Message ID | 149142338597.5101.14728426552744019377.stgit@warthog.procyon.org.uk (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On Wed, 5 Apr 2017, David Howells wrote: > 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> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; }