[PATCH] selinux: extend selinuxfs context interface
This patch extends the selinuxfs context interface to allow return the
canonical form of the context to userspace.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index fdc3823..0e1352a 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -271,46 +271,38 @@
.write = sel_write_load,
};
-
-static ssize_t sel_write_context(struct file * file, const char __user * buf,
- size_t count, loff_t *ppos)
-
+static ssize_t sel_write_context(struct file * file, char *buf, size_t size)
{
- char *page;
- u32 sid;
+ char *canon;
+ u32 sid, len;
ssize_t length;
length = task_has_security(current, SECURITY__CHECK_CONTEXT);
if (length)
return length;
- if (count >= PAGE_SIZE)
- return -ENOMEM;
- if (*ppos != 0) {
- /* No partial writes. */
- return -EINVAL;
- }
- page = (char*)get_zeroed_page(GFP_KERNEL);
- if (!page)
- return -ENOMEM;
- length = -EFAULT;
- if (copy_from_user(page, buf, count))
- goto out;
-
- length = security_context_to_sid(page, count, &sid);
+ length = security_context_to_sid(buf, size, &sid);
if (length < 0)
- goto out;
+ return length;
- length = count;
+ length = security_sid_to_context(sid, &canon, &len);
+ if (length < 0)
+ return length;
+
+ if (len > SIMPLE_TRANSACTION_LIMIT) {
+ printk(KERN_ERR "%s: context size (%u) exceeds payload "
+ "max\n", __FUNCTION__, len);
+ length = -ERANGE;
+ goto out;
+ }
+
+ memcpy(buf, canon, len);
+ length = len;
out:
- free_page((unsigned long) page);
+ kfree(canon);
return length;
}
-static struct file_operations sel_context_ops = {
- .write = sel_write_context,
-};
-
static ssize_t sel_read_checkreqprot(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
@@ -375,6 +367,7 @@
[SEL_RELABEL] = sel_write_relabel,
[SEL_USER] = sel_write_user,
[SEL_MEMBER] = sel_write_member,
+ [SEL_CONTEXT] = sel_write_context,
};
static ssize_t selinux_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
@@ -1220,7 +1213,7 @@
static struct tree_descr selinux_files[] = {
[SEL_LOAD] = {"load", &sel_load_ops, S_IRUSR|S_IWUSR},
[SEL_ENFORCE] = {"enforce", &sel_enforce_ops, S_IRUGO|S_IWUSR},
- [SEL_CONTEXT] = {"context", &sel_context_ops, S_IRUGO|S_IWUGO},
+ [SEL_CONTEXT] = {"context", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_ACCESS] = {"access", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_CREATE] = {"create", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_RELABEL] = {"relabel", &transaction_ops, S_IRUGO|S_IWUGO},