Grant additional permissions for ASAN builds
ASAN builds may require additional permissions to launch processes
with ASAN wrappers. In this case, system_server needs permission to
execute /system/bin/sh.
Create with_asan() macro which can be used exclusively on debug
builds. Note this means that ASAN builds with these additional
permission will not pass the security portion of CTS - like any
other debug build.
Addresses:
avc: denied { execute } for name="sh" dev="dm-0" ino=571
scontext=u:r:system_server:s0 tcontext=u:object_r:shell_exec:s0
tclass=file
Test: lunch aosp_marlin-userdebug;
cd system/sepolicy; mm SANITIZE_TARGET=address;
Verify permissions granted using with_asan() are granted.
Test: lunch aosp_marlin-userdebug;
cd system/sepolicy; mm;
Verify permissions granted using with_asan() are not granted.
Test: lunch aosp_marlin-user;
cd system/sepolicy; mm SANITIZE_TARGET=address;
Verify permissions granted using with_asan() are not granted.
Bug: 36138508
Change-Id: I6e39ada4bacd71687a593023f16b45bc16cd7ef8
diff --git a/Android.mk b/Android.mk
index 254acd0..e288356 100644
--- a/Android.mk
+++ b/Android.mk
@@ -131,6 +131,11 @@
intermediates := $(TARGET_OUT_INTERMEDIATES)/ETC/sepolicy_intermediates
+with_asan := false
+ifneq (,$(filter address,$(SANITIZE_TARGET)))
+ with_asan := true
+endif
+
##################################
# reqd_policy_mask - a policy.conf file which contains only the bare minimum
# policy necessary to use checkpolicy. This bare-minimum policy needs to be
@@ -143,6 +148,7 @@
$(reqd_policy_mask.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
$(reqd_policy_mask.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
$(reqd_policy_mask.conf): PRIVATE_TGT_ARCH := $(my_target_arch)
+$(reqd_policy_mask.conf): PRIVATE_TGT_WITH_ASAN := $(with_asan)
$(reqd_policy_mask.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
$(reqd_policy_mask.conf): $(call build_policy, $(sepolicy_build_files), $(REQD_MASK_POLICY))
@mkdir -p $(dir $@)
@@ -151,6 +157,7 @@
-D target_build_variant=$(TARGET_BUILD_VARIANT) \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=$(PRIVATE_TGT_WITH_ASAN) \
-s $^ > $@
reqd_policy_mask.cil := $(intermediates)/reqd_policy_mask.cil
@@ -170,6 +177,7 @@
$(plat_pub_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
$(plat_pub_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
$(plat_pub_policy.conf): PRIVATE_TGT_ARCH := $(my_target_arch)
+$(plat_pub_policy.conf): PRIVATE_TGT_WITH_ASAN := $(with_asan)
$(plat_pub_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
$(plat_pub_policy.conf): $(call build_policy, $(sepolicy_build_files), \
$(BOARD_SEPOLICY_VERS_DIR) $(REQD_MASK_POLICY))
@@ -179,6 +187,7 @@
-D target_build_variant=$(TARGET_BUILD_VARIANT) \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=$(PRIVATE_TGT_WITH_ASAN) \
-s $^ > $@
plat_pub_policy.cil := $(intermediates)/plat_pub_policy.cil
@@ -223,6 +232,7 @@
$(plat_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
$(plat_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
$(plat_policy.conf): PRIVATE_TGT_ARCH := $(my_target_arch)
+$(plat_policy.conf): PRIVATE_TGT_WITH_ASAN := $(with_asan)
$(plat_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
$(plat_policy.conf): $(call build_policy, $(sepolicy_build_files), \
$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
@@ -232,6 +242,7 @@
-D target_build_variant=$(TARGET_BUILD_VARIANT) \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=$(PRIVATE_TGT_WITH_ASAN) \
-s $^ > $@
$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
@@ -320,6 +331,7 @@
$(nonplat_policy.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
$(nonplat_policy.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
$(nonplat_policy.conf): PRIVATE_TGT_ARCH := $(my_target_arch)
+$(nonplat_policy.conf): PRIVATE_TGT_WITH_ASAN := $(with_asan)
$(nonplat_policy.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
$(nonplat_policy.conf): $(call build_policy, $(sepolicy_build_files), \
$(BOARD_SEPOLICY_VERS_DIR) $(REQD_MASK_POLICY) $(PLAT_VENDOR_POLICY) $(BOARD_SEPOLICY_DIRS))
@@ -329,6 +341,7 @@
-D target_build_variant=$(TARGET_BUILD_VARIANT) \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=$(PRIVATE_TGT_WITH_ASAN) \
-s $^ > $@
$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
@@ -452,6 +465,7 @@
$(plat_pub_policy.recovery.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
$(plat_pub_policy.recovery.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
$(plat_pub_policy.recovery.conf): PRIVATE_TGT_ARCH := $(my_target_arch)
+$(plat_pub_policy.recovery.conf): PRIVATE_TGT_WITH_ASAN := $(with_asan)
$(plat_pub_policy.recovery.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
$(plat_pub_policy.recovery.conf): $(call build_policy, $(sepolicy_build_files), \
$(BOARD_SEPOLICY_VERS_DIR) $(REQD_MASK_POLICY))
@@ -461,6 +475,7 @@
-D target_build_variant=$(TARGET_BUILD_VARIANT) \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=$(PRIVATE_TGT_WITH_ASAN) \
-D target_recovery=true \
-s $^ > $@
@@ -479,6 +494,7 @@
$(plat_policy.recovery.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
$(plat_policy.recovery.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
$(plat_policy.recovery.conf): PRIVATE_TGT_ARCH := $(my_target_arch)
+$(plat_policy.recovery.conf): PRIVATE_TGT_WITH_ASAN := $(with_asan)
$(plat_policy.recovery.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
$(plat_policy.recovery.conf): $(call build_policy, $(sepolicy_build_files), \
$(PLAT_PUBLIC_POLICY) $(PLAT_PRIVATE_POLICY))
@@ -488,6 +504,7 @@
-D target_build_variant=$(TARGET_BUILD_VARIANT) \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=$(PRIVATE_TGT_WITH_ASAN) \
-D target_recovery=true \
-s $^ > $@
$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
@@ -526,6 +543,7 @@
$(nonplat_policy.recovery.conf): PRIVATE_MLS_SENS := $(MLS_SENS)
$(nonplat_policy.recovery.conf): PRIVATE_MLS_CATS := $(MLS_CATS)
$(nonplat_policy.recovery.conf): PRIVATE_TGT_ARCH := $(my_target_arch)
+$(nonplat_policy.recovery.conf): PRIVATE_TGT_WITH_ASAN := $(with_asan)
$(nonplat_policy.recovery.conf): PRIVATE_ADDITIONAL_M4DEFS := $(LOCAL_ADDITIONAL_M4DEFS)
$(nonplat_policy.recovery.conf): $(call build_policy, $(sepolicy_build_files), \
$(BOARD_SEPOLICY_VERS_DIR) $(REQD_MASK_POLICY) $(PLAT_VENDOR_POLICY) $(BOARD_SEPOLICY_DIRS))
@@ -535,6 +553,7 @@
-D target_build_variant=$(TARGET_BUILD_VARIANT) \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=$(PRIVATE_TGT_WITH_ASAN) \
-D target_recovery=true \
-s $^ > $@
$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
@@ -603,6 +622,7 @@
-D target_build_variant=user \
-D target_with_dexpreopt=$(WITH_DEXPREOPT) \
-D target_arch=$(PRIVATE_TGT_ARCH) \
+ -D target_with_asan=false \
-s $^ > $@
$(hide) sed '/dontaudit/d' $@ > $@.dontaudit
@@ -1090,5 +1110,6 @@
plat_pub_policy.cil :=
reqd_policy_mask.cil :=
sepolicy_build_files :=
+with_asan :=
include $(call all-makefiles-under,$(LOCAL_PATH))
diff --git a/private/system_server.te b/private/system_server.te
index 7361307..d1f9bc3 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -623,6 +623,12 @@
allow system_server debugfs_tracing_instances:dir search;
allow system_server debugfs_wifi_tracing:file rw_file_perms;
+# allow system_server to exec shell on ASAN builds. Needed to run
+# asanwrapper.
+with_asan(`
+ allow system_server shell_exec:file rx_file_perms;
+')
+
###
### Neverallow rules
###
@@ -644,7 +650,12 @@
# example, https://www.linuxprogrammingblog.com/threads-and-fork-think-twice-before-using-them
# Prevent the addition of new file execs to stop the problem from
# getting worse. b/28035297
-neverallow system_server { file_type -toolbox_exec -logcat_exec }:file execute_no_trans;
+neverallow system_server {
+ file_type
+ -toolbox_exec
+ -logcat_exec
+ with_asan(`-shell_exec')
+}:file execute_no_trans;
# Ensure that system_server doesn't perform any domain transitions other than
# transitioning to the crash_dump domain when a crash occurs.
diff --git a/public/te_macros b/public/te_macros
index 0e1bffb..d31bb1d 100644
--- a/public/te_macros
+++ b/public/te_macros
@@ -386,6 +386,12 @@
#
define(`userdebug_or_eng', ifelse(target_build_variant, `eng', $1, ifelse(target_build_variant, `userdebug', $1)))
+#####################################
+# asan builds
+# SELinux rules which apply only to asan builds
+#
+define(`with_asan', ifelse(target_with_asan, `true', userdebug_or_eng(`$1'), ))
+
####################################
# Fallback crash handling for processes that can't exec crash_dump (e.g. because of seccomp).
#