From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933780AbeAYDio (ORCPT ); Wed, 24 Jan 2018 22:38:44 -0500 Received: from alln-iport-5.cisco.com ([173.37.142.92]:56485 "EHLO alln-iport-5.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933490AbeAYDhh (ORCPT ); Wed, 24 Jan 2018 22:37:37 -0500 X-IronPort-AV: E=Sophos;i="5.46,409,1511827200"; d="scan'208";a="60755462" From: Taras Kondratiuk To: "H. Peter Anvin" , Al Viro , Arnd Bergmann , Rob Landley , Mimi Zohar , Jonathan Corbet , James McMechan Cc: initramfs@vger.kernel.org, Victor Kamensky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, xe-linux-external@cisco.com Subject: [PATCH v2 15/15] selinux: delay sid population for rootfs till init is complete Date: Thu, 25 Jan 2018 03:27:55 +0000 Message-Id: <1516850875-25066-16-git-send-email-takondra@cisco.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1516850875-25066-1-git-send-email-takondra@cisco.com> References: <1516850875-25066-1-git-send-email-takondra@cisco.com> X-Auto-Response-Suppress: DR, OOF, AutoReply X-Authenticated-User: takondra@cisco.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Victor Kamensky With initramfs cpio format that supports extended attributes we need to skip sid population on sys_lsetxattr call from initramfs for rootfs if security server is not initialized yet. Otherwise callback in selinux_inode_post_setxattr will try to translate give security.selinux label into sid context and since security server is not available yet inode will receive default sid (typically kernel_t). Note that in the same time proper label will be stored in inode xattrs. Later, since inode sid would be already populated system will never look back at actual xattrs. But if we skip sid population for rootfs and we have policy that direct use of xattrs for rootfs, proper sid will be filled in from extended attributes one node is accessed and server is initialized. Note new DELAYAFTERINIT_MNT super block flag is introduced to only mark rootfs for such behavior. For other types of tmpfs original logic is still used. Signed-off-by: Victor Kamensky --- security/selinux/hooks.c | 9 ++++++++- security/selinux/include/security.h | 1 + 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index f3fe65589f02..bb25268f734e 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -716,7 +716,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, */ if (!strncmp(sb->s_type->name, "rootfs", sizeof("rootfs"))) - sbsec->flags |= SBLABEL_MNT; + sbsec->flags |= SBLABEL_MNT|DELAYAFTERINIT_MNT; /* Defer initialization until selinux_complete_init, after the initial policy is loaded and the security @@ -3253,6 +3253,7 @@ static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name, { struct inode *inode = d_backing_inode(dentry); struct inode_security_struct *isec; + struct superblock_security_struct *sbsec; u32 newsid; int rc; @@ -3261,6 +3262,12 @@ static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name, return; } + if (!ss_initialized) { + sbsec = inode->i_sb->s_security; + if (sbsec->flags & DELAYAFTERINIT_MNT) + return; + } + rc = security_context_to_sid_force(value, size, &newsid); if (rc) { printk(KERN_ERR "SELinux: unable to map context to SID" diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 02f0412d42f2..585acfd6cbcf 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -52,6 +52,7 @@ #define ROOTCONTEXT_MNT 0x04 #define DEFCONTEXT_MNT 0x08 #define SBLABEL_MNT 0x10 +#define DELAYAFTERINIT_MNT 0x20 /* Non-mount related flags */ #define SE_SBINITIALIZED 0x0100 #define SE_SBPROC 0x0200 -- 2.10.3.dirty