From: Kees Cook <keescook@chromium.org>
To: Matthew Garrett <matthewgarrett@google.com>
Cc: jmorris@namei.org, linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
David Howells <dhowells@redhat.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Matthew Garrett <mjg59@google.com>,
"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
davem@davemloft.net, Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH V34 22/29] Lock down tracing and perf kprobes when in confidentiality mode
Date: Sat, 22 Jun 2019 17:09:00 -0700 [thread overview]
Message-ID: <201906221708.4E617CD@keescook> (raw)
In-Reply-To: <20190622000358.19895-23-matthewgarrett@google.com>
On Fri, Jun 21, 2019 at 05:03:51PM -0700, Matthew Garrett wrote:
> From: David Howells <dhowells@redhat.com>
>
> Disallow the creation of perf and ftrace kprobes when the kernel is
> locked down in confidentiality mode by preventing their registration.
> This prevents kprobes from being used to access kernel memory to steal
> crypto data, but continues to allow the use of kprobes from signed
> modules.
>
> Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Signed-off-by: Matthew Garrett <mjg59@google.com>
> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
> Cc: davem@davemloft.net
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/security.h | 1 +
> kernel/trace/trace_kprobe.c | 5 +++++
> security/lockdown/lockdown.c | 1 +
> 3 files changed, 7 insertions(+)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 3875f6df2ecc..e6e3e2403474 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -96,6 +96,7 @@ enum lockdown_reason {
> LOCKDOWN_MMIOTRACE,
> LOCKDOWN_INTEGRITY_MAX,
> LOCKDOWN_KCORE,
> + LOCKDOWN_KPROBES,
> LOCKDOWN_CONFIDENTIALITY_MAX,
> };
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 5d5129b05df7..5a76a0f79d48 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -11,6 +11,7 @@
> #include <linux/uaccess.h>
> #include <linux/rculist.h>
> #include <linux/error-injection.h>
> +#include <linux/security.h>
>
> #include "trace_dynevent.h"
> #include "trace_kprobe_selftest.h"
> @@ -415,6 +416,10 @@ static int __register_trace_kprobe(struct trace_kprobe *tk)
> {
> int i, ret;
>
> + ret = security_locked_down(LOCKDOWN_KPROBES);
> + if (ret)
> + return ret;
> +
> if (trace_probe_is_registered(&tk->tp))
> return -EINVAL;
>
> diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
> index 4c9b324dfc55..5a08c17f224d 100644
> --- a/security/lockdown/lockdown.c
> +++ b/security/lockdown/lockdown.c
> @@ -32,6 +32,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
> [LOCKDOWN_MMIOTRACE] = "unsafe mmio",
> [LOCKDOWN_INTEGRITY_MAX] = "integrity",
> [LOCKDOWN_KCORE] = "/proc/kcore access",
> + [LOCKDOWN_KPROBES] = "use of kprobes",
> [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
> };
>
> --
> 2.22.0.410.gd8fdbe21b5-goog
>
--
Kees Cook
next prev parent reply other threads:[~2019-06-23 0:09 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-22 0:03 [PATCH V34 00/29] Lockdown as an LSM Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 01/29] security: Support early LSMs Matthew Garrett
2019-06-22 23:36 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 02/29] security: Add a "locked down" LSM hook Matthew Garrett
2019-06-22 23:37 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 03/29] security: Add a static lockdown policy LSM Matthew Garrett
2019-06-22 23:37 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 04/29] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-06-22 23:48 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 05/29] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-06-22 23:52 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 06/29] kexec_load: Disable at runtime if " Matthew Garrett
2019-06-22 23:52 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 07/29] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-06-22 23:53 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-06-24 2:01 ` Dave Young
2019-06-25 2:35 ` Dave Young
2019-06-22 0:03 ` [PATCH V34 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-06-22 23:54 ` Kees Cook
2019-06-27 4:59 ` James Morris
2019-06-27 15:28 ` Matthew Garrett
2019-06-27 18:14 ` James Morris
2019-06-27 23:17 ` Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 10/29] hibernate: Disable when " Matthew Garrett
2019-06-22 17:52 ` Pavel Machek
2019-06-24 13:21 ` Jiri Kosina
2019-07-10 15:26 ` Joey Lee
2019-07-11 4:11 ` joeyli
2019-06-22 23:55 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 11/29] PCI: Lock down BAR access " Matthew Garrett
2019-06-22 23:55 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 12/29] x86: Lock down IO port " Matthew Garrett
2019-06-22 23:58 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 13/29] x86/msr: Restrict MSR " Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 14/29] ACPI: Limit access to custom_method " Matthew Garrett
2019-06-22 23:59 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-06-22 23:59 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 16/29] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-06-23 0:00 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 17/29] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-06-23 0:00 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 18/29] Lock down TIOCSSERIAL Matthew Garrett
2019-06-23 0:01 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 19/29] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-06-23 0:04 ` Kees Cook
2019-06-27 1:49 ` Daniel Axtens
2019-06-27 15:30 ` Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 20/29] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-06-23 0:04 ` Kees Cook
2019-06-23 11:08 ` Thomas Gleixner
2019-06-22 0:03 ` [PATCH V34 21/29] Lock down /proc/kcore Matthew Garrett
2019-06-23 0:05 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 22/29] Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-06-23 0:09 ` Kees Cook [this message]
2019-06-23 1:57 ` Masami Hiramatsu
2019-06-22 0:03 ` [PATCH V34 23/29] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-06-23 0:09 ` Kees Cook
2019-06-24 15:15 ` Daniel Borkmann
2019-06-24 19:54 ` Matthew Garrett
2019-06-24 20:08 ` Andy Lutomirski
2019-06-24 20:15 ` Matthew Garrett
2019-06-24 20:59 ` Daniel Borkmann
2019-06-24 21:30 ` Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 24/29] Lock down perf when " Matthew Garrett
2019-06-23 0:12 ` Kees Cook
2019-06-22 0:03 ` [PATCH V34 25/29] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 26/29] debugfs: Restrict debugfs when the kernel is " Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 27/29] tracefs: Restrict tracefs " Matthew Garrett
2019-06-22 0:03 ` [PATCH V34 28/29] efi: Restrict efivar_ssdt_load " Matthew Garrett
2019-06-23 0:14 ` Kees Cook
2019-06-25 15:00 ` Ard Biesheuvel
2019-06-22 0:03 ` [PATCH V34 29/29] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-06-23 0:25 ` Kees Cook
2019-06-24 23:01 ` [PATCH V34 00/29] Lockdown as an LSM James Morris
2019-06-24 23:47 ` Casey Schaufler
2019-06-24 23:56 ` Matthew Garrett
2019-06-25 6:04 ` James Morris
2019-06-25 8:16 ` John Johansen
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