From: "Aneesh Kumar K.V" Subject: [PATCH -V2 07/16] richacl: Update the file masks in chmod() Date: Sat, 3 Jul 2010 00:13:38 +0530 Message-ID: <1278096227-16784-8-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1278096227-16784-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, nfsv4@linux-nfs.org, linux-kernel@vger.kernel.org To: sfrench@us.ibm.com, ffilz@us.ibm.com, agruen@suse.de, adilger@sun.com, sandeen@redhat.com, tytso@mit.edu, staubach@redhat.com, bfields@citi.umich.edu, jlayton@redhat.com Return-path: In-Reply-To: <1278096227-16784-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nfsv4-bounces@linux-nfs.org Errors-To: nfsv4-bounces@linux-nfs.org List-Id: linux-ext4.vger.kernel.org From: Andreas Gruenbacher Doing a chmod() sets the file mode, which includes the file permission bits. When a file has a richacl, the permissions that the richacl grants need to be limited to what the new file permission bits allow. This is done by setting the file masks in the richacl to what the file permission bits map to. The richacl access check algorithm takes the file masks into account, which ensures that the richacl cannot grant too many permissions. It is possible to explicitly add permissions to the file masks which go beyond what the file permission bits can grant (like the ACE4_WRITE_ACL permission). The POSIX.1 standard calls this an alternate file access control mechanism. A subsequent chmod() would ensure that those permissions are disabled again. Signed-off-by: Andreas Gruenbacher Signed-off-by: Aneesh Kumar K.V --- fs/richacl_base.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 1 + 2 files changed, 38 insertions(+), 0 deletions(-) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index d78ef35..bb9b762 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -331,3 +331,40 @@ restart: } } EXPORT_SYMBOL_GPL(richacl_compute_max_masks); + +/** + * richacl_chmod - update the file masks to reflect the new mode + * @mode: new file permission bits + * + * Return a copy of @acl where the file masks have been replaced by the file + * masks corresponding to the file permission bits in @mode, or returns @acl + * itself if the file masks are already up to date. Takes over a reference + * to @acl. + */ +struct richacl * +richacl_chmod(struct richacl *acl, mode_t mode) +{ + unsigned int owner_mask, group_mask, other_mask; + struct richacl *clone; + + owner_mask = richacl_mode_to_mask(mode >> 6); + group_mask = richacl_mode_to_mask(mode >> 3); + other_mask = richacl_mode_to_mask(mode); + + if (acl->a_owner_mask == owner_mask && + acl->a_group_mask == group_mask && + acl->a_other_mask == other_mask) + return acl; + + clone = richacl_clone(acl); + richacl_put(acl); + if (!clone) + return ERR_PTR(-ENOMEM); + + clone->a_owner_mask = owner_mask; + clone->a_group_mask = group_mask; + clone->a_other_mask = other_mask; + + return clone; +} +EXPORT_SYMBOL_GPL(richacl_chmod); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 738fd76..1ea33ee 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -269,5 +269,6 @@ extern int richacl_masks_to_mode(const struct richacl *); extern unsigned int richacl_mode_to_mask(mode_t); extern unsigned int richacl_want_to_mask(int); extern void richacl_compute_max_masks(struct richacl *); +extern struct richacl *richacl_chmod(struct richacl *, mode_t); #endif /* __RICHACL_H */ -- 1.7.2.rc1 _______________________________________________ NOTE: THIS LIST IS DEPRECATED. Please use linux-nfs@vger.kernel.org instead. (To subscribe to linux-nfs@vger.kernel.org: send "subscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org.) NFSv4 mailing list NFSv4@linux-nfs.org http://linux-nfs.org/cgi-bin/mailman/listinfo/nfsv4