Perforce 2000.1 System Administrator's Guide (2000.1.sa.3)
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Chapter 4
Administering Perforce:
Protections

Perforce provides a protection scheme to prevent unauthorized or inadvertent access to the depot. The protections determine which Perforce commands can be run, on which files, by whom, and from which host. Protections are set with the p4 protect command.

When Should Protections Be Set?


Before p4 protect is run, every Perforce user is a superuser, and can access and change anything in the depot. The first time protect is invoked, a protections table is created that gives the invoking user superuser access from all hosts, and lowers everyone else's access level to write permission on all files from all hosts. Therefore, protect should be run as the concluding step of all new Perforce installations; the superuser can change the access levels as needed at any time.

The Perforce protections are stored in the db.protect file in the server root directory; if p4 protect is first run by an unauthorized user (or if you accidentally lock yourself out!) the depot can be brought back to its unprotected state by removing this file.

Setting Protections with "p4 protect"


The p4 protect form contains a single form field called Protections: that consists of multiple lines. Each line in Protections: contains subfields; the contents look something like this:

The Permission Lines' Five Fields

Each line specifies a particular permission; each permission is always described by five fields.

The meanings of these fields are:

Field
Meaning

Access Level

Which access level is being granted: list, read, open, write, review, or super. These are described below.

User/Group

Does this protection apply to a user or a group? The value must be user or group.

Name

The user or group whose protection level is being defined. This field can contain the "*" wildcard: "*" by itself would grant this protection to everyone; "*e" would grant this protection to every user (or group) whose username ends with an "e".

Host

The TCP/IP address of the host being granted access. This must be provided as the numeric address of the host in dotted quad notation (e.g. 206.14.52.194).

This field may contain the "*" wildcard. A "*" by itself means that this protection is being granted for all hosts. The wildcard can be used as in any string, so "127.30.41.*" would define access to any subnet within 127.30.41, and "*3*" would refer to any IP address with a "3" in it.

Since the client's IP address is provided by the Internet Protocol itself, this field provides as much security as is provided by the network.

Files

A file specification representing the files in the depot on which permissions are being granted. Perforce wildcards can be used in the specification.

"//..." means all files in all depots.

Access Levels

The access level is described by the first value on each line. The six access levels are:

Access Level
Meaning

list

Permission is granted to run Perforce commands that display file metadata, (e.g. p4 filelog). No permission is granted to view or change the contents of the files.

read

The user(s) can run those Perforce commands that are needed to read files, such as p4 client and p4 sync. The read permission includes list access.

open

Grants permission to read files from the depot into the client workspace, and gives permission to open and edit those files. This permission does not allow the user to write the files back to the depot. open is similar to write, except that with open permission, users are not allowed to run p4 submit or p4 lock.

The open permission includes read and list access.

write

Permission is granted to run those commands that edit, delete, or add files. The write permission includes read, list, and open access.

This permission allows use of all Perforce commands except protect, depot, obliterate, and verify.

review

A special permission granted to review daemons. It includes list and read access, plus use of the p4 review command. It is needed only by review daemons.

super

For Perforce superusers; grants permission to run all Perforce commands. Provides write and review access plus the added ability to edit protections, create depots, obliterate files, and verify files.

Each Perforce command is associated with a particular minimum access level; for example, to run p4 sync on a particular file, the user must have been granted at least read access on that file. The access level required to run a particular command can usually be reasoned from knowledge of what the command does; for example, it is somewhat obvious that p4 print would require read access. For a full list of the minimum access levels required to run each Perforce command, see "How Protections are Implemented" on page 47.

Which Users Should Receive Which Permissions?

The simplest method of granting permissions is to give write permission to all users who don't need to manage the Perforce system, and give super access to those who do, but there are times when this simple solution isn't sufficient.

Read access to particular files should be granted to users who don't ever need to edit those files. For example, an engineer might have write permission for source files, but have only read access to the documentation; managers might be granted only read access to all files.

Because open access allows local editing of files, but doesn't allow these files to be written to the depot, open access is usually granted only in unusual circumstances. Choose open access over write access when users will be testing their changes locally, but when these changes should not be seen by other users. For instance, bug testers may want to change code in order to test theories as to why particular bugs occur, but these changes would be for their own use, and would not be written to the depot. Perhaps a codeline has been frozen, and local changes are to be submitted to the depot only after careful review by the development team. In these cases, open access would be granted until the code changes have been approved; after which time the protection level would be upgraded to write and the changes submitted.

Default Protections

Before p4 protect is invoked, every user has superuser privileges. When p4 protect is first run, two permissions are set by default. The default protections table looks like this:

write        user        *        *        //...
super        user        edk      *        //...

This indicates that write access is granted to all users, on all hosts, to all files. Additionally, the user who first invoked p4 protect (in this case, edk) is granted superuser privileges.

Interpreting Multiple Permission Lines

The access rights granted to any user are defined by the union of mappings in the protection lines that match her user name and client IP address. (This behavior is slightly different when exclusionary protections are provided; this is described in the next section).

Exclusionary Protections

A user can be denied access from particular files by prefacing the fifth field in a permission line with a minus sign ("-"). This is useful for giving most users access to a particular set of files, while denying access to the same files to only a few users.

To use exclusionary mappings properly, it is necessary to understand some peculiarities associated with them:

Granting Access to Groups of Users


Perforce groups simplify maintenance of the protections table. The names of users with identical access requirements can be stored in a single group; the group name can then be entered in the table, and all the users in that group will receive the specified permissions.

Groups are maintained with p4 group and their protections assigned with p4 protect. Only Perforce superusers may use these commands.

Creating and Editing Groups

If p4 group groupname is called with a non-existent groupname, a new group named groupname will be created. Calling p4 group with an existing groupname allows editing of the user list for this group.

The command p4 group groupname displays a form with two fields: Group: and Users:. The Group: field stores the group name, and cannot be edited; Users: is empty when the group is first created, and must be filled in. User names are entered under the Users: field header; each user name must be typed on its own line, and should be indented. A single user may be listed in any number of groups.

As of Release 99.2, groups can contain other groups, not just users. To add all users in a previously-defined group to the group you're presently working with, include the group name in the Subgroups: field of the p4 group form. User and group names occupy separate namespaces; thus, groups and users can have the same names.

Groups and Protections

To use a group with the p4 protect form, specify a group name instead of a user name in any line in the protections table, and set the value of the second field on the line to group instead of user. All the users in that group will be granted the specified access.

If a user belongs to multiple groups, one permission may override another, but the actual permissions granted to a specific user can be determined by replacing the names of all groups that a particular user belongs to with the user's name within the protections table, and applying the rules described earlier in this chapter.

Deleting Groups

To delete a group, invoke

Alternately, invoke p4 group groupname and delete all the users from the group in the resulting editor form. The group will be deleted when the form is closed.

How Protections are Implemented


This section describes the algorithm that Perforce follows to implement its protection scheme. Protections can be used properly without reading this section; the material here is provided to explain the logic behind the behavior described above.

Users' access to files is determined by the following steps:

The first pass is used to determine whether or not the user is allowed to know whether or not the file exists. This search simply looks for the first line encountered that matches the user name, host IP address, and file argument. If the first matching line found is an inclusionary protection, then the user has permission to at least list the file, and Perforce proceeds to the second pass. Otherwise, if the first matching protection found is an exclusionary mapping, or if the top of the protections table is reached without a matching protection being found, then the user has no permission to even list the file, and will receive a message like File not on client.

If an inclusionary protection line is the first line encountered that matches the user name, IP address, file argument, and has an access level greater than or equal to the access level required by the given command, then the user is given permission to run the command.

If an exclusionary mapping is the first line encountered that matches according to the above criteria, or if the top of the protections table is reached without finding a matching protection, then the user has no permission to run the command, and will receive the message "You don't have permission for this operation".

Access Levels Required by Perforce Commands


The following table lists the minimum access level required to run each command. For example, since p4 add requires at least open access, p4 add can be run if open, write or super protections are granted.

Command
Access Level
Command
Access Level

add

open

integrate d

open

admin

super

integrated

list

branch

open

job b

open

branches

list

jobs a

list

change

open

jobspec a b

super

changes a

list

label a

open

client

list

labels a b

list

clients

list

labelsync

open

counter c

review

lock

write

counters

list

obliterate

super

delete

open

opened

list

depot a b

super

passwd

list

depots a

list

print

read

describe

read

protect a

super

describe -s

list

reopen

open

diff

read

resolve

open

diff2

read

resolved

open

dirs

list

revert

open

edit

open

review a

review

filelog

list

reviews a

list

files

list

set

list

fix a

open

submit

write

fixes a

list

sync

read

fstat

list

triggers

super

group a b

super

typemap

super

groups a

list

unlock

open

have

list

user a b

list

help

none

users a

list

info

none

verify

review

where a

none

a This command doesn't operate on specific files. Thus, permission is granted to run the command if the user has the specified access to at least one file in the depot.
b The -o flag to this command, which allows the form to be read but not edited, requires only list access.
c list access is required to view an existing counter's value; review access is required to change a counter's value or create a new counter.
d To run p4 integrate, the user needs open access on the target files and read access on the donor files.
Those commands that list files, such as p4 describe, will only list those files to which the user has at least list access. Some of these commands take a -f flag which can only be run by Perforce superusers. See "Forcing operations with the -f flag" on page 32 for details.


Perforce 2000.1 System Administrator's Guide (2000.1.sa.3)
<< Previous Chapter
Administering Perforce:
Superuser Tasks

Table of Contents
Index
Perforce on the Web
Next Chapter >>
Customizing Perforce:
Job Specifications

Please send comments and questions about this manual to [email protected].
Copyright 1999, 2000 Perforce Software. All rights reserved.
Last updated: 10/11/00