From: Matthew Garrett
Git-commit: Not yet, reviewing
Patch-mainline: Not yet, reviewing
References: fate#314486
Target: SLE-11 SP3
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.
Signed-off-by: Matthew Garrett
Acked-by: Lee, Chun-Yi
---
arch/x86/kernel/ioport.c | 4 ++--
drivers/char/mem.c | 3 +++
2 files changed, 5 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -28,7 +28,7 @@ asmlinkage long sys_ioperm(unsigned long
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) || !capable(CAP_COMPROMISE_KERNEL)))
return -EPERM;
/*
@@ -102,7 +102,7 @@ long sys_iopl(unsigned int level, struct
return -EINVAL;
/* Trying to gain more privileges? */
if (level > old) {
- if (!capable(CAP_SYS_RAWIO))
+ if (!capable(CAP_SYS_RAWIO) || !capable(CAP_COMPROMISE_KERNEL))
return -EPERM;
}
regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | (level << 12);
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -609,6 +609,9 @@ static ssize_t write_port(struct file *f
unsigned long i = *ppos;
const char __user * tmp = buf;
+ if (!capable(CAP_COMPROMISE_KERNEL))
+ return -EPERM;
+
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
while (count-- > 0 && i < 65536) {
--
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