From: ebiederm@xmission.com (Eric W. Biederman) To: Casey Schaufler <casey@schaufler-ca.com> Cc: "David P. Quigley" <dpquigl@tycho.nsa.gov>, jmorris@namei.org, Stephen Smalley <sds@tycho.nsa.gov>, gregkh@susa.de, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov Subject: Re: [PATCH] Security/sysfs: Enable security xattrs to be set on sysfs files, directories, and symlinks. Date: Fri, 14 Aug 2009 15:02:25 -0700 [thread overview] Message-ID: <m1my62xde6.fsf@fess.ebiederm.org> (raw) In-Reply-To: <4A84EF1D.8060408@schaufler-ca.com> (Casey Schaufler's message of "Thu\, 13 Aug 2009 21\:59\:09 -0700") >From a long term maintenance perspective I have to say I like Casey's version that doesn't require any magic security module compression hooks to implement this. >From an implementation point of view Stephen's comments seem accurate. Is there any debate that Casey's version will get the job done? If not the only real question is how do we store xattrs efficiently for in memory filesystems. Let me propose a different xattr compression scheme instead of making the security module responsible for compression. How about we have: struct sysfs_xattr *sysfs_store_xattr(const char *name, const void *value, size_t size); void sysfs_release_xattr(struct sysfs_xattr *xattr); Where sysfs_xattr looks something like: struct sysfs_xattr { struct hlist_node list; atomic_t count; const char *name; const void *value; size_t size; } And then at the end of of what is today s_iattr we have something like: struct sysfs_xattr *xattrs[2]; The key point here is that sysfs_store_xattr will look to see in a hash table to see if another inode/dentry has already stored the specified xattr and if so increment the count of sysfs_xattr count and return it. My design assumption is that the set of xattrs that people want to apply to filesystems is small. By optimizing for a small number of distinct xattrs we keep the storage size small (even for those filesystems who want to label everything), and we keep the generality by not making storage of xattrs a security module responsibility. Does that sound like it will work? Eric
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From: ebiederm@xmission.com (Eric W. Biederman) To: Casey Schaufler <casey@schaufler-ca.com> Cc: "David P. Quigley" <dpquigl@tycho.nsa.gov>, jmorris@namei.org, Stephen Smalley <sds@tycho.nsa.gov>, gregkh@susa.de, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov Subject: Re: [PATCH] Security/sysfs: Enable security xattrs to be set on sysfs files, directories, and symlinks. Date: Fri, 14 Aug 2009 15:02:25 -0700 [thread overview] Message-ID: <m1my62xde6.fsf@fess.ebiederm.org> (raw) In-Reply-To: <4A84EF1D.8060408@schaufler-ca.com> (Casey Schaufler's message of "Thu\, 13 Aug 2009 21\:59\:09 -0700") >From a long term maintenance perspective I have to say I like Casey's version that doesn't require any magic security module compression hooks to implement this. >From an implementation point of view Stephen's comments seem accurate. Is there any debate that Casey's version will get the job done? If not the only real question is how do we store xattrs efficiently for in memory filesystems. Let me propose a different xattr compression scheme instead of making the security module responsible for compression. How about we have: struct sysfs_xattr *sysfs_store_xattr(const char *name, const void *value, size_t size); void sysfs_release_xattr(struct sysfs_xattr *xattr); Where sysfs_xattr looks something like: struct sysfs_xattr { struct hlist_node list; atomic_t count; const char *name; const void *value; size_t size; } And then at the end of of what is today s_iattr we have something like: struct sysfs_xattr *xattrs[2]; The key point here is that sysfs_store_xattr will look to see in a hash table to see if another inode/dentry has already stored the specified xattr and if so increment the count of sysfs_xattr count and return it. My design assumption is that the set of xattrs that people want to apply to filesystems is small. By optimizing for a small number of distinct xattrs we keep the storage size small (even for those filesystems who want to label everything), and we keep the generality by not making storage of xattrs a security module responsibility. Does that sound like it will work? Eric -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@tycho.nsa.gov with the words "unsubscribe selinux" without quotes as the message.
next prev parent reply other threads:[~2009-08-14 22:02 UTC|newest] Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-07-15 13:48 [PATCH] Security/sysfs: Enable security xattrs to be set on sysfs files, directories, and symlinks David P. Quigley 2009-07-15 13:48 ` David P. Quigley 2009-07-15 14:28 ` David P. Quigley 2009-07-15 14:28 ` David P. Quigley 2009-07-15 14:31 ` David P. Quigley 2009-07-15 14:31 ` David P. Quigley 2009-07-21 16:29 ` David P. Quigley 2009-07-21 16:29 ` David P. Quigley 2009-07-21 16:49 ` Greg KH 2009-07-21 16:49 ` Greg KH 2009-07-21 16:34 ` David P. Quigley 2009-07-21 16:34 ` David P. Quigley 2009-07-21 17:01 ` David P. Quigley 2009-07-21 17:01 ` David P. Quigley 2009-07-24 8:13 ` James Morris 2009-07-24 8:13 ` James Morris 2009-07-24 14:34 ` David P. Quigley 2009-07-24 14:34 ` David P. Quigley 2009-07-24 14:54 ` Casey Schaufler 2009-07-24 14:54 ` Casey Schaufler 2009-08-14 4:59 ` Casey Schaufler 2009-08-14 4:59 ` Casey Schaufler 2009-08-14 12:20 ` Stephen Smalley 2009-08-14 12:20 ` Stephen Smalley 2009-08-14 12:40 ` Stephen Smalley 2009-08-14 12:40 ` Stephen Smalley 2009-08-15 1:33 ` Casey Schaufler 2009-08-15 1:33 ` Casey Schaufler 2009-08-17 12:01 ` Stephen Smalley 2009-08-17 12:01 ` Stephen Smalley 2009-08-15 1:19 ` Casey Schaufler 2009-08-15 1:19 ` Casey Schaufler 2009-08-17 11:53 ` Stephen Smalley 2009-08-17 11:53 ` Stephen Smalley 2009-08-14 22:02 ` Eric W. Biederman [this message] 2009-08-14 22:02 ` Eric W. Biederman 2009-08-15 1:42 ` Casey Schaufler 2009-08-15 1:42 ` Casey Schaufler 2009-08-15 2:15 ` Eric W. Biederman 2009-08-15 2:15 ` Eric W. Biederman 2009-08-15 4:56 ` Casey Schaufler 2009-08-15 4:56 ` Casey Schaufler 2009-08-15 6:01 ` Eric W. Biederman 2009-08-15 6:01 ` Eric W. Biederman 2009-08-16 17:25 ` Casey Schaufler 2009-08-16 17:25 ` Casey Schaufler 2009-08-18 3:55 ` [PATCH] Security/sysfs: v2 - " Casey Schaufler 2009-08-18 3:55 ` Casey Schaufler 2009-08-18 12:14 ` Stephen Smalley 2009-08-18 12:14 ` Stephen Smalley 2009-08-18 14:12 ` Casey Schaufler 2009-08-18 14:12 ` Casey Schaufler 2009-08-18 14:23 ` Stephen Smalley 2009-08-18 14:23 ` Stephen Smalley 2009-08-19 4:37 ` Casey Schaufler 2009-08-19 4:37 ` Casey Schaufler 2009-08-19 11:58 ` Stephen Smalley 2009-08-19 11:58 ` Stephen Smalley 2009-08-19 17:47 ` Casey Schaufler 2009-08-19 17:47 ` Casey Schaufler 2009-08-19 23:59 ` Casey Schaufler 2009-08-19 23:59 ` Casey Schaufler 2009-08-20 2:41 ` Eric W. Biederman 2009-08-20 2:41 ` Eric W. Biederman 2009-08-20 11:53 ` Stephen Smalley 2009-08-20 11:53 ` Stephen Smalley 2009-08-20 13:18 ` [PATCH] Security/sysfs: " David P. Quigley 2009-08-20 13:18 ` David P. Quigley 2009-08-21 3:38 ` Casey Schaufler 2009-08-21 3:38 ` Casey Schaufler -- strict thread matches above, loose matches on Subject: below -- 2009-09-03 18:25 David P. Quigley 2009-07-08 17:28 David P. Quigley 2009-07-09 1:44 ` Casey Schaufler 2009-07-09 14:05 ` David P. Quigley 2009-07-09 14:49 ` Casey Schaufler 2009-07-09 14:56 ` David P. Quigley 2009-07-09 15:16 ` David P. Quigley 2009-07-09 15:16 ` Greg KH 2009-07-09 14:11 ` David P. Quigley 2009-07-09 17:26 ` David P. Quigley 2009-07-09 17:50 ` Greg KH 2009-07-09 19:32 ` David P. Quigley 2009-07-09 20:13 ` Greg KH 2009-07-10 3:25 ` Casey Schaufler 2009-07-13 15:07 ` David P. Quigley 2009-07-09 15:18 ` Greg KH 2009-07-09 17:13 ` David P. Quigley 2009-07-09 17:52 ` Greg KH 2009-07-09 19:28 ` David P. Quigley 2009-07-09 20:12 ` Greg KH 2009-07-09 20:19 ` David P. Quigley 2009-07-09 20:41 ` Greg KH 2009-07-14 16:37 ` David P. Quigley 2009-07-14 17:50 ` Greg KH 2009-07-14 20:16 ` David P. Quigley 2009-07-14 20:35 ` Greg KH 2009-07-14 20:35 ` David P. Quigley [not found] ` <m1r5wmnee0.fsf@fess.ebiederm.org> [not found] ` <1247498399.4398.259.camel@localhost> 2009-07-13 16:50 ` Eric W. Biederman 2009-07-13 19:18 ` David P. Quigley 2009-07-14 0:29 ` Eric W. Biederman 2009-07-14 13:55 ` David P. Quigley 2009-07-14 3:06 ` Casey Schaufler
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