167407dc47
This tracing daemon interfaces with perf_events, and is used for callstack sampling. Currently, we only handle userspace stacks. We have the ability to collect kernel frame addresses (as unwound by the kernel itself), but need /proc/kallsyms to symbolize them. This patch mirrors what was done for traced_probes (ftrace event kptr symbolization) in aosp/1455337 - the daemon can set a sysprop that causes "init" to temporarily relax kptr_restrict, then the daemon can open and read /proc/kallsyms. After the file is parsed, the kptr_restrict value is restored. To reiterate, this is confined to userdebug_or_eng due to the reasons outlined in go/perfetto-kallsyms. Bug: 173124818 Change-Id: I9077bbfe6fea3318f4c37947a5c455061ca43d8d
63 lines
2.4 KiB
Text
63 lines
2.4 KiB
Text
# Performance profiler, backed by perf_event_open(2).
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# See go/perfetto-perf-android.
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typeattribute traced_perf coredomain;
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typeattribute traced_perf mlstrustedsubject;
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type traced_perf_exec, system_file_type, exec_type, file_type;
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init_daemon_domain(traced_perf)
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perfetto_producer(traced_perf)
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# Allow traced_perf full use of perf_event_open(2). It will perform cpu-wide
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# profiling, but retain samples only for profileable processes.
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# Thread-specific profiling is still disallowed due to a PTRACE_MODE_ATTACH
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# check (which would require a process:attach SELinux allow-rule).
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allow traced_perf self:perf_event { open cpu kernel read write tracepoint };
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# Allow CAP_KILL for delivery of dedicated signal to obtain proc-fds from a
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# process. Allow CAP_DAC_READ_SEARCH for stack unwinding and symbolization of
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# sampled stacks, which requires opening the backing libraries/executables (as
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# symbols are usually not mapped into the process space). Not all such files
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# are world-readable, e.g. odex files that included user profiles during
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# profile-guided optimization.
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allow traced_perf self:capability { kill dac_read_search };
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# Allow reading /system/data/packages.list.
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allow traced_perf packages_list_file:file r_file_perms;
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# Allow reading files for stack unwinding and symbolization.
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r_dir_file(traced_perf, nativetest_data_file)
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r_dir_file(traced_perf, system_file_type)
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r_dir_file(traced_perf, apk_data_file)
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r_dir_file(traced_perf, dalvikcache_data_file)
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r_dir_file(traced_perf, vendor_file_type)
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# Allow to temporarily lift the kptr_restrict setting and build a symbolization
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# map reading /proc/kallsyms.
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userdebug_or_eng(`set_prop(traced_perf, lower_kptr_restrict_prop)')
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allow traced_perf proc_kallsyms:file r_file_perms;
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# Do not audit the cases where traced_perf attempts to access /proc/[pid] for
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# domains that it cannot read.
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dontaudit traced_perf domain:dir { search getattr open };
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# Do not audit failures to signal a process, as there are cases when this is
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# expected (native processes on debug builds use the policy for enforcing which
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# processes are profileable).
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dontaudit traced_perf domain:process signal;
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# Never allow access to app data files
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neverallow traced_perf { app_data_file privapp_data_file system_app_data_file }:file *;
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# Never allow profiling highly privileged processes.
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never_profile_heap(`{
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bpfloader
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init
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kernel
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keystore
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llkd
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logd
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ueventd
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vendor_init
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vold
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}')
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