diff options
| -rw-r--r-- | fs/exec.c | 2 | ||||
| -rw-r--r-- | include/linux/capability.h | 1 | ||||
| -rw-r--r-- | include/linux/ptrace.h | 1 | ||||
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/capability.c | 20 | ||||
| -rw-r--r-- | kernel/ptrace.c | 11 |
6 files changed, 30 insertions, 6 deletions
diff --git a/fs/exec.c b/fs/exec.c index d392c8ad0de0..04c9cab4d4d3 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1254,7 +1254,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm) unsigned n_fs; if (p->ptrace) { - if (p->ptrace & PT_PTRACE_CAP) + if (ptracer_capable(p, current_user_ns())) bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; else bprm->unsafe |= LSM_UNSAFE_PTRACE; diff --git a/include/linux/capability.h b/include/linux/capability.h index af9f0b9e80e6..99d19db09908 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -244,6 +244,7 @@ static inline bool ns_capable(struct user_namespace *ns, int cap) #endif /* CONFIG_MULTIUSER */ extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); +extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns); /* audit system wants to get cap info from files as well */ extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 998c098dd172..e615c7553959 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -19,7 +19,6 @@ #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */ #define PT_PTRACED 0x00000001 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */ -#define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */ #define PT_OPT_FLAG_SHIFT 3 /* PT_TRACE_* event enable flags */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 9e39deaeddd6..c68ecb17a7e1 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1454,6 +1454,7 @@ struct task_struct { struct list_head cpu_timers[3]; /* process credentials */ + const struct cred __rcu *ptracer_cred; /* Tracer's credentials at attach */ const struct cred __rcu *real_cred; /* objective and real subjective task * credentials (COW) */ const struct cred __rcu *cred; /* effective (overridable) subjective task diff --git a/kernel/capability.c b/kernel/capability.c index 45432b54d5c6..022df097a6bc 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -447,3 +447,23 @@ bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) kgid_has_mapping(ns, inode->i_gid); } EXPORT_SYMBOL(capable_wrt_inode_uidgid); + +/** + * ptracer_capable - Determine if the ptracer holds CAP_SYS_PTRACE in the namespace + * @tsk: The task that may be ptraced + * @ns: The user namespace to search for CAP_SYS_PTRACE in + * + * Return true if the task that is ptracing the current task had CAP_SYS_PTRACE + * in the specified user namespace. + */ +bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns) +{ + int ret = 0; /* An absent tracer adds no restrictions */ + const struct cred *cred; + rcu_read_lock(); + cred = rcu_dereference(tsk->ptracer_cred); + if (cred) + ret = security_capable_noaudit(cred, ns, CAP_SYS_PTRACE); + rcu_read_unlock(); + return (ret == 0); +} diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 9650e7aee267..c67aab541ee2 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -40,6 +40,9 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) BUG_ON(!list_empty(&child->ptrace_entry)); list_add(&child->ptrace_entry, &new_parent->ptraced); child->parent = new_parent; + rcu_read_lock(); + child->ptracer_cred = get_cred(__task_cred(new_parent)); + rcu_read_unlock(); } /** @@ -72,11 +75,15 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) */ void __ptrace_unlink(struct task_struct *child) { + const struct cred *old_cred; BUG_ON(!child->ptrace); child->ptrace = 0; child->parent = child->real_parent; list_del_init(&child->ptrace_entry); + old_cred = child->ptracer_cred; + child->ptracer_cred = NULL; + put_cred(old_cred); spin_lock(&child->sighand->siglock); @@ -366,10 +373,6 @@ static int ptrace_attach(struct task_struct *task, long request, if (seize) flags |= PT_SEIZED; - rcu_read_lock(); - if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE)) - flags |= PT_PTRACE_CAP; - rcu_read_unlock(); task->ptrace = flags; __ptrace_link(task, current); |