Ubuntu Feisty 7.04 manual page repository

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Provided by: apparmor_2.0.1+510.dfsg-0ubuntu4_i386

 

NAME

        AppArmor - kernel enhancement to confine programs to a limited set of
        resources.
 

DESCRIPTION

        AppArmor is a kernel enhancement to confine programs to a limited set
        of resources. AppArmor’s unique security model is to bind access con‐
        trol attributes to programs rather than to users.
 
        AppArmor confinement is provided via profiles loaded into the kernel
apparmor_parser(8), typically through the /etc/init.d/boot.apparmor
        SysV initscript, which is used like this:
 
                # /etc/init.d/boot.apparmor start
                # /etc/init.d/boot.apparmor stop
                # /etc/init.d/boot.apparmor restart
 
        AppArmor can operate in two modes: enforcement, and complain or learn‐
        ing:
 
        ·   enforcement -  Profiles loaded in enforcement mode will result in
            enforcement of the policy defined in the profile as well as report‐
            ing policy violation attempts to syslogd.
 
        ·   complain - Profiles loaded in  "complain" mode will not enforce
            policy.  Instead, it will report policy violation attempts. This
            mode is convenient for developing profiles. To manage complain mode
aa-complain(8) and
aa-enforce(8) can be used.  These utilities take a program name as
            an argument.
 
        Profiles are traditionally stored in files in /etc/apparmor.d/ under
        filenames with the convention of replacing the / in pathnames with .
        (except for the root /) so profiles are easier to manage (e.g. the
        /usr/sbin/nscd profile would be named usr.sbin.nscd).
 
exec(3) time (as seen through the
execve(2) system call); an already running process cannot be confined.
        However, once a profile is loaded for a program, that program will be
exec(3).
 
        AppArmor supports the Linux kernel’s securityfs filesystem, and makes
        available the list of the profiles currently loaded; to mount the
        filesystem:
 
                # mount -tsecurityfs securityfs /sys/kernel/security
                $ cat /sys/kernel/security/apparmor/profiles
                /usr/bin/mutt
                /usr/bin/gpg
                   ...
 
        Normally, the initscript will mount securityfs if it has not already
        been done.
 
        AppArmor also restricts what privileged operations a confined process
        may execute, even if the process is running as root. A confined process
        cannot call the following system calls:
 
ioperm(2)
setdomainname(2)
sysctl(2)
 
mknod(2) to create character or block
        devices.
 

ERRORS

        When a confined process tries to access a file it does not have permis‐
        sion to access, the kernel will report a message through audit, similar
        to:
 
                audit(1148420912.879:96): REJECTING x access to /bin/uname
                  (sh(6646) profile /tmp/sh active /tmp/sh)
 
                audit(1148420912.879:97): REJECTING r access to /bin/uname
                  (sh(6646) profile /tmp/sh active /tmp/sh)
 
                audit(1148420944.837:98): REJECTING access to capability
                  ’dac_override’ (sh(6641) profile /tmp/sh active /tmp/sh)
 
        The permissions requested by the process are immediately after REJECT‐
        ING. The "name" and process id of the running program are reported, as
        well as the profile name and any "hat" that may be active. ("Name" is
        in quotes, because the process name is limited to 15 bytes; it is the
        same as reported through the Berkeley process accounting.) If no hat is
change_hat(2)) then the profile name is printed for
        "active".
 
        For confined processes running under a profile that has been loaded in
        complain mode, enforcement will not take place and the log messages
        reported to audit will be of the form:
 
                audit(1146868287.904:237): PERMITTING r access to
                  /etc/apparmor.d/tunables (du(3811) profile /usr/bin/du active
                  /usr/bin/du)
 
                audit(1146868287.904:238): PERMITTING r access to /etc/apparmor.d
                  (du(3811) profile /usr/bin/du active /usr/bin/du)
 
        If the userland auditd is not running, the kernel will send audit
        events to klogd; klogd will send the messages to syslog, which will log
        the messages with the KERN facility. Thus, REJECTING and PERMITTING
        messages may go to either /var/log/audit/audit.log or /var/log/mes‐
        sages, depending upon local configuration.
 

FILES

        /etc/init.d/boot.apparmor
        /etc/apparmor.d/
        /lib/apparmor/
        /var/log/audit/audit.log
        /var/log/messages
subdomain.conf(5),
enforce(1), com‐
plain(1), and <http://forge.novell.com/modules/xfmod/project/?appar‐
        mor>.
 

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