namei: make do_mknodat() take struct filename

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>

diff --git a/fs/namei.c b/fs/namei.c
index e9358e6..ea575dd 100644 (file)
--- 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 @@ retry:
                                          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);
 }
 
 /**