Commit 0cdd192c authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar

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: default avatarAndy Lutomirski <luto@amacapital.net>
Acked-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/c4e339882c121aa76254f2adde3fcbdf502faec2.1405099506.git.luto@amacapital.netSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 44851541
...@@ -574,6 +574,9 @@ int kprobe_int3_handler(struct pt_regs *regs) ...@@ -574,6 +574,9 @@ int kprobe_int3_handler(struct pt_regs *regs)
struct kprobe *p; struct kprobe *p;
struct kprobe_ctlblk *kcb; struct kprobe_ctlblk *kcb;
if (user_mode_vm(regs))
return 0;
addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t)); addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
/* /*
* We don't want to be preempted for the entire * We don't want to be preempted for the entire
......
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