From c00d2c7e89880036f288a764599b2b8b87c0a364 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 20 Dec 2016 07:04:57 -0500
Subject: move aio compat to fs/aio.c

... and fix the minor buglet in compat io_submit() - native one
kills ioctx as cleanup when put_user() fails.  Get rid of
bogus compat_... in !CONFIG_AIO case, while we are at it - they
should simply fail with ENOSYS, same as for native counterparts.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/aio.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 95 insertions(+), 2 deletions(-)

(limited to 'fs/aio.c')

diff --git a/fs/aio.c b/fs/aio.c
index 8edf253484af..8c79e1a53af9 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1367,6 +1367,39 @@ out:
 	return ret;
 }
 
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
+{
+	struct kioctx *ioctx = NULL;
+	unsigned long ctx;
+	long ret;
+
+	ret = get_user(ctx, ctx32p);
+	if (unlikely(ret))
+		goto out;
+
+	ret = -EINVAL;
+	if (unlikely(ctx || nr_events == 0)) {
+		pr_debug("EINVAL: ctx %lu nr_events %u\n",
+		         ctx, nr_events);
+		goto out;
+	}
+
+	ioctx = ioctx_alloc(nr_events);
+	ret = PTR_ERR(ioctx);
+	if (!IS_ERR(ioctx)) {
+		/* truncating is ok because it's a user address */
+		ret = put_user((u32)ioctx->user_id, ctx32p);
+		if (ret)
+			kill_ioctx(current->mm, ioctx, NULL);
+		percpu_ref_put(&ioctx->users);
+	}
+
+out:
+	return ret;
+}
+#endif
+
 /* sys_io_destroy:
  *	Destroy the aio_context specified.  May cancel any outstanding 
  *	AIOs and block on completion.  Will fail with -ENOSYS if not
@@ -1591,8 +1624,8 @@ out_put_req:
 	return ret;
 }
 
-long do_io_submit(aio_context_t ctx_id, long nr,
-		  struct iocb __user *__user *iocbpp, bool compat)
+static long do_io_submit(aio_context_t ctx_id, long nr,
+			  struct iocb __user *__user *iocbpp, bool compat)
 {
 	struct kioctx *ctx;
 	long ret = 0;
@@ -1662,6 +1695,44 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
 	return do_io_submit(ctx_id, nr, iocbpp, 0);
 }
 
+#ifdef CONFIG_COMPAT
+static inline long
+copy_iocb(long nr, u32 __user *ptr32, struct iocb __user * __user *ptr64)
+{
+	compat_uptr_t uptr;
+	int i;
+
+	for (i = 0; i < nr; ++i) {
+		if (get_user(uptr, ptr32 + i))
+			return -EFAULT;
+		if (put_user(compat_ptr(uptr), ptr64 + i))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+#define MAX_AIO_SUBMITS 	(PAGE_SIZE/sizeof(struct iocb *))
+
+COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
+		       int, nr, u32 __user *, iocb)
+{
+	struct iocb __user * __user *iocb64;
+	long ret;
+
+	if (unlikely(nr < 0))
+		return -EINVAL;
+
+	if (nr > MAX_AIO_SUBMITS)
+		nr = MAX_AIO_SUBMITS;
+
+	iocb64 = compat_alloc_user_space(nr * sizeof(*iocb64));
+	ret = copy_iocb(nr, iocb, iocb64);
+	if (!ret)
+		ret = do_io_submit(ctx_id, nr, iocb64, 1);
+	return ret;
+}
+#endif
+
 /* lookup_kiocb
  *	Finds a given iocb for cancellation.
  */
@@ -1761,3 +1832,25 @@ SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
 	}
 	return ret;
 }
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id,
+		       compat_long_t, min_nr,
+		       compat_long_t, nr,
+		       struct io_event __user *, events,
+		       struct compat_timespec __user *, timeout)
+{
+	struct timespec t;
+	struct timespec __user *ut = NULL;
+
+	if (timeout) {
+		if (compat_get_timespec(&t, timeout))
+			return -EFAULT;
+
+		ut = compat_alloc_user_space(sizeof(*ut));
+		if (copy_to_user(ut, &t, sizeof(t)))
+			return -EFAULT;
+	}
+	return sys_io_getevents(ctx_id, min_nr, nr, events, ut);
+}
+#endif
-- 
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