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authordkf <donal.k.fellows@manchester.ac.uk>2005-11-18 13:57:52 (GMT)
committerdkf <donal.k.fellows@manchester.ac.uk>2005-11-18 13:57:52 (GMT)
commit16253c9b715db75cb94e8d56dd04fee6d2da73a9 (patch)
treeb0d41e51d785087e5be9fabe8ddd1c46a9076358 /library/http
parentcf11ece61c146343faa805a7eaeebc2919bfce19 (diff)
downloadtcl-16253c9b715db75cb94e8d56dd04fee6d2da73a9.zip
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Improved URL validation that better describes why validation failed. [Bug 1358369]
Diffstat (limited to 'library/http')
-rw-r--r--library/http/http.tcl296
1 files changed, 199 insertions, 97 deletions
diff --git a/library/http/http.tcl b/library/http/http.tcl
index 655da99..c8dbe9b 100644
--- a/library/http/http.tcl
+++ b/library/http/http.tcl
@@ -1,30 +1,29 @@
# http.tcl --
#
-# Client-side HTTP for GET, POST, and HEAD commands.
-# These routines can be used in untrusted code that uses
-# the Safesock security policy. These procedures use a
-# callback interface to avoid using vwait, which is not
+# Client-side HTTP for GET, POST, and HEAD commands. These routines can
+# be used in untrusted code that uses the Safesock security policy. These
+# procedures use a callback interface to avoid using vwait, which is not
# defined in the safe base.
#
-# See the file "license.terms" for information on usage and
-# redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+# See the file "license.terms" for information on usage and redistribution of
+# this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
-# RCS: @(#) $Id: http.tcl,v 1.53 2005/11/15 22:58:18 dgp Exp $
+# RCS: @(#) $Id: http.tcl,v 1.54 2005/11/18 13:57:53 dkf Exp $
# Rough version history:
-# 1.0 Old http_get interface
-# 2.0 http:: namespace and http::geturl
-# 2.1 Added callbacks to handle arriving data, and timeouts
-# 2.2 Added ability to fetch into a channel
-# 2.3 Added SSL support, and ability to post from a channel
-# This version also cleans up error cases and eliminates the
-# "ioerror" status in favor of raising an error
-# 2.4 Added -binary option to http::geturl and charset element
-# to the state array.
+# 1.0 Old http_get interface.
+# 2.0 http:: namespace and http::geturl.
+# 2.1 Added callbacks to handle arriving data, and timeouts.
+# 2.2 Added ability to fetch into a channel.
+# 2.3 Added SSL support, and ability to post from a channel. This version
+# also cleans up error cases and eliminates the "ioerror" status in
+# favor of raising an error
+# 2.4 Added -binary option to http::geturl and charset element to the state
+# array.
package require Tcl 8.4
-# keep this in sync with pkgIndex.tcl
-# and with the install directories in Makefiles
+# Keep this in sync with pkgIndex.tcl and with the install directories
+# in Makefiles
package provide http 2.5.2
namespace eval http {
@@ -39,12 +38,11 @@ namespace eval http {
set http(-useragent) "Tcl http client package [package provide http]"
proc init {} {
- # Set up the map for quoting chars
- # RFC3986 Section 2.3 say percent encode all except:
- # "... percent-encoded octets in the ranges of ALPHA
- # (%41-%5A and %61-%7A), DIGIT (%30-%39), hyphen (%2D),
- # period (%2E), underscore (%5F), or tilde (%7E) should
- # not be created by URI producers ..."
+ # Set up the map for quoting chars. RFC3986 Section 2.3 say percent
+ # encode all except: "... percent-encoded octets in the ranges of ALPHA
+ # (%41-%5A and %61-%7A), DIGIT (%30-%39), hyphen (%2D), period (%2E),
+ # underscore (%5F), or tilde (%7E) should not be created by URI
+ # producers ..."
for {set i 0} {$i <= 256} {incr i} {
set c [format %c $i]
if {![string match {[-._~a-zA-Z0-9]} $c]} {
@@ -152,9 +150,9 @@ proc http::config {args} {
# Arguments:
# token Connection token.
# errormsg (optional) If set, forces status to error.
-# skipCB (optional) If set, don't call the -command callback. This
+# skipCB (optional) If set, don't call the -command callback. This
# is useful when geturl wants to throw an exception instead
-# of calling the callback. That way, the same error isn't
+# of calling the callback. That way, the same error isn't
# reported to two places.
#
# Side Effects:
@@ -218,17 +216,16 @@ proc http::reset { token {why reset} } {
# args Option value pairs. Valid options include:
# -blocksize, -validate, -headers, -timeout
# Results:
-# Returns a token for this connection.
-# This token is the name of an array that the caller should
-# unset to garbage collect the state.
+# Returns a token for this connection. This token is the name of an array
+# that the caller should unset to garbage collect the state.
proc http::geturl { url args } {
variable http
variable urlTypes
variable defaultCharset
- # Initialize the state variable, an array. We'll return the
- # name of this array as the token for the transaction.
+ # Initialize the state variable, an array. We'll return the name of this
+ # array as the token for the transaction.
if {![info exists http(uid)]} {
set http(uid) 0
@@ -301,17 +298,118 @@ proc http::geturl { url args } {
}
# Validate URL, determine the server host and port, and check proxy case
- # Recognize user:pass@host URLs also, although we do not do anything
- # with that info yet.
+ # Recognize user:pass@host URLs also, although we do not do anything with
+ # that info yet.
+
+ # URLs have basically four parts.
+ # First, before the colon, is the protocol scheme (e.g. http)
+ # Second, for HTTP-like protocols, is the authority
+ # The authority is preceded by // and lasts up to (but not including)
+ # the following / and it identifies up to four parts, of which only one,
+ # the host, is required (if an authority is present at all). All other
+ # parts of the authority (user name, password, port number) are optional.
+ # Third is the resource name, which is split into two parts at a ?
+ # The first part (from the single "/" up to "?") is the path, and the
+ # second part (from that "?" up to "#") is the query. *HOWEVER*, we do
+ # not need to separate them; we send the whole lot to the server.
+ # Fourth is the fragment identifier, which is everything after the first
+ # "#" in the URL. The fragment identifier MUST NOT be sent to the server
+ # and indeed, we don't bother to validate it (it could be an error to
+ # pass it in here, but it's cheap to strip).
+ #
+ # An example of a URL that has all the parts:
+ # http://jschmoe:xyzzy@www.bogus.net:8000/foo/bar.tml?q=foo#changes
+ # The "http" is the protocol, the user is "jschmoe", the password is
+ # "xyzzy", the host is "www.bogus.net", the port is "8000", the path is
+ # "/foo/bar.tml", the query is "q=foo", and the fragment is "changes".
+ #
+ # Note that the RE actually combines the user and password parts, as
+ # recommended in RFC 3986. Indeed, that RFC states that putting passwords
+ # in URLs is a Really Bad Idea, something with which I would agree utterly.
+ # Also note that we do not currently support IPv6 addresses.
+ #
+ # From a validation perspective, we need to ensure that the parts of the
+ # URL that are going to the server are correctly encoded.
+
+ set URLmatcher {(?x) # this is _expanded_ syntax
+ ^
+ (?: (\w+) : ) # <protocol scheme>
+ (?: //
+ (?:
+ (
+ [^@/\#?]+ # <userinfo part of authority>
+ ) @
+ )?
+ ( [^/:\#?]+ ) # <host part of authority>
+ (?: : (\d+) )? # <port part of authority>
+ )?
+ ( / [^\#?]* (?: \? [^\#?]* ) )? # <path> (including query)
+ (?: \# (.*) )? # <fragment>
+ $
+ }
- set exp {^(([^:]*)://)?([^@]+@)?([^/:]+)(:([0-9]+))?(/.*)?$}
- if {![regexp -nocase $exp $url x prefix proto user host y port srvurl]} {
+ # Phase one: parse
+ if {![regexp -- $URLmatcher $url -> proto user host port srvurl]} {
unset $token
return -code error "Unsupported URL: $url"
}
+ # Phase two: validate
+ if {$host eq ""} {
+ # Caller has to provide a host name; we do not have a "default host"
+ # that would enable us to handle relative URLs.
+ unset $token
+ return -code error "Missing host part: $url"
+ # Note that we don't check the hostname for validity here; if it's
+ # invalid, we'll simply fail to resolve it later on.
+ }
+ if {$port ne "" && $port>65535} {
+ unset $token
+ return -code error "Invalid port number: $port"
+ }
+ # The user identification and resource identification parts of the URL can
+ # have encoded characters in them; take care!
+ if {$user ne ""} {
+ # Check for validity according to RFC 3986, Appendix A
+ set validityRE {(?xi)
+ ^
+ (?: [\w-.~!$&'()*+,;=:] | %[0-9a-f][0-9a-f] )+
+ $
+ }
+ if {![regexp -- $validityRE $user]} {
+ unset $token
+ # Provide a better error message in this error case
+ if {[regexp {(?i)%(?![0-9a-f][0-9a-f]).?.?} $path bad]} {
+ return -code error \
+ "Illegal encoding character usage \"$bad\" in URL user"
+ }
+ return -code error "Illegal characters in URL user"
+ }
+ }
+ if {$srvurl ne ""} {
+ # Check for validity according to RFC 3986, Appendix A
+ set validityRE {(?xi)
+ ^
+ # Path part (already must start with / character)
+ (?: [\w-.~!$&'()*+,;=:@/] | %[0-9a-f][0-9a-f] )*
+ # Query part (optional, permits ? characters)
+ (?: ? (?: [\w-.~!$&'()*+,;=:@/?] | %[0-9a-f][0-9a-f] )* )?
+ $
+ }
+ if {![regexp -- $validityRE $srvurl]} {
+ unset $token
+ # Provide a better error message in this error case
+ if {[regexp {(?i)%(?![0-9a-f][0-9a-f])..} $path bad]} {
+ return -code error \
+ "Illegal encoding character usage \"$bad\" in URL path"
+ }
+ return -code error "Illegal characters in URL path"
+ }
+ } else {
+ set srvurl /
+ }
if {[string length $proto] == 0} {
set proto http
- set url ${proto}://$url
+ set url ${proto}:$url
}
if {![info exists urlTypes($proto)]} {
unset $token
@@ -323,20 +421,27 @@ proc http::geturl { url args } {
if {[string length $port] == 0} {
set port $defport
}
- if {[string length $srvurl] == 0} {
- set srvurl /
- }
- if {[string length $proto] == 0} {
- set url http://$url
- }
- set state(url) $url
if {![catch {$http(-proxyfilter) $host} proxy]} {
set phost [lindex $proxy 0]
set pport [lindex $proxy 1]
}
- # If a timeout is specified we set up the after event
- # and arrange for an asynchronous socket connection.
+ # OK, now reassemble into a full URL
+ set url ${proto}://
+ if {$user ne ""} {
+ append url $user
+ append url @
+ }
+ append url $host
+ if {$port != $defport} {
+ append url : $port
+ }
+ append url $srvurl
+ # Don't append the fragment!
+ set state(url) $url
+
+ # If a timeout is specified we set up the after event and arrange for an
+ # asynchronous socket connection.
if {$state(-timeout) > 0} {
set state(after) [after $state(-timeout) \
@@ -346,8 +451,8 @@ proc http::geturl { url args } {
set async ""
}
- # If we are using the proxy, we must pass in the full URL that
- # includes the server name.
+ # If we are using the proxy, we must pass in the full URL that includes
+ # the server name.
if {[info exists phost] && [string length $phost]} {
set srvurl $url
@@ -355,11 +460,11 @@ proc http::geturl { url args } {
} else {
set conStat [catch {eval $defcmd $async {$host $port}} s]
}
- if {$conStat} {
- # something went wrong while trying to establish the connection
- # Clean up after events and such, but DON'T call the command callback
- # (if available) because we're going to throw an exception from here
+ if {$conStat} {
+ # Something went wrong while trying to establish the connection. Clean
+ # up after events and such, but DON'T call the command callback (if
+ # available) because we're going to throw an exception from here
# instead.
Finish $token "" 1
cleanup $token
@@ -367,16 +472,16 @@ proc http::geturl { url args } {
}
set state(sock) $s
- # Wait for the connection to complete
+ # Wait for the connection to complete.
if {$state(-timeout) > 0} {
fileevent $s writable [list http::Connect $token]
http::wait $token
if {$state(status) eq "error"} {
- # something went wrong while trying to establish the connection
+ # Something went wrong while trying to establish the connection.
# Clean up after events and such, but DON'T call the command
- # callback (if available) because we're going to throw an
+ # callback (if available) because we're going to throw an
# exception from here instead.
set err [lindex $state(error) 0]
cleanup $token
@@ -392,8 +497,8 @@ proc http::geturl { url args } {
fconfigure $s -translation {auto crlf} -buffersize $state(-blocksize)
- # The following is disallowed in safe interpreters, but the socket
- # is already in non-blocking mode in that case.
+ # The following is disallowed in safe interpreters, but the socket is
+ # already in non-blocking mode in that case.
catch {fconfigure $s -blocking off}
set how GET
@@ -403,7 +508,7 @@ proc http::geturl { url args } {
set how POST
set contDone 0
} else {
- # there's no query data
+ # There's no query data.
unset state(-query)
set isQuery 0
}
@@ -421,8 +526,8 @@ proc http::geturl { url args } {
puts $s "$how $srvurl HTTP/1.0"
puts $s "Accept: $http(-accept)"
if {$port == $defport} {
- # Don't add port in this case, to handle broken servers.
- # [Bug #504508]
+ # Don't add port in this case, to handle broken servers. [Bug
+ # 504508]
puts $s "Host: $host"
} else {
puts $s "Host: $host:$port"
@@ -440,8 +545,8 @@ proc http::geturl { url args } {
}
}
if {$isQueryChannel && $state(querylength) == 0} {
- # Try to determine size of data in channel
- # If we cannot seek, the surrounding catch will trap us
+ # Try to determine size of data in channel. If we cannot seek, the
+ # surrounding catch will trap us
set start [tell $state(-querychannel)]
seek $state(-querychannel) 0 end
@@ -450,22 +555,21 @@ proc http::geturl { url args } {
seek $state(-querychannel) $start
}
- # Flush the request header and set up the fileevent that will
- # either push the POST data or read the response.
+ # Flush the request header and set up the fileevent that will either
+ # push the POST data or read the response.
#
# fileevent note:
#
- # It is possible to have both the read and write fileevents active
- # at this point. The only scenario it seems to affect is a server
- # that closes the connection without reading the POST data.
- # (e.g., early versions TclHttpd in various error cases).
- # Depending on the platform, the client may or may not be able to
- # get the response from the server because of the error it will
- # get trying to write the post data. Having both fileevents active
- # changes the timing and the behavior, but no two platforms
- # (among Solaris, Linux, and NT) behave the same, and none
- # behave all that well in any case. Servers should always read thier
- # POST data if they expect the client to read their response.
+ # It is possible to have both the read and write fileevents active at
+ # this point. The only scenario it seems to affect is a server that
+ # closes the connection without reading the POST data. (e.g., early
+ # versions TclHttpd in various error cases). Depending on the platform,
+ # the client may or may not be able to get the response from the server
+ # because of the error it will get trying to write the post data.
+ # Having both fileevents active changes the timing and the behavior,
+ # but no two platforms (among Solaris, Linux, and NT) behave the same,
+ # and none behave all that well in any case. Servers should always read
+ # their POST data if they expect the client to read their response.
if {$isQuery || $isQueryChannel} {
puts $s "Content-Type: $state(-type)"
@@ -482,9 +586,8 @@ proc http::geturl { url args } {
}
if {! [info exists state(-command)]} {
-
- # geturl does EVERYTHING asynchronously, so if the user
- # calls it synchronously, we just do a wait here.
+ # geturl does EVERYTHING asynchronously, so if the user calls it
+ # synchronously, we just do a wait here.
wait $token
if {$state(status) eq "error"} {
@@ -494,8 +597,8 @@ proc http::geturl { url args } {
}
}
} err]} {
- # The socket probably was never connected,
- # or the connection dropped later.
+ # The socket probably was never connected, or the connection dropped
+ # later.
# Clean up after events and such, but DON'T call the command callback
# (if available) because we're going to throw an exception from here
@@ -622,8 +725,8 @@ proc http::Write {token} {
# Catch I/O errors on dead sockets
if {[info exists state(-query)]} {
- # Chop up large query strings so queryprogress callback
- # can give smooth feedback
+ # Chop up large query strings so queryprogress callback can give
+ # smooth feedback.
puts -nonewline $s \
[string range $state(-query) $state(queryoffset) \
@@ -644,8 +747,8 @@ proc http::Write {token} {
}
}
} err]} {
- # Do not call Finish here, but instead let the read half of
- # the socket process whatever server reply there is to get.
+ # Do not call Finish here, but instead let the read half of the socket
+ # process whatever server reply there is to get.
set state(posterror) $err
set done 1
@@ -656,7 +759,7 @@ proc http::Write {token} {
fileevent $s readable [list http::Event $token]
}
- # Callback to the client after we've completely handled everything
+ # Callback to the client after we've completely handled everything.
if {[string length $state(-queryprogress)]} {
eval $state(-queryprogress) [list $token $state(querylength)\
@@ -698,10 +801,10 @@ proc http::Event {token} {
fconfigure $state(-channel) -translation binary
}
} else {
- # If we are getting text, set the incoming channel's
- # encoding correctly. iso8859-1 is the RFC default, but
- # this could be any IANA charset. However, we only know
- # how to convert what we have encodings for.
+ # If we are getting text, set the incoming channel's encoding
+ # correctly. iso8859-1 is the RFC default, but this could be
+ # any IANA charset. However, we only know how to convert what
+ # we have encodings for.
set idx [lsearch -exact $encodings \
[string tolower $state(charset)]]
if {$idx >= 0} {
@@ -855,16 +958,15 @@ proc http::wait {token} {
# http::formatQuery --
#
-# See documentaion for details.
-# Call http::formatQuery with an even number of arguments, where
-# the first is a name, the second is a value, the third is another
-# name, and so on.
+# See documentaion for details. Call http::formatQuery with an even
+# number of arguments, where the first is a name, the second is a value,
+# the third is another name, and so on.
#
# Arguments:
# args A list of name-value pairs.
#
# Results:
-# TODO
+# TODO
proc http::formatQuery {args} {
set result ""
@@ -894,9 +996,9 @@ proc http::mapReply {string} {
variable http
variable formMap
- # The spec says: "non-alphanumeric characters are replaced by '%HH'"
- # Use a pre-computed map and [string map] to do the conversion
- # (much faster than [regsub]/[subst]). [Bug 1020491]
+ # The spec says: "non-alphanumeric characters are replaced by '%HH'". Use
+ # a pre-computed map and [string map] to do the conversion (much faster
+ # than [regsub]/[subst]). [Bug 1020491]
if {$http(-urlencoding) ne ""} {
set string [encoding convertto $http(-urlencoding) $string]
@@ -913,7 +1015,7 @@ proc http::mapReply {string} {
}
# http::ProxyRequired --
-# Default proxy filter.
+# Default proxy filter.
#
# Arguments:
# host The destination host