From: Xiaoming Ni <nixiaoming@huawei.com>
To: <linux-kernel@vger.kernel.org>, <mcgrof@kernel.org>,
<keescook@chromium.org>, <yzaikin@google.com>,
<adobriyan@gmail.com>, <linux-fsdevel@vger.kernel.org>,
<vbabka@suse.cz>, <akpm@linux-foundation.org>, <mhocko@suse.com>,
<andy.shevchenko@gmail.com>
Cc: <nixiaoming@huawei.com>, <wangle6@huawei.com>
Subject: [PATCH v3] proc_sysctl: fix oops caused by incorrect command parameters.
Date: Tue, 12 Jan 2021 11:31:55 +0800 [thread overview]
Message-ID: <20210112033155.91502-1-nixiaoming@huawei.com> (raw)
The process_sysctl_arg() does not check whether val is empty before
invoking strlen(val). If the command line parameter () is incorrectly
configured and val is empty, oops is triggered.
For example:
"hung_task_panic=1" is incorrectly written as "hung_task_panic", oops is
triggered. The call stack is as follows:
Kernel command line: .... hung_task_panic
......
Call trace:
__pi_strlen+0x10/0x98
parse_args+0x278/0x344
do_sysctl_args+0x8c/0xfc
kernel_init+0x5c/0xf4
ret_from_fork+0x10/0x30
To fix it, check whether "val" is empty when "phram" is a sysctl field.
Error codes are returned in the failure branch, and error logs are
generated by parse_args().
Fixes: 3db978d480e2843 ("kernel/sysctl: support setting sysctl parameters
from kernel command line")
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
---------
v3:
Return -EINVAL, When phram is the sysctl field and val is empty.
v2: https://lore.kernel.org/lkml/20210108023339.55917-1-nixiaoming@huawei.com/
Added log output of the failure branch based on the review comments of Kees Cook.
v1: https://lore.kernel.org/lkml/20201224074256.117413-1-nixiaoming@huawei.com/
---------
---
fs/proc/proc_sysctl.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 317899222d7f..d493a50058a5 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1770,6 +1770,9 @@ static int process_sysctl_arg(char *param, char *val,
return 0;
}
+ if (!val)
+ return -EINVAL;
+
/*
* To set sysctl options, we use a temporary mount of proc, look up the
* respective sys/ file and write to it. To avoid mounting it when no
--
2.27.0
next reply other threads:[~2021-01-12 3:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 3:31 Xiaoming Ni [this message]
2021-01-12 4:33 ` [PATCH v3] proc_sysctl: fix oops caused by incorrect command parameters Andrew Morton
2021-01-12 6:24 ` Xiaoming Ni
2021-01-12 6:28 ` Andrew Morton
2021-01-12 7:24 ` Michal Hocko
2021-01-12 11:42 ` Vlastimil Babka
2021-01-17 2:59 ` Xiaoming Ni
2021-01-18 10:50 ` Vlastimil Babka
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