From 7797251bb5ab7f184dafdfebd05f469ff6a67b77 Mon Sep 17 00:00:00 2001
From: Dmitry Kadashev <dkadashev@gmail.com>
Date: Thu, 8 Jul 2021 13:34:40 +0700
Subject: [PATCH] namei: make do_mknodat() take struct filename
Git-commit: 7797251bb5ab7f184dafdfebd05f469ff6a67b77
Patch-mainline: v5.15-rc1
References: bsc#1205205

Pass in the struct filename pointers instead of the user string, for
uniformity with the recently converted do_unlinkat(), do_renameat(),
do_mkdirat().

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/io-uring/20210330071700.kpjoyp5zlni7uejm@wittgenstein/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-5-dkadashev@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 fs/namei.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index e9358e61fce2..ea575dd788b7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3739,7 +3739,7 @@ static int may_mknod(umode_t mode)
 	}
 }
 
-static long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+static long do_mknodat(int dfd, struct filename *name, umode_t mode,
 		unsigned int dev)
 {
 	struct user_namespace *mnt_userns;
@@ -3750,17 +3750,18 @@ static long do_mknodat(int dfd, const char __user *filename, umode_t mode,
 
 	error = may_mknod(mode);
 	if (error)
-		return error;
+		goto out1;
 retry:
-	dentry = user_path_create(dfd, filename, &path, lookup_flags);
+	dentry = __filename_create(dfd, name, &path, lookup_flags);
+	error = PTR_ERR(dentry);
 	if (IS_ERR(dentry))
-		return PTR_ERR(dentry);
+		goto out1;
 
 	if (!IS_POSIXACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mknod(&path, dentry, mode, dev);
 	if (error)
-		goto out;
+		goto out2;
 
 	mnt_userns = mnt_user_ns(path.mnt);
 	switch (mode & S_IFMT) {
@@ -3779,24 +3780,26 @@ static long do_mknodat(int dfd, const char __user *filename, umode_t mode,
 					  dentry, mode, 0);
 			break;
 	}
-out:
+out2:
 	done_path_create(&path, dentry);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
+out1:
+	putname(name);
 	return error;
 }
 
 SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
 		unsigned int, dev)
 {
-	return do_mknodat(dfd, filename, mode, dev);
+	return do_mknodat(dfd, getname(filename), mode, dev);
 }
 
 SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev)
 {
-	return do_mknodat(AT_FDCWD, filename, mode, dev);
+	return do_mknodat(AT_FDCWD, getname(filename), mode, dev);
 }
 
 /**
-- 
2.35.3