linux-kernel - Re: [RFC][PATCH] Lock down kprobes

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Date:   Thu, 09 Nov 2017 15:31:10 +0000
From:   David Howells <dhowells@...hat.com>
To:     ananth@...ux.vnet.ibm.com
Cc:     dhowells@...hat.com,
        Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
        "David S. Miller" <davem@...emloft.net>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH] Lock down kprobes

So this?

Thanks,
David
---
commit b5bb759d5e7f99c357b82b8066a9106b817de965
Author: David Howells <dhowells@...hat.com>
Date:   Wed Nov 8 16:14:12 2017 +0000

    Lock down kprobes
    
    Disallow the creation of kprobes when the kernel is locked down by
    preventing their registration.
    
    Signed-off-by: David Howells <dhowells@...hat.com>

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index a1606a4224e1..f06023b0936c 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1530,6 +1530,9 @@ int register_kprobe(struct kprobe *p)
 	struct module *probed_mod;
 	kprobe_opcode_t *addr;
 
+	if (kernel_is_locked_down("Use of kprobes"))
+		return -EPERM;
+
 	/* Adjust probe address from symbol */
 	addr = kprobe_addr(p);
 	if (IS_ERR(addr))