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authorEric W. Biederman <ebiederm@xmission.com>2012-07-26 05:05:21 -0700
committerEric W. Biederman <ebiederm@xmission.com>2012-11-20 04:17:44 -0800
commit4c44aaafa8108f584831850ab48a975e971db2de (patch)
treec86f225e8256d28271acf3ea8926e70358f3e5c1 /include/linux/cred.h
parentbcf58e725ddc45d31addbc6627d4f0edccc824c1 (diff)
downloadlinux-4c44aaafa8108f584831850ab48a975e971db2de.tar.gz
userns: Kill task_user_ns
The task_user_ns function hides the fact that it is getting the user namespace from struct cred on the task. struct cred may go away as soon as the rcu lock is released. This leads to a race where we can dereference a stale user namespace pointer. To make it obvious a struct cred is involved kill task_user_ns. To kill the race modify the users of task_user_ns to only reference the user namespace while the rcu lock is held. Cc: Kees Cook <keescook@chromium.org> Cc: James Morris <james.l.morris@oracle.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'include/linux/cred.h')
-rw-r--r--include/linux/cred.h2
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h
index ebbed2ce663..856d2622d83 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -357,10 +357,8 @@ static inline void put_cred(const struct cred *_cred)
extern struct user_namespace init_user_ns;
#ifdef CONFIG_USER_NS
#define current_user_ns() (current_cred_xxx(user_ns))
-#define task_user_ns(task) (task_cred_xxx((task), user_ns))
#else
#define current_user_ns() (&init_user_ns)
-#define task_user_ns(task) (&init_user_ns)
#endif