/etc/apparmor.d/, og de inneholder en liste over adgangskontrollregler om ressurser som hvert program kan gjøre bruk av. Profilene er kompilert og lastet inn i kjernen av apparmor_parser-kommandoen. Hver profil kan lastes enten i håndhevings- eller klagemodus. Den første håndhever politikk og rapporterer krenkingsforsøk, mens sistnevnte ikke håndhever politikken, men logger likevel systempåkallinger som ville ha blitt nektet.
apt install apparmor apparmor-profiles apparmor-utils with root privileges.
aa-status will confirm it quickly:
#aa-statusapparmor module is loaded. 40 profiles are loaded. 23 profiles are in enforce mode. /usr/bin/evince /usr/bin/evince-previewer [...] 17 profiles are in complain mode. /usr/sbin/dnsmasq [...] 14 processes have profiles defined. 12 processes are in enforce mode. /usr/bin/evince (3462) [...] 2 processes are in complain mode. /usr/sbin/avahi-daemon (429) avahi-daemon /usr/sbin/avahi-daemon (511) avahi-daemon 0 processes are unconfined but have a profile defined.
aa-enforce og aa-complain, som gir som parameter enten banen til den kjørbare filen, eller til policy-filen. I tillegg kan en profil helt deaktiveres aa-disable, eller sette i revisjonsmodus (for å logge aksepterte systemanrop også) med aa-audit.
#aa-enforce /usr/bin/pidginSetting /usr/bin/pidgin to enforce mode.#aa-complain /usr/sbin/dnsmasqSetting /usr/sbin/dnsmasq to complain mode.
aa-unconfined-kommando for å liste programmer som ikke har noen tilknyttet profil, og som eksponerer en åpen nettverkssocket. Med --paranoid-alternativet får du alle ubeskyttede prosesser med minst én aktiv nettverkstilkobling.
#aa-unconfined801 /sbin/dhclient not confined 409 /usr/sbin/NetworkManager not confined 411 /usr/sbin/cupsd confined by '/usr/sbin/cupsd (enforce)' 429 /usr/sbin/avahi-daemon confined by 'avahi-daemon (enforce)' 516 /usr/sbin/cups-browsed confined by '/usr/sbin/cups-browsed (enforce)' 538 /usr/sbin/zebra not confined 591 /usr/sbin/named not confined 847 /usr/sbin/mysqld not confined 849 /usr/sbin/sshd not confined 1013 /usr/sbin/dhclient (/sbin/dhclient) not confined 1276 /usr/sbin/apache2 not confined 1322 /usr/sbin/apache2 not confined 1323 /usr/sbin/apache2 not confined 1324 /usr/sbin/apache2 not confined 1325 /usr/sbin/apache2 not confined 1327 /usr/sbin/apache2 not confined 1829 /usr/lib/ipsec/charon confined by '/usr/lib/ipsec/charon (enforce)' 2132 /usr/sbin/exim4 not confined 12865 /usr/bin/python3.7 (/usr/bin/python3) not confined 12873 /usr/bin/python3.7 (/usr/bin/python3) not confined
/sbin/dhclient. For this we will use aa-genprof dhclient. On Debian Buster, there is a known bug (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=928160) that makes the previous command may fail with the following error: ERROR: Include file /etc/apparmor.d/local/usr.lib.dovecot.deliver not found. To fix it create the missing files with touch file. It will invite you to use the application in another window and when done to come back to aa-genprof to scan for AppArmor events in the system logs and convert those logs into access rules. For each logged event, it will make one or more rule suggestions that you can either approve or further edit in multiple ways:
#aa-genprof dhclientWriting updated profile for /usr/sbin/dhclient. Setting /usr/sbin/dhclient to complain mode. Before you begin, you may wish to check if a profile already exists for the application you wish to confine. See the following wiki page for more information: https://gitlab.com/apparmor/apparmor/wikis/Profiles Profiling: /usr/sbin/dhclient Please start the application to be profiled in another window and exercise its functionality now. Once completed, select the "Scan" option below in order to scan the system logs for AppArmor events. For each AppArmor event, you will be given the opportunity to choose whether the access should be allowed or denied. [(S)can system log for AppArmor events] / (F)inish Reading log entries from /var/log/syslog. Updating AppArmor profiles in /etc/apparmor.d. Profile: /usr/sbin/dhclientExecute: /usr/sbin/dhclient-script Severity: unknown (I)nherit / (C)hild / (P)rofile / (N)amed / (U)nconfined / (X) ix On / (D)eny / Abo(r)t / (F)inish
PShould AppArmor sanitise the environment when switching profiles? Sanitising environment is more secure, but some applications depend on the presence of LD_PRELOAD or LD_LIBRARY_PATH. (Y)es / [(N)o]YWriting updated profile for /usr/sbin/dhclient-script. Complain-mode changes: Profile: /usr/sbin/dhclientCapability: net_raw Severity: 8 [1 - capability net_raw,] [(A)llow] / (D)eny / (I)gnore / Audi(t) / Abo(r)t / (F)inish
AAdding capability net_raw to profile. Profile: /sbin/dhclient Capability: net_bind_service Severity: 8 [1 - #include <abstractions/nis> ] 2 - capability net_bind_service, (A)llow / [(D)eny] / (I)gnore / Audi(t) / Abo(r)t / (F)inishAAdding #include <abstractions/nis> to profile. Profile: /usr/sbin/dhclientPath: /etc/ssl/openssl.cnf New Mode: owner r Severity: 2 [1 - #include <abstractions/lightdm>] 2 - #include <abstractions/openssl> 3 - #include <abstractions/ssl_keys> 4 - owner /etc/ssl/openssl.cnf r, (A)llow / [(D)eny] / (I)gnore / (G)lob / Glob with (E)xtension / (N)ew / Audi(t) / (O)wner permissions off / Abo(r)t / (F)inish
2Profile: /usr/sbin/dhclient Path: /etc/ssl/openssl.cnf New Mode: owner r Severity: 2 1 - #include <abstractions/lightdm> [2 - #include <abstractions/openssl>] 3 - #include <abstractions/ssl_keys> 4 - owner /etc/ssl/openssl.cnf r, [(A)llow] / (D)eny / (I)gnore / (G)lob / Glob with (E)xtension / (N)ew / Abo(r)t / (F)inish / (M)oreA[...] Profile: /usr/sbin/dhclient-scriptPath: /usr/bin/dash New Mode: owner r Severity: unknown [1 - #include <abstractions/lightdm>] 2 - #include <abstractions/ubuntu-browsers.d/plugins-common> 3 - owner /usr/bin/dash r, (A)llow / [(D)eny] / (I)gnore / (G)lob / Glob with (E)xtension / (N)ew / Audi(t) / (O)wner permissions off / Abo(r)t / (F)inish
AAdding #include <abstractions/lightdm> to profile. Deleted 2 previous matching profile entries. = Changed Local Profiles = The following local profiles were changed. Would you like to save them? [1 - /usr/sbin/dhclient] 2 - /usr/sbin/dhclient-script (S)ave Changes / Save Selec(t)ed Profile / [(V)iew Changes] / View Changes b/w (C)lean profiles / Abo(r)tSWriting updated profile for /usr/sbin/dhclient. Writing updated profile for /usr/sbin/dhclient-script. Profiling: /usr/sbin/dhclient Please start the application to be profiled in another window and exercise its functionality now. Once completed, select the "Scan" option below in order to scan the system logs for AppArmor events. For each AppArmor event, you will be given the opportunity to choose whether the access should be allowed or denied. [(S)can system log for AppArmor events] / (F)inishFReloaded AppArmor profiles in enforce mode. Please consider contributing your new profile! See the following wiki page for more information: https://gitlab.com/apparmor/apparmor/wikis/Profiles Finished generating profile for /usr/sbin/dhclient.
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Den første oppdagede hendelsen er kjøring av et annet program. I så fall har du flere valg: Du kan kjøre programmet med profilen til den overordnede prosessen («Inherit»-valget), du kan kjøre den med sin egen dedikerte profil («Profile»- og «Named»-valgene, som bare avviker i muligheten til å bruke et vilkårlig profilnavn), du kan kjøre den med en under-profil til den overordnede prosessen («Child»-valget), du kan kjøre den uten profil («Unconfined»-valget), eller du kan bestemme deg for å ikke kjøre i det hele tatt («Deny»-valget).
Merk at når du velger å kjøre den under en øremerket profil som ikke finnes ennå, vil verktøyet opprette den manglende profilen for deg, og lager regelforslag for den profilen i det samme løpet.
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På kjernenivå er de spesielle rettighetene til rotbrukeren delt etter «kvalifikasjone»". Når en systempåkalling krever en bestemt kvalifikasjon, vil AppArmor verifisere om profilen tillater programmet å bruke denne muligheten.
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Here the program seeks read permissions for /etc/ssl/openssl.cnf. aa-genprof detected that this permission was also granted by multiple “abstractions” and offers them as alternative choices. An abstraction provides a reusable set of access rules grouping together multiple resources that are commonly used together. In this specific case, the file is generally accessed through the nameservice related functions of the C library and we type “2” to first select the “#include <abstractions/openssl>” choice and then “A” to allow it.
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Notice that this access request is not part of the dhclient profile but of the new profile that we created when we allowed /usr/sbin/dhclient-script to run with its own profile.
Etter å ha gått gjennom alle de loggede hendelsene, tilbyr programmet å lagre alle profilene som ble opprettet under kjøringen. I dette tilfellet har vi to profiler som vi sparer med én gang med «Lagre» (men du kan lagre dem enkeltvis også) før du forlater programmet med «Ferdig».
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aa-genprof er i realiteten bare et smart omslag rundt aa-logprof; den skaper en tom profil, laster den i klagemodus, og kjører deretter aa-logprof, som er et verktøy for å oppdatere en profil basert på profilovertredelsen som har blitt logget. Så du kan kjøre dette verktøyet igjen senere for å forbedre profilen du nettopp opprettet.
/etc/apparmor.d/usr.sbin.dhclient close to this:
# Last Modified: Fri Jul 5 00:51:02 2019
#include <tunables/global>
/usr/sbin/dhclient {
#include <abstractions/base>
#include <abstractions/nameservice>
capability net_bind_service,
capability net_raw,
/bin/dash r,
/etc/dhcp/* r,
/etc/dhcp/dhclient-enter-hooks.d/* r,
/etc/dhcp/dhclient-exit-hooks.d/* r,
/etc/resolv.conf.* w,
/etc/samba/dhcp.conf.* w,
/proc/*/net/dev r,
/proc/filesystems r,
/run/dhclient*.pid w,
/sbin/dhclient mr,
/sbin/dhclient-script rCx,
/usr/lib/NetworkManager/nm-dhcp-helper Px,
/var/lib/NetworkManager/* r,
/var/lib/NetworkManager/*.lease rw,
/var/lib/dhcp/*.leases rw,
owner /etc/** mrwk,
owner /var/** mrwk,
owner /{,var/}run/** mrwk,
}
/etc/apparmor.d/usr.sbin.dhclient-script might be similar to this:
# Last Modified: Fri Jul 5 00:51:55 2019
#include <tunables/global>
/usr/sbin/dhclient-script {
#include <abstractions/base>
#include <abstractions/bash>
#include <abstractions/lightdm>
}