selinux: export initial SID contexts via selinuxfs
Make the initial SID contexts accessible to userspace via selinuxfs.
An initial use of this support will be to make the unlabeled context
available to libselinux for use for invalidated userspace SIDs.
Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 93b3177..e24235c 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -102,6 +102,9 @@
SEL_COMPAT_NET, /* whether to use old compat network packet controls */
};
+#define SEL_INITCON_INO_OFFSET 0x01000000
+#define SEL_INO_MASK 0x00ffffff
+
#define TMPBUFLEN 12
static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
@@ -1240,6 +1243,55 @@
return ret;
}
+static ssize_t sel_read_initcon(struct file * file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct inode *inode;
+ char *con;
+ u32 sid, len;
+ ssize_t ret;
+
+ inode = file->f_path.dentry->d_inode;
+ sid = inode->i_ino&SEL_INO_MASK;
+ ret = security_sid_to_context(sid, &con, &len);
+ if (ret < 0)
+ return ret;
+
+ ret = simple_read_from_buffer(buf, count, ppos, con, len);
+ kfree(con);
+ return ret;
+}
+
+static const struct file_operations sel_initcon_ops = {
+ .read = sel_read_initcon,
+};
+
+static int sel_make_initcon_files(struct dentry *dir)
+{
+ int i, ret = 0;
+
+ for (i = 1; i <= SECINITSID_NUM; i++) {
+ struct inode *inode;
+ struct dentry *dentry;
+ dentry = d_alloc_name(dir, security_get_initial_sid_context(i));
+ if (!dentry) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
+ if (!inode) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ inode->i_fop = &sel_initcon_ops;
+ inode->i_ino = i|SEL_INITCON_INO_OFFSET;
+ d_add(dentry, inode);
+ }
+out:
+ return ret;
+}
+
static int sel_make_dir(struct inode *dir, struct dentry *dentry)
{
int ret = 0;
@@ -1336,6 +1388,21 @@
ret = sel_make_avc_files(dentry);
if (ret)
goto err;
+
+ dentry = d_alloc_name(sb->s_root, "initial_contexts");
+ if (!dentry) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ ret = sel_make_dir(root_inode, dentry);
+ if (ret)
+ goto err;
+
+ ret = sel_make_initcon_files(dentry);
+ if (ret)
+ goto err;
+
out:
return ret;
err: