jar.go

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package cookiejar implements an in-memory RFC 6265-compliant http.CookieJar.
     6  package cookiejar
     7  
     8  import (
     9  	"errors"
    10  	"fmt"
    11  	"net"
    12  	"net/http"
    13  	"net/http/internal/ascii"
    14  	"net/url"
    15  	"sort"
    16  	"strings"
    17  	"sync"
    18  	"time"
    19  )
    20  
    21  // PublicSuffixList provides the public suffix of a domain. For example:
    22  //      - the public suffix of "example.com" is "com",
    23  //      - the public suffix of "foo1.foo2.foo3.co.uk" is "co.uk", and
    24  //      - the public suffix of "bar.pvt.k12.ma.us" is "pvt.k12.ma.us".
    25  //
    26  // Implementations of PublicSuffixList must be safe for concurrent use by
    27  // multiple goroutines.
    28  //
    29  // An implementation that always returns "" is valid and may be useful for
    30  // testing but it is not secure: it means that the HTTP server for foo.com can
    31  // set a cookie for bar.com.
    32  //
    33  // A public suffix list implementation is in the package
    34  // golang.org/x/net/publicsuffix.
    35  type PublicSuffixList interface {
    36  	// PublicSuffix returns the public suffix of domain.
    37  	//
    38  	// TODO: specify which of the caller and callee is responsible for IP
    39  	// addresses, for leading and trailing dots, for case sensitivity, and
    40  	// for IDN/Punycode.
    41  	PublicSuffix(domain string) string
    42  
    43  	// String returns a description of the source of this public suffix
    44  	// list. The description will typically contain something like a time
    45  	// stamp or version number.
    46  	String() string
    47  }
    48  
    49  // Options are the options for creating a new Jar.
    50  type Options struct {
    51  	// PublicSuffixList is the public suffix list that determines whether
    52  	// an HTTP server can set a cookie for a domain.
    53  	//
    54  	// A nil value is valid and may be useful for testing but it is not
    55  	// secure: it means that the HTTP server for foo.co.uk can set a cookie
    56  	// for bar.co.uk.
    57  	PublicSuffixList PublicSuffixList
    58  }
    59  
    60  // Jar implements the http.CookieJar interface from the net/http package.
    61  type Jar struct {
    62  	psList PublicSuffixList
    63  
    64  	// mu locks the remaining fields.
    65  	mu sync.Mutex
    66  
    67  	// entries is a set of entries, keyed by their eTLD+1 and subkeyed by
    68  	// their name/domain/path.
    69  	entries map[string]map[string]entry
    70  
    71  	// nextSeqNum is the next sequence number assigned to a new cookie
    72  	// created SetCookies.
    73  	nextSeqNum uint64
    74  }
    75  
    76  // New returns a new cookie jar. A nil *Options is equivalent to a zero
    77  // Options.
    78  func New(o *Options) (*Jar, error) {
    79  	jar := &Jar{
    80  		entries: make(map[string]map[string]entry),
    81  	}
    82  	if o != nil {
    83  		jar.psList = o.PublicSuffixList
    84  	}
    85  	return jar, nil
    86  }
    87  
    88  // entry is the internal representation of a cookie.
    89  //
    90  // This struct type is not used outside of this package per se, but the exported
    91  // fields are those of RFC 6265.
    92  type entry struct {
    93  	Name       string
    94  	Value      string
    95  	Domain     string
    96  	Path       string
    97  	SameSite   string
    98  	Secure     bool
    99  	HttpOnly   bool
   100  	Persistent bool
   101  	HostOnly   bool
   102  	Expires    time.Time
   103  	Creation   time.Time
   104  	LastAccess time.Time
   105  
   106  	// seqNum is a sequence number so that Cookies returns cookies in a
   107  	// deterministic order, even for cookies that have equal Path length and
   108  	// equal Creation time. This simplifies testing.
   109  	seqNum uint64
   110  }
   111  
   112  // id returns the domain;path;name triple of e as an id.
   113  func (e *entry) id() string {
   114  	return fmt.Sprintf("%s;%s;%s", e.Domain, e.Path, e.Name)
   115  }
   116  
   117  // shouldSend determines whether e's cookie qualifies to be included in a
   118  // request to host/path. It is the caller's responsibility to check if the
   119  // cookie is expired.
   120  func (e *entry) shouldSend(https bool, host, path string) bool {
   121  	return e.domainMatch(host) && e.pathMatch(path) && (https || !e.Secure)
   122  }
   123  
   124  // domainMatch implements "domain-match" of RFC 6265 section 5.1.3.
   125  func (e *entry) domainMatch(host string) bool {
   126  	if e.Domain == host {
   127  		return true
   128  	}
   129  	return !e.HostOnly && hasDotSuffix(host, e.Domain)
   130  }
   131  
   132  // pathMatch implements "path-match" according to RFC 6265 section 5.1.4.
   133  func (e *entry) pathMatch(requestPath string) bool {
   134  	if requestPath == e.Path {
   135  		return true
   136  	}
   137  	if strings.HasPrefix(requestPath, e.Path) {
   138  		if e.Path[len(e.Path)-1] == '/' {
   139  			return true // The "/any/" matches "/any/path" case.
   140  		} else if requestPath[len(e.Path)] == '/' {
   141  			return true // The "/any" matches "/any/path" case.
   142  		}
   143  	}
   144  	return false
   145  }
   146  
   147  // hasDotSuffix reports whether s ends in "."+suffix.
   148  func hasDotSuffix(s, suffix string) bool {
   149  	return len(s) > len(suffix) && s[len(s)-len(suffix)-1] == '.' && s[len(s)-len(suffix):] == suffix
   150  }
   151  
   152  // Cookies implements the Cookies method of the http.CookieJar interface.
   153  //
   154  // It returns an empty slice if the URL's scheme is not HTTP or HTTPS.
   155  func (j *Jar) Cookies(u *url.URL) (cookies []*http.Cookie) {
   156  	return j.cookies(u, time.Now())
   157  }
   158  
   159  // cookies is like Cookies but takes the current time as a parameter.
   160  func (j *Jar) cookies(u *url.URL, now time.Time) (cookies []*http.Cookie) {
   161  	if u.Scheme != "http" && u.Scheme != "https" {
   162  		return cookies
   163  	}
   164  	host, err := canonicalHost(u.Host)
   165  	if err != nil {
   166  		return cookies
   167  	}
   168  	key := jarKey(host, j.psList)
   169  
   170  	j.mu.Lock()
   171  	defer j.mu.Unlock()
   172  
   173  	submap := j.entries[key]
   174  	if submap == nil {
   175  		return cookies
   176  	}
   177  
   178  	https := u.Scheme == "https"
   179  	path := u.Path
   180  	if path == "" {
   181  		path = "/"
   182  	}
   183  
   184  	modified := false
   185  	var selected []entry
   186  	for id, e := range submap {
   187  		if e.Persistent && !e.Expires.After(now) {
   188  			delete(submap, id)
   189  			modified = true
   190  			continue
   191  		}
   192  		if !e.shouldSend(https, host, path) {
   193  			continue
   194  		}
   195  		e.LastAccess = now
   196  		submap[id] = e
   197  		selected = append(selected, e)
   198  		modified = true
   199  	}
   200  	if modified {
   201  		if len(submap) == 0 {
   202  			delete(j.entries, key)
   203  		} else {
   204  			j.entries[key] = submap
   205  		}
   206  	}
   207  
   208  	// sort according to RFC 6265 section 5.4 point 2: by longest
   209  	// path and then by earliest creation time.
   210  	sort.Slice(selected, func(i, j int) bool {
   211  		s := selected
   212  		if len(s[i].Path) != len(s[j].Path) {
   213  			return len(s[i].Path) > len(s[j].Path)
   214  		}
   215  		if !s[i].Creation.Equal(s[j].Creation) {
   216  			return s[i].Creation.Before(s[j].Creation)
   217  		}
   218  		return s[i].seqNum < s[j].seqNum
   219  	})
   220  	for _, e := range selected {
   221  		cookies = append(cookies, &http.Cookie{Name: e.Name, Value: e.Value})
   222  	}
   223  
   224  	return cookies
   225  }
   226  
   227  // SetCookies implements the SetCookies method of the http.CookieJar interface.
   228  //
   229  // It does nothing if the URL's scheme is not HTTP or HTTPS.
   230  func (j *Jar) SetCookies(u *url.URL, cookies []*http.Cookie) {
   231  	j.setCookies(u, cookies, time.Now())
   232  }
   233  
   234  // setCookies is like SetCookies but takes the current time as parameter.
   235  func (j *Jar) setCookies(u *url.URL, cookies []*http.Cookie, now time.Time) {
   236  	if len(cookies) == 0 {
   237  		return
   238  	}
   239  	if u.Scheme != "http" && u.Scheme != "https" {
   240  		return
   241  	}
   242  	host, err := canonicalHost(u.Host)
   243  	if err != nil {
   244  		return
   245  	}
   246  	key := jarKey(host, j.psList)
   247  	defPath := defaultPath(u.Path)
   248  
   249  	j.mu.Lock()
   250  	defer j.mu.Unlock()
   251  
   252  	submap := j.entries[key]
   253  
   254  	modified := false
   255  	for _, cookie := range cookies {
   256  		e, remove, err := j.newEntry(cookie, now, defPath, host)
   257  		if err != nil {
   258  			continue
   259  		}
   260  		id := e.id()
   261  		if remove {
   262  			if submap != nil {
   263  				if _, ok := submap[id]; ok {
   264  					delete(submap, id)
   265  					modified = true
   266  				}
   267  			}
   268  			continue
   269  		}
   270  		if submap == nil {
   271  			submap = make(map[string]entry)
   272  		}
   273  
   274  		if old, ok := submap[id]; ok {
   275  			e.Creation = old.Creation
   276  			e.seqNum = old.seqNum
   277  		} else {
   278  			e.Creation = now
   279  			e.seqNum = j.nextSeqNum
   280  			j.nextSeqNum++
   281  		}
   282  		e.LastAccess = now
   283  		submap[id] = e
   284  		modified = true
   285  	}
   286  
   287  	if modified {
   288  		if len(submap) == 0 {
   289  			delete(j.entries, key)
   290  		} else {
   291  			j.entries[key] = submap
   292  		}
   293  	}
   294  }
   295  
   296  // canonicalHost strips port from host if present and returns the canonicalized
   297  // host name.
   298  func canonicalHost(host string) (string, error) {
   299  	var err error
   300  	if hasPort(host) {
   301  		host, _, err = net.SplitHostPort(host)
   302  		if err != nil {
   303  			return "", err
   304  		}
   305  	}
   306  	if strings.HasSuffix(host, ".") {
   307  		// Strip trailing dot from fully qualified domain names.
   308  		host = host[:len(host)-1]
   309  	}
   310  	encoded, err := toASCII(host)
   311  	if err != nil {
   312  		return "", err
   313  	}
   314  	// We know this is ascii, no need to check.
   315  	lower, _ := ascii.ToLower(encoded)
   316  	return lower, nil
   317  }
   318  
   319  // hasPort reports whether host contains a port number. host may be a host
   320  // name, an IPv4 or an IPv6 address.
   321  func hasPort(host string) bool {
   322  	colons := strings.Count(host, ":")
   323  	if colons == 0 {
   324  		return false
   325  	}
   326  	if colons == 1 {
   327  		return true
   328  	}
   329  	return host[0] == '[' && strings.Contains(host, "]:")
   330  }
   331  
   332  // jarKey returns the key to use for a jar.
   333  func jarKey(host string, psl PublicSuffixList) string {
   334  	if isIP(host) {
   335  		return host
   336  	}
   337  
   338  	var i int
   339  	if psl == nil {
   340  		i = strings.LastIndex(host, ".")
   341  		if i <= 0 {
   342  			return host
   343  		}
   344  	} else {
   345  		suffix := psl.PublicSuffix(host)
   346  		if suffix == host {
   347  			return host
   348  		}
   349  		i = len(host) - len(suffix)
   350  		if i <= 0 || host[i-1] != '.' {
   351  			// The provided public suffix list psl is broken.
   352  			// Storing cookies under host is a safe stopgap.
   353  			return host
   354  		}
   355  		// Only len(suffix) is used to determine the jar key from
   356  		// here on, so it is okay if psl.PublicSuffix("www.buggy.psl")
   357  		// returns "com" as the jar key is generated from host.
   358  	}
   359  	prevDot := strings.LastIndex(host[:i-1], ".")
   360  	return host[prevDot+1:]
   361  }
   362  
   363  // isIP reports whether host is an IP address.
   364  func isIP(host string) bool {
   365  	return net.ParseIP(host) != nil
   366  }
   367  
   368  // defaultPath returns the directory part of an URL's path according to
   369  // RFC 6265 section 5.1.4.
   370  func defaultPath(path string) string {
   371  	if len(path) == 0 || path[0] != '/' {
   372  		return "/" // Path is empty or malformed.
   373  	}
   374  
   375  	i := strings.LastIndex(path, "/") // Path starts with "/", so i != -1.
   376  	if i == 0 {
   377  		return "/" // Path has the form "/abc".
   378  	}
   379  	return path[:i] // Path is either of form "/abc/xyz" or "/abc/xyz/".
   380  }
   381  
   382  // newEntry creates an entry from a http.Cookie c. now is the current time and
   383  // is compared to c.Expires to determine deletion of c. defPath and host are the
   384  // default-path and the canonical host name of the URL c was received from.
   385  //
   386  // remove records whether the jar should delete this cookie, as it has already
   387  // expired with respect to now. In this case, e may be incomplete, but it will
   388  // be valid to call e.id (which depends on e's Name, Domain and Path).
   389  //
   390  // A malformed c.Domain will result in an error.
   391  func (j *Jar) newEntry(c *http.Cookie, now time.Time, defPath, host string) (e entry, remove bool, err error) {
   392  	e.Name = c.Name
   393  
   394  	if c.Path == "" || c.Path[0] != '/' {
   395  		e.Path = defPath
   396  	} else {
   397  		e.Path = c.Path
   398  	}
   399  
   400  	e.Domain, e.HostOnly, err = j.domainAndType(host, c.Domain)
   401  	if err != nil {
   402  		return e, false, err
   403  	}
   404  
   405  	// MaxAge takes precedence over Expires.
   406  	if c.MaxAge < 0 {
   407  		return e, true, nil
   408  	} else if c.MaxAge > 0 {
   409  		e.Expires = now.Add(time.Duration(c.MaxAge) * time.Second)
   410  		e.Persistent = true
   411  	} else {
   412  		if c.Expires.IsZero() {
   413  			e.Expires = endOfTime
   414  			e.Persistent = false
   415  		} else {
   416  			if !c.Expires.After(now) {
   417  				return e, true, nil
   418  			}
   419  			e.Expires = c.Expires
   420  			e.Persistent = true
   421  		}
   422  	}
   423  
   424  	e.Value = c.Value
   425  	e.Secure = c.Secure
   426  	e.HttpOnly = c.HttpOnly
   427  
   428  	switch c.SameSite {
   429  	case http.SameSiteDefaultMode:
   430  		e.SameSite = "SameSite"
   431  	case http.SameSiteStrictMode:
   432  		e.SameSite = "SameSite=Strict"
   433  	case http.SameSiteLaxMode:
   434  		e.SameSite = "SameSite=Lax"
   435  	}
   436  
   437  	return e, false, nil
   438  }
   439  
   440  var (
   441  	errIllegalDomain   = errors.New("cookiejar: illegal cookie domain attribute")
   442  	errMalformedDomain = errors.New("cookiejar: malformed cookie domain attribute")
   443  	errNoHostname      = errors.New("cookiejar: no host name available (IP only)")
   444  )
   445  
   446  // endOfTime is the time when session (non-persistent) cookies expire.
   447  // This instant is representable in most date/time formats (not just
   448  // Go's time.Time) and should be far enough in the future.
   449  var endOfTime = time.Date(9999, 12, 31, 23, 59, 59, 0, time.UTC)
   450  
   451  // domainAndType determines the cookie's domain and hostOnly attribute.
   452  func (j *Jar) domainAndType(host, domain string) (string, bool, error) {
   453  	if domain == "" {
   454  		// No domain attribute in the SetCookie header indicates a
   455  		// host cookie.
   456  		return host, true, nil
   457  	}
   458  
   459  	if isIP(host) {
   460  		// According to RFC 6265 domain-matching includes not being
   461  		// an IP address.
   462  		// TODO: This might be relaxed as in common browsers.
   463  		return "", false, errNoHostname
   464  	}
   465  
   466  	// From here on: If the cookie is valid, it is a domain cookie (with
   467  	// the one exception of a public suffix below).
   468  	// See RFC 6265 section 5.2.3.
   469  	if domain[0] == '.' {
   470  		domain = domain[1:]
   471  	}
   472  
   473  	if len(domain) == 0 || domain[0] == '.' {
   474  		// Received either "Domain=." or "Domain=..some.thing",
   475  		// both are illegal.
   476  		return "", false, errMalformedDomain
   477  	}
   478  
   479  	domain, isASCII := ascii.ToLower(domain)
   480  	if !isASCII {
   481  		// Received non-ASCII domain, e.g. "perché.com" instead of "xn--perch-fsa.com"
   482  		return "", false, errMalformedDomain
   483  	}
   484  
   485  	if domain[len(domain)-1] == '.' {
   486  		// We received stuff like "Domain=www.example.com.".
   487  		// Browsers do handle such stuff (actually differently) but
   488  		// RFC 6265 seems to be clear here (e.g. section 4.1.2.3) in
   489  		// requiring a reject.  4.1.2.3 is not normative, but
   490  		// "Domain Matching" (5.1.3) and "Canonicalized Host Names"
   491  		// (5.1.2) are.
   492  		return "", false, errMalformedDomain
   493  	}
   494  
   495  	// See RFC 6265 section 5.3 #5.
   496  	if j.psList != nil {
   497  		if ps := j.psList.PublicSuffix(domain); ps != "" && !hasDotSuffix(domain, ps) {
   498  			if host == domain {
   499  				// This is the one exception in which a cookie
   500  				// with a domain attribute is a host cookie.
   501  				return host, true, nil
   502  			}
   503  			return "", false, errIllegalDomain
   504  		}
   505  	}
   506  
   507  	// The domain must domain-match host: www.mycompany.com cannot
   508  	// set cookies for .ourcompetitors.com.
   509  	if host != domain && !hasDotSuffix(host, domain) {
   510  		return "", false, errIllegalDomain
   511  	}
   512  
   513  	return domain, false, nil
   514  }
   515
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