From: Casey Schaufler <casey@schaufler-ca.com>
To: Mimi Zohar <zohar@linux.ibm.com>,
Roberto Sassu <roberto.sassu@huaweicloud.com>,
dmitry.kasatkin@gmail.com, paul@paul-moore.com,
jmorris@namei.org, serge@hallyn.com,
stephen.smalley.work@gmail.com, eparis@parisplace.org
Cc: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
reiserfs-devel@vger.kernel.org, linux-kernel@vger.kernel.org,
keescook@chromium.org, nicolas.bouchinet@clip-os.org,
Roberto Sassu <roberto.sassu@huawei.com>,
casey@schaufler-ca.com
Subject: Re: [PATCH v4 3/5] security: Allow all LSMs to provide xattrs for inode_init_security hook
Date: Thu, 17 Nov 2022 09:40:20 -0800 [thread overview]
Message-ID: <66df8ebe-1ed2-c839-8a5f-cc0a26bad6c3@schaufler-ca.com> (raw)
In-Reply-To: <6b4d47765a4ddcfdf07158f3ad0737fa3aa5823e.camel@linux.ibm.com>
On 11/17/2022 9:24 AM, Mimi Zohar wrote:
> On Thu, 2022-11-17 at 09:18 -0800, Casey Schaufler wrote:
>> On 11/17/2022 8:05 AM, Mimi Zohar wrote:
>>> hOn Thu, 2022-11-10 at 10:46 +0100, Roberto Sassu wrote:
>>>> From: Roberto Sassu <roberto.sassu@huawei.com>
>>>>
>>>> Currently, security_inode_init_security() supports only one LSM providing
>>>> an xattr and EVM calculating the HMAC on that xattr, plus other inode
>>>> metadata.
>>>>
>>>> Allow all LSMs to provide one or multiple xattrs, by extending the security
>>>> blob reservation mechanism. Introduce the new lbs_xattr field of the
>>>> lsm_blob_sizes structure, so that each LSM can specify how many xattrs it
>>>> needs, and the LSM infrastructure knows how many xattr slots it should
>>>> allocate.
>>> Perhaps supporting per LSM multiple xattrs is a nice idea, but EVM
>>> doesn't currently support it. The LSM xattrs are hard coded in
>>> evm_config_default_xattrnames[], based on whether the LSM is
>>> configured. Additional security xattrs may be included in the
>>> security.evm calculation, by extending the list via
>>> security/integrity/evm/evm_xattrs.
>> Smack uses multiple xattrs. All file system objects have a SMACK64
>> attribute, which is used for access control. A program file may have
>> a SMACK64EXEC attribute, which is the label the program will run with.
>> A library may have a SMACK64MMAP attribute to restrict loading. A
>> directory may have a SMACK64TRANSMUTE attribute, which modifies the
>> new object creation behavior.
>>
>> The point being that it may be more than a "nice idea" to support
>> multiple xattrs. It's not a hypothetical situation.
> And each of these addiitonal Smack xattrs are already defined in
> evm_config_default_xattrnames[].
Then I'm confused by the statement that "EVM doesn't currently support it".
next prev parent reply other threads:[~2022-11-17 17:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-10 9:46 [PATCH v4 0/5] evm: Prepare for moving to the LSM infrastructure Roberto Sassu
2022-11-10 9:46 ` [PATCH v4 1/5] reiserfs: Add missing calls to reiserfs_security_free() Roberto Sassu
2022-11-16 21:03 ` Mimi Zohar
2022-11-21 23:41 ` Paul Moore
2022-11-22 8:11 ` Roberto Sassu
2022-11-22 22:47 ` Paul Moore
2022-11-10 9:46 ` [PATCH v4 2/5] security: Rewrite security_old_inode_init_security() Roberto Sassu
2022-11-17 13:03 ` Mimi Zohar
2022-11-18 9:04 ` Roberto Sassu
2022-11-21 9:45 ` Roberto Sassu
2022-11-21 20:54 ` Mimi Zohar
2022-11-21 23:55 ` Paul Moore
2022-11-22 8:29 ` Roberto Sassu
2022-11-10 9:46 ` [PATCH v4 3/5] security: Allow all LSMs to provide xattrs for inode_init_security hook Roberto Sassu
2022-11-17 16:05 ` Mimi Zohar
2022-11-17 17:18 ` Casey Schaufler
2022-11-17 17:24 ` Mimi Zohar
2022-11-17 17:40 ` Casey Schaufler [this message]
2022-11-17 18:07 ` Mimi Zohar
2022-11-18 9:32 ` Roberto Sassu
2022-11-18 15:33 ` Mimi Zohar
2022-11-18 9:14 ` Roberto Sassu
2022-11-18 15:10 ` Mimi Zohar
2022-11-18 17:31 ` Casey Schaufler
2022-11-21 13:29 ` Roberto Sassu
2022-11-21 20:58 ` Mimi Zohar
2022-11-18 17:15 ` Casey Schaufler
2022-11-10 9:46 ` [PATCH v4 4/5] evm: Align evm_inode_init_security() definition with LSM infrastructure Roberto Sassu
2022-11-17 17:07 ` Mimi Zohar
2022-11-18 9:30 ` Roberto Sassu
2022-11-18 14:45 ` Mimi Zohar
2022-11-18 15:11 ` Mimi Zohar
2022-11-10 9:46 ` [PATCH v4 5/5] evm: Support multiple LSMs providing an xattr Roberto Sassu
2022-11-17 17:09 ` Mimi Zohar
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