ksmbd: handle caseless file creation

Ray Zhang reported ksmbd can not create file if parent filename is
caseless.

Y:\>mkdir A
Y:\>echo 123 >a\b.txt
The system cannot find the path specified.
Y:\>echo 123 >A\b.txt

This patch convert name obtained by caseless lookup to parent name.

Cc: stable@vger.kernel.org # v5.15+
Reported-by: Ray Zhang <zhanglei002@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
index 13dad48d950c969696760d8ab2b703f7af6c5c26..7cbd580120d129deb415cba8bf49830f35185d09 100644 (file)
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -1167,7 +1167,7 @@ static bool __caseless_lookup(struct dir_context *ctx, const char *name,
        if (cmp < 0)
                cmp = strncasecmp((char *)buf->private, name, namlen);
        if (!cmp) {
-               memcpy((char *)buf->private, name, namlen);
+               memcpy((char *)buf->private, name, buf->used);
                buf->dirent_count = 1;
                return false;
        }
@@ -1235,10 +1235,7 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name,
                char *filepath;
                size_t path_len, remain_len;
 
-               filepath = kstrdup(name, GFP_KERNEL);
-               if (!filepath)
-                       return -ENOMEM;
-
+               filepath = name;
                path_len = strlen(filepath);
                remain_len = path_len;
 
@@ -1281,10 +1278,9 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name,
                err = -EINVAL;
 out2:
                path_put(parent_path);
-out1:
-               kfree(filepath);
        }
 
+out1:
        if (!err) {
                err = mnt_want_write(parent_path->mnt);
                if (err) {