exec_attr(4) (man pages section 4: File Formats)

man pages section 4: File Formats

exec_attr(4)

NAME

exec_attr– execution profiles database

SYNOPSIS

/etc/security/exec_attr

DESCRIPTION

/etc/security/exec_attr is a local database that specifies the execution attributes associated with profiles. The exec_attr file can be used with other sources for execution profiles, including the exec_attr NIS map and NIS+ table. Programs use the getexecattr(3SECDB) routines to access this information.

The search order for multiple execution profile sources is specified in the /etc/nsswitch.conf file, as described in the nsswitch.conf(4) man page. The search order follows the entry for prof_attr(4).

A profile is a logical grouping of authorizations and commands that is interpreted by a profile shell to form a secure execution environment. The shells that interpret profiles are pfcsh, pfksh, and pfsh. See the pfsh(1) man page. Each user's account is assigned zero or more profiles in the user_attr(4) database file.

Each entry in the exec_attr database consists of one line of text containing seven fields separated by colons (:). Line continuations using the backslash (\) character are permitted. The basic format of each entry is:

name:policy:type:res1:res2:id:attr

name

The name of the profile. Profile names are case-sensitive.

policy

The policy that is associated with the profile entry. The only valid policy is suser.

type

The type of object defined in the profile. The only valid type is cmd.

res1

Reserved for future use.

res2

Reserved for future use.

id

A string that uniquely identifies the object described by the profile. For a profile of type cmd, the id is either the full path to the command or the asterisk (*) symbol, which is used to allow all commands. An asterisk that replaces the filename component in a pathname indicates all files in a particular directory.

To specify arguments, the pathname should point to a shell script that is written to execute the command with the desired argument. In a Bourne shell, the effective UID is reset to the real UID of the process when the effective UID is less than 100 and not equal to the real UID. Depending on the euid and egid values, Bourne shell limitations might make other shells preferable. To prevent the effective UIDs from being reset to real UIDs, you can start the script with the -p option:

#!/bin/sh -p

attr

An optional list of semicolon-separated (;) key-value pairs that describe the security attributes to apply to the object upon execution. Zero or more keys may be specified. The list of valid key words depends on the policy enforced. The following key words are valid: euid, uid, egid, and gid.

euid and uid contain a single user name or a numeric user ID. Commands designated with euid run with the effective UID indicated, which is similar to setting the setuid bit on an executable file. Commands designated with uid run with both the real and effective UIDs. Setting uid may be more appropriate than setting the euid on privileged shell scripts.

egid and gid contain a single group name or a numeric group ID. Commands designated with egid run with the effective GID indicated, which is similar to setting the setgid bit on a file. Commands designated with gid run with both the real and effective GIDs. Setting gid may be more appropriate than setting guid on privileged shell scripts.

EXAMPLES

Example 1 Using effective user and group IDs

The following example shows the audit command specified in the Audit Control profile to execute with an effective user ID of root (0) and effective group ID of bin (3):

Audit Control:suser:cmd:::/etc/init.d/audit:euid=0;egid=3

FILES

/etc/nsswitch.conf

/etc/user_attr

/etc/security/exec_attr

CAVEATS

When deciding which authorization source to use (see DESCRIPTION), keep in mind that NIS+ provides stronger authentication than NIS.

Because the list of legal keys is likely to expand, any code that parses this database must be written to ignore unknown key-value pairs without error. When any new keywords are created, the names should be prefixed with a unique string, such as the company's stock symbol, to avoid potential naming conflicts.

The following characters are used in describing the database format and must be escaped with a backslash if used as data: colon (:), semicolon (;), equals (=), and backslash (\).