From b7e724d303b684655e4ca3dabd5a6840ad19012d Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: capabilities: reverse arguments to security_capable security_capable takes ns, cred, cap. But the LSM capable() hook takes cred, ns, cap. The capability helper functions also take cred, ns, cap. Rather than flip argument order just to flip it back, leave them alone. Heck, this should be a little faster since argument will be in the right place! Signed-off-by: Eric Paris --- kernel/capability.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/capability.c') diff --git a/kernel/capability.c b/kernel/capability.c index 283c529f8b1c..d98392719adb 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -374,7 +374,7 @@ bool ns_capable(struct user_namespace *ns, int cap) BUG(); } - if (security_capable(ns, current_cred(), cap) == 0) { + if (security_capable(current_cred(), ns, cap) == 0) { current->flags |= PF_SUPERPRIV; return true; } -- cgit v1.2.3-58-ga151 From 2920a8409de5a51575d03deca07e5bb2be6fc98d Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: capabilities: remove all _real_ interfaces The name security_real_capable and security_real_capable_noaudit just don't make much sense to me. Convert them to use security_capable and security_capable_noaudit. Signed-off-by: Eric Paris Acked-by: Serge E. Hallyn --- include/linux/security.h | 25 ------------------------- kernel/capability.c | 18 +++++++++++++++--- security/security.c | 24 ------------------------ 3 files changed, 15 insertions(+), 52 deletions(-) (limited to 'kernel/capability.c') diff --git a/include/linux/security.h b/include/linux/security.h index caff54eee686..e345a9313a60 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1670,10 +1670,6 @@ int security_capable(const struct cred *cred, struct user_namespace *ns, int cap); int security_capable_noaudit(const struct cred *cred, struct user_namespace *ns, int cap); -int security_real_capable(struct task_struct *tsk, struct user_namespace *ns, - int cap); -int security_real_capable_noaudit(struct task_struct *tsk, - struct user_namespace *ns, int cap); int security_quotactl(int cmds, int type, int id, struct super_block *sb); int security_quota_on(struct dentry *dentry); int security_syslog(int type); @@ -1876,27 +1872,6 @@ static inline int security_capable_noaudit(const struct cred *cred, return cap_capable(cred, ns, cap, SECURITY_CAP_NOAUDIT); } -static inline int security_real_capable(struct task_struct *tsk, struct user_namespace *ns, int cap) -{ - int ret; - - rcu_read_lock(); - ret = cap_capable(__task_cred(tsk), ns, cap, SECURITY_CAP_AUDIT); - rcu_read_unlock(); - return ret; -} - -static inline -int security_real_capable_noaudit(struct task_struct *tsk, struct user_namespace *ns, int cap) -{ - int ret; - - rcu_read_lock(); - ret = cap_capable(__task_cred(tsk), ns, cap, SECURITY_CAP_NOAUDIT); - rcu_read_unlock(); - return ret; -} - static inline int security_quotactl(int cmds, int type, int id, struct super_block *sb) { diff --git a/kernel/capability.c b/kernel/capability.c index d98392719adb..ff50ab62cfca 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -298,7 +298,11 @@ error: */ bool has_capability(struct task_struct *t, int cap) { - int ret = security_real_capable(t, &init_user_ns, cap); + int ret; + + rcu_read_lock(); + ret = security_capable(__task_cred(t), &init_user_ns, cap); + rcu_read_unlock(); return (ret == 0); } @@ -317,7 +321,11 @@ bool has_capability(struct task_struct *t, int cap) bool has_ns_capability(struct task_struct *t, struct user_namespace *ns, int cap) { - int ret = security_real_capable(t, ns, cap); + int ret; + + rcu_read_lock(); + ret = security_capable(__task_cred(t), ns, cap); + rcu_read_unlock(); return (ret == 0); } @@ -335,7 +343,11 @@ bool has_ns_capability(struct task_struct *t, */ bool has_capability_noaudit(struct task_struct *t, int cap) { - int ret = security_real_capable_noaudit(t, &init_user_ns, cap); + int ret; + + rcu_read_lock(); + ret = security_capable_noaudit(__task_cred(t), &init_user_ns, cap); + rcu_read_unlock(); return (ret == 0); } diff --git a/security/security.c b/security/security.c index b7edaae77d1d..8900c5c4db5c 100644 --- a/security/security.c +++ b/security/security.c @@ -166,30 +166,6 @@ int security_capable_noaudit(const struct cred *cred, struct user_namespace *ns, return security_ops->capable(cred, ns, cap, SECURITY_CAP_NOAUDIT); } -int security_real_capable(struct task_struct *tsk, struct user_namespace *ns, - int cap) -{ - const struct cred *cred; - int ret; - - cred = get_task_cred(tsk); - ret = security_ops->capable(cred, ns, cap, SECURITY_CAP_AUDIT); - put_cred(cred); - return ret; -} - -int security_real_capable_noaudit(struct task_struct *tsk, - struct user_namespace *ns, int cap) -{ - const struct cred *cred; - int ret; - - cred = get_task_cred(tsk); - ret = security_ops->capable(cred, ns, cap, SECURITY_CAP_NOAUDIT); - put_cred(cred); - return ret; -} - int security_quotactl(int cmds, int type, int id, struct super_block *sb) { return security_ops->quotactl(cmds, type, id, sb); -- cgit v1.2.3-58-ga151 From 25e75703410a84b80623da3653db6b70282e5c6a Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: capabilities: call has_ns_capability from has_capability Declare the more specific has_ns_capability first in the code and then call it from has_capability. The declaration reversal isn't stricty necessary since they are both declared in header files, but it just makes sense to put more specific functions first in the code. Signed-off-by: Eric Paris Acked-by: Serge E. Hallyn --- kernel/capability.c | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-) (limited to 'kernel/capability.c') diff --git a/kernel/capability.c b/kernel/capability.c index ff50ab62cfca..fb815d1b9ea2 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -287,47 +287,41 @@ error: } /** - * has_capability - Does a task have a capability in init_user_ns + * has_ns_capability - Does a task have a capability in a specific user ns * @t: The task in question + * @ns: target user namespace * @cap: The capability to be tested for * * Return true if the specified task has the given superior capability - * currently in effect to the initial user namespace, false if not. + * currently in effect to the specified user namespace, false if not. * * Note that this does not set PF_SUPERPRIV on the task. */ -bool has_capability(struct task_struct *t, int cap) +bool has_ns_capability(struct task_struct *t, + struct user_namespace *ns, int cap) { int ret; rcu_read_lock(); - ret = security_capable(__task_cred(t), &init_user_ns, cap); + ret = security_capable(__task_cred(t), ns, cap); rcu_read_unlock(); return (ret == 0); } /** - * has_capability - Does a task have a capability in a specific user ns + * has_capability - Does a task have a capability in init_user_ns * @t: The task in question - * @ns: target user namespace * @cap: The capability to be tested for * * Return true if the specified task has the given superior capability - * currently in effect to the specified user namespace, false if not. + * currently in effect to the initial user namespace, false if not. * * Note that this does not set PF_SUPERPRIV on the task. */ -bool has_ns_capability(struct task_struct *t, - struct user_namespace *ns, int cap) +bool has_capability(struct task_struct *t, int cap) { - int ret; - - rcu_read_lock(); - ret = security_capable(__task_cred(t), ns, cap); - rcu_read_unlock(); - - return (ret == 0); + return has_ns_capability(t, &init_user_ns, cap); } /** -- cgit v1.2.3-58-ga151 From 7b61d648499e74dbec3d4ce645675e0ae040ae78 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: capabilites: introduce new has_ns_capabilities_noaudit For consistency in interfaces, introduce a new interface called has_ns_capabilities_noaudit. It checks if the given task has the given capability in the given namespace. Use this new function by has_capabilities_noaudit. Signed-off-by: Eric Paris Acked-by: Serge E. Hallyn --- include/linux/capability.h | 2 ++ kernel/capability.c | 30 +++++++++++++++++++++++++----- 2 files changed, 27 insertions(+), 5 deletions(-) (limited to 'kernel/capability.c') diff --git a/include/linux/capability.h b/include/linux/capability.h index c42112350003..63f59fa8769d 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -543,6 +543,8 @@ extern bool has_capability(struct task_struct *t, int cap); extern bool has_ns_capability(struct task_struct *t, struct user_namespace *ns, int cap); extern bool has_capability_noaudit(struct task_struct *t, int cap); +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); diff --git a/kernel/capability.c b/kernel/capability.c index fb815d1b9ea2..d8398e962470 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -325,27 +325,47 @@ bool has_capability(struct task_struct *t, int cap) } /** - * has_capability_noaudit - Does a task have a capability (unaudited) + * has_ns_capability_noaudit - Does a task have a capability (unaudited) + * in a specific user ns. * @t: The task in question + * @ns: target user namespace * @cap: The capability to be tested for * * Return true if the specified task has the given superior capability - * currently in effect to init_user_ns, false if not. Don't write an - * audit message for the check. + * currently in effect to the specified user namespace, false if not. + * Do not write an audit message for the check. * * Note that this does not set PF_SUPERPRIV on the task. */ -bool has_capability_noaudit(struct task_struct *t, int cap) +bool has_ns_capability_noaudit(struct task_struct *t, + struct user_namespace *ns, int cap) { int ret; rcu_read_lock(); - ret = security_capable_noaudit(__task_cred(t), &init_user_ns, cap); + ret = security_capable_noaudit(__task_cred(t), ns, cap); rcu_read_unlock(); return (ret == 0); } +/** + * has_capability_noaudit - Does a task have a capability (unaudited) in the + * initial user ns + * @t: The task in question + * @cap: The capability to be tested for + * + * Return true if the specified task has the given superior capability + * currently in effect to init_user_ns, false if not. Don't write an + * audit message for the check. + * + * Note that this does not set PF_SUPERPRIV on the task. + */ +bool has_capability_noaudit(struct task_struct *t, int cap) +{ + return has_ns_capability_noaudit(t, &init_user_ns, cap); +} + /** * capable - Determine if the current task has a superior capability in effect * @cap: The capability to be tested for -- cgit v1.2.3-58-ga151 From 105ddf49cd301b7929a92f269440e8e562ef19db Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: capabilities: style only - move capable below ns_capable Although the current code is fine for consistency this moves the capable code below the function it calls in the c file. It doesn't actually change code. Signed-off-by: Eric Paris Acked-by: Serge E. Hallyn --- kernel/capability.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) (limited to 'kernel/capability.c') diff --git a/kernel/capability.c b/kernel/capability.c index d8398e962470..5f99e5d68e1f 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -366,22 +366,6 @@ bool has_capability_noaudit(struct task_struct *t, int cap) return has_ns_capability_noaudit(t, &init_user_ns, cap); } -/** - * capable - Determine if the current task has a superior capability in effect - * @cap: The capability to be tested for - * - * Return true if the current task has the given superior capability currently - * available for use, false if not. - * - * This sets PF_SUPERPRIV on the task if the capability is available on the - * assumption that it's about to be used. - */ -bool capable(int cap) -{ - return ns_capable(&init_user_ns, cap); -} -EXPORT_SYMBOL(capable); - /** * ns_capable - Determine if the current task has a superior capability in effect * @ns: The usernamespace we want the capability in @@ -408,6 +392,22 @@ bool ns_capable(struct user_namespace *ns, int cap) } EXPORT_SYMBOL(ns_capable); +/** + * capable - Determine if the current task has a superior capability in effect + * @cap: The capability to be tested for + * + * Return true if the current task has the given superior capability currently + * available for use, false if not. + * + * This sets PF_SUPERPRIV on the task if the capability is available on the + * assumption that it's about to be used. + */ +bool capable(int cap) +{ + return ns_capable(&init_user_ns, cap); +} +EXPORT_SYMBOL(capable); + /** * task_ns_capable - Determine whether current task has a superior * capability targeted at a specific task's user namespace. -- cgit v1.2.3-58-ga151 From d2a7009f0bb03fa22ad08dd25472efa0568126b9 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: capabitlies: ns_capable can use the cap helpers rather than lsm call Just to reduce the number of places to change if we every change the LSM hook, use the capability helpers internally when possible. Signed-off-by: Eric Paris Acked-by: Serge E. Hallyn --- kernel/capability.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/capability.c') diff --git a/kernel/capability.c b/kernel/capability.c index 5f99e5d68e1f..47626446c39a 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -384,7 +384,7 @@ bool ns_capable(struct user_namespace *ns, int cap) BUG(); } - if (security_capable(current_cred(), ns, cap) == 0) { + if (has_ns_capability(current, ns, cap)) { current->flags |= PF_SUPERPRIV; return true; } -- cgit v1.2.3-58-ga151 From f1c84dae0ecc51aa35c81f19a0ebcd6c0921ddcb Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Jan 2012 12:25:15 -0500 Subject: 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(-) (limited to 'kernel/capability.c') 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); -- cgit v1.2.3-58-ga151