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-rw-r--r--include/linux/capability.h2
-rw-r--r--kernel/ptrace.c27
-rw-r--r--security/commoncap.c40
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;
}
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