cases this avoids allocation.
var (
foldWidthT transform.SpanningTransformer = width.Fold
lowerCaseT transform.SpanningTransformer = cases.Lower(language.Und, cases.HandleFinalSigma(false))
)
// TODO: make this a method on profile.
func (b *buffers) enforce(p *Profile, src []byte, comparing bool) (str []byte, err error) {
b.src = src
ascii := true
for _, c := range src {
if c >= utf8.RuneSelf {
ascii = false
break
}
}
// ASCII fast path.
if ascii {
for _, f := range p.options.additional {
if err = b.apply(f()); err != nil {
return nil, err
}
}
switch {
case p.options.asciiLower || (comparing && p.options.ignorecase):
for i, c := range b.src {
if 'A' <= c && c <= 'Z' {
b.src[i] = c ^ 1<<5
}
}
case p.options.cases != nil:
b.apply(p.options.cases)
}
c := checker{p: p}
if _, err := c.span(b.src, true); err != nil {
return nil, err
}
if p.disallow != nil {
for _, c := range b.src {
if p.disallow.Contains(rune(c)) {
return nil, errDisallowedRune
}
}
}
if p.options.disallowEmpty && len(b.src) == 0 {
return nil, errEmptyString
}
return b.src, nil
}
// These transforms are applied in the order defined in
// https://tools.ietf.org/html/rfc7564#section-7
// TODO: allow different width transforms options.
if p.options.foldWidth || (p.options.ignorecase && comparing) {
b.apply(foldWidthT)
}
for _, f := range p.options.additional {
if err = b.apply(f()); err != nil {
return nil, err
}
}
if p.options.cases != nil {
b.apply(p.options.cases)
}
if comparing && p.options.ignorecase {
b.apply(lowerCaseT)
}
b.apply(p.norm)
if p.options.bidiRule && !bidirule.Valid(b.src) {
return nil, bidirule.ErrInvalid
}
c := checker{p: p}
if _, err := c.span(b.src, true); err != nil {
return nil, err
}
if p.disallow != nil {
for i := 0; i < len(b.src); {
r, size := utf8.DecodeRune(b.src[i:])
if p.disallow.Contains(r) {
return nil, errDisallowedRune
}
i += size
}
}
if p.options.disallowEmpty && len(b.src) == 0 {
return nil, errEmptyString
}
return b.src, nil
}
// Append appends the result of applying p to src writing the result to dst.
// It returns an error if the input string is invalid.
func (p *Profile) Append(dst, src []byte) ([]byte, error) {
var buf buffers
b, err := buf.enforce(p, src, false)
if err != nil {
return nil, err
}
return append(dst, b...), nil
}
func processBytes(p *Profile, b []byte, key bool) ([]byte, error) {
var buf buffers
b, err := buf.enforce(p, b, key)
if err != nil {
return nil, err
}
if buf.next == 0 {
c := make([]byte, len(b))
copy(c, b)
return c, nil
}
return b, nil
}
// Bytes returns a new byte slice with the result of applying the profile to b.
func (p *Profile) Bytes(b []byte) ([]byte, error) {
return processBytes(p, b, false)
}
// AppendCompareKey appends the result of applying p to src (including any
// optional rules to make strings comparable or useful in a map key such as
// applying lowercasing) writing the result to dst. It returns an error if the
// input string is invalid.
func (p *Profile) AppendCompareKey(dst, src []byte) ([]byte, error) {
var buf buffers
b, err := buf.enforce(p, src, true)
if err != nil {
return nil, err
}
return append(dst, b...), nil
}
func processString(p *Profile, s string, key bool) (string, error) {
var buf buffers
b, err := buf.enforce(p, []byte(s), key)
if err != nil {
return "", err
}
return string(b), nil
}
// String returns a string with the result of applying the profile to s.
func (p *Profile) String(s string) (string, error) {
return processString(p, s, false)
}
// CompareKey returns a string that can be used for comparison, hashing, or
// collation.
func (p *Profile) CompareKey(s string) (string, error) {
return processString(p, s, true)
}
// Compare enforces both strings, and then compares them for bit-string identity
// (byte-for-byte equality). If either string cannot be enforced, the comparison
// is false.
func (p *Profile) Compare(a, b string) bool {
var buf buffers
akey, err := buf.enforce(p, []byte(a), true)
if err != nil {
return false
}
buf = buffers{}
bkey, err := buf.enforce(p, []byte(b), true)
if err != nil {
return false
}
return bytes.Compare(akey, bkey) == 0
}
// Allowed returns a runes.Set containing every rune that is a member of the
// underlying profile's string class and not disallowed by any profile specific
// rules.
func (p *Profile) Allowed() runes.Set {
if p.options.disallow != nil {
return runes.Predicate(func(r rune) bool {
return p.class.Contains(r) && !p.options.disallow.Contains(r)
})
}
return p.class
}
type checker struct {
p *Profile
allowed runes.Set
beforeBits catBitmap
termBits catBitmap
acceptBits catBitmap
}
func (c *checker) Reset() {
c.beforeBits = 0
c.termBits = 0
c.acceptBits = 0
}
func (c *checker) span(src []byte, atEOF bool) (n int, err error) {
for n < len(src) {
e, sz := dpTrie.lookup(src[n:])
d := categoryTransitions[category(e&catMask)]
if sz == 0 {
if !atEOF {
return n, transform.ErrShortSrc
}
return n, errDisallowedRune
}
doLookAhead := false
if property(e) < c.p.class.validFrom {
if d.rule == nil {
return n, errDisallowedRune
}
doLookAhead, err = d.rule(c.beforeBits)
if err != nil {
return n, err
}
}
c.beforeBits &= d.keep
c.beforeBits |= d.set
if c.termBits != 0 {
// We are currently in an unterminated lookahead.
if c.beforeBits&c.termBits != 0 {
c.termBits = 0
c.acceptBits = 0
} else if c.beforeBits&c.acceptBits == 0 {
// Invalid continuation of the unterminated lookahead sequence.
return n, errContext
}
}
if doLookAhead {
if c.termBits != 0 {
// A previous lookahead run has not been terminated yet.
return n, errContext
}
c.termBits = d.term
c.acceptBits = d.accept
}
n += sz
}
if m := c.beforeBits >> finalShift; c.beforeBits&m != m || c.termBits != 0 {
err = errContext
}
return n, err
}
// TODO: we may get rid of this transform if transform.Chain understands
// something like a Spanner interface.
func (c checker) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
short := false
if len(dst) < len(src) {
src = src[:len(dst)]
atEOF = false
short = true
}
nSrc, err = c.span(src, atEOF)
nDst = copy(dst, src[:nSrc])
if short && (err == transform.ErrShortSrc || err == nil) {
err = transform.ErrShortDst
}
return nDst, nSrc, err
}
|