[PATCH 1/1] io_uring/rsrc: check size when importing reg buffer

[Pavel Begunkov <asml.silence@gmail.com>]

We're relying on callers to verify the IO size, do it inside of
io_import_fixed() instead. It's safer, easier to deal with, and more
consistent as now it's done close to the iter init site.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/rsrc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 607b09bd8374..6a449d108234 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1016,6 +1016,8 @@ static int io_import_fixed(int ddir, struct iov_iter *iter,
 	/* not inside the mapped region */
 	if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))
 		return -EFAULT;
+	if (unlikely(len > MAX_RW_COUNT))
+		return -EFAULT;
 	if (!(imu->dir & (1 << ddir)))
 		return -EFAULT;
 
-- 
2.48.1