2015-08-05 1:29 GMT+02:00 平松雅巳 / HIRAMATU，MASAMI <[email protected]>: > Hi, > >> From: Frederic Weisbecker [mailto:[email protected]] >> >> On Thu, Jul 30, 2015 at 08:32:40PM -0700, Andy Lutomirski wrote: >> > Code on the kprobe blacklist doesn't want unexpected int3 >> > exceptions. It probably doesn't want unexpected debug exceptions >> > either. Be safe: disallow breakpoints in nokprobes code. >> > >> > On non-CONFIG_KPROBES kernels, there is no kprobe blacklist. In >> > that case, disallow kernel breakpoints entirely. >> > >> > It will be particularly important to keep hw breakpoints out of the >> > entry and NMI code once we move debug exceptions off the IST stack. >> > >> > Signed-off-by: Andy Lutomirski <[email protected]> >> > --- >> > arch/x86/kernel/hw_breakpoint.c | 15 +++++++++++++++ >> > include/linux/kprobes.h | 2 ++ >> > kernel/kprobes.c | 2 +- >> > 3 files changed, 18 insertions(+), 1 deletion(-) >> > >> > diff --git a/arch/x86/kernel/hw_breakpoint.c >> > b/arch/x86/kernel/hw_breakpoint.c >> > index 7114ba220fd4..78f3e90c5659 100644 >> > --- a/arch/x86/kernel/hw_breakpoint.c >> > +++ b/arch/x86/kernel/hw_breakpoint.c >> > @@ -32,6 +32,7 @@ >> > #include <linux/irqflags.h> >> > #include <linux/notifier.h> >> > #include <linux/kallsyms.h> >> > +#include <linux/kprobes.h> >> > #include <linux/percpu.h> >> > #include <linux/kdebug.h> >> > #include <linux/kernel.h> >> > @@ -243,6 +244,20 @@ static int arch_build_bp_info(struct perf_event *bp) >> > info->type = X86_BREAKPOINT_RW; >> > break; >> > case HW_BREAKPOINT_X: >> > + /* >> > + * We don't allow kernel breakpoints in places that are not >> > + * acceptable for kprobes. On non-kprobes kernels, we don't >> > + * allow kernel breakpoints at all. >> > + */ >> > + if (bp->attr.bp_addr >= TASK_SIZE_MAX) { >> > +#ifdef CONFIG_KPROBES >> > + if (within_kprobe_blacklist(bp->attr.bp_addr)) >> > + return -EINVAL; >> > +#else >> > + return -EINVAL; >> > +#endif >> > + } >> > + >> >> It should be done on generic code I think. In validate_hw_breakpoint() >> under the arch_check_bp_in_kernelspace() check. > > Agreed, kprobes also does it in generic code.
Well, the patchset got applied anyway and the reviews ignored... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
