From 0cdd192cf40fb6dbf03ec3af1c670068de3fd26c Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Fri, 11 Jul 2014 10:27:01 -0700 Subject: [PATCH] kprobes/x86: Don't try to resolve kprobe faults from userspace This commit: commit 6f6343f53d133bae516caf3d254bce37d8774625 Author: Masami Hiramatsu 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 Acked-by: Masami Hiramatsu Link: http://lkml.kernel.org/r/c4e339882c121aa76254f2adde3fcbdf502faec2.1405099506.git.luto@amacapital.net Signed-off-by: Ingo Molnar --- arch/x86/kernel/kprobes/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 7596df664901..67e6d19ef1be 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -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 -- 2.45.2