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Diffstat (limited to 'kernel/futex/syscalls.c')
-rw-r--r--kernel/futex/syscalls.c148
1 files changed, 81 insertions, 67 deletions
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index 4b6da9116aa6..2fa19d9d008d 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -25,20 +25,66 @@
* @head: pointer to the list-head
* @len: length of the list-head, as userspace expects
*/
-SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
- size_t, len)
+SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head, size_t, len)
{
- /*
- * The kernel knows only one size for now:
- */
+ /* The kernel knows only one size for now. */
if (unlikely(len != sizeof(*head)))
return -EINVAL;
- current->robust_list = head;
-
+ current->futex.robust_list = head;
return 0;
}
+static inline void __user *futex_task_robust_list(struct task_struct *p, bool compat)
+{
+#ifdef CONFIG_COMPAT
+ if (compat)
+ return p->futex.compat_robust_list;
+#endif
+ return p->futex.robust_list;
+}
+
+static void __user *futex_get_robust_list_common(int pid, bool compat)
+{
+ struct task_struct *p = current;
+ void __user *head;
+ int ret;
+
+ scoped_guard(rcu) {
+ if (pid) {
+ p = find_task_by_vpid(pid);
+ if (!p)
+ return (void __user *)ERR_PTR(-ESRCH);
+ }
+ get_task_struct(p);
+ }
+
+ /*
+ * Hold exec_update_lock to serialize with concurrent exec()
+ * so ptrace_may_access() is checked against stable credentials
+ */
+ ret = down_read_killable(&p->signal->exec_update_lock);
+ if (ret)
+ goto err_put;
+
+ ret = -EPERM;
+ if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
+ goto err_unlock;
+
+ head = futex_task_robust_list(p, compat);
+
+ up_read(&p->signal->exec_update_lock);
+ put_task_struct(p);
+
+ return head;
+
+err_unlock:
+ up_read(&p->signal->exec_update_lock);
+err_put:
+ put_task_struct(p);
+ return (void __user *)ERR_PTR(ret);
+}
+
/**
* sys_get_robust_list() - Get the robust-futex list head of a task
* @pid: pid of the process [zero for current task]
@@ -49,36 +95,14 @@ SYSCALL_DEFINE3(get_robust_list, int, pid,
struct robust_list_head __user * __user *, head_ptr,
size_t __user *, len_ptr)
{
- struct robust_list_head __user *head;
- unsigned long ret;
- struct task_struct *p;
-
- rcu_read_lock();
-
- ret = -ESRCH;
- if (!pid)
- p = current;
- else {
- p = find_task_by_vpid(pid);
- if (!p)
- goto err_unlock;
- }
+ struct robust_list_head __user *head = futex_get_robust_list_common(pid, false);
- ret = -EPERM;
- if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
- goto err_unlock;
-
- head = p->robust_list;
- rcu_read_unlock();
+ if (IS_ERR(head))
+ return PTR_ERR(head);
if (put_user(sizeof(*head), len_ptr))
return -EFAULT;
return put_user(head, head_ptr);
-
-err_unlock:
- rcu_read_unlock();
-
- return ret;
}
long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
@@ -94,6 +118,13 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
return -ENOSYS;
}
+ if (flags & FLAGS_ROBUST_UNLOCK) {
+ if (cmd != FUTEX_WAKE &&
+ cmd != FUTEX_WAKE_BITSET &&
+ cmd != FUTEX_UNLOCK_PI)
+ return -ENOSYS;
+ }
+
switch (cmd) {
case FUTEX_WAIT:
val3 = FUTEX_BITSET_MATCH_ANY;
@@ -104,7 +135,7 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
val3 = FUTEX_BITSET_MATCH_ANY;
fallthrough;
case FUTEX_WAKE_BITSET:
- return futex_wake(uaddr, flags, val, val3);
+ return futex_wake(uaddr, flags, uaddr2, val, val3);
case FUTEX_REQUEUE:
return futex_requeue(uaddr, flags, uaddr2, flags, val, val2, NULL, 0);
case FUTEX_CMP_REQUEUE:
@@ -117,7 +148,7 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
case FUTEX_LOCK_PI2:
return futex_lock_pi(uaddr, flags, timeout, 0);
case FUTEX_UNLOCK_PI:
- return futex_unlock_pi(uaddr, flags);
+ return futex_unlock_pi(uaddr, flags, uaddr2);
case FUTEX_TRYLOCK_PI:
return futex_lock_pi(uaddr, flags, NULL, 1);
case FUTEX_WAIT_REQUEUE_PI:
@@ -305,7 +336,7 @@ SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
if (timeout && (ret = futex2_setup_timeout(timeout, clockid, &to)))
return ret;
- futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
+ futexv = kzalloc_objs(*futexv, nr_futexes);
if (!futexv) {
ret = -ENOMEM;
goto destroy_timer;
@@ -351,7 +382,7 @@ SYSCALL_DEFINE4(futex_wake,
if (!futex_validate_input(flags, mask))
return -EINVAL;
- return futex_wake(uaddr, FLAGS_STRICT | flags, nr, mask);
+ return futex_wake(uaddr, FLAGS_STRICT | flags, NULL, nr, mask);
}
/*
@@ -431,6 +462,14 @@ SYSCALL_DEFINE4(futex_requeue,
if (ret)
return ret;
+ /*
+ * For now mandate both flags are identical, like the sys_futex()
+ * interface has. If/when we merge the variable sized futex support,
+ * that patch can modify this test to allow a difference in size.
+ */
+ if (futexes[0].w.flags != futexes[1].w.flags)
+ return -EINVAL;
+
cmpval = futexes[0].w.val;
return futex_requeue(u64_to_user_ptr(futexes[0].w.uaddr), futexes[0].w.flags,
@@ -439,15 +478,13 @@ SYSCALL_DEFINE4(futex_requeue,
}
#ifdef CONFIG_COMPAT
-COMPAT_SYSCALL_DEFINE2(set_robust_list,
- struct compat_robust_list_head __user *, head,
- compat_size_t, len)
+COMPAT_SYSCALL_DEFINE2(set_robust_list, struct compat_robust_list_head __user *, head,
+ compat_size_t, len)
{
if (unlikely(len != sizeof(*head)))
return -EINVAL;
- current->compat_robust_list = head;
-
+ current->futex.compat_robust_list = head;
return 0;
}
@@ -455,36 +492,14 @@ COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
compat_uptr_t __user *, head_ptr,
compat_size_t __user *, len_ptr)
{
- struct compat_robust_list_head __user *head;
- unsigned long ret;
- struct task_struct *p;
-
- rcu_read_lock();
-
- ret = -ESRCH;
- if (!pid)
- p = current;
- else {
- p = find_task_by_vpid(pid);
- if (!p)
- goto err_unlock;
- }
+ struct compat_robust_list_head __user *head = futex_get_robust_list_common(pid, true);
- ret = -EPERM;
- if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
- goto err_unlock;
-
- head = p->compat_robust_list;
- rcu_read_unlock();
+ if (IS_ERR(head))
+ return PTR_ERR(head);
if (put_user(sizeof(*head), len_ptr))
return -EFAULT;
return put_user(ptr_to_compat(head), head_ptr);
-
-err_unlock:
- rcu_read_unlock();
-
- return ret;
}
#endif /* CONFIG_COMPAT */
@@ -509,4 +524,3 @@ SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
}
#endif /* CONFIG_COMPAT_32BIT_TIME */
-