[PATCH 3.10 115/268] apparmor: internal paths should be treated as disconnected

Willy Tarreau
2017-06-19T19:35:14Z

From: John Johansen <john.johansen@canonical.com>

commit bd35db8b8ca6e27fc17a9057ef78e1ddfc0de351 upstream.

Internal mounts are not mounted anywhere and as such should be treated
as disconnected paths.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
security/apparmor/path.c | 64 +++++++++++++++++++++++++++---------------------
1 file changed, 36 insertions(+), 28 deletions(-)

diff --git a/security/apparmor/path.c b/security/apparmor/path.c
index ebc7780..07bf2ac 100644
--- a/security/apparmor/path.c
+++ b/security/apparmor/path.c
@@ -25,7 +25,6 @@
#include "include/path.h"
#include "include/policy.h"

-
/* modified from dcache.c */
static int prepend(char **buffer, int buflen, const char *str, int namelen)
{
@@ -39,6 +38,38 @@ static int prepend(char **buffer, int buflen, const char *str, int namelen)

#define CHROOT_NSCONNECT (PATH_CHROOT_REL | PATH_CHROOT_NSCONNECT)

+/* If the path is not connected to the expected root,
+ * check if it is a sysctl and handle specially else remove any
+ * leading / that __d_path may have returned.
+ * Unless
+ * specifically directed to connect the path,
+ * OR
+ * if in a chroot and doing chroot relative paths and the path
+ * resolves to the namespace root (would be connected outside
+ * of chroot) and specifically directed to connect paths to
+ * namespace root.
+ */
+static int disconnect(const struct path *path, char *buf, char **name,
+ int flags)
+{
+ int error = 0;
+
+ if (!(flags & PATH_CONNECT_PATH) &&
+ !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) &&
+ our_mnt(path->mnt))) {
+ /* disconnected path, don't return pathname starting
+ * with '/'
+ */
+ error = -EACCES;
+ if (**name == '/')
+ *name = *name + 1;
+ } else if (**name != '/')
+ /* CONNECT_PATH with missing root */
+ error = prepend(name, *name - buf, "/", 1);
+
+ return error;
+}
+
/**
* d_namespace_path - lookup a name associated with a given path
* @path: path to lookup (NOT NULL)
@@ -74,7 +105,8 @@ static int d_namespace_path(struct path *path, char *buf, int buflen,
* control instead of hard coded /proc
*/
return prepend(name, *name - buf, "/proc", 5);
- }
+ } else
+ return disconnect(path, buf, name, flags);
return 0;
}

@@ -120,32 +152,8 @@ static int d_namespace_path(struct path *path, char *buf, int buflen,
goto out;
}

- /* If the path is not connected to the expected root,
- * check if it is a sysctl and handle specially else remove any
- * leading / that __d_path may have returned.
- * Unless
- * specifically directed to connect the path,
- * OR
- * if in a chroot and doing chroot relative paths and the path
- * resolves to the namespace root (would be connected outside
- * of chroot) and specifically directed to connect paths to
- * namespace root.
- */
- if (!connected) {
- if (!(flags & PATH_CONNECT_PATH) &&
- !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) &&
- our_mnt(path->mnt))) {
- /* disconnected path, don't return pathname starting
- * with '/'
- */
- error = -EACCES;
- if (*res == '/')
- *name = res + 1;
- } else if (*res != '/')
- /* CONNECT_PATH with missing root */
- error = prepend(name, *name - buf, "/", 1);
-
- }
+ if (!connected)
+ error = disconnect(path, buf, name, flags);

out:
return error;
--
2.8.0.rc2.1.gbe9624a