linux-kernel - [PATCH] kprobes: handle empty/invalid input to debugfs "enabled" file

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 31 May 2013 23:15:10 +0200
From:	Mathias Krause <minipli@...glemail.com>
To:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc:	linux-kernel@...r.kernel.org,
	Mathias Krause <minipli@...glemail.com>,
	"David S. Miller" <davem@...emloft.net>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH] kprobes: handle empty/invalid input to debugfs "enabled" file

When writing invalid input to 'debug/kprobes/enabled' it'll silently
be ignored. Even worse, when writing an empty string to this file,
the outcome is purely random as the switch statement will make its
decision based on the value of an uninitialized stack variable.

Fix this by handling invalid/empty input as error returning -EINVAL.

Cc: Ananth N Mavinakayanahalli <ananth@...ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Mathias Krause <minipli@...glemail.com>
---
 kernel/kprobes.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3fed7f0..948b597 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2322,6 +2322,7 @@ static ssize_t write_enabled_file_bool(struct file *file,
 	if (copy_from_user(buf, user_buf, buf_size))
 		return -EFAULT;
 
+	buf[buf_size] = '\0';
 	switch (buf[0]) {
 	case 'y':
 	case 'Y':
@@ -2333,6 +2334,8 @@ static ssize_t write_enabled_file_bool(struct file *file,
 	case '0':
 		disarm_all_kprobes();
 		break;
+	default:
+		return -EINVAL;
 	}
 
 	return count;
-- 
1.7.10.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/