From: Matthew Garrett <matthewgarrett@google.com> To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com Subject: [PATCH 12/27] x86: Lock down IO port access when the kernel is locked down Date: Thu, 28 Feb 2019 15:11:48 -0800 Message-ID: <20190228231203.212359-12-matthewgarrett@google.com> (raw) In-Reply-To: <20190228231203.212359-1-matthewgarrett@google.com> 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@srcf.ucam.org> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com> cc: x86@kernel.org --- arch/x86/kernel/ioport.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 0fe1c8782208..abc702a6ae9c 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -31,7 +31,8 @@ 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) || + kernel_is_locked_down("ioperm"))) return -EPERM; /* @@ -126,7 +127,8 @@ 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) || + kernel_is_locked_down("iopl")) return -EPERM; } regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | -- 2.21.0.352.gf09ad66450-goog
next prev parent reply index Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-02-28 21:28 [PULL REQUEST] Lock down patches Matthew Garrett 2019-02-28 22:20 ` Mimi Zohar 2019-02-28 23:13 ` Matthew Garrett 2019-03-01 0:05 ` Mimi Zohar 2019-03-01 1:01 ` Matthew Garrett 2019-03-01 1:44 ` Mimi Zohar 2019-03-01 3:33 ` Matthew Garrett 2019-03-01 4:16 ` Mimi Zohar 2019-02-28 22:44 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett 2019-02-28 22:44 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett 2019-02-28 23:10 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett 2019-02-28 23:10 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett 2019-02-28 23:11 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett 2019-02-28 23:11 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett 2019-02-28 23:11 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett 2019-02-28 23:11 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett 2019-02-28 23:11 ` [PATCH 03/27] Enforce module signatures if the kernel is locked down Matthew Garrett 2019-02-28 23:11 ` [PATCH 04/27] Restrict /dev/{mem,kmem,port} when " Matthew Garrett 2019-02-28 23:11 ` [PATCH 05/27] kexec_load: Disable at runtime if " Matthew Garrett 2019-02-28 23:11 ` [PATCH 06/27] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett 2019-02-28 23:11 ` [PATCH 07/27] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett 2019-02-28 23:11 ` [PATCH 08/27] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett 2019-03-01 2:05 ` Mimi Zohar 2019-02-28 23:11 ` [PATCH 09/27] hibernate: Disable when " Matthew Garrett 2019-03-19 22:15 ` Pavel Machek 2019-02-28 23:11 ` [PATCH 10/27] uswsusp: " Matthew Garrett 2019-02-28 23:11 ` [PATCH 11/27] PCI: Lock down BAR access " Matthew Garrett 2019-02-28 23:11 ` Matthew Garrett [this message] 2019-02-28 23:11 ` [PATCH 13/27] x86/msr: Restrict MSR " Matthew Garrett 2019-02-28 23:11 ` [PATCH 14/27] ACPI: Limit access to custom_method " Matthew Garrett 2019-02-28 23:11 ` [PATCH 15/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett 2019-02-28 23:11 ` [PATCH 16/27] acpi: Disable ACPI table override if the kernel is " Matthew Garrett 2019-02-28 23:11 ` [PATCH 17/27] acpi: Disable APEI error injection " Matthew Garrett 2019-02-28 23:11 ` [PATCH 18/27] Prohibit PCMCIA CIS storage when " Matthew Garrett 2019-02-28 23:11 ` [PATCH 19/27] Lock down TIOCSSERIAL Matthew Garrett 2019-02-28 23:11 ` [PATCH 20/27] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett 2019-02-28 23:11 ` [PATCH 21/27] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett 2019-02-28 23:11 ` [PATCH 22/27] Lock down /proc/kcore Matthew Garrett 2019-02-28 23:11 ` [PATCH 23/27] Lock down kprobes Matthew Garrett 2019-02-28 23:12 ` [PATCH 24/27] bpf: Restrict kernel image access functions when the kernel is locked down Matthew Garrett 2019-02-28 23:12 ` [PATCH 25/27] Lock down perf Matthew Garrett 2019-02-28 23:12 ` [PATCH 26/27] debugfs: Restrict debugfs when the kernel is locked down Matthew Garrett 2019-02-28 23:12 ` [PATCH 27/27] lockdown: Print current->comm in restriction messages Matthew Garrett 2019-02-28 23:24 ` [PULL REQUEST] Lock down patches Randy Dunlap 2019-03-04 22:10 ` Matthew Garrett 2019-03-06 23:58 [PULL REQUEST] Kernel lockdown patches for 5.2 Matthew Garrett 2019-03-06 23:58 ` [PATCH 12/27] x86: Lock down IO port access when the kernel is locked down Matthew Garrett
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