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  	"cmp"
    10  	"errors"
    11  	"fmt"
    12  	"net"
    13  	"net/http"
    14  	"net/http/internal/ascii"
    15  	"net/url"
    16  	"slices"
    17  	"strings"
    18  	"sync"
    19  	"time"
    20  )
    21  
    22  // PublicSuffixList provides the public suffix of a domain. For example:
    23  //   - the public suffix of "example.com" is "com",
    24  //   - the public suffix of "foo1.foo2.foo3.co.uk" is "co.uk", and
    25  //   - the public suffix of "bar.pvt.k12.ma.us" is "pvt.k12.ma.us".
    26  //
    27  // Implementations of PublicSuffixList must be safe for concurrent use by
    28  // multiple goroutines.
    29  //
    30  // An implementation that always returns "" is valid and may be useful for
    31  // testing but it is not secure: it means that the HTTP server for foo.com can
    32  // set a cookie for bar.com.
    33  //
    34  // A public suffix list implementation is in the package
    35  // golang.org/x/net/publicsuffix.
    36  type PublicSuffixList interface {
    37  	// PublicSuffix returns the public suffix of domain.
    38  	//
    39  	// TODO: specify which of the caller and callee is responsible for IP
    40  	// addresses, for leading and trailing dots, for case sensitivity, and
    41  	// for IDN/Punycode.
    42  	PublicSuffix(domain string) string
    43  
    44  	// String returns a description of the source of this public suffix
    45  	// list. The description will typically contain something like a time
    46  	// stamp or version number.
    47  	String() string
    48  }
    49  
    50  // Options are the options for creating a new Jar.
    51  type Options struct {
    52  	// PublicSuffixList is the public suffix list that determines whether
    53  	// an HTTP server can set a cookie for a domain.
    54  	//
    55  	// A nil value is valid and may be useful for testing but it is not
    56  	// secure: it means that the HTTP server for foo.co.uk can set a cookie
    57  	// for bar.co.uk.
    58  	PublicSuffixList PublicSuffixList
    59  }
    60  
    61  // Jar implements the http.CookieJar interface from the net/http package.
    62  type Jar struct {
    63  	psList PublicSuffixList
    64  
    65  	// mu locks the remaining fields.
    66  	mu sync.Mutex
    67  
    68  	// entries is a set of entries, keyed by their eTLD+1 and subkeyed by
    69  	// their name/domain/path.
    70  	entries map[string]map[string]entry
    71  
    72  	// nextSeqNum is the next sequence number assigned to a new cookie
    73  	// created SetCookies.
    74  	nextSeqNum uint64
    75  }
    76  
    77  // New returns a new cookie jar. A nil [*Options] is equivalent to a zero
    78  // Options.
    79  func New(o *Options) (*Jar, error) {
    80  	jar := &Jar{
    81  		entries: make(map[string]map[string]entry),
    82  	}
    83  	if o != nil {
    84  		jar.psList = o.PublicSuffixList
    85  	}
    86  	return jar, nil
    87  }
    88  
    89  // entry is the internal representation of a cookie.
    90  //
    91  // This struct type is not used outside of this package per se, but the exported
    92  // fields are those of RFC 6265.
    93  type entry struct {
    94  	Name       string
    95  	Value      string
    96  	Quoted     bool
    97  	Domain     string
    98  	Path       string
    99  	SameSite   string
   100  	Secure     bool
   101  	HttpOnly   bool
   102  	Persistent bool
   103  	HostOnly   bool
   104  	Expires    time.Time
   105  	Creation   time.Time
   106  	LastAccess time.Time
   107  
   108  	// seqNum is a sequence number so that Cookies returns cookies in a
   109  	// deterministic order, even for cookies that have equal Path length and
   110  	// equal Creation time. This simplifies testing.
   111  	seqNum uint64
   112  }
   113  
   114  // id returns the domain;path;name triple of e as an id.
   115  func (e *entry) id() string {
   116  	return fmt.Sprintf("%s;%s;%s", e.Domain, e.Path, e.Name)
   117  }
   118  
   119  // shouldSend determines whether e's cookie qualifies to be included in a
   120  // request to host/path. It is the caller's responsibility to check if the
   121  // cookie is expired.
   122  func (e *entry) shouldSend(https bool, host, path string) bool {
   123  	return e.domainMatch(host) && e.pathMatch(path) && (https || !e.Secure)
   124  }
   125  
   126  // domainMatch checks whether e's Domain allows sending e back to host.
   127  // It differs from "domain-match" of RFC 6265 section 5.1.3 because we treat
   128  // a cookie with an IP address in the Domain always as a host cookie.
   129  func (e *entry) domainMatch(host string) bool {
   130  	if e.Domain == host {
   131  		return true
   132  	}
   133  	return !e.HostOnly && hasDotSuffix(host, e.Domain)
   134  }
   135  
   136  // pathMatch implements "path-match" according to RFC 6265 section 5.1.4.
   137  func (e *entry) pathMatch(requestPath string) bool {
   138  	if requestPath == e.Path {
   139  		return true
   140  	}
   141  	if strings.HasPrefix(requestPath, e.Path) {
   142  		if e.Path[len(e.Path)-1] == '/' {
   143  			return true // The "/any/" matches "/any/path" case.
   144  		} else if requestPath[len(e.Path)] == '/' {
   145  			return true // The "/any" matches "/any/path" case.
   146  		}
   147  	}
   148  	return false
   149  }
   150  
   151  // hasDotSuffix reports whether s ends in "."+suffix.
   152  func hasDotSuffix(s, suffix string) bool {
   153  	return len(s) > len(suffix) && s[len(s)-len(suffix)-1] == '.' && s[len(s)-len(suffix):] == suffix
   154  }
   155  
   156  // Cookies implements the Cookies method of the [http.CookieJar] interface.
   157  //
   158  // It returns an empty slice if the URL's scheme is not HTTP or HTTPS.
   159  func (j *Jar) Cookies(u *url.URL) (cookies []*http.Cookie) {
   160  	return j.cookies(u, time.Now())
   161  }
   162  
   163  // cookies is like Cookies but takes the current time as a parameter.
   164  func (j *Jar) cookies(u *url.URL, now time.Time) (cookies []*http.Cookie) {
   165  	if u.Scheme != "http" && u.Scheme != "https" {
   166  		return cookies
   167  	}
   168  	host, err := canonicalHost(u.Host)
   169  	if err != nil {
   170  		return cookies
   171  	}
   172  	key := jarKey(host, j.psList)
   173  
   174  	j.mu.Lock()
   175  	defer j.mu.Unlock()
   176  
   177  	submap := j.entries[key]
   178  	if submap == nil {
   179  		return cookies
   180  	}
   181  
   182  	https := u.Scheme == "https"
   183  	path := u.Path
   184  	if path == "" {
   185  		path = "/"
   186  	}
   187  
   188  	modified := false
   189  	var selected []entry
   190  	for id, e := range submap {
   191  		if e.Persistent && !e.Expires.After(now) {
   192  			delete(submap, id)
   193  			modified = true
   194  			continue
   195  		}
   196  		if !e.shouldSend(https, host, path) {
   197  			continue
   198  		}
   199  		e.LastAccess = now
   200  		submap[id] = e
   201  		selected = append(selected, e)
   202  		modified = true
   203  	}
   204  	if modified {
   205  		if len(submap) == 0 {
   206  			delete(j.entries, key)
   207  		} else {
   208  			j.entries[key] = submap
   209  		}
   210  	}
   211  
   212  	// sort according to RFC 6265 section 5.4 point 2: by longest
   213  	// path and then by earliest creation time.
   214  	slices.SortFunc(selected, func(a, b entry) int {
   215  		if r := cmp.Compare(b.Path, a.Path); r != 0 {
   216  			return r
   217  		}
   218  		if r := a.Creation.Compare(b.Creation); r != 0 {
   219  			return r
   220  		}
   221  		return cmp.Compare(a.seqNum, b.seqNum)
   222  	})
   223  	for _, e := range selected {
   224  		cookies = append(cookies, &http.Cookie{Name: e.Name, Value: e.Value, Quoted: e.Quoted})
   225  	}
   226  
   227  	return cookies
   228  }
   229  
   230  // SetCookies implements the SetCookies method of the [http.CookieJar] interface.
   231  //
   232  // It does nothing if the URL's scheme is not HTTP or HTTPS.
   233  func (j *Jar) SetCookies(u *url.URL, cookies []*http.Cookie) {
   234  	j.setCookies(u, cookies, time.Now())
   235  }
   236  
   237  // setCookies is like SetCookies but takes the current time as parameter.
   238  func (j *Jar) setCookies(u *url.URL, cookies []*http.Cookie, now time.Time) {
   239  	if len(cookies) == 0 {
   240  		return
   241  	}
   242  	if u.Scheme != "http" && u.Scheme != "https" {
   243  		return
   244  	}
   245  	host, err := canonicalHost(u.Host)
   246  	if err != nil {
   247  		return
   248  	}
   249  	key := jarKey(host, j.psList)
   250  	defPath := defaultPath(u.Path)
   251  
   252  	j.mu.Lock()
   253  	defer j.mu.Unlock()
   254  
   255  	submap := j.entries[key]
   256  
   257  	modified := false
   258  	for _, cookie := range cookies {
   259  		e, remove, err := j.newEntry(cookie, now, defPath, host)
   260  		if err != nil {
   261  			continue
   262  		}
   263  		id := e.id()
   264  		if remove {
   265  			if submap != nil {
   266  				if _, ok := submap[id]; ok {
   267  					delete(submap, id)
   268  					modified = true
   269  				}
   270  			}
   271  			continue
   272  		}
   273  		if submap == nil {
   274  			submap = make(map[string]entry)
   275  		}
   276  
   277  		if old, ok := submap[id]; ok {
   278  			e.Creation = old.Creation
   279  			e.seqNum = old.seqNum
   280  		} else {
   281  			e.Creation = now
   282  			e.seqNum = j.nextSeqNum
   283  			j.nextSeqNum++
   284  		}
   285  		e.LastAccess = now
   286  		submap[id] = e
   287  		modified = true
   288  	}
   289  
   290  	if modified {
   291  		if len(submap) == 0 {
   292  			delete(j.entries, key)
   293  		} else {
   294  			j.entries[key] = submap
   295  		}
   296  	}
   297  }
   298  
   299  // canonicalHost strips port from host if present and returns the canonicalized
   300  // host name.
   301  func canonicalHost(host string) (string, error) {
   302  	var err error
   303  	if hasPort(host) {
   304  		host, _, err = net.SplitHostPort(host)
   305  		if err != nil {
   306  			return "", err
   307  		}
   308  	}
   309  	// Strip trailing dot from fully qualified domain names.
   310  	host = strings.TrimSuffix(host, ".")
   311  	encoded, err := toASCII(host)
   312  	if err != nil {
   313  		return "", err
   314  	}
   315  	// We know this is ascii, no need to check.
   316  	lower, _ := ascii.ToLower(encoded)
   317  	return lower, nil
   318  }
   319  
   320  // hasPort reports whether host contains a port number. host may be a host
   321  // name, an IPv4 or an IPv6 address.
   322  func hasPort(host string) bool {
   323  	colons := strings.Count(host, ":")
   324  	if colons == 0 {
   325  		return false
   326  	}
   327  	if colons == 1 {
   328  		return true
   329  	}
   330  	return host[0] == '[' && strings.Contains(host, "]:")
   331  }
   332  
   333  // jarKey returns the key to use for a jar.
   334  func jarKey(host string, psl PublicSuffixList) string {
   335  	if isIP(host) {
   336  		return host
   337  	}
   338  
   339  	var i int
   340  	if psl == nil {
   341  		i = strings.LastIndex(host, ".")
   342  		if i <= 0 {
   343  			return host
   344  		}
   345  	} else {
   346  		suffix := psl.PublicSuffix(host)
   347  		if suffix == host {
   348  			return host
   349  		}
   350  		i = len(host) - len(suffix)
   351  		if i <= 0 || host[i-1] != '.' {
   352  			// The provided public suffix list psl is broken.
   353  			// Storing cookies under host is a safe stopgap.
   354  			return host
   355  		}
   356  		// Only len(suffix) is used to determine the jar key from
   357  		// here on, so it is okay if psl.PublicSuffix("www.buggy.psl")
   358  		// returns "com" as the jar key is generated from host.
   359  	}
   360  	prevDot := strings.LastIndex(host[:i-1], ".")
   361  	return host[prevDot+1:]
   362  }
   363  
   364  // isIP reports whether host is an IP address.
   365  func isIP(host string) bool {
   366  	if strings.ContainsAny(host, ":%") {
   367  		// Probable IPv6 address.
   368  		// Hostnames can't contain : or %, so this is definitely not a valid host.
   369  		// Treating it as an IP is the more conservative option, and avoids the risk
   370  		// of interpreting ::1%.www.example.com as a subdomain of www.example.com.
   371  		return true
   372  	}
   373  	return net.ParseIP(host) != nil
   374  }
   375  
   376  // defaultPath returns the directory part of a URL's path according to
   377  // RFC 6265 section 5.1.4.
   378  func defaultPath(path string) string {
   379  	if len(path) == 0 || path[0] != '/' {
   380  		return "/" // Path is empty or malformed.
   381  	}
   382  
   383  	i := strings.LastIndex(path, "/") // Path starts with "/", so i != -1.
   384  	if i == 0 {
   385  		return "/" // Path has the form "/abc".
   386  	}
   387  	return path[:i] // Path is either of form "/abc/xyz" or "/abc/xyz/".
   388  }
   389  
   390  // newEntry creates an entry from an http.Cookie c. now is the current time and
   391  // is compared to c.Expires to determine deletion of c. defPath and host are the
   392  // default-path and the canonical host name of the URL c was received from.
   393  //
   394  // remove records whether the jar should delete this cookie, as it has already
   395  // expired with respect to now. In this case, e may be incomplete, but it will
   396  // be valid to call e.id (which depends on e's Name, Domain and Path).
   397  //
   398  // A malformed c.Domain will result in an error.
   399  func (j *Jar) newEntry(c *http.Cookie, now time.Time, defPath, host string) (e entry, remove bool, err error) {
   400  	e.Name = c.Name
   401  
   402  	if c.Path == "" || c.Path[0] != '/' {
   403  		e.Path = defPath
   404  	} else {
   405  		e.Path = c.Path
   406  	}
   407  
   408  	e.Domain, e.HostOnly, err = j.domainAndType(host, c.Domain)
   409  	if err != nil {
   410  		return e, false, err
   411  	}
   412  
   413  	// MaxAge takes precedence over Expires.
   414  	if c.MaxAge < 0 {
   415  		return e, true, nil
   416  	} else if c.MaxAge > 0 {
   417  		e.Expires = now.Add(time.Duration(c.MaxAge) * time.Second)
   418  		e.Persistent = true
   419  	} else {
   420  		if c.Expires.IsZero() {
   421  			e.Expires = endOfTime
   422  			e.Persistent = false
   423  		} else {
   424  			if !c.Expires.After(now) {
   425  				return e, true, nil
   426  			}
   427  			e.Expires = c.Expires
   428  			e.Persistent = true
   429  		}
   430  	}
   431  
   432  	e.Value = c.Value
   433  	e.Quoted = c.Quoted
   434  	e.Secure = c.Secure
   435  	e.HttpOnly = c.HttpOnly
   436  
   437  	switch c.SameSite {
   438  	case http.SameSiteDefaultMode:
   439  		e.SameSite = "SameSite"
   440  	case http.SameSiteStrictMode:
   441  		e.SameSite = "SameSite=Strict"
   442  	case http.SameSiteLaxMode:
   443  		e.SameSite = "SameSite=Lax"
   444  	}
   445  
   446  	return e, false, nil
   447  }
   448  
   449  var (
   450  	errIllegalDomain   = errors.New("cookiejar: illegal cookie domain attribute")
   451  	errMalformedDomain = errors.New("cookiejar: malformed cookie domain attribute")
   452  )
   453  
   454  // endOfTime is the time when session (non-persistent) cookies expire.
   455  // This instant is representable in most date/time formats (not just
   456  // Go's time.Time) and should be far enough in the future.
   457  var endOfTime = time.Date(9999, 12, 31, 23, 59, 59, 0, time.UTC)
   458  
   459  // domainAndType determines the cookie's domain and hostOnly attribute.
   460  func (j *Jar) domainAndType(host, domain string) (string, bool, error) {
   461  	if domain == "" {
   462  		// No domain attribute in the SetCookie header indicates a
   463  		// host cookie.
   464  		return host, true, nil
   465  	}
   466  
   467  	if isIP(host) {
   468  		// RFC 6265 is not super clear here, a sensible interpretation
   469  		// is that cookies with an IP address in the domain-attribute
   470  		// are allowed.
   471  
   472  		// RFC 6265 section 5.2.3 mandates to strip an optional leading
   473  		// dot in the domain-attribute before processing the cookie.
   474  		//
   475  		// Most browsers don't do that for IP addresses, only curl
   476  		// (version 7.54) and IE (version 11) do not reject a
   477  		//     Set-Cookie: a=1; domain=.127.0.0.1
   478  		// This leading dot is optional and serves only as hint for
   479  		// humans to indicate that a cookie with "domain=.bbc.co.uk"
   480  		// would be sent to every subdomain of bbc.co.uk.
   481  		// It just doesn't make sense on IP addresses.
   482  		// The other processing and validation steps in RFC 6265 just
   483  		// collapse to:
   484  		if host != domain {
   485  			return "", false, errIllegalDomain
   486  		}
   487  
   488  		// According to RFC 6265 such cookies should be treated as
   489  		// domain cookies.
   490  		// As there are no subdomains of an IP address the treatment
   491  		// according to RFC 6265 would be exactly the same as that of
   492  		// a host-only cookie. Contemporary browsers (and curl) do
   493  		// allows such cookies but treat them as host-only cookies.
   494  		// So do we as it just doesn't make sense to label them as
   495  		// domain cookies when there is no domain; the whole notion of
   496  		// domain cookies requires a domain name to be well defined.
   497  		return host, true, nil
   498  	}
   499  
   500  	// From here on: If the cookie is valid, it is a domain cookie (with
   501  	// the one exception of a public suffix below).
   502  	// See RFC 6265 section 5.2.3.
   503  	domain = strings.TrimPrefix(domain, ".")
   504  
   505  	if len(domain) == 0 || domain[0] == '.' {
   506  		// Received either "Domain=." or "Domain=..some.thing",
   507  		// both are illegal.
   508  		return "", false, errMalformedDomain
   509  	}
   510  
   511  	domain, isASCII := ascii.ToLower(domain)
   512  	if !isASCII {
   513  		// Received non-ASCII domain, e.g. "perché.com" instead of "xn--perch-fsa.com"
   514  		return "", false, errMalformedDomain
   515  	}
   516  
   517  	if domain[len(domain)-1] == '.' {
   518  		// We received stuff like "Domain=www.example.com.".
   519  		// Browsers do handle such stuff (actually differently) but
   520  		// RFC 6265 seems to be clear here (e.g. section 4.1.2.3) in
   521  		// requiring a reject.  4.1.2.3 is not normative, but
   522  		// "Domain Matching" (5.1.3) and "Canonicalized Host Names"
   523  		// (5.1.2) are.
   524  		return "", false, errMalformedDomain
   525  	}
   526  
   527  	// See RFC 6265 section 5.3 #5.
   528  	if j.psList != nil {
   529  		if ps := j.psList.PublicSuffix(domain); ps != "" && !hasDotSuffix(domain, ps) {
   530  			if host == domain {
   531  				// This is the one exception in which a cookie
   532  				// with a domain attribute is a host cookie.
   533  				return host, true, nil
   534  			}
   535  			return "", false, errIllegalDomain
   536  		}
   537  	}
   538  
   539  	// The domain must domain-match host: www.mycompany.com cannot
   540  	// set cookies for .ourcompetitors.com.
   541  	if host != domain && !hasDotSuffix(host, domain) {
   542  		return "", false, errIllegalDomain
   543  	}
   544  
   545  	return domain, false, nil
   546  }
   547
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