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-rw-r--r--contrib/tcl/doc/safe.n285
1 files changed, 164 insertions, 121 deletions
diff --git a/contrib/tcl/doc/safe.n b/contrib/tcl/doc/safe.n
index 03adf0f38b63..3be9c5f7b261 100644
--- a/contrib/tcl/doc/safe.n
+++ b/contrib/tcl/doc/safe.n
@@ -4,7 +4,7 @@
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
-'\" SCCS: @(#) safe.n 1.3 97/08/13 12:44:45
+'\" SCCS: @(#) safe.n 1.11 97/10/31 12:51:13
'\"
.so man.macros
.TH "Safe Tcl" n 8.0 Tcl "Tcl Built-In Commands"
@@ -29,7 +29,10 @@ Safe Base \- A mechanism for creating and manipulating safe interpreters.
\fB::safe::setLogCmd\fR ?\fIcmd arg...\fR?
.SH OPTIONS
.PP
-?\fB\-accessPath\fR \fIpathList\fR? ?\fB\-noStatics\fR? ?\fB\-nestedLoadOk\fR? ?\fB\-deleteHook\fR \fIscript\fR?
+?\fB\-accessPath\fR \fIpathList\fR?
+?\fB\-statics\fR \fIboolean\fR? ?\fB\-noStatics\fR?
+?\fB\-nested\fR \fIboolean\fR? ?\fB\-nestedLoadOk\fR?
+?\fB\-deleteHook\fR \fIscript\fR?
.BE
.SH DESCRIPTION
@@ -54,95 +57,23 @@ No knowledge of the file system structure is leaked to the
safe interpreter, because it has access only to a virtualized path
containing tokens. When the safe interpreter requests to source a file, it
uses the token in the virtual path as part of the file name to source; the
-master interpreter translates the token into a real directory name and
-executes the requested operation.
+master interpreter transparently
+translates the token into a real directory name and executes the
+requested operation (see the section \fBSECURITY\fR below for details).
Different levels of security can be selected by using the optional flags
of the commands described below.
.PP
All commands provided in the master interpreter by the Safe Base reside in
-the \fBsafe\fR namespace.
-\fB::safe::interpCreate\fR creates a new safe interpreter with options,
-described in the section \fBOPTIONS\fR.
-The return value is the name of the new safe interpreter created.
-\fB::safe::interpInit\fR is similar to \fB::safe::interpCreate\fR except that
-it requires as its first argument the name of a safe interpreter that was
-previously created directly using the \fBinterp\fR command.
-\fB::safe::interpDelete\fR deletes the interpreter named by its argument.
-\fB::safe::interpConfigure\fR can be used to set or get options for the named
-safe interpreters; the options are described in the section \fBOPTIONS\fR.
-.PP
-A virtual path is maintained in the master interpreter for each safe
-interpreter created by \fB::safe::interpCreate\fR or initialized by
-\fB::safe::interpInit\fR.
-The path maps tokens accessible in the safe interpreter into real path
-names on the local file system.
-This prevents safe interpreters from gaining knowledge about the
-structure of the file system of the host on which the interpeter is
-executing.
-When a token is used in a safe interpreter in a request to source or
-load a file, the token is translated to a real path name and the file to be
-sourced or loaded is located on the file system.
-The safe interpreter never gains knowledge of the actual path name under
-which the file is stored on the file system.
-Commands are provided in the master interpreter to manipulate the virtual
-path for a safe interpreter.
-\fB::safe::interpConfigure\fR can be used to set a new path for a safe
-interpreter.
-\fB::safe::interpAddToAccessPath\fR adds a directory to the virtual path for
-the named safe interpreter and returns the token by which that directory
-will be accessible in the safe interpreter.
-\fB::safe::interpFindInAccessPath\fR finds the
-requested directory in the virtual path for the named safe interpreter and
-returns the token by which that directory can be accessed in the safe
-interpreter.
-If the path is not found, an error is raised.
-.PP
-\fB::safe::setLogCommand\fR installs a script to be called when interesting
-life cycle events happen.
-This script will be called with one argument, a string describing the event.
-.SH ALIASES
-.PP
-The following aliases are provided in a safe interpreter:
-.TP
-\fBsource\fB \fIfileName\fR
-The requested file, a Tcl source file, is sourced into the safe interpreter
-if it is found.
-The \fBsource\fR alias can only source files from directories in
-the virtual path for the safe interpreter. The \fBsource\fR alias requires
-the safe interpreter to
-use one of the token names in its virtual path to denote the directory in
-which the file to be sourced can be found.
-See the section on \fBSECURITY\fR for more discussion of restrictions on
-valid filenames.
-.TP
-\fBload\fR \fIfileName\fR
-The requested file, a shared object file, in dynamically loaded into the
-safe interpreter if it is found.
-The filename must contain a token name mentioned in the virtual path for
-the safe interpreter for it to be found successfully.
-Additionally, the shared object file must contain a safe entry point; see
-the manual page for the \fBload\fR command for more details.
-.TP
-\fBfile\fR ?\fIoptions\fR?
-The \fBfile\fR alias provides access to a safe subset of the subcommands of
-the \fBfile\fR command; it allows only \fBdirname\fR, \fBjoin\fR,
-\fBextension\fR, \fBroot\fR, \fBtail\fR, \fBpathname\fR and \fBsplit\fR
-subcommands. For more details on what these subcommands do see the manual
-page for the \fBfile\fR command.
-.TP
-\fBexit\fR
-The calling interpreter is deleted and its computation is stopped, but the
-Tcl process in which this interpreter exists is not terminated.
-.PP
+the \fBsafe\fR namespace:
+
.SH COMMANDS
-.PP
The following commands are provided in the master interpreter:
.TP
\fB::safe::interpCreate\fR ?\fIslave\fR? ?\fIoptions...\fR?
Creates a safe interpreter, installs the aliases described in the section
\fBALIASES\fR and initializes the auto-loading and package mechanism as
specified by the supplied \fBoptions\fR.
-See the \fBOPTIONS\fR section below for a description of the common
+See the \fBOPTIONS\fR section below for a description of the
optional arguments.
If the \fIslave\fR argument is omitted, a name will be generated.
\fB::safe::interpCreate\fR always returns the interpreter name.
@@ -150,18 +81,36 @@ If the \fIslave\fR argument is omitted, a name will be generated.
\fB::safe::interpInit\fR \fIslave\fR ?\fIoptions...\fR?
This command is similar to \fBinterpCreate\fR except it that does not
create the safe interpreter. \fIslave\fR must have been created by some
-other means, like \fB::interp create \-safe\fR.
+other means, like \fBinterp create \-safe\fR.
.TP
\fB::safe::interpConfigure\fR \fIslave\fR ?\fIoptions...\fR?
If no \fIoptions\fR are given, returns the settings for all options for the
-named safe interpreter.
-If \fIoptions\fR are supplied, sets the options for the named safe
-interpreter. See the section on \fBOPTIONS\fR below.
+named safe interpreter as a list of options and their current values
+for that \fIslave\fR.
+If a single additional argument is provided,
+it will return a list of 2 elements \fIname\fR and \fIvalue\fR where
+\fIname\fR is the full name of that option and \fIvalue\fR the current value
+for that option and the \fIslave\fR.
+If more than two additional arguments are provided, it will reconfigure the
+safe interpreter and change each and only the provided options.
+See the section on \fBOPTIONS\fR below for options description.
+Example of use:
+.RS
+.CS
+# Create a new interp with the same configuration as "$i0" :
+set i1 [eval safe::interpCreate [safe::interpConfigure $i0]]
+# Get the current deleteHook
+set dh [safe::interpConfigure $i0 \-del]
+# Change (only) the statics loading ok attribute of an interp
+# and its deleteHook (leaving the rest unchanged) :
+safe::interpConfigure $i0 \-delete {foo bar} \-statics 0 ;
+.CE
+.RE
.TP
\fB::safe::interpDelete\fR \fIslave\fR
Deletes the safe interpreter and cleans up the corresponding
master interpreter data structures.
-If a \fIdeletehook\fR script was specified for this interpreter it is
+If a \fIdeleteHook\fR script was specified for this interpreter it is
evaluated before the interpreter is deleted, with the name of the
interpreter as an additional argument.
.TP
@@ -170,9 +119,11 @@ This command finds and returns the token for the real directory
\fIdirectory\fR in the safe interpreter's current virtual access path.
It generates an error if the directory is not found.
Example of use:
+.RS
.CS
$slave eval [list set tk_library [::safe::interpFindInAccessPath $name $tk_library]]
.CE
+.RE
.TP
\fB::safe::interpAddToAccessPath\fR \fIslave\fR \fIdirectory\fR
This command adds \fIdirectory\fR to the virtual path maintained for the
@@ -181,13 +132,15 @@ the safe interpreter to obtain access to files in that directory.
If the directory is already in the virtual path, it only returns the token
without adding the directory to the virtual path again.
Example of use:
+.RS
.CS
$slave eval [list set tk_library [::safe::interpAddToAccessPath $name $tk_library]]
.CE
+.RE
.TP
\fB::safe::setLogCmd\fR ?\fIcmd arg...\fR?
This command installs a script that will be called when interesting
-lifecycle events occur for a safe interpreter.
+life cycle events occur for a safe interpreter.
When called with no arguments, it returns the currently installed script.
When called with one argument, an empty string, the currently installed
script is removed and logging is turned off.
@@ -224,75 +177,165 @@ Any option name can be abbreviated to its minimal
non-ambiguous name.
Option names are not case sensitive.
.TP
-\fB\-accessPath\fR ?\fIdirectoryList\fR?
+\fB\-accessPath\fR \fIdirectoryList\fR
This option sets the list of directories from which the safe interpreter
-can \fBsource\fR and \fBload\fR files, and returns a list of tokens that
-will allow the safe interpreter access to these directories.
-If a value for \fBdirectoryList\fR is not given, or if it is given as the
-empty list, the safe interpreter will use the same directories than its
+can \fBsource\fR and \fBload\fR files.
+If this option is not specified, or if it is given as the
+empty list, the safe interpreter will use the same directories as its
master for auto-loading.
See the section \fBSECURITY\fR below for more detail about virtual paths,
tokens and access control.
.TP
-\fB\-noStatics\fR
-This option specifies that the safe interpreter will not be allowed
+\fB\-statics\fR \fIboolean\fR
+This option specifies if the safe interpreter will be allowed
to load statically linked packages (like \fBload {} Tk\fR).
-The default is that safe interpreters are allowed to load statically linked
-packages.
+The default value is \fBtrue\fR :
+safe interpreters are allowed to load statically linked packages.
+.TP
+\fB\-noStatics\fR
+This option is a convenience shortcut for \fB-statics false\fR and
+thus specifies that the safe interpreter will not be allowed
+to load statically linked packages.
+.TP
+\fB\-nested\fR \fIboolean\fR
+This option specifies if the safe interpreter will be allowed
+to load packages into its own sub-interpreters.
+The default value is \fBfalse\fR :
+safe interpreters are not allowed to load packages into
+their own sub-interpreters.
.TP
\fB\-nestedLoadOk\fR
-This option specifies that the safe interpreter will be allowed
-to load packages into its own subinterpreters.
-The default is that safe interpreters are not allowed to load packages into
-their own subinterpreters.
+This option is a convenience shortcut for \fB-nested true\fR and
+thus specifies the safe interpreter will be allowed
+to load packages into its own sub-interpreters.
.TP
-\fB\-deleteHook\fR ?\fIscript\fR?
-If \fIscript\fR is given, it is evaluated in the master with the name of
-the safe interpreter as an additional argument just before deleting the
-safe interpreter.
-If no value is given for \fIscript\fR any currently installed deletion hook
-script for that safe interpreter is removed; it will no longer be called
-when the interpreter is deleted.
-There is no deletion hook script installed by default.
+\fB\-deleteHook\fR \fIscript\fR
+When this option is given an non empty \fIscript\fR, it will be
+evaluated in the master with the name of
+the safe interpreter as an additional argument
+just before actually deleting the safe interpreter.
+Giving an empty value removes any currently installed deletion hook
+script for that safe interpreter.
+The default value (\fB{}\fR) is not to have any deletion call back.
+.SH ALIASES
+The following aliases are provided in a safe interpreter:
+.TP
+\fBsource\fR \fIfileName\fR
+The requested file, a Tcl source file, is sourced into the safe interpreter
+if it is found.
+The \fBsource\fR alias can only source files from directories in
+the virtual path for the safe interpreter. The \fBsource\fR alias requires
+the safe interpreter to
+use one of the token names in its virtual path to denote the directory in
+which the file to be sourced can be found.
+See the section on \fBSECURITY\fR for more discussion of restrictions on
+valid filenames.
+.TP
+\fBload\fR \fIfileName\fR
+The requested file, a shared object file, is dynamically loaded into the
+safe interpreter if it is found.
+The filename must contain a token name mentioned in the virtual path for
+the safe interpreter for it to be found successfully.
+Additionally, the shared object file must contain a safe entry point; see
+the manual page for the \fBload\fR command for more details.
+.TP
+\fBfile\fR ?\fIsubCmd args...\fR?
+The \fBfile\fR alias provides access to a safe subset of the subcommands of
+the \fBfile\fR command; it allows only \fBdirname\fR, \fBjoin\fR,
+\fBextension\fR, \fBroot\fR, \fBtail\fR, \fBpathname\fR and \fBsplit\fR
+subcommands. For more details on what these subcommands do see the manual
+page for the \fBfile\fR command.
+.TP
+\fBexit\fR
+The calling interpreter is deleted and its computation is stopped, but the
+Tcl process in which this interpreter exists is not terminated.
.SH SECURITY
-.PP
The Safe Base does not attempt to completely prevent annoyance and
denial of service attacks. These forms of attack prevent the
application or user from temporarily using the computer to perform
useful work, for example by consuming all available CPU time or
all available screen real estate.
-These attacks, while agravating, are deemed to be of lesser importance
+These attacks, while aggravating, are deemed to be of lesser importance
in general than integrity and privacy attacks that the Safe Base
is to prevent.
-
+.PP
The commands available in a safe interpreter, in addition to
the safe set as defined in \fBinterp\fR manual page, are mediated aliases
for \fBsource\fR, \fBload\fR, \fBexit\fR, and a safe subset of \fBfile\fR.
-The safe interpreter can also auto-load code and it can request to load
-packages.
+The safe interpreter can also auto-load code and it can request that
+packages be loaded.
+.PP
Because some of these commands access the local file system, there is a
potential for information leakage about its directory structure.
-To prevent this, commands which take file names as arguments in a safe
+To prevent this, commands that take file names as arguments in a safe
interpreter use tokens instead of the real directory names.
These tokens are translated to the real directory name while a request to,
e.g., source a file is mediated by the master interpreter.
+This virtual path system is maintained in the master interpreter for each safe
+interpreter created by \fB::safe::interpCreate\fR or initialized by
+\fB::safe::interpInit\fR and
+the path maps tokens accessible in the safe interpreter into real path
+names on the local file system thus preventing safe interpreters
+from gaining knowledge about the
+structure of the file system of the host on which the interpreter is
+executing.
+The only valid file names arguments
+for the \fBsource\fR and \fBload\fR aliases provided to the slave
+are path in the form of
+\fB[file join \fR\fItoken filename\fR\fB]\fR (ie, when using the
+native file path formats: \fItoken\fR\fB/\fR\fIfilename\fR
+on Unix, \fItoken\fR\fB\\\fIfilename\fR on Windows,
+and \fItoken\fR\fB:\fR\fIfilename\fR on the Mac),
+where \fItoken\fR is representing one of the directories
+of the \fIaccessPath\fR list and \fIfilename\fR is
+one file in that directory (no sub directories access are allowed).
+.PP
+When a token is used in a safe interpreter in a request to source or
+load a file, the token is checked and
+translated to a real path name and the file to be
+sourced or loaded is located on the file system.
+The safe interpreter never gains knowledge of the actual path name under
+which the file is stored on the file system.
.PP
To further prevent potential information leakage from sensitive files that
are accidentally included in the set of files that can be sourced by a safe
-interpreter, the \fBsource\fR alias is restricted so that it can only
-source files with names that have the extension \fB.tcl\fR, that contain
-only one dot and that are forteen characters long or shorter.
+interpreter, the \fBsource\fR alias restricts access to files
+meeting the following constraints: the file name must
+fourteen characters or shorter, must not contain more than one dot ("\fB.\fR"),
+must end up with the extension \fB.tcl\fR or be called \fBtclIndex\fR.
+.PP
+Each element of the initial access path
+list will be assigned a token that will be set in
+the slave \fBauto_path\fR and the first element of that list will be set as
+the \fBtcl_library\fR for that slave.
.PP
-The default value of the Tcl variable \fBauto_path\fR in a safe interpreter
-is a virtualized token list for the directories in the value of its
-master's \fBauto_path\fR variable and their immediate subdirectories.
-The first token in this list is also assigned to the Tcl varibale
-\fBtcl_library\fR in the safe interpreter.
+If the access path argument is not given or is the empty list,
+the default behavior is to let the slave access the same packages
+as the master has access to (Or to be more precise:
+only packages written in Tcl (which by definition can't be dangerous
+as they run in the slave interpreter) and C extensions that
+provides a Safe_Init entry point). For that purpose, the master's
+\fBauto_path\fR will be used to construct the slave access path.
+In order that the slave successfully loads the Tcl library files
+(which includes the auto-loading mechanism itself) the \fBtcl_library\fR will be
+added or moved to the first position if necessary, in the
+slave access path, so the slave
+\fBtcl_library\fR will be the same as the master's (its real
+path will still be invisible to the slave though).
+In order that auto-loading works the same for the slave and
+the master in this by default case, the first-level
+sub directories of each directory in the master \fBauto_path\fR will
+also be added (if not already included) to the slave access path.
You can always specify a more
restrictive path for which sub directories will never be searched by
explicitly specifying your directory list with the \fB\-accessPath\fR flag
instead of relying on this default mechanism.
+.PP
+When the \fIaccessPath\fR is changed after the first creation or
+initialization (ie through \fBinterpConfigure -accessPath \fR\fIlist\fR),
+an \fBauto_reset\fR is automatically evaluated in the safe interpreter
+to synchronize its \fBauto_index\fR with the new token list.
.SH "SEE ALSO"
interp(n), library(n), load(n), package(n), source(n), unknown(n)