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From: Ondrej Mosnacek <omosnace@redhat.com>
To: selinux@vger.kernel.org, Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>,
	linux-security-module@vger.kernel.org,
	Casey Schaufler <casey@schaufler-ca.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>,
	linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org,
	Ondrej Mosnacek <omosnace@redhat.com>
Subject: [PATCH v4 4/5] selinux: implement the kernfs_init_security hook
Date: Tue,  5 Feb 2019 09:59:14 +0100
Message-ID: <20190205085915.5183-5-omosnace@redhat.com> (raw)
In-Reply-To: <20190205085915.5183-1-omosnace@redhat.com>

The hook applies the same logic as selinux_determine_inode_label(), with
the exception of the super_block handling, which will be enforced on the
actual inodes later by other hooks.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 security/selinux/hooks.c | 62 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 758a99d1086e..e013cc02de50 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3354,6 +3354,66 @@ static int selinux_inode_copy_up_xattr(const char *name)
 	return -EOPNOTSUPP;
 }
 
+/* kernfs node operations */
+
+int selinux_kernfs_init_security(const struct qstr *qstr,
+				 const struct iattr *dir_iattr,
+				 struct simple_xattrs *dir_secattr,
+				 const struct iattr *iattr,
+				 struct simple_xattrs *secattr)
+{
+	const struct task_security_struct *tsec = current_security();
+	u32 parent_sid, newsid, clen;
+	int rc;
+	char *context;
+
+	rc = simple_xattr_get(dir_secattr, XATTR_SELINUX_SUFFIX, NULL, 0);
+	if (rc == -ENODATA)
+		return 0;
+	else if (rc < 0)
+		return rc;
+
+	clen = (u32)rc;
+	context = kmalloc(clen, GFP_KERNEL);
+	if (!context)
+		return -ENOMEM;
+
+	rc = simple_xattr_get(dir_secattr, XATTR_SELINUX_SUFFIX, context, clen);
+	if (rc < 0) {
+		kfree(context);
+		return rc;
+	}
+
+	rc = security_context_to_sid(&selinux_state, context, clen, &parent_sid,
+				     GFP_KERNEL);
+	kfree(context);
+	if (rc)
+		return rc;
+
+	if (tsec->create_sid) {
+		newsid = tsec->create_sid;
+	} else {
+		u16 secclass = inode_mode_to_security_class(iattr->ia_mode);
+
+		rc = security_transition_sid(&selinux_state, tsec->sid,
+					     parent_sid, secclass, qstr,
+					     &newsid);
+		if (rc)
+			return rc;
+	}
+
+	rc = security_sid_to_context_force(&selinux_state, newsid,
+					   &context, &clen);
+	if (rc)
+		return rc;
+
+	rc = simple_xattr_set(secattr, XATTR_SELINUX_SUFFIX, context, clen,
+			      XATTR_CREATE);
+	kfree(context);
+	return rc;
+}
+
+
 /* file security operations */
 
 static int selinux_revalidate_file_permission(struct file *file, int mask)
@@ -6800,6 +6860,8 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(inode_copy_up, selinux_inode_copy_up),
 	LSM_HOOK_INIT(inode_copy_up_xattr, selinux_inode_copy_up_xattr),
 
+	LSM_HOOK_INIT(kernfs_init_security, selinux_kernfs_init_security),
+
 	LSM_HOOK_INIT(file_permission, selinux_file_permission),
 	LSM_HOOK_INIT(file_alloc_security, selinux_file_alloc_security),
 	LSM_HOOK_INIT(file_free_security, selinux_file_free_security),
-- 
2.20.1


  parent reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-05  8:59 [PATCH v4 0/5] Allow initializing the kernfs node's secctx based on its parent Ondrej Mosnacek
2019-02-05  8:59 ` [PATCH v4 1/5] selinux: try security xattr after genfs for kernfs filesystems Ondrej Mosnacek
2019-02-05  8:59 ` [PATCH v4 2/5] kernfs: use simple_xattrs for security attributes Ondrej Mosnacek
2019-02-05  8:59 ` [PATCH v4 3/5] LSM: add new hook for kernfs node initialization Ondrej Mosnacek
2019-02-05  9:51   ` kbuild test robot
2019-02-05 11:10     ` Ondrej Mosnacek
2019-02-05 10:25   ` kbuild test robot
2019-02-05  8:59 ` Ondrej Mosnacek [this message]
2019-02-05  8:59 ` [PATCH v4 5/5] kernfs: initialize security of newly created nodes Ondrej Mosnacek
2019-02-05 10:18   ` kbuild test robot

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