From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A71C32192FC; Wed, 30 Jul 2025 09:26:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.132 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753867606; cv=none; b=XFV9s8EsAEoznm87ketkVXZUM5JRN4nrsztaCFW06V4NAQu+5DSZsTS0FvlRgsEtz6oyqX2WujIBCwR1yQ/HuKIbgtOPEDirKoe55MkedKIi9BGc2oXMvCqFRv8E74JZlSgmy4c5jOpXKyBwqbPeJvKyGdkg3vT01vhpWgq4r/o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753867606; c=relaxed/simple; bh=ZLwtql3PAv5rT5fZZseO69SnXuOKkCikTwuzUTrOy8M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=P94w6pHjGar13KEUa55w6oUqCzC0+H0hzLqNY5cQMiHrv+fWGWSCjzYXIFqxoh2l4yVuLBm3C8AQUwysbaJZcJthTkCcDRRLZfQjdXcisOrJRvOL2w7Cr0YPBztWX6YYto5E/gvO4AVHC12vT8y/oMOYJrrYwk1M2EGP3AkgQNs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=enw/ndHO; arc=none smtp.client-ip=115.124.30.132 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="enw/ndHO" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1753867593; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=ftYGM2w9MWCsVNvyG5RJGXhmw0ACmw9Xueyrdwm3brw=; b=enw/ndHOeliff3jRd8awu9wDpqa+OCDrsYqa+aK6vifA3+6W20W3Fs+PVx7o2XBOiAJE1Oiql2KBzL5SDT3JTMHoAUyMWpOleJOlVGXZsSUzvbrW5VTyATJFFatDqCYoEiuPI+jLaWJl0BgtNYdLpdXtmgcg7/6SS8aIwFH1bvM= Received: from 30.246.163.44(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0WkUQDEK_1753867555 cluster:ay36) by smtp.aliyun-inc.com; Wed, 30 Jul 2025 17:26:33 +0800 Message-ID: Date: Wed, 30 Jul 2025 17:25:50 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] lsm: simplify security_inode_copy_up_xattr() To: Paul Moore , Casey Schaufler Cc: James Morris , "Serge E. Hallyn" , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250729090933.94942-1-tianjia.zhang@linux.alibaba.com> Content-Language: en-US From: "tianjia.zhang" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 7/29/25 11:09 PM, Paul Moore wrote: > On Tue, Jul 29, 2025 at 10:43 AM Casey Schaufler wrote: >> On 7/29/2025 2:09 AM, Tianjia Zhang wrote: >>> The implementation of function security_inode_copy_up_xattr can be >>> simplified to directly call call_int_hook(). >>> >>> Signed-off-by: Tianjia Zhang >>> --- >>> security/security.c | 8 +------- >>> 1 file changed, 1 insertion(+), 7 deletions(-) >>> >>> diff --git a/security/security.c b/security/security.c >>> index 596d41818577..a5c2e5a8009f 100644 >>> --- a/security/security.c >>> +++ b/security/security.c >>> @@ -2774,13 +2774,7 @@ EXPORT_SYMBOL(security_inode_copy_up); >>> */ >>> int security_inode_copy_up_xattr(struct dentry *src, const char *name) >>> { >>> - int rc; >>> - >>> - rc = call_int_hook(inode_copy_up_xattr, src, name); >>> - if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr)) >>> - return rc; >>> - >>> - return LSM_RET_DEFAULT(inode_copy_up_xattr); >>> + return call_int_hook(inode_copy_up_xattr, src, name); >> >> Both the existing code and the proposed change are incorrect. >> If two LSMs supply the hook, and the first does not recognize >> the attribute, the second, which might recognize the attribute, >> will not be called. As SELinux and EVM both supply this hook >> there may be a real problem here. > > It appears that Smack also supplies a inode_copy_up_xattr() callback > via smack_inode_copy_up_xattr(). > > Someone should double check this logic, but looking at it very > quickly, it would appear that LSM framework should run the individual > LSM callbacks in order so long as they return -EOPNOTSUPP, if they do > not return -EOPNOTSUPP, the return value should be returned to the > caller without executing any further callbacks. As a default return > value, or if all of the LSM callbacks succeed with -EOPNOTSUPP, the > hook should return -EOPNOTSUPP. > > Tianjia Zhang, would you be able to develop and test a patch for this? > Yes, I will submit a new patch to try to fix this issue. Thanks for your suggestion. Cheers, Tianjia