Commit 0cdd192c authored Jul 11, 2014 by Andy Lutomirski Committed by Ingo Molnar Jul 16, 2014

kprobes/x86: Don't try to resolve kprobe faults from userspace



This commit:

    commit 6f6343f5
    Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    Date:   Thu Apr 17 17:17:33 2014 +0900

        kprobes/x86: Call exception handlers directly from do_int3/do_debug

appears to have inadvertently dropped a check that the int3 came
from kernel mode.  Trying to dereference addr when addr is
user-controlled is completely bogus.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/c4e339882c121aa76254f2adde3fcbdf502faec2.1405099506.git.luto@amacapital.net


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 44851541

arch/x86/kernel/kprobes/core.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -574,6 +574,9 @@ int kprobe_int3_handler(struct pt_regs *regs)
		struct kprobe *p;
		struct kprobe_ctlblk *kcb;

		if (user_mode_vm(regs))
		return 0;

		addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
		/*
		* We don't want to be preempted for the entire