namei: make do_mkdirat() take struct filename

Pass in the struct filename pointers instead of the user string, and
update the three callers to do the same. This is heavily based on
commit dbea8d345177 ("fs: make do_renameat2() take struct filename").

This behaves like do_unlinkat() and do_renameat2().

Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-4-dkadashev@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/internal.h b/fs/internal.h
index 82e8eb32ff3dd8686dc6ce5a23c8c32eef544dd6..fa0b107e828cf8ac9bb3e73e9b1b16552ef6c89e 100644 (file)
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -76,6 +76,7 @@ long do_unlinkat(int dfd, struct filename *name);
 int may_linkat(struct user_namespace *mnt_userns, struct path *link);
 int do_renameat2(int olddfd, struct filename *oldname, int newdfd,
                 struct filename *newname, unsigned int flags);
+long do_mkdirat(int dfd, struct filename *name, umode_t mode);
 
 /*
  * namespace.c

diff --git a/fs/namei.c b/fs/namei.c
index aaba6b42b2223da5759f6c9b522189a855e049d1..e9358e61fce2588a3c334392ec7e6ad2be1637a5 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3573,7 +3573,7 @@ struct file *do_file_open_root(const struct path *root,
        return file;
 }
 
-static struct dentry *filename_create(int dfd, struct filename *name,
+static struct dentry *__filename_create(int dfd, struct filename *name,
                                struct path *path, unsigned int lookup_flags)
 {
        struct dentry *dentry = ERR_PTR(-EEXIST);
@@ -3589,7 +3589,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
         */
        lookup_flags &= LOOKUP_REVAL;
 
-       error = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
+       error = __filename_parentat(dfd, name, lookup_flags, path, &last, &type);
        if (error)
                return ERR_PTR(error);
 
@@ -3642,6 +3642,15 @@ out:
        return dentry;
 }
 
+static inline struct dentry *filename_create(int dfd, struct filename *name,
+                               struct path *path, unsigned int lookup_flags)
+{
+       struct dentry *res = __filename_create(dfd, name, path, lookup_flags);
+
+       putname(name);
+       return res;
+}
+
 struct dentry *kern_path_create(int dfd, const char *pathname,
                                struct path *path, unsigned int lookup_flags)
 {
@@ -3832,7 +3841,7 @@ int vfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 }
 EXPORT_SYMBOL(vfs_mkdir);
 
-static long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
+long do_mkdirat(int dfd, struct filename *name, umode_t mode)
 {
        struct dentry *dentry;
        struct path path;
@@ -3840,9 +3849,10 @@ static long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
        unsigned int lookup_flags = LOOKUP_DIRECTORY;
 
 retry:
-       dentry = user_path_create(dfd, pathname, &path, lookup_flags);
+       dentry = __filename_create(dfd, name, &path, lookup_flags);
+       error = PTR_ERR(dentry);
        if (IS_ERR(dentry))
-               return PTR_ERR(dentry);
+               goto out_putname;
 
        if (!IS_POSIXACL(path.dentry->d_inode))
                mode &= ~current_umask();
@@ -3858,17 +3868,19 @@ retry:
                lookup_flags |= LOOKUP_REVAL;
                goto retry;
        }
+out_putname:
+       putname(name);
        return error;
 }
 
 SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
 {
-       return do_mkdirat(dfd, pathname, mode);
+       return do_mkdirat(dfd, getname(pathname), mode);
 }
 
 SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
 {
-       return do_mkdirat(AT_FDCWD, pathname, mode);
+       return do_mkdirat(AT_FDCWD, getname(pathname), mode);
 }
 
 /**