From: Casey Schaufler <casey@schaufler-ca.com>
To: Jeff Mahoney <jeffm@suse.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, Dave Kleikamp <shaggy@kernel.org>,
LSM <linux-security-module@vger.kernel.org>,
Casey Schaufler <casey@schaufler-ca.com>
Subject: Re: [RFC] setxattr bugs
Date: Tue, 05 Feb 2013 09:14:13 -0800 [thread overview]
Message-ID: <51113DE5.10008@schaufler-ca.com> (raw)
In-Reply-To: <51106AF1.4030804@suse.com>
On 2/4/2013 6:14 PM, Jeff Mahoney wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 2/2/13 11:30 PM, Al Viro wrote:
>> * JFS, since 2005: setxattr(name, "system.posix_acl_access", NULL,
>> 0, 0) succeeds, creating an empty EA with "system.posix_acl_access"
>> as name. Validity checks should apply _after_ if (value == NULL) {
>> /* empty EA, do not remove */ value = ""; value_len = 0; } and not
>> before it. * reiserfs, since 2009: setxattr(name, attr_name, NULL,
>> 0, 0) is treated as removexattr(name, attr_name), not as emptying
>> given xattr.
>>
>> The question is, does either of those cross into "established
>> weirdness in ABI" or are they still at the "bugs to be fixed"
>> stage?
> Since the behavior changed once already in 2009 I'd call it a bug.
> That code was in the SLES kernel for a while before then and I still
> haven't seen a bug report on it.
>
> - -Jeff
>
>> FWIW, I'm seriously tempted to stop passing NULL as the third
>> argument of ->setxattr(), essentially taking all those if (!value)
>> value = ""; pieces from individual ->setxattr() instances to
>> __vfs_setxattr_noperm() (all other callers of ->setxattr() never
>> pass NULL data or 0 size, so it's irrelevant for them). Would fix
>> both jfs and reiserfs weirdness....
>>
>> Objections?
None from me. I know of no one using either of those filesystems
in ways I care about. There's a chance the SELinux crowd may care,
so I'm adding the LSM list. We're the primary consumer of xattrs.
>
> - --
> Jeff Mahoney
> SUSE Labs
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prev parent reply other threads:[~2013-02-05 17:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-03 4:30 [RFC] setxattr bugs Al Viro
2013-02-03 13:59 ` Dave Kleikamp
2013-02-05 2:14 ` Jeff Mahoney
2013-02-05 17:14 ` Casey Schaufler [this message]
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