From: "Maciej Żenczykowski" <zenczykowski@gmail.com>
To: "Maciej Żenczykowski" <maze@google.com>
Cc: linux-security-module@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Mahesh Bandewar <maheshb@google.com>,
Willem de Bruijn <willemb@google.com>
Subject: [PATCH] userns: honour no_new_privs for cap_bset during user ns creation/switch
Date: Thu, 21 Dec 2017 13:06:05 -0800 [thread overview]
Message-ID: <20171221210605.181720-1-zenczykowski@gmail.com> (raw)
From: Maciej Żenczykowski <maze@google.com>
This allows locking down user namespaces tighter,
and it could even be considered a security fix.
Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
kernel/user_namespace.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 246d4d4ce5c7..2354f7ade78a 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -50,11 +50,12 @@ static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns)
* anything as the capabilities are bound to the new user namespace.
*/
cred->securebits = SECUREBITS_DEFAULT;
+ cred->cap_bset = task_no_new_privs(current) ? current_cred()->cap_bset
+ : CAP_FULL_SET;
cred->cap_inheritable = CAP_EMPTY_SET;
- cred->cap_permitted = CAP_FULL_SET;
- cred->cap_effective = CAP_FULL_SET;
+ cred->cap_permitted = cred->cap_bset;
+ cred->cap_effective = cred->cap_bset;
cred->cap_ambient = CAP_EMPTY_SET;
- cred->cap_bset = CAP_FULL_SET;
#ifdef CONFIG_KEYS
key_put(cred->request_key_auth);
cred->request_key_auth = NULL;
--
2.15.1.620.gb9897f4670-goog
next reply other threads:[~2017-12-21 21:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-21 21:06 Maciej Żenczykowski [this message]
2017-12-21 21:44 ` [PATCH] userns: honour no_new_privs for cap_bset during user ns creation/switch Eric W. Biederman
2017-12-22 1:03 ` Maciej Żenczykowski
2017-12-22 1:18 ` Eric W. Biederman
2017-12-22 1:51 ` Maciej Żenczykowski
2017-12-22 14:08 ` Eric W. Biederman
2018-01-03 11:23 ` Christian Brauner
2017-12-22 2:17 ` Aleksa Sarai
2017-12-22 14:21 ` Eric W. Biederman
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