man find

   -perm mode
          File's  permission  bits  are  exactly mode (octal or symbolic).  Since an exact match is required, if you want to use this form for symbolic modes, you may have to specify a rather complex mode string.  For example `-perm g=w' will
          only match files which have mode 0020 (that is, ones for which group write permission is the only permission set).  It is more likely that you will want to use the `/' or `-' forms, for example `-perm -g=w', which matches  any  file
          with group write permission.  See the EXAMPLES section for some illustrative examples.

   -perm -mode
          All  of  the  permission bits mode are set for the file.  Symbolic modes are accepted in this form, and this is usually the way in which you would want to use them.  You must specify `u', `g' or `o' if you use a symbolic mode.   See
          the EXAMPLES section for some illustrative examples.

   -perm /mode
          Any of the permission bits mode are set for the file.  Symbolic modes are accepted in this form.  You must specify `u', `g' or `o' if you use a symbolic mode.  See the EXAMPLES section for some illustrative examples.  If no  permis‐
          sion bits in mode are set, this test matches any file (the idea here is to be consistent with the behaviour of -perm -000).

所以，确切匹配为： -perm mode，只匹配模式为 mode 的文件，加 / 为 or 匹配， - 为 and 匹配。其他书写方式：-perm -u+s,g+s -perm /u+s,g+s