56 lines
2.0 KiB
Diff
56 lines
2.0 KiB
Diff
From: Matthew Garrett <matthew.garrett@nebula.com>
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Date: Wed, 5 Apr 2017 17:40:30 +0100
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Subject: [50/61] x86: Lock down IO port access when the kernel is locked down
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Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=37a19fd0d859cc12f1d6f47085071e35d34a0a41
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IO port access would permit users to gain access to PCI configuration
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registers, which in turn (on a lot of hardware) give access to MMIO
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register space. This would potentially permit root to trigger arbitrary
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DMA, so lock it down by default.
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This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and
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KDDISABIO console ioctls.
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Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
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Signed-off-by: David Howells <dhowells@redhat.com>
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---
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arch/x86/kernel/ioport.c | 4 ++--
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drivers/char/mem.c | 2 ++
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2 files changed, 4 insertions(+), 2 deletions(-)
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diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
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index 9c3cf0944bce..4a613fed94b6 100644
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--- a/arch/x86/kernel/ioport.c
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+++ b/arch/x86/kernel/ioport.c
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@@ -30,7 +30,7 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
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if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
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return -EINVAL;
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- if (turn_on && !capable(CAP_SYS_RAWIO))
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+ if (turn_on && (!capable(CAP_SYS_RAWIO) || kernel_is_locked_down()))
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return -EPERM;
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/*
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@@ -120,7 +120,7 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
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return -EINVAL;
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/* Trying to gain more privileges? */
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if (level > old) {
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- if (!capable(CAP_SYS_RAWIO))
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+ if (!capable(CAP_SYS_RAWIO) || kernel_is_locked_down())
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return -EPERM;
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}
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regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) |
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diff --git a/drivers/char/mem.c b/drivers/char/mem.c
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index f8144049bda3..9afebb60550f 100644
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--- a/drivers/char/mem.c
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+++ b/drivers/char/mem.c
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@@ -741,6 +741,8 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
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static int open_port(struct inode *inode, struct file *filp)
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{
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+ if (kernel_is_locked_down())
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+ return -EPERM;
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return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
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}
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