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+# safe.tcl --
+#
+# This file provide a safe loading/sourcing mechanism for safe interpreters.
+# It implements a virtual path mecanism to hide the real pathnames from the
+# slave. It runs in a master interpreter and sets up data structure and
+# aliases that will be invoked when used from a slave interpreter.
+#
+# See the safe.n man page for details.
+#
+# Copyright (c) 1996-1997 Sun Microsystems, Inc.
+#
+# See the file "license.terms" for information on usage and redistribution
+# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+#
+# SCCS: @(#) safe.tcl 1.26 97/08/21 11:57:20
+
+#
+# The implementation is based on namespaces. These naming conventions
+# are followed:
+# Private procs starts with uppercase.
+# Public procs are exported and starts with lowercase
+#
+
+# Needed utilities package
+package require opt 0.2;
+
+# Create the safe namespace
+namespace eval ::safe {
+
+ # Exported API:
+ namespace export interpCreate interpInit interpConfigure interpDelete \
+ interpAddToAccessPath interpFindInAccessPath \
+ setLogCmd ;
+
+# Proto/dummy declarations for auto_mkIndex
+proc ::safe::interpCreate {} {}
+proc ::safe::interpInit {} {}
+proc ::safe::interpConfigure {} {}
+
+
+ ####
+ #
+ # Setup the arguments parsing
+ #
+ ####
+
+ # Share the descriptions
+ set temp [::tcl::OptKeyRegister {
+ {-accessPath -list {} "access path for the slave"}
+ {-noStatics "prevent loading of statically linked pkgs"}
+ {-statics true "loading of statically linked pkgs"}
+ {-nestedLoadOk "allow nested loading"}
+ {-nested false "nested loading"}
+ {-deleteHook -script {} "delete hook"}
+ }]
+
+ # create case (slave is optional)
+ ::tcl::OptKeyRegister {
+ {?slave? -name {} "name of the slave (optional)"}
+ } ::safe::interpCreate ;
+ # adding the flags sub programs to the command program
+ # (relying on Opt's internal implementation details)
+ lappend ::tcl::OptDesc(::safe::interpCreate) $::tcl::OptDesc($temp);
+
+ # init and configure (slave is needed)
+ ::tcl::OptKeyRegister {
+ {slave -name {} "name of the slave"}
+ } ::safe::interpIC;
+ # adding the flags sub programs to the command program
+ # (relying on Opt's internal implementation details)
+ lappend ::tcl::OptDesc(::safe::interpIC) $::tcl::OptDesc($temp);
+ # temp not needed anymore
+ ::tcl::OptKeyDelete $temp;
+
+
+ # Helper function to resolve the dual way of specifying staticsok
+ # (either by -noStatics or -statics 0)
+ proc InterpStatics {} {
+ foreach v {Args statics noStatics} {
+ upvar $v $v
+ }
+ set flag [::tcl::OptProcArgGiven -noStatics];
+ if {$flag && ($noStatics == $statics)
+ && ([::tcl::OptProcArgGiven -statics])} {
+ return -code error\
+ "conflicting values given for -statics and -noStatics";
+ }
+ if {$flag} {
+ return [expr {!$noStatics}];
+ } else {
+ return $statics
+ }
+ }
+
+ # Helper function to resolve the dual way of specifying nested loading
+ # (either by -nestedLoadOk or -nested 1)
+ proc InterpNested {} {
+ foreach v {Args nested nestedLoadOk} {
+ upvar $v $v
+ }
+ set flag [::tcl::OptProcArgGiven -nestedLoadOk];
+ # note that the test here is the opposite of the "InterpStatics"
+ # one (it is not -noNested... because of the wanted default value)
+ if {$flag && ($nestedLoadOk != $nested)
+ && ([::tcl::OptProcArgGiven -nested])} {
+ return -code error\
+ "conflicting values given for -nested and -nestedLoadOk";
+ }
+ if {$flag} {
+ # another difference with "InterpStatics"
+ return $nestedLoadOk
+ } else {
+ return $nested
+ }
+ }
+
+ ####
+ #
+ # API entry points that needs argument parsing :
+ #
+ ####
+
+
+ # Interface/entry point function and front end for "Create"
+ proc interpCreate {args} {
+ set Args [::tcl::OptKeyParse ::safe::interpCreate $args]
+ InterpCreate $slave $accessPath \
+ [InterpStatics] [InterpNested] $deleteHook;
+ }
+
+ proc interpInit {args} {
+ set Args [::tcl::OptKeyParse ::safe::interpIC $args]
+ if {![::interp exists $slave]} {
+ return -code error \
+ "\"$slave\" is not an interpreter";
+ }
+ InterpInit $slave $accessPath \
+ [InterpStatics] [InterpNested] $deleteHook;
+ }
+
+ proc CheckInterp {slave} {
+ if {![IsInterp $slave]} {
+ return -code error \
+ "\"$slave\" is not an interpreter managed by ::safe::" ;
+ }
+ }
+
+ # Interface/entry point function and front end for "Configure"
+ # This code is awfully pedestrian because it would need
+ # more coupling and support between the way we store the
+ # configuration values in safe::interp's and the Opt package
+ # Obviously we would like an OptConfigure
+ # to avoid duplicating all this code everywhere. -> TODO
+ # (the app should share or access easily the program/value
+ # stored by opt)
+ # This is even more complicated by the boolean flags with no values
+ # that we had the bad idea to support for the sake of user simplicity
+ # in create/init but which makes life hard in configure...
+ # So this will be hopefully written and some integrated with opt1.0
+ # (hopefully for tcl8.1 ?)
+ proc interpConfigure {args} {
+ switch [llength $args] {
+ 1 {
+ # If we have exactly 1 argument
+ # the semantic is to return all the current configuration
+ # We still call OptKeyParse though we know that "slave"
+ # is our given argument because it also checks
+ # for the "-help" option.
+ set Args [::tcl::OptKeyParse ::safe::interpIC $args];
+ CheckInterp $slave;
+ set res {}
+ lappend res [list -accessPath [Set [PathListName $slave]]]
+ lappend res [list -statics [Set [StaticsOkName $slave]]]
+ lappend res [list -nested [Set [NestedOkName $slave]]]
+ lappend res [list -deleteHook [Set [DeleteHookName $slave]]]
+ join $res
+ }
+ 2 {
+ # If we have exactly 2 arguments
+ # the semantic is a "configure get"
+ ::tcl::Lassign $args slave arg;
+ # get the flag sub program (we 'know' about Opt's internal
+ # representation of data)
+ set desc [lindex [::tcl::OptKeyGetDesc ::safe::interpIC] 2]
+ set hits [::tcl::OptHits desc $arg];
+ if {$hits > 1} {
+ return -code error [::tcl::OptAmbigous $desc $arg]
+ } elseif {$hits == 0} {
+ return -code error [::tcl::OptFlagUsage $desc $arg]
+ }
+ CheckInterp $slave;
+ set item [::tcl::OptCurDesc $desc];
+ set name [::tcl::OptName $item];
+ switch -exact -- $name {
+ -accessPath {
+ return [list -accessPath [Set [PathListName $slave]]]
+ }
+ -statics {
+ return [list -statics [Set [StaticsOkName $slave]]]
+ }
+ -nested {
+ return [list -nested [Set [NestedOkName $slave]]]
+ }
+ -deleteHook {
+ return [list -deleteHook [Set [DeleteHookName $slave]]]
+ }
+ -noStatics {
+ # it is most probably a set in fact
+ # but we would need then to jump to the set part
+ # and it is not *sure* that it is a set action
+ # that the user want, so force it to use the
+ # unambigous -statics ?value? instead:
+ return -code error\
+ "ambigous query (get or set -noStatics ?)\
+ use -statics instead";
+ }
+ -nestedLoadOk {
+ return -code error\
+ "ambigous query (get or set -nestedLoadOk ?)\
+ use -nested instead";
+ }
+ default {
+ return -code error "unknown flag $name (bug)";
+ }
+ }
+ }
+ default {
+ # Otherwise we want to parse the arguments like init and create
+ # did
+ set Args [::tcl::OptKeyParse ::safe::interpIC $args];
+ CheckInterp $slave;
+ # Get the current (and not the default) values of
+ # whatever has not been given:
+ if {![::tcl::OptProcArgGiven -accessPath]} {
+ set doreset 1
+ set accessPath [Set [PathListName $slave]]
+ } else {
+ set doreset 0
+ }
+ if { (![::tcl::OptProcArgGiven -statics])
+ && (![::tcl::OptProcArgGiven -noStatics]) } {
+ set statics [Set [StaticsOkName $slave]]
+ } else {
+ set statics [InterpStatics]
+ }
+ if { ([::tcl::OptProcArgGiven -nested])
+ || ([::tcl::OptProcArgGiven -nestedLoadOk]) } {
+ set nested [InterpNested]
+ } else {
+ set nested [Set [NestedOkName $slave]]
+ }
+ if {![::tcl::OptProcArgGiven -deleteHook]} {
+ set deleteHook [Set [DeleteHookName $slave]]
+ }
+ # we can now reconfigure :
+ InterpSetConfig $slave $accessPath \
+ $statics $nested $deleteHook;
+ # auto_reset the slave (to completly synch the new access_path)
+ if {$doreset} {
+ if {[catch {::interp eval $slave {auto_reset}} msg]} {
+ Log $slave "auto_reset failed: $msg";
+ } else {
+ Log $slave "successful auto_reset" NOTICE;
+ }
+ }
+ }
+ }
+ }
+
+
+ ####
+ #
+ # Functions that actually implements the exported APIs
+ #
+ ####
+
+
+ #
+ # safe::InterpCreate : doing the real job
+ #
+ # This procedure creates a safe slave and initializes it with the
+ # safe base aliases.
+ # NB: slave name must be simple alphanumeric string, no spaces,
+ # no (), no {},... {because the state array is stored as part of the name}
+ #
+ # Returns the slave name.
+ #
+ # Optional Arguments :
+ # + slave name : if empty, generated name will be used
+ # + access_path: path list controlling where load/source can occur,
+ # if empty: the master auto_path will be used.
+ # + staticsok : flag, if 0 :no static package can be loaded (load {} Xxx)
+ # if 1 :static packages are ok.
+ # + nestedok: flag, if 0 :no loading to sub-sub interps (load xx xx sub)
+ # if 1 : multiple levels are ok.
+
+ # use the full name and no indent so auto_mkIndex can find us
+ proc ::safe::InterpCreate {
+ slave
+ access_path
+ staticsok
+ nestedok
+ deletehook
+ } {
+ # Create the slave.
+ if {[string compare "" $slave]} {
+ ::interp create -safe $slave;
+ } else {
+ # empty argument: generate slave name
+ set slave [::interp create -safe];
+ }
+ Log $slave "Created" NOTICE;
+
+ # Initialize it. (returns slave name)
+ InterpInit $slave $access_path $staticsok $nestedok $deletehook;
+ }
+
+
+ #
+ # InterpSetConfig (was setAccessPath) :
+ # Sets up slave virtual auto_path and corresponding structure
+ # within the master. Also sets the tcl_library in the slave
+ # to be the first directory in the path.
+ # Nb: If you change the path after the slave has been initialized
+ # you probably need to call "auto_reset" in the slave in order that it
+ # gets the right auto_index() array values.
+
+ proc ::safe::InterpSetConfig {slave access_path staticsok\
+ nestedok deletehook} {
+
+ # determine and store the access path if empty
+ if {[string match "" $access_path]} {
+ set access_path [uplevel #0 set auto_path];
+ # Make sure that tcl_library is in auto_path
+ # and at the first position (needed by setAccessPath)
+ set where [lsearch -exact $access_path [info library]];
+ if {$where == -1} {
+ # not found, add it.
+ set access_path [concat [list [info library]] $access_path];
+ Log $slave "tcl_library was not in auto_path,\
+ added it to slave's access_path" NOTICE;
+ } elseif {$where != 0} {
+ # not first, move it first
+ set access_path [concat [list [info library]]\
+ [lreplace $access_path $where $where]];
+ Log $slave "tcl_libray was not in first in auto_path,\
+ moved it to front of slave's access_path" NOTICE;
+
+ }
+
+ # Add 1st level sub dirs (will searched by auto loading from tcl
+ # code in the slave using glob and thus fail, so we add them
+ # here so by default it works the same).
+ set access_path [AddSubDirs $access_path];
+ }
+
+ Log $slave "Setting accessPath=($access_path) staticsok=$staticsok\
+ nestedok=$nestedok deletehook=($deletehook)" NOTICE;
+
+ # clear old autopath if it existed
+ set nname [PathNumberName $slave];
+ if {[Exists $nname]} {
+ set n [Set $nname];
+ for {set i 0} {$i<$n} {incr i} {
+ Unset [PathToken $i $slave];
+ }
+ }
+
+ # build new one
+ set slave_auto_path {}
+ set i 0;
+ foreach dir $access_path {
+ Set [PathToken $i $slave] $dir;
+ lappend slave_auto_path "\$[PathToken $i]";
+ incr i;
+ }
+ Set $nname $i;
+ Set [PathListName $slave] $access_path;
+ Set [VirtualPathListName $slave] $slave_auto_path;
+
+ Set [StaticsOkName $slave] $staticsok
+ Set [NestedOkName $slave] $nestedok
+ Set [DeleteHookName $slave] $deletehook
+
+ SyncAccessPath $slave;
+ }
+
+ #
+ #
+ # FindInAccessPath:
+ # Search for a real directory and returns its virtual Id
+ # (including the "$")
+proc ::safe::interpFindInAccessPath {slave path} {
+ set access_path [GetAccessPath $slave];
+ set where [lsearch -exact $access_path $path];
+ if {$where == -1} {
+ return -code error "$path not found in access path $access_path";
+ }
+ return "\$[PathToken $where]";
+ }
+
+ #
+ # addToAccessPath:
+ # add (if needed) a real directory to access path
+ # and return its virtual token (including the "$").
+proc ::safe::interpAddToAccessPath {slave path} {
+ # first check if the directory is already in there
+ if {![catch {interpFindInAccessPath $slave $path} res]} {
+ return $res;
+ }
+ # new one, add it:
+ set nname [PathNumberName $slave];
+ set n [Set $nname];
+ Set [PathToken $n $slave] $path;
+
+ set token "\$[PathToken $n]";
+
+ Lappend [VirtualPathListName $slave] $token;
+ Lappend [PathListName $slave] $path;
+ Set $nname [expr $n+1];
+
+ SyncAccessPath $slave;
+
+ return $token;
+ }
+
+ # This procedure applies the initializations to an already existing
+ # interpreter. It is useful when you want to install the safe base
+ # aliases into a preexisting safe interpreter.
+ proc ::safe::InterpInit {
+ slave
+ access_path
+ staticsok
+ nestedok
+ deletehook
+ } {
+
+ # Configure will generate an access_path when access_path is
+ # empty.
+ InterpSetConfig $slave $access_path $staticsok $nestedok $deletehook;
+
+ # These aliases let the slave load files to define new commands
+
+ # NB we need to add [namespace current], aliases are always
+ # absolute paths.
+ ::interp alias $slave source {} [namespace current]::AliasSource $slave
+ ::interp alias $slave load {} [namespace current]::AliasLoad $slave
+
+ # This alias lets the slave have access to a subset of the 'file'
+ # command functionality.
+
+ AliasSubset $slave file file dir.* join root.* ext.* tail \
+ path.* split
+
+ # This alias interposes on the 'exit' command and cleanly terminates
+ # the slave.
+
+ ::interp alias $slave exit {} [namespace current]::interpDelete $slave
+
+ # The allowed slave variables already have been set
+ # by Tcl_MakeSafe(3)
+
+
+ # Source init.tcl into the slave, to get auto_load and other
+ # procedures defined:
+
+ # We don't try to use the -rsrc on the mac because it would get
+ # confusing if you would want to customize init.tcl
+ # for a given set of safe slaves, on all the platforms
+ # you just need to give a specific access_path and
+ # the mac should be no exception. As there is no
+ # obvious full "safe ressources" design nor implementation
+ # for the mac, safe interps there will just don't
+ # have that ability. (A specific app can still reenable
+ # that using custom aliases if they want to).
+ # It would also make the security analysis and the Safe Tcl security
+ # model platform dependant and thus more error prone.
+
+ if {[catch {::interp eval $slave\
+ {source [file join $tcl_library init.tcl]}}\
+ msg]} {
+ Log $slave "can't source init.tcl ($msg)";
+ error "can't source init.tcl into slave $slave ($msg)"
+ }
+
+ return $slave
+ }
+
+
+ # Add (only if needed, avoid duplicates) 1 level of
+ # sub directories to an existing path list.
+ # Also removes non directories from the returned list.
+ proc AddSubDirs {pathList} {
+ set res {}
+ foreach dir $pathList {
+ if {[file isdirectory $dir]} {
+ # check that we don't have it yet as a children
+ # of a previous dir
+ if {[lsearch -exact $res $dir]<0} {
+ lappend res $dir;
+ }
+ foreach sub [glob -nocomplain -- [file join $dir *]] {
+ if { ([file isdirectory $sub])
+ && ([lsearch -exact $res $sub]<0) } {
+ # new sub dir, add it !
+ lappend res $sub;
+ }
+ }
+ }
+ }
+ return $res;
+ }
+
+ # This procedure deletes a safe slave managed by Safe Tcl and
+ # cleans up associated state:
+
+proc ::safe::interpDelete {slave} {
+
+ Log $slave "About to delete" NOTICE;
+
+ # If the slave has a cleanup hook registered, call it.
+ # check the existance because we might be called to delete an interp
+ # which has not been registered with us at all
+ set hookname [DeleteHookName $slave];
+ if {[Exists $hookname]} {
+ set hook [Set $hookname];
+ if {![::tcl::Lempty $hook]} {
+ # remove the hook now, otherwise if the hook
+ # calls us somehow, we'll loop
+ Unset $hookname;
+ if {[catch {eval $hook $slave} err]} {
+ Log $slave "Delete hook error ($err)";
+ }
+ }
+ }
+
+ # Discard the global array of state associated with the slave, and
+ # delete the interpreter.
+
+ set statename [InterpStateName $slave];
+ if {[Exists $statename]} {
+ Unset $statename;
+ }
+
+ # if we have been called twice, the interp might have been deleted
+ # already
+ if {[::interp exists $slave]} {
+ ::interp delete $slave;
+ Log $slave "Deleted" NOTICE;
+ }
+
+ return
+ }
+
+ # Set (or get) the loging mecanism
+
+proc ::safe::setLogCmd {args} {
+ variable Log;
+ if {[llength $args] == 0} {
+ return $Log;
+ } else {
+ if {[llength $args] == 1} {
+ set Log [lindex $args 0];
+ } else {
+ set Log $args
+ }
+ }
+}
+
+ # internal variable
+ variable Log {}
+
+ # ------------------- END OF PUBLIC METHODS ------------
+
+
+ #
+ # sets the slave auto_path to the master recorded value.
+ # also sets tcl_library to the first token of the virtual path.
+ #
+ proc SyncAccessPath {slave} {
+ set slave_auto_path [Set [VirtualPathListName $slave]];
+ ::interp eval $slave [list set auto_path $slave_auto_path];
+ Log $slave \
+ "auto_path in $slave has been set to $slave_auto_path"\
+ NOTICE;
+ ::interp eval $slave [list set tcl_library [lindex $slave_auto_path 0]];
+ }
+
+ # base name for storing all the slave states
+ # the array variable name for slave foo is thus "Sfoo"
+ # and for sub slave {foo bar} "Sfoo bar" (spaces are handled
+ # ok everywhere (or should))
+ # We add the S prefix to avoid that a slave interp called "Log"
+ # would smash our "Log" variable.
+ proc InterpStateName {slave} {
+ return "S$slave";
+ }
+
+ # Check that the given slave is "one of us"
+ proc IsInterp {slave} {
+ expr { ([Exists [InterpStateName $slave]])
+ && ([::interp exists $slave])}
+ }
+
+ # returns the virtual token for directory number N
+ # if the slave argument is given,
+ # it will return the corresponding master global variable name
+ proc PathToken {n {slave ""}} {
+ if {[string compare "" $slave]} {
+ return "[InterpStateName $slave](access_path,$n)";
+ } else {
+ # We need to have a ":" in the token string so
+ # [file join] on the mac won't turn it into a relative
+ # path.
+ return "p(:$n:)";
+ }
+ }
+ # returns the variable name of the complete path list
+ proc PathListName {slave} {
+ return "[InterpStateName $slave](access_path)";
+ }
+ # returns the variable name of the complete path list
+ proc VirtualPathListName {slave} {
+ return "[InterpStateName $slave](access_path_slave)";
+ }
+ # returns the variable name of the number of items
+ proc PathNumberName {slave} {
+ return "[InterpStateName $slave](access_path,n)";
+ }
+ # returns the staticsok flag var name
+ proc StaticsOkName {slave} {
+ return "[InterpStateName $slave](staticsok)";
+ }
+ # returns the nestedok flag var name
+ proc NestedOkName {slave} {
+ return "[InterpStateName $slave](nestedok)";
+ }
+ # Run some code at the namespace toplevel
+ proc Toplevel {args} {
+ namespace eval [namespace current] $args;
+ }
+ # set/get values
+ proc Set {args} {
+ eval Toplevel set $args;
+ }
+ # lappend on toplevel vars
+ proc Lappend {args} {
+ eval Toplevel lappend $args;
+ }
+ # unset a var/token (currently just an global level eval)
+ proc Unset {args} {
+ eval Toplevel unset $args;
+ }
+ # test existance
+ proc Exists {varname} {
+ Toplevel info exists $varname;
+ }
+ # short cut for access path getting
+ proc GetAccessPath {slave} {
+ Set [PathListName $slave]
+ }
+ # short cut for statics ok flag getting
+ proc StaticsOk {slave} {
+ Set [StaticsOkName $slave]
+ }
+ # short cut for getting the multiples interps sub loading ok flag
+ proc NestedOk {slave} {
+ Set [NestedOkName $slave]
+ }
+ # interp deletion storing hook name
+ proc DeleteHookName {slave} {
+ return [InterpStateName $slave](cleanupHook)
+ }
+
+ #
+ # translate virtual path into real path
+ #
+ proc TranslatePath {slave path} {
+ # somehow strip the namespaces 'functionality' out (the danger
+ # is that we would strip valid macintosh "../" queries... :
+ if {[regexp {(::)|(\.\.)} $path]} {
+ error "invalid characters in path $path";
+ }
+ set n [expr [Set [PathNumberName $slave]]-1];
+ for {} {$n>=0} {incr n -1} {
+ # fill the token virtual names with their real value
+ set [PathToken $n] [Set [PathToken $n $slave]];
+ }
+ # replaces the token by their value
+ subst -nobackslashes -nocommands $path;
+ }
+
+
+ # Log eventually log an error
+ # to enable error logging, set Log to {puts stderr} for instance
+ proc Log {slave msg {type ERROR}} {
+ variable Log;
+ if {[info exists Log] && [llength $Log]} {
+ eval $Log [list "$type for slave $slave : $msg"];
+ }
+ }
+
+
+ # file name control (limit access to files/ressources that should be
+ # a valid tcl source file)
+ proc CheckFileName {slave file} {
+ # limit what can be sourced to .tcl
+ # and forbid files with more than 1 dot and
+ # longer than 14 chars
+ set ftail [file tail $file];
+ if {[string length $ftail]>14} {
+ error "$ftail: filename too long";
+ }
+ if {[regexp {\..*\.} $ftail]} {
+ error "$ftail: more than one dot is forbidden";
+ }
+ if {[string compare $ftail "tclIndex"] && \
+ [string compare [string tolower [file extension $ftail]]\
+ ".tcl"]} {
+ error "$ftail: must be a *.tcl or tclIndex";
+ }
+
+ if {![file exists $file]} {
+ # don't tell the file path
+ error "no such file or directory";
+ }
+
+ if {![file readable $file]} {
+ # don't tell the file path
+ error "not readable";
+ }
+
+ }
+
+
+ # AliasSource is the target of the "source" alias in safe interpreters.
+
+ proc AliasSource {slave args} {
+
+ set argc [llength $args];
+ # Allow only "source filename"
+ # (and not mac specific -rsrc for instance - see comment in ::init
+ # for current rationale)
+ if {$argc != 1} {
+ set msg "wrong # args: should be \"source fileName\""
+ Log $slave "$msg ($args)";
+ return -code error $msg;
+ }
+ set file [lindex $args 0]
+
+ # get the real path from the virtual one.
+ if {[catch {set file [TranslatePath $slave $file]} msg]} {
+ Log $slave $msg;
+ return -code error "permission denied"
+ }
+
+ # check that the path is in the access path of that slave
+ if {[catch {FileInAccessPath $slave $file} msg]} {
+ Log $slave $msg;
+ return -code error "permission denied"
+ }
+
+ # do the checks on the filename :
+ if {[catch {CheckFileName $slave $file} msg]} {
+ Log $slave "$file:$msg";
+ return -code error $msg;
+ }
+
+ # passed all the tests , lets source it:
+ if {[catch {::interp invokehidden $slave source $file} msg]} {
+ Log $slave $msg;
+ return -code error "script error";
+ }
+ return $msg
+ }
+
+ # AliasLoad is the target of the "load" alias in safe interpreters.
+
+ proc AliasLoad {slave file args} {
+
+ set argc [llength $args];
+ if {$argc > 2} {
+ set msg "load error: too many arguments";
+ Log $slave "$msg ($argc) {$file $args}";
+ return -code error $msg;
+ }
+
+ # package name (can be empty if file is not).
+ set package [lindex $args 0];
+
+ # Determine where to load. load use a relative interp path
+ # and {} means self, so we can directly and safely use passed arg.
+ set target [lindex $args 1];
+ if {[string length $target]} {
+ # we will try to load into a sub sub interp
+ # check that we want to authorize that.
+ if {![NestedOk $slave]} {
+ Log $slave "loading to a sub interp (nestedok)\
+ disabled (trying to load $package to $target)";
+ return -code error "permission denied (nested load)";
+ }
+
+ }
+
+ # Determine what kind of load is requested
+ if {[string length $file] == 0} {
+ # static package loading
+ if {[string length $package] == 0} {
+ set msg "load error: empty filename and no package name";
+ Log $slave $msg;
+ return -code error $msg;
+ }
+ if {![StaticsOk $slave]} {
+ Log $slave "static packages loading disabled\
+ (trying to load $package to $target)";
+ return -code error "permission denied (static package)";
+ }
+ } else {
+ # file loading
+
+ # get the real path from the virtual one.
+ if {[catch {set file [TranslatePath $slave $file]} msg]} {
+ Log $slave $msg;
+ return -code error "permission denied"
+ }
+
+ # check the translated path
+ if {[catch {FileInAccessPath $slave $file} msg]} {
+ Log $slave $msg;
+ return -code error "permission denied (path)"
+ }
+ }
+
+ if {[catch {::interp invokehidden\
+ $slave load $file $package $target} msg]} {
+ Log $slave $msg;
+ return -code error $msg
+ }
+
+ return $msg
+ }
+
+ # FileInAccessPath raises an error if the file is not found in
+ # the list of directories contained in the (master side recorded) slave's
+ # access path.
+
+ # the security here relies on "file dirname" answering the proper
+ # result.... needs checking ?
+ proc FileInAccessPath {slave file} {
+
+ set access_path [GetAccessPath $slave];
+
+ if {[file isdirectory $file]} {
+ error "\"$file\": is a directory"
+ }
+ set parent [file dirname $file]
+ if {[lsearch -exact $access_path $parent] == -1} {
+ error "\"$file\": not in access_path";
+ }
+ }
+
+ # This procedure enables access from a safe interpreter to only a subset of
+ # the subcommands of a command:
+
+ proc Subset {slave command okpat args} {
+ set subcommand [lindex $args 0]
+ if {[regexp $okpat $subcommand]} {
+ return [eval {$command $subcommand} [lrange $args 1 end]]
+ }
+ set msg "not allowed to invoke subcommand $subcommand of $command";
+ Log $slave $msg;
+ error $msg;
+ }
+
+ # This procedure installs an alias in a slave that invokes "safesubset"
+ # in the master to execute allowed subcommands. It precomputes the pattern
+ # of allowed subcommands; you can use wildcards in the pattern if you wish
+ # to allow subcommand abbreviation.
+ #
+ # Syntax is: AliasSubset slave alias target subcommand1 subcommand2...
+
+ proc AliasSubset {slave alias target args} {
+ set pat ^(; set sep ""
+ foreach sub $args {
+ append pat $sep$sub
+ set sep |
+ }
+ append pat )\$
+ ::interp alias $slave $alias {}\
+ [namespace current]::Subset $slave $target $pat
+ }
+
+}