From 278842ee38edb148a3296de5440b812f47481721 Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Wed, 19 Jun 2013 10:07:23 +1000 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. Signed-off-by: Mathias Krause Cc: Ananth N Mavinakayanahalli Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Masami Hiramatsu Signed-off-by: Andrew Morton --- kernel/kprobes.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3fed7f0cbcdf..948b597671dd 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; -- 2.39.5