logd: logpersistd

- Enable logpersistd to write to /data/misc/logd
- Enable logpersistd to read from pstore to help complete any content
  lost by reboot disruption
- Enable shell readonly ability logpersistd files in /data/misc/logd
- Enable logcat -f when placed into logd context to act as a
  logpersistd (nee logcatd) agent, restrict access to run only in
  userdebug or eng

Bug: 19608716
Change-Id: I3209582bc796a1093c325c90068a48bf268e5ab5

file.te

@@ -165,6 +165,7 @@ type logdr_socket, file_type, mlstrustedobject;
 type logdw_socket, file_type, mlstrustedobject;
 type mdns_socket, file_type;
 type mdnsd_socket, file_type, mlstrustedobject;
+type misc_logd_file, file_type;
 type mtpd_socket, file_type;
 type netd_socket, file_type;
 type property_socket, file_type;

file_contexts

@@ -236,6 +236,7 @@
 /data/misc/gatekeeper(/.*)?     u:object_r:gatekeeper_data_file:s0
 /data/misc/keychain(/.*)?       u:object_r:keychain_data_file:s0
 /data/misc/keystore(/.*)?       u:object_r:keystore_data_file:s0
+/data/misc/logd(/.*)?           u:object_r:misc_logd_file:s0
 /data/misc/media(/.*)?          u:object_r:media_data_file:s0
 /data/misc/net(/.*)?            u:object_r:net_data_file:s0
 /data/misc/shared_relro(/.*)?   u:object_r:shared_relro_file:s0

init.te

@@ -161,6 +161,10 @@ recovery_only(`
 domain_trans(init, shell_exec, shell)
 domain_trans(init, init_exec, ueventd)
 domain_trans(init, init_exec, watchdogd)
+# case where logpersistd is actually logcat -f in logd context (nee: logcatd)
+userdebug_or_eng(`
+  domain_auto_trans(init, logcat_exec, logd)
+')
 
 # Support "adb shell stop"
 allow init self:capability kill;

logd.te

@@ -10,6 +10,10 @@ allow logd self:netlink_audit_socket { create_socket_perms nlmsg_write };
 allow logd kernel:system syslog_read;
 allow logd kmsg_device:chr_file w_file_perms;
 allow logd system_data_file:file r_file_perms;
+allow logd misc_logd_file:file create_file_perms;
+allow logd misc_logd_file:dir rw_dir_perms;
+allow logd pstorefs:dir search;
+allow logd pstorefs:file r_file_perms;
 
 r_dir_file(logd, domain)
 
@@ -17,6 +21,11 @@ allow logd kernel:system syslog_mod;
 
 control_logd(logd)
 
+# case where logpersistd is actually logcat -f in logd context (nee: logcatd)
+userdebug_or_eng(`
+  unix_socket_connect(logd, logdr, logd)
+')
+
 ###
 ### Neverallow rules
 ###

shell.te

@@ -15,6 +15,9 @@ control_logd(shell)
 # logcat -L (directly, or via dumpstate)
 allow shell pstorefs:dir search;
 allow shell pstorefs:file r_file_perms;
+# logpersistd (nee logcatd) files
+allow shell misc_logd_file:dir r_dir_perms;
+allow shell misc_logd_file:file r_file_perms;
 
 # read files in /data/anr
 allow shell anr_data_file:dir r_dir_perms;