diff options
| -rw-r--r-- | include/linux/capability.h | 2 | ||||
| -rw-r--r-- | kernel/ptrace.c | 27 | ||||
| -rw-r--r-- | security/commoncap.c | 40 |
3 files changed, 49 insertions, 20 deletions
diff --git a/include/linux/capability.h b/include/linux/capability.h index 7c9c829..2ec4a8c 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -553,6 +553,8 @@ static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, */ #define has_capability(t, cap) (security_real_capable((t), &init_user_ns, (cap)) == 0) +#define has_ns_capability(t, ns, cap) (security_real_capable((t), (ns), (cap)) == 0) + /** * has_capability_noaudit - Determine if a task has a superior capability available (unaudited) * @t: The task in question diff --git a/kernel/ptrace.c b/kernel/ptrace.c index e2302e4..0fc1eed 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -134,21 +134,24 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode) return 0; rcu_read_lock(); tcred = __task_cred(task); - if ((cred->uid != tcred->euid || - cred->uid != tcred->suid || - cred->uid != tcred->uid || - cred->gid != tcred->egid || - cred->gid != tcred->sgid || - cred->gid != tcred->gid) && - !capable(CAP_SYS_PTRACE)) { - rcu_read_unlock(); - return -EPERM; - } + if (cred->user->user_ns == tcred->user->user_ns && + (cred->uid == tcred->euid && + cred->uid == tcred->suid && + cred->uid == tcred->uid && + cred->gid == tcred->egid && + cred->gid == tcred->sgid && + cred->gid == tcred->gid)) + goto ok; + if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE)) + goto ok; + rcu_read_unlock(); + return -EPERM; +ok: rcu_read_unlock(); smp_rmb(); if (task->mm) dumpable = get_dumpable(task->mm); - if (!dumpable && !capable(CAP_SYS_PTRACE)) + if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE)) return -EPERM; return security_ptrace_access_check(task, mode); @@ -198,7 +201,7 @@ static int ptrace_attach(struct task_struct *task) goto unlock_tasklist; task->ptrace = PT_PTRACED; - if (capable(CAP_SYS_PTRACE)) + if (task_ns_capable(task, CAP_SYS_PTRACE)) task->ptrace |= PT_PTRACE_CAP; __ptrace_link(task, current); diff --git a/security/commoncap.c b/security/commoncap.c index 43a205b..f20e984 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -127,18 +127,30 @@ int cap_settime(const struct timespec *ts, const struct timezone *tz) * @child: The process to be accessed * @mode: The mode of attachment. * + * If we are in the same or an ancestor user_ns and have all the target + * task's capabilities, then ptrace access is allowed. + * If we have the ptrace capability to the target user_ns, then ptrace + * access is allowed. + * Else denied. + * * Determine whether a process may access another, returning 0 if permission * granted, -ve if denied. */ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) { int ret = 0; + const struct cred *cred, *child_cred; rcu_read_lock(); - if (!cap_issubset(__task_cred(child)->cap_permitted, - current_cred()->cap_permitted) && - !capable(CAP_SYS_PTRACE)) - ret = -EPERM; + cred = current_cred(); + child_cred = __task_cred(child); + if (cred->user->user_ns == child_cred->user->user_ns && + cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) + goto out; + if (ns_capable(child_cred->user->user_ns, CAP_SYS_PTRACE)) + goto out; + ret = -EPERM; +out: rcu_read_unlock(); return ret; } @@ -147,18 +159,30 @@ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) * cap_ptrace_traceme - Determine whether another process may trace the current * @parent: The task proposed to be the tracer * + * If parent is in the same or an ancestor user_ns and has all current's + * capabilities, then ptrace access is allowed. + * If parent has the ptrace capability to current's user_ns, then ptrace + * access is allowed. + * Else denied. + * * Determine whether the nominated task is permitted to trace the current * process, returning 0 if permission is granted, -ve if denied. */ int cap_ptrace_traceme(struct task_struct *parent) { int ret = 0; + const struct cred *cred, *child_cred; rcu_read_lock(); - if (!cap_issubset(current_cred()->cap_permitted, - __task_cred(parent)->cap_permitted) && - !has_capability(parent, CAP_SYS_PTRACE)) - ret = -EPERM; + cred = __task_cred(parent); + child_cred = current_cred(); + if (cred->user->user_ns == child_cred->user->user_ns && + cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) + goto out; + if (has_ns_capability(parent, child_cred->user->user_ns, CAP_SYS_PTRACE)) + goto out; + ret = -EPERM; +out: rcu_read_unlock(); return ret; } |
