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Message-ID: <m1k5p9zk6b.fsf_-_@ebiederm.dsl.xmission.com> Date: Fri, 26 Oct 2007 14:37:48 -0600 From: ebiederm@...ssion.com (Eric W. Biederman) To: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org, Pavel Emelyanov <xemul@...nvz.org>, Sukadev Bhattiprolu <sukadev@...ibm.com>, Linux Containers <containers@...ts.osdl.org>, Oleg Nesterov <oleg@...sign.ru> Subject: [PATCH] pidns: Limit kill -1 and cap_set_all This patch implements task_in_pid_ns and uses it to limit cap_set_all and sys_kill(-1,) to only those tasks in the current pid namespace. Without this we have a setup for a very nasty surprise. Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com> --- include/linux/pid_namespace.h | 2 ++ kernel/capability.c | 3 +++ kernel/pid.c | 11 +++++++++++ kernel/signal.c | 5 ++++- 4 files changed, 20 insertions(+), 1 deletions(-) diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index 0227e68..b454678 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -78,4 +78,6 @@ static inline struct task_struct *task_child_reaper(struct task_struct *tsk) return tsk->nsproxy->pid_ns->child_reaper; } +extern int task_in_pid_ns(struct task_struct *tsk, struct pid_namespace *ns); + #endif /* _LINUX_PID_NS_H */ diff --git a/kernel/capability.c b/kernel/capability.c index efbd9cd..a801016 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -125,6 +125,7 @@ static inline int cap_set_all(kernel_cap_t *effective, kernel_cap_t *inheritable, kernel_cap_t *permitted) { + struct pid_namespace *pid_ns = current->nsproxy->pid_ns; struct task_struct *g, *target; int ret = -EPERM; int found = 0; @@ -132,6 +133,8 @@ static inline int cap_set_all(kernel_cap_t *effective, do_each_thread(g, target) { if (target == current || is_container_init(target->group_leader)) continue; + if (!task_in_pid_ns(target, pid_ns)) + continue; found = 1; if (security_capset_check(target, effective, inheritable, permitted)) diff --git a/kernel/pid.c b/kernel/pid.c index f815455..1c332ca 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -430,6 +430,17 @@ struct pid *find_get_pid(pid_t nr) return pid; } +static int pid_in_pid_ns(struct pid *pid, struct pid_namespace *ns) +{ + return pid && (ns->level <= pid->level) && + pid->numbers[ns->level].ns == ns; +} + +int task_in_pid_ns(struct task_struct *task, struct pid_namespace *ns) +{ + return pid_in_pid_ns(task_pid(task), ns); +} + pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns) { struct upid *upid; diff --git a/kernel/signal.c b/kernel/signal.c index 1200630..8f5a31f 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1147,10 +1147,13 @@ static int kill_something_info(int sig, struct siginfo *info, int pid) } else if (pid == -1) { int retval = 0, count = 0; struct task_struct * p; + struct pid_namespace *ns = current->nsproxy->pid_ns; read_lock(&tasklist_lock); for_each_process(p) { - if (p->pid > 1 && !same_thread_group(p, current)) { + if (!is_container_init(p) && + !same_thread_group(p, current) && + task_in_pid_ns(p, ns)) { int err = group_send_sig_info(sig, info, p); ++count; if (err != -EPERM) -- 1.5.3.rc6.17.g1911 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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