Messages in this thread | | | From | Kari Hurtta <> | Subject | Re: [RFC/PATCH] revoke/frevoke system calls | Date | 20 Jul 2006 23:02:53 +0300 |
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Pekka J Enberg <penberg@cs.Helsinki.FI> writes in gmane.linux.file-systems,gmane.linux.kernel:
> From: Pekka Enberg <penberg@cs.helsinki.fi> > > This patch implements the revoke(2) and frevoke(2) system calls for all > types of files. We revoke files in two passes: first we scan all open > files that refer to the inode and substitute the struct file pointer in fd > table with NULL causing all subsequent operations on that fd to fail. > After we have done that to all file descriptors, we close the files and > take down mmaps. > > Note that now we need to unconditionally do fput/fget in sys_write and > sys_read because they race with do_revoke. > > Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
What permissions is needed revoke access of other users open files ?
> +asmlinkage int sys_revoke(const char __user *filename) > +{ > + int err; > + struct nameidata nd; > + > + err = __user_walk(filename, 0, &nd); > + if (!err) { > + err = do_revoke(nd.dentry->d_inode, NULL); > + path_release(&nd); > + } > + return err; > +} > + > +asmlinkage int sys_frevoke(unsigned int fd) > +{ > + struct file *file = fget(fd); > + int err = -EBADF; > + > + if (file) { > + err = do_revoke(file->f_dentry->d_inode, file); > + fput(file); > + } > + return err; > +}
Is that requiring only that user is able to refer file ?
BSD manual page for revoke(2) seems say:
Access to a file may be revoked only by its owner or the super user.
/ Kari Hurtta
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