From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 8 Apr 2018 11:57:10 -0400
Subject: [PATCH] getname_kernel() needs to make sure that ->name != ->iname in
 long case
Git-commit: 30ce4d1903e1d8a7ccd110860a5eef3c638ed8be
Patch-mainline: v4.17-rc1
References: git-fixes

missed it in "kill struct filename.separate" several years ago.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/namei.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/namei.c
+++ b/fs/namei.c
@@ -221,9 +221,10 @@ getname_kernel(const char * filename)
 	if (len <= EMBEDDED_NAME_MAX) {
 		result->name = (char *)result->iname;
 	} else if (len <= PATH_MAX) {
+		const size_t size = offsetof(struct filename, iname[1]);
 		struct filename *tmp;
 
-		tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+		tmp = kmalloc(size, GFP_KERNEL);
 		if (unlikely(!tmp)) {
 			__putname(result);
 			return ERR_PTR(-ENOMEM);