7 files changed, 113 insertions, 6 deletions
diff --git a/Documentation/security/00-INDEX b/Documentation/security/00-INDEX
index 19bc49439cac..eeed1de546d4 100644
--- a/Documentation/security/00-INDEX
+++ b/Documentation/security/00-INDEX
@@ -1,9 +1,13 @@
 00-INDEX
 	- this file.
+LSM.txt
+	- description of the Linux Security Module framework.
 SELinux.txt
 	- how to get started with the SELinux security enhancement.
 Smack.txt
 	- documentation on the Smack Linux Security Module.
+Yama.txt
+	- documentation on the Yama Linux Security Module.
 apparmor.txt
 	- documentation on the AppArmor security extension.
 credentials.txt
diff --git a/Documentation/security/LSM.txt b/Documentation/security/LSM.txt
new file mode 100644
index 000000000000..c335a763a2ed
--- /dev/null
+++ b/Documentation/security/LSM.txt
@@ -0,0 +1,34 @@
+Linux Security Module framework
+-------------------------------
+
+The Linux Security Module (LSM) framework provides a mechanism for
+various security checks to be hooked by new kernel extensions. The name
+"module" is a bit of a misnomer since these extensions are not actually
+loadable kernel modules. Instead, they are selectable at build-time via
+CONFIG_DEFAULT_SECURITY and can be overridden at boot-time via the
+"security=..." kernel command line argument, in the case where multiple
+LSMs were built into a given kernel.
+
+The primary users of the LSM interface are Mandatory Access Control
+(MAC) extensions which provide a comprehensive security policy. Examples
+include SELinux, Smack, Tomoyo, and AppArmor. In addition to the larger
+MAC extensions, other extensions can be built using the LSM to provide
+specific changes to system operation when these tweaks are not available
+in the core functionality of Linux itself.
+
+Without a specific LSM built into the kernel, the default LSM will be the
+Linux capabilities system. Most LSMs choose to extend the capabilities
+system, building their checks on top of the defined capability hooks.
+For more details on capabilities, see capabilities(7) in the Linux
+man-pages project.
+
+Based on http://kerneltrap.org/Linux/Documenting_Security_Module_Intent,
+a new LSM is accepted into the kernel when its intent (a description of
+what it tries to protect against and in what cases one would expect to
+use it) has been appropriately documented in Documentation/security/.
+This allows an LSM's code to be easily compared to its goals, and so
+that end users and distros can make a more informed decision about which
+LSMs suit their requirements.
+
+For extensive documentation on the available LSM hook interfaces, please
+see include/linux/security.h.
diff --git a/Documentation/security/Smack.txt b/Documentation/security/Smack.txt
index e9dab41c0fe0..d2f72ae66432 100644
--- a/Documentation/security/Smack.txt
+++ b/Documentation/security/Smack.txt
@@ -536,6 +536,6 @@ writing a single character to the /smack/logging file :
 3 : log denied & accepted
 
 Events are logged as 'key=value' pairs, for each event you at least will get
-the subjet, the object, the rights requested, the action, the kernel function
+the subject, the object, the rights requested, the action, the kernel function
 that triggered the event, plus other pairs depending on the type of event
 audited.
diff --git a/Documentation/security/Yama.txt b/Documentation/security/Yama.txt
new file mode 100644
index 000000000000..a9511f179069
--- /dev/null
+++ b/Documentation/security/Yama.txt
@@ -0,0 +1,65 @@
+Yama is a Linux Security Module that collects a number of system-wide DAC
+security protections that are not handled by the core kernel itself. To
+select it at boot time, specify "security=yama" (though this will disable
+any other LSM).
+
+Yama is controlled through sysctl in /proc/sys/kernel/yama:
+
+- ptrace_scope
+
+==============================================================
+
+ptrace_scope:
+
+As Linux grows in popularity, it will become a larger target for
+malware. One particularly troubling weakness of the Linux process
+interfaces is that a single user is able to examine the memory and
+running state of any of their processes. For example, if one application
+(e.g. Pidgin) was compromised, it would be possible for an attacker to
+attach to other running processes (e.g. Firefox, SSH sessions, GPG agent,
+etc) to extract additional credentials and continue to expand the scope
+of their attack without resorting to user-assisted phishing.
+
+This is not a theoretical problem. SSH session hijacking
+(http://www.storm.net.nz/projects/7) and arbitrary code injection
+(http://c-skills.blogspot.com/2007/05/injectso.html) attacks already
+exist and remain possible if ptrace is allowed to operate as before.
+Since ptrace is not commonly used by non-developers and non-admins, system
+builders should be allowed the option to disable this debugging system.
+
+For a solution, some applications use prctl(PR_SET_DUMPABLE, ...) to
+specifically disallow such ptrace attachment (e.g. ssh-agent), but many
+do not. A more general solution is to only allow ptrace directly from a
+parent to a child process (i.e. direct "gdb EXE" and "strace EXE" still
+work), or with CAP_SYS_PTRACE (i.e. "gdb --pid=PID", and "strace -p PID"
+still work as root).
+
+For software that has defined application-specific relationships
+between a debugging process and its inferior (crash handlers, etc),
+prctl(PR_SET_PTRACER, pid, ...) can be used. An inferior can declare which
+other process (and its descendents) are allowed to call PTRACE_ATTACH
+against it. Only one such declared debugging process can exists for
+each inferior at a time. For example, this is used by KDE, Chromium, and
+Firefox's crash handlers, and by Wine for allowing only Wine processes
+to ptrace each other. If a process wishes to entirely disable these ptrace
+restrictions, it can call prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, ...)
+so that any otherwise allowed process (even those in external pid namespaces)
+may attach.
+
+The sysctl settings are:
+
+0 - classic ptrace permissions: a process can PTRACE_ATTACH to any other
+    process running under the same uid, as long as it is dumpable (i.e.
+    did not transition uids, start privileged, or have called
+    prctl(PR_SET_DUMPABLE...) already).
+
+1 - restricted ptrace: a process must have a predefined relationship
+    with the inferior it wants to call PTRACE_ATTACH on. By default,
+    this relationship is that of only its descendants when the above
+    classic criteria is also met. To change the relationship, an
+    inferior can call prctl(PR_SET_PTRACER, debugger, ...) to declare
+    an allowed debugger PID to call PTRACE_ATTACH on the inferior.
+
+The original children-only logic was based on the restrictions in grsecurity.
+
+==============================================================
diff --git a/Documentation/security/credentials.txt b/Documentation/security/credentials.txt
index fc0366cbd7ce..86257052e31a 100644
--- a/Documentation/security/credentials.txt
+++ b/Documentation/security/credentials.txt
@@ -221,10 +221,10 @@ The Linux kernel supports the following types of credentials:
  (5) LSM
 
      The Linux Security Module allows extra controls to be placed over the
-     operations that a task may do.  Currently Linux supports two main
-     alternate LSM options: SELinux and Smack.
+     operations that a task may do.  Currently Linux supports several LSM
+     options.
 
-     Both work by labelling the objects in a system and then applying sets of
+     Some work by labelling the objects in a system and then applying sets of
      rules (policies) that say what operations a task with one label may do to
      an object with another label.
 
diff --git a/Documentation/security/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt
index c9e4855ed3d7..e105ae97a4f5 100644
--- a/Documentation/security/keys-trusted-encrypted.txt
+++ b/Documentation/security/keys-trusted-encrypted.txt
@@ -1,7 +1,7 @@
 			Trusted and Encrypted Keys
 
 Trusted and Encrypted Keys are two new key types added to the existing kernel
-key ring service.  Both of these new types are variable length symmetic keys,
+key ring service.  Both of these new types are variable length symmetric keys,
 and in both cases all keys are created in the kernel, and user space sees,
 stores, and loads only encrypted blobs.  Trusted Keys require the availability
 of a Trusted Platform Module (TPM) chip for greater security, while Encrypted
diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt
index 4d75931d2d79..787717091421 100644
--- a/Documentation/security/keys.txt
+++ b/Documentation/security/keys.txt
@@ -554,6 +554,10 @@ The keyctl syscall functions are:
      process must have write permission on the keyring, and it must be a
      keyring (or else error ENOTDIR will result).
 
+     This function can also be used to clear special kernel keyrings if they
+     are appropriately marked if the user has CAP_SYS_ADMIN capability.  The
+     DNS resolver cache keyring is an example of this.
+
 
  (*) Link a key into a keyring:
 
@@ -668,7 +672,7 @@ The keyctl syscall functions are:
 
      If the kernel calls back to userspace to complete the instantiation of a
      key, userspace should use this call mark the key as negative before the
-     invoked process returns if it is unable to fulfil the request.
+     invoked process returns if it is unable to fulfill the request.
 
      The process must have write access on the key to be able to instantiate
      it, and the key must be uninstantiated.