From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932983AbcGLLjm (ORCPT ); Tue, 12 Jul 2016 07:39:42 -0400 Received: from mail-qt0-f176.google.com ([209.85.216.176]:33519 "EHLO mail-qt0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753379AbcGLLjj (ORCPT ); Tue, 12 Jul 2016 07:39:39 -0400 Message-ID: <1468323574.7798.8.camel@redhat.com> Subject: Re: [PATCH v23 15/22] richacl: Check if an acl is equivalent to a file mode From: Jeff Layton To: Andreas Gruenbacher , Alexander Viro Cc: Christoph Hellwig , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , Trond Myklebust , Anna Schumaker , Dave Chinner , linux-ext4@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-api@vger.kernel.org Date: Tue, 12 Jul 2016 07:39:34 -0400 In-Reply-To: <1467294433-3222-16-git-send-email-agruenba@redhat.com> References: <1467294433-3222-1-git-send-email-agruenba@redhat.com> <1467294433-3222-16-git-send-email-agruenba@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.3 (3.20.3-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2016-06-30 at 15:47 +0200, Andreas Gruenbacher wrote: > ACLs are considered equivalent to file modes if they only consist of > owner@, group@, and everyone@ entries, the owner@ permissions do not > depend on whether the owner is a member in the owning group, and no > inheritance flags are set.  This test is used to avoid storing richacls > if the acl can be computed from the file permission bits. > > Signed-off-by: Andreas Gruenbacher > Reviewed-by: J. Bruce Fields > --- >  fs/richacl.c            | 104 ++++++++++++++++++++++++++++++++++++++++++++++++ >  include/linux/richacl.h |   1 + >  2 files changed, 105 insertions(+) > > diff --git a/fs/richacl.c b/fs/richacl.c > index ba110a6..e8a383b 100644 > --- a/fs/richacl.c > +++ b/fs/richacl.c > @@ -618,3 +618,107 @@ richacl_chmod(struct inode *inode, umode_t mode) >   return retval; >  } >  EXPORT_SYMBOL(richacl_chmod); > + > +/** > + * richacl_equiv_mode  -  compute the mode equivalent of @acl > + * > + * An acl is considered equivalent to a file mode if it only consists of > + * owner@, group@, and everyone@ entries and the owner@ permissions do not > + * depend on whether the owner is a member in the owning group. > + */ > +int > +richacl_equiv_mode(const struct richacl *acl, umode_t *mode_p) > +{ > + umode_t mode = *mode_p; > + > + /* > +  * The RICHACE_DELETE_CHILD flag is meaningless for non-directories, so > +  * we ignore it. > +  */ > + unsigned int x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD; > + struct { > + unsigned int allowed; > + unsigned int defined;  /* allowed or denied */ > + } owner = { > + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | > +    RICHACE_POSIX_OWNER_ALLOWED  | x, > + }, group = { > + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x, > + }, everyone = { > + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x, > + }; > + const struct richace *ace; > + > + if (acl->a_flags & ~(RICHACL_WRITE_THROUGH | RICHACL_MASKED)) > + return -1; > + > + richacl_for_each_entry(ace, acl) { > + if (ace->e_flags & ~RICHACE_SPECIAL_WHO) > + return -1; > + > + if (richace_is_owner(ace) || richace_is_everyone(ace)) { > + x = ace->e_mask & ~owner.defined; > + if (richace_is_allow(ace)) { > + unsigned int group_denied = > + group.defined & ~group.allowed; > + > + if (x & group_denied) > + return -1; > + owner.allowed |= x; > + } else /* if (richace_is_deny(ace)) */ { > + if (x & group.allowed) > + return -1; > + } > + owner.defined |= x; > + > + if (richace_is_everyone(ace)) { > + x = ace->e_mask; > + if (richace_is_allow(ace)) { > + group.allowed |= > + x & ~group.defined; > + everyone.allowed |= > + x & ~everyone.defined; > + } > + group.defined |= x; > + everyone.defined |= x; > + } > + } else if (richace_is_group(ace)) { > + x = ace->e_mask & ~group.defined; > + if (richace_is_allow(ace)) > + group.allowed |= x; > + group.defined |= x; > + } else > + return -1; > + } > + > + if (group.allowed & ~owner.defined) > + return -1; > + > + if (acl->a_flags & RICHACL_MASKED) { > + if (acl->a_flags & RICHACL_WRITE_THROUGH) { > + owner.allowed = acl->a_owner_mask; > + everyone.allowed = acl->a_other_mask; > + } else { > + owner.allowed &= acl->a_owner_mask; > + everyone.allowed &= acl->a_other_mask; > + } > + group.allowed &= acl->a_group_mask; > + } > + > + mode = (mode & ~S_IRWXUGO) | > +        (richacl_mask_to_mode(owner.allowed) << 6) | > +        (richacl_mask_to_mode(group.allowed) << 3) | > + richacl_mask_to_mode(everyone.allowed); > + > + /* Mask flags we can ignore */ > + x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD; > + > + if (((richacl_mode_to_mask(mode >> 6) ^ owner.allowed)    & ~x) || > +     ((richacl_mode_to_mask(mode >> 3) ^ group.allowed)    & ~x) || > +     ((richacl_mode_to_mask(mode)      ^ everyone.allowed) & ~x)) > + return -1; > + > + *mode_p = mode; > + return 0; > +} > +EXPORT_SYMBOL_GPL(richacl_equiv_mode); > diff --git a/include/linux/richacl.h b/include/linux/richacl.h > index db82fab..9212edb 100644 > --- a/include/linux/richacl.h > +++ b/include/linux/richacl.h > @@ -191,5 +191,6 @@ extern unsigned int richacl_want_to_mask(unsigned int); >  extern void richacl_compute_max_masks(struct richacl *); >  extern int richacl_permission(struct inode *, const struct richacl *, int); >  extern int richacl_chmod(struct inode *, umode_t); > +extern int richacl_equiv_mode(const struct richacl *, umode_t *); >   >  #endif /* __RICHACL_H */ Reviewed-by: Jeff Layton