lkml.org 
[lkml]   [2008]   [May]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [TOMOYO #8 (2.6.25-mm1) 1/7] Introduce new LSM hooks.
    From
    Date
    Hello.

    Chris Wright wrote:

    > * Toshiharu Harada (haradats@nttdata.co.jp) wrote:
    > > This patch allows LSM to check permission using "struct vfsmount"
    > > without passing "struct vfsmount" to VFS helper functions.
    >
    > This is simply duplicating many of the existing checks.
    > I don't see how this is an improvement.
    >
    > > --- mm.orig/fs/namei.c
    > > +++ mm/fs/namei.c
    > > @@ -1595,6 +1595,9 @@ int vfs_create(struct inode *dir, struct
    > > error = security_inode_create(dir, dentry, mode);
    > > if (error)
    > > return error;
    > > + error = security_path_create(dir, dentry, mode, nd);
    > > + if (error)
    > > + return error;
    >
    > Pure duplication (of course adding nameidata, although I think you just
    > want path).

    Right. I should have added "path" parameter rather than adding a new hook.
    But to avoid touching vfs_*(), I moved security_path_create() to
    the callers of vfs_create().

    > > DQUOT_INIT(dir);
    > > error = dir->i_op->create(dir, dentry, mode, nd);
    > > if (!error)
    > > @@ -1650,6 +1653,17 @@ int may_open(struct nameidata *nd, int a
    > ...
    > error = vfs_permission(nd, acc_mode);
    > if (error)
    > return error;
    > ...
    > > return -EPERM;
    > >
    > > /*
    > > + * security_inode_permission() called from vfs_permission()
    > > + * can't know that the file is going to be truncated when
    > > + * open(filename, O_WRONLY | O_TRUNC | O_APPEND) is used.
    > > + * So, this hook checks O_APPEND and O_TRUNC flags as well
    > > + * as MAY_READ and MAY_WRITE flags.
    > > + */
    > > + error = security_path_open(nd->path.dentry, nd->path.mnt, flag);
    > > + if (error)
    > > + return error;
    >
    > Also duplication. And why the unique flag handling, you don't seem to
    > ever check?

    Sorry. I didn't know security_dentry_open() is available.
    Now, security_path_open() and security_path_uselib() have gone away.
    But it also turned out that security_dentry_open() is too late for
    checking open(O_CREAT) and open(O_TRUNC) cases. Thus, somehow,
    I want to check O_CREAT before entering vfs_create() and
    check O_TRUNC before entering do_truncate() from may_open().

    Regards.


    \
     
     \ /
      Last update: 2008-05-07 17:19    [W:3.902 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site