diff options
Diffstat (limited to 'security/commoncap.c')
| -rw-r--r-- | security/commoncap.c | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index 43a205bc7d7..f20e984ccfb 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; } |