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,
Matthew Garrett <mjg59@srcf.ucam.org>,
Matthew Garrett <mjg59@google.com>,
David Howells <dhowells@redhat.com>,
x86@kernel.org
Subject: Re: [PATCH V34 12/29] x86: Lock down IO port access when the kernel is locked down
Date: Sat, 22 Jun 2019 16:58:22 -0700 [thread overview]
Message-ID: <201906221658.C4956B7@keescook> (raw)
In-Reply-To: <20190622000358.19895-13-matthewgarrett@google.com>
On Fri, Jun 21, 2019 at 05:03:41PM -0700, Matthew Garrett wrote:
> From: Matthew Garrett <mjg59@srcf.ucam.org>
>
> IO port access would permit users to gain access to PCI configuration
> registers, which in turn (on a lot of hardware) give access to MMIO
> register space. This would potentially permit root to trigger arbitrary
> DMA, so lock it down by default.
>
> This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and
> KDDISABIO console ioctls.
>
> Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: x86@kernel.org
> ---
> arch/x86/kernel/ioport.c | 7 +++++--
> include/linux/security.h | 1 +
> security/lockdown/lockdown.c | 1 +
> 3 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
> index 0fe1c8782208..61a89d3c0382 100644
> --- a/arch/x86/kernel/ioport.c
> +++ b/arch/x86/kernel/ioport.c
> @@ -11,6 +11,7 @@
> #include <linux/errno.h>
> #include <linux/types.h>
> #include <linux/ioport.h>
> +#include <linux/security.h>
> #include <linux/smp.h>
> #include <linux/stddef.h>
> #include <linux/slab.h>
> @@ -31,7 +32,8 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
>
> if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
> return -EINVAL;
> - if (turn_on && !capable(CAP_SYS_RAWIO))
> + if (turn_on && (!capable(CAP_SYS_RAWIO) ||
> + security_locked_down(LOCKDOWN_IOPORT)))
> return -EPERM;
>
> /*
> @@ -126,7 +128,8 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
> return -EINVAL;
> /* Trying to gain more privileges? */
> if (level > old) {
> - if (!capable(CAP_SYS_RAWIO))
> + if (!capable(CAP_SYS_RAWIO) ||
> + security_locked_down(LOCKDOWN_IOPORT))
> return -EPERM;
> }
> regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) |
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 1b849f10dec6..60569b7e9465 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -87,6 +87,7 @@ enum lockdown_reason {
> LOCKDOWN_KEXEC,
> LOCKDOWN_HIBERNATION,
> LOCKDOWN_PCI_ACCESS,
> + LOCKDOWN_IOPORT,
> LOCKDOWN_INTEGRITY_MAX,
> LOCKDOWN_CONFIDENTIALITY_MAX,
> };
> diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
> index e2ee8a16b94c..895ef3ba1b4c 100644
> --- a/security/lockdown/lockdown.c
> +++ b/security/lockdown/lockdown.c
> @@ -23,6 +23,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
> [LOCKDOWN_KEXEC] = "kexec of unsigned images",
> [LOCKDOWN_HIBERNATION] = "hibernation",
> [LOCKDOWN_PCI_ACCESS] = "direct PCI access",
> + [LOCKDOWN_IOPORT] = "raw io port access",
> [LOCKDOWN_INTEGRITY_MAX] = "integrity",
> [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
> };
> --
> 2.22.0.410.gd8fdbe21b5-goog
>
--
Kees Cook
next prev parent reply other threads:[~2019-06-22 23:58 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 [this message]
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
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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