From: David Howells <dhowells@redhat.com> To: linux-kernel@vger.kernel.org Cc: matthew.garrett@nebula.com, linux-efi@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk, gregkh@linuxfoundation.org, dhowells@redhat.com, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org Subject: [PATCH 13/24] x86: Lock down IO port access when the kernel is locked down Date: Wed, 05 Apr 2017 18:11:57 +0100 [thread overview] Message-ID: <149141231727.31282.13136365348865384649.stgit@warthog.procyon.org.uk> (raw) In-Reply-To: <149141219387.31282.6648284836568938717.stgit@warthog.procyon.org.uk> From: Matthew Garrett <matthew.garrett@nebula.com> 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 <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com> --- arch/x86/kernel/ioport.c | 4 ++-- drivers/char/mem.c | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 9c3cf0944bce..4a613fed94b6 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -30,7 +30,7 @@ asmlinkage long sys_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())) return -EPERM; /* @@ -120,7 +120,7 @@ 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()) return -EPERM; } regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | diff --git a/drivers/char/mem.c b/drivers/char/mem.c index f8144049bda3..9afebb60550f 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -741,6 +741,8 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig) static int open_port(struct inode *inode, struct file *filp) { + if (kernel_is_locked_down()) + return -EPERM; return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; }
WARNING: multiple messages have this Message-ID (diff)
From: dhowells@redhat.com (David Howells) To: linux-security-module@vger.kernel.org Subject: [PATCH 13/24] x86: Lock down IO port access when the kernel is locked down Date: Wed, 05 Apr 2017 18:11:57 +0100 [thread overview] Message-ID: <149141231727.31282.13136365348865384649.stgit@warthog.procyon.org.uk> (raw) In-Reply-To: <149141219387.31282.6648284836568938717.stgit@warthog.procyon.org.uk> From: Matthew Garrett <matthew.garrett@nebula.com> 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 <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com> --- arch/x86/kernel/ioport.c | 4 ++-- drivers/char/mem.c | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 9c3cf0944bce..4a613fed94b6 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -30,7 +30,7 @@ asmlinkage long sys_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())) return -EPERM; /* @@ -120,7 +120,7 @@ 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()) return -EPERM; } regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | diff --git a/drivers/char/mem.c b/drivers/char/mem.c index f8144049bda3..9afebb60550f 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -741,6 +741,8 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig) static int open_port(struct inode *inode, struct file *filp) { + if (kernel_is_locked_down()) + return -EPERM; return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; } -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2017-04-05 17:14 UTC|newest] Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-04-05 17:09 [PATCH 00/24] Kernel lockdown David Howells 2017-04-05 17:09 ` David Howells 2017-04-05 17:10 ` [PATCH 01/24] efi: Add EFI_SECURE_BOOT bit David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:10 ` [PATCH 02/24] Add the ability to lock down access to the running kernel image David Howells 2017-04-05 17:10 ` David Howells 2017-04-06 8:44 ` James Morris 2017-04-06 8:44 ` James Morris 2017-04-06 8:44 ` James Morris 2017-04-06 10:43 ` David Howells 2017-04-06 10:43 ` David Howells 2017-04-06 21:55 ` James Morris 2017-04-06 21:55 ` James Morris 2017-04-06 21:55 ` James Morris 2017-04-05 17:10 ` [PATCH 03/24] efi: Lock down the kernel if booted in secure boot mode David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:10 ` [PATCH 04/24] Enforce module signatures if the kernel is locked down David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:10 ` [PATCH 05/24] Restrict /dev/mem and /dev/kmem when " David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:10 ` [PATCH 06/24] Add a sysrq option to exit secure boot mode David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:10 ` [PATCH 07/24] kexec: Disable at runtime if the kernel is locked down David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:11 ` [PATCH 08/24] Copy secure_boot flag in boot params across kexec reboot David Howells 2017-04-05 17:11 ` David Howells 2017-04-05 17:11 ` [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set David Howells 2017-04-05 17:11 ` David Howells 2017-04-05 17:11 ` [PATCH 10/24] hibernate: Disable when the kernel is locked down David Howells 2017-04-05 17:11 ` David Howells 2017-04-05 17:11 ` David Howells 2017-04-05 17:11 ` [PATCH 11/24] uswsusp: " David Howells 2017-04-05 17:11 ` David Howells 2017-04-05 17:11 ` [PATCH 12/24] PCI: Lock down BAR access " David Howells 2017-04-05 17:11 ` David Howells 2017-04-05 17:11 ` David Howells [this message] 2017-04-05 17:11 ` [PATCH 13/24] x86: Lock down IO port " David Howells 2017-04-05 17:12 ` [PATCH 14/24] x86: Restrict MSR " David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 17:34 ` Kees Cook 2017-04-05 17:34 ` Kees Cook 2017-04-05 17:34 ` Kees Cook 2017-04-05 17:12 ` [PATCH 15/24] asus-wmi: Restrict debugfs interface " David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 17:12 ` [PATCH 16/24] ACPI: Limit access to custom_method " David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 17:12 ` [PATCH 17/24] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 17:12 ` [PATCH 18/24] acpi: Disable ACPI table override if the kernel is " David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 17:12 ` [PATCH 19/24] acpi: Disable APEI error injection " David Howells 2017-04-05 17:12 ` David Howells 2017-04-05 19:57 ` [PATCH 00/24] Kernel lockdown David Howells 2017-04-05 19:57 ` David Howells 2017-04-05 19:57 ` David Howells 2017-04-06 8:25 ` James Morris 2017-04-06 8:25 ` James Morris 2017-04-06 8:25 ` James Morris 2017-04-06 8:37 ` David Howells 2017-04-06 8:37 ` David Howells 2017-04-06 8:37 ` David Howells 2017-04-05 20:14 David Howells 2017-04-05 20:16 ` [PATCH 13/24] x86: Lock down IO port access when the kernel is locked down David Howells 2017-04-05 20:16 ` David Howells 2017-04-05 20:16 ` David Howells 2017-04-14 18:28 ` Thomas Gleixner 2017-04-14 18:28 ` Thomas Gleixner 2017-04-14 18:28 ` Thomas Gleixner
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