Messages in this thread | | | Date | Tue, 18 Aug 2009 14:56:45 +0800 | From | Amerigo Wang <> | Subject | Re: [Patch 1/2] selinux: ajust rules for ATTR_FORCE |
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OGAWA Hirofumi wrote: > Could you review this? I've added ATTR_TIMES_SET to check explicit > utimes(), and tried it with minimum change. > > [I'm not sure this handles notify_change() usage of nfsd (and perhaps > other network fs too) correctly, and whether selinux may want to check > it. I guess network fs _may_ try to change the multiple attributes at a > time. Well, even if it's true, it would be another topic...] > >
Ah, according to the discussion here, I know I misunderstood ATTR_FORCE... sorry. > OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> > > > From: Amerigo Wang <amwang@redhat.com> > > As suggested by OGAWA Hirofumi in thread: http://lkml.org/lkml/2009/8/7/132, > we should let selinux_inode_setattr() to match our ATTR_* rules. > ATTR_FORCE should not force things like ATTR_SIZE. > > Cc: Stephen Smalley <sds@tycho.nsa.gov> > Cc: Eric Paris <eparis@redhat.com> > Signed-off-by: WANG Cong <amwang@redhat.com> > [tweaks] > Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> >
Great!
Some comments below.
> --- > > security/selinux/hooks.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff -puN security/selinux/hooks.c~selinux-truncate-fix security/selinux/hooks.c > --- linux-2.6/security/selinux/hooks.c~selinux-truncate-fix 2009-08-18 03:50:09.000000000 +0900 > +++ linux-2.6-hirofumi/security/selinux/hooks.c 2009-08-18 05:35:11.000000000 +0900 > @@ -2711,12 +2711,17 @@ static int selinux_inode_permission(stru > static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) > { > const struct cred *cred = current_cred(); > + unsigned int ia_valid = iattr->ia_valid; > > - if (iattr->ia_valid & ATTR_FORCE) > - return 0; > + /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */ > + if (ia_valid & ATTR_FORCE) { > + ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE); > + if (!ia_valid) > + return 0; >
So if I read this correctly, (ATTR_FORCE| ATTR_KILL_SUID|ATTR_MODE) will not return here, since 'ia_valid' will be ATTR_FORCE finally.
I think you forgot to clear ATTR_FORCE here...
> + } > > - if (iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | > - ATTR_ATIME_SET | ATTR_MTIME_SET)) > + if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | > + ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET)) > return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR); > > return dentry_has_perm(cred, NULL, dentry, FILE__WRITE); > _ > > I am not sure about ATTR_TIMES_SET here, but looks fine. :-/
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