Enable users to use perf-trace to trace their own processes, like strace but without the overhead of ptrace(). Ensure that users cannot access other users' or systemwide tracing data.
Changes in v5: - Move event_define_fields() before directory creation. If event_define_fields() fails then we don't need to cleanup whatever dirs were created. - New read-only eventfs file system with the same structure as /sys/kernel/tracing/events/ to handle files read by unprivileged users. - Allow unprivileged users to fall back to /sys/kernel/events/ when they cannot access /sys/kernel/tracing/events/. - Factor out reused code into helper function that checks if a tracepoint should be restricted in commit 5. Changes in v4: - Preserve security_perf_event_open(PERF_SECURITY_KERNEL) LSM hook in the tp_bypass path. - Lift the PERF_SAMPLE_IP check out of the tp_bypass path above the PERF_SAMPLE_RAW branch so it applies to counting and sampling. This also allows us to ensure PERF_SAMPLE_IP is set for uprobes. - Block counting path for TRACE_EVENT_FL_CAP_ANY for unprivileged users with sysctl_perf_event_paranoid > 1. Changes in v3: - Don't set PERF_SAMPLE_IP for unprivileged tracepoints. This allows us to exclude PERF_SAMPLE_IP from kaddr_leak without weakening KASLR. - Mount tracefs as world-traversable so users can access eventfs directories. Anubhav Shelat (5): eventfs: define event fields before directory creation tracefs: add read-only eventfs filesystem at /sys/kernel/events perf tools: fall back to eventfs for unprivileged event discovery perf evsel: don't set PERF_SAMPLE_IP for unprivileged tracepoints perf: enable unprivileged syscall tracing with perf trace fs/tracefs/event_inode.c | 61 ++++++++++++++++++ fs/tracefs/inode.c | 95 ++++++++++++++++++++++++++- fs/tracefs/internal.h | 3 + include/linux/trace_events.h | 1 + include/linux/tracefs.h | 4 ++ include/uapi/linux/magic.h | 1 + kernel/events/core.c | 28 +++++++- kernel/trace/trace.h | 2 + kernel/trace/trace_event_perf.c | 28 +++++++- kernel/trace/trace_events.c | 100 +++++++++++++++++++++++++++-- tools/lib/api/fs/fs.c | 10 +++ tools/lib/api/fs/fs.h | 1 + tools/lib/api/fs/tracing_path.c | 52 +++++++++++++-- tools/lib/api/fs/tracing_path.h | 1 + tools/perf/util/evsel.c | 14 +++- tools/perf/util/tp_pmu.c | 5 +- tools/perf/util/trace-event-info.c | 19 +++--- 17 files changed, 395 insertions(+), 30 deletions(-) -- 2.54.0
