[PATCH 6.13 110/138] lib/iov_iter: fix import_iovec_ubuf iovec management

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pavel Begunkov <asml.silence@gmail.com>

commit f4b78260fc678ccd7169f32dc9f3bfa3b93931c7 upstream.

import_iovec() says that it should always be fine to kfree the iovec
returned in @iovp regardless of the error code.  __import_iovec_ubuf()
never reallocates it and thus should clear the pointer even in cases when
copy_iovec_*() fail.

Link: https://lkml.kernel.org/r/378ae26923ffc20fd5e41b4360d673bf47b1775b.1738332461.git.asml.silence@gmail.com
Fixes: 3b2deb0e46da ("iov_iter: import single vector iovecs as ITER_UBUF")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/iov_iter.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1428,6 +1428,8 @@ static ssize_t __import_iovec_ubuf(int t
 	struct iovec *iov = *iovp;
 	ssize_t ret;
 
+	*iovp = NULL;
+
 	if (compat)
 		ret = copy_compat_iovec_from_user(iov, uvec, 1);
 	else
@@ -1438,7 +1440,6 @@ static ssize_t __import_iovec_ubuf(int t
 	ret = import_ubuf(type, iov->iov_base, iov->iov_len, i);
 	if (unlikely(ret))
 		return ret;
-	*iovp = NULL;
 	return i->count;
 }