[PATCH v8 2/6] ocfs2: Switch to security_inode_init_security()

[Mimi Zohar]

On Tue, 2023-03-14 at 09:17 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu at huawei.com>
> 
> In preparation for removing security_old_inode_init_security(), switch to
> security_inode_init_security().
> 
> Extend the existing ocfs2_initxattrs() to take the
> ocfs2_security_xattr_info structure from fs_info, and populate the
> name/value/len triple with the first xattr provided by LSMs.
> 
> As fs_info was not used before, ocfs2_initxattrs() can now handle the case
> of replicating the behavior of security_old_inode_init_security(), i.e.
> just obtaining the xattr, in addition to setting all xattrs provided by
> LSMs.
> 
> Supporting multiple xattrs is not currently supported where
> security_old_inode_init_security() was called (mknod, symlink), as it
> requires non-trivial changes that can be done at a later time. Like for
> reiserfs, even if EVM is invoked, it will not provide an xattr (if it is
> not the first to set it, its xattr will be discarded; if it is the first,
> it does not have xattrs to calculate the HMAC on).
> 
> Finally, since security_inode_init_security(), unlike
> security_old_inode_init_security(), returns zero instead of -EOPNOTSUPP if
> no xattrs were provided by LSMs or if inodes are private, additionally
> check in ocfs2_init_security_get() if the xattr name is set.
> 
> If not, act as if security_old_inode_init_security() returned -EOPNOTSUPP,
> and set si->enable to zero to notify to the functions following
> ocfs2_init_security_get() that no xattrs are available.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
> Reviewed-by: Casey Schaufler <casey at schaufler-ca.com>
> Acked-by: Joseph Qi <joseph.qi at linux.alibaba.com>

Reviewed-by: Mimi Zohar <zohar at linux.ibm.com>