Commit b0c8fdc7 authored by David Howells's avatar David Howells Committed by James Morris
Browse files

lockdown: Lock down perf when in confidentiality mode



Disallow the use of certain perf facilities that might allow userspace to
access kernel data.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarMatthew Garrett <mjg59@google.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 9d1f8be5
......@@ -119,6 +119,7 @@ enum lockdown_reason {
LOCKDOWN_KCORE,
LOCKDOWN_KPROBES,
LOCKDOWN_BPF_READ,
LOCKDOWN_PERF,
LOCKDOWN_CONFIDENTIALITY_MAX,
};
......
......@@ -10798,6 +10798,13 @@ SYSCALL_DEFINE5(perf_event_open,
perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
return -EACCES;
err = security_locked_down(LOCKDOWN_PERF);
if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
/* REGS_INTR can leak data, lockdown must prevent this */
return err;
err = 0;
/*
* In cgroup mode, the pid argument is used to pass the fd
* opened to the cgroup directory in cgroupfs. The cpu argument
......
......@@ -34,6 +34,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
[LOCKDOWN_KCORE] = "/proc/kcore access",
[LOCKDOWN_KPROBES] = "use of kprobes",
[LOCKDOWN_BPF_READ] = "use of bpf to read kernel RAM",
[LOCKDOWN_PERF] = "unsafe use of perf",
[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
};
......
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