[PATCH] userns: honour no_new_privs for cap_bset during user ns creation/switch
From: Maciej Żenczykowski <hidden>
Date: 2017-12-21 21:06:36
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Maciej ?enczykowski <redacted> This allows locking down user namespaces tighter, and it could even be considered a security fix. Signed-off-by: Maciej ?enczykowski <redacted> --- 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
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