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| author | David Howells <dhowells@redhat.com> | 2019-08-19 17:18:00 -0700 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2019-08-19 21:54:16 -0700 |
| commit | b0c8fdc7fdb77586c3d1937050925b960743306e (patch) | |
| tree | bdd70cb78f6630c2e98a06aaae45600fcbb03f89 | |
| parent | 9d1f8be5cf42b497a3bddf1d523f2bb142e9318c (diff) | |
| download | linux-rpi-b0c8fdc7fdb77586c3d1937050925b960743306e.tar.gz linux-rpi-b0c8fdc7fdb77586c3d1937050925b960743306e.tar.bz2 linux-rpi-b0c8fdc7fdb77586c3d1937050925b960743306e.zip | |
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: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees 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: James Morris <jmorris@namei.org>
| -rw-r--r-- | include/linux/security.h | 1 | ||||
| -rw-r--r-- | kernel/events/core.c | 7 | ||||
| -rw-r--r-- | security/lockdown/lockdown.c | 1 |
3 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/security.h b/include/linux/security.h index e604f4c67f03..b94f1e697537 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -119,6 +119,7 @@ enum lockdown_reason { LOCKDOWN_KCORE, LOCKDOWN_KPROBES, LOCKDOWN_BPF_READ, + LOCKDOWN_PERF, LOCKDOWN_CONFIDENTIALITY_MAX, }; diff --git a/kernel/events/core.c b/kernel/events/core.c index f85929ce13be..8732f980a4fc 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -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 diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 2397772c56bd..3d7b1039457b 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -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", }; |