From f1c84dae0ecc51aa35c81f19a0ebcd6c0921ddcb Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: [PATCH] capabilities: remove task_ns_* functions task_ in the front of a function, in the security subsystem anyway, means to me at least, that we are operating with that task as the subject of the security decision. In this case what it means is that we are using current as the subject but we use the task to get the right namespace. Who in the world would ever realize that's what task_ns_capability means just by the name? This patch eliminates the task_ns functions entirely and uses the has_ns_capability function instead. This means we explicitly open code the ns in question in the caller. I think it makes the caller a LOT more clear what is going on. Signed-off-by: Eric Paris Acked-by: Serge E. Hallyn --- include/linux/capability.h | 1 - include/linux/cred.h | 6 ++++-- kernel/capability.c | 14 -------------- kernel/ptrace.c | 4 ++-- kernel/sched.c | 2 +- 5 files changed, 7 insertions(+), 20 deletions(-) diff --git a/include/linux/capability.h b/include/linux/capability.h index 63f59fa8769d..e3e8d9cb9b08 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -547,7 +547,6 @@ extern bool has_ns_capability_noaudit(struct task_struct *t, struct user_namespace *ns, int cap); extern bool capable(int cap); extern bool ns_capable(struct user_namespace *ns, int cap); -extern bool task_ns_capable(struct task_struct *t, int cap); extern bool nsown_capable(int cap); /* audit system wants to get cap info from files as well */ diff --git a/include/linux/cred.h b/include/linux/cred.h index 40308969ed00..adadf71a7327 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -358,10 +358,12 @@ static inline void put_cred(const struct cred *_cred) #define current_security() (current_cred_xxx(security)) #ifdef CONFIG_USER_NS -#define current_user_ns() (current_cred_xxx(user_ns)) +#define current_user_ns() (current_cred_xxx(user_ns)) +#define task_user_ns(task) (task_cred_xxx((task), user_ns)) #else extern struct user_namespace init_user_ns; -#define current_user_ns() (&init_user_ns) +#define current_user_ns() (&init_user_ns) +#define task_user_ns(task) (&init_user_ns) #endif diff --git a/kernel/capability.c b/kernel/capability.c index 47626446c39a..74fb3b603045 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -408,20 +408,6 @@ bool capable(int cap) } EXPORT_SYMBOL(capable); -/** - * task_ns_capable - Determine whether current task has a superior - * capability targeted at a specific task's user namespace. - * @t: The task whose user namespace is targeted. - * @cap: The capability in question. - * - * Return true if it does, false otherwise. - */ -bool task_ns_capable(struct task_struct *t, int cap) -{ - return ns_capable(task_cred_xxx(t, user)->user_ns, cap); -} -EXPORT_SYMBOL(task_ns_capable); - /** * nsown_capable - Check superior capability to one's own user_ns * @cap: The capability in question diff --git a/kernel/ptrace.c b/kernel/ptrace.c index a70d2a5d8c7b..210bbf045ee9 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -196,7 +196,7 @@ ok: smp_rmb(); if (task->mm) dumpable = get_dumpable(task->mm); - if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE)) + if (!dumpable && !ns_capable(task_user_ns(task), CAP_SYS_PTRACE)) return -EPERM; return security_ptrace_access_check(task, mode); @@ -266,7 +266,7 @@ static int ptrace_attach(struct task_struct *task, long request, task->ptrace = PT_PTRACED; if (seize) task->ptrace |= PT_SEIZED; - if (task_ns_capable(task, CAP_SYS_PTRACE)) + if (ns_capable(task_user_ns(task), CAP_SYS_PTRACE)) task->ptrace |= PT_PTRACE_CAP; __ptrace_link(task, current); diff --git a/kernel/sched.c b/kernel/sched.c index b50b0f0c9aa9..5670028a9c16 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5409,7 +5409,7 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) goto out_free_cpus_allowed; } retval = -EPERM; - if (!check_same_owner(p) && !task_ns_capable(p, CAP_SYS_NICE)) + if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE)) goto out_unlock; retval = security_task_setscheduler(p);