Re: [PATCH 24/27] NFS: Use local caching [try #2]

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From: David Howells

Subject: [PATCH 00/27] Permit filesystem local caching [try #2]

Date: Wednesday, January 23, 2008 - 10:20 am

These patches add local caching for network filesystems such as NFS.

The patches can roughly be broken down into a number of sets:

  (*) 01-keys-inc-payload.diff
  (*) 02-keys-search-keyring.diff
  (*) 03-keys-callout-blob.diff

      Three patches to the keyring code made to help the CIFS people.
      Included because of patches 05-08.

  (*) 04-keys-get-label.diff

      A patch to allow the security label of a key to be retrieved.
      Included because of patches 05-08.

  (*) 05-security-current-fsugid.diff
  (*) 06-security-separate-task-bits.diff
  (*) 07-security-subjective.diff
  (*) 08-security-secctx2secid.diff
  (*) 09-security-additional-classes.diff
  (*) 10-security-kernel_service-class.diff
  (*) 11-security-kernel-service.diff
  (*) 12-security-nfsd.diff

      Patches to permit the subjective security of a task to be overridden.
      All the security details in task_struct are decanted into a new struct
      that task_struct then has two pointers two: one that defines the
      objective security of that task (how other tasks may affect it) and one
      that defines the subjective security (how it may affect other objects).

      Note that I have dropped the idea of struct cred for the moment.  With
      the amount of stuff that was excluded from it, it wasn't actually any
      use to me.  However, it can be added later.

      Required for cachefiles.

  (*) 13-release-page.diff
  (*) 14-fscache-page-flags.diff
  (*) 15-add_wait_queue_tail.diff
  (*) 16-fscache.diff

      Patches to provide a local caching facility for network filesystems.

  (*) 17-cachefiles-ia64.diff
  (*) 18-cachefiles-ext3-f_mapping.diff
  (*) 19-cachefiles-write.diff
  (*) 20-cachefiles-monitor.diff
  (*) 21-cachefiles-export.diff
  (*) 22-cachefiles.diff

      Patches to provide a local cache in a directory of an already mounted
      filesystem.

  (*) 23-nfs-memleak.diff
  (*) 24-fscache-nfs.diff
  (*) 25-fscache-nfs-mount.diff
  (*) ...[ message continues ]

[view original message]

From: David Howells

Subject: [PATCH 02/27] KEYS: Check starting keyring as part of search [try #2]

Date: Wednesday, January 23, 2008 - 10:20 am

Check the starting keyring as part of the search to (a) see if that is what
we're searching for, and (b) to check it is still valid for searching.

The scenario:  User in process A does things that cause things to be
created in its process session keyring.  The user then does an su to
another user and starts a new process, B.  The two processes now
share the same process session keyring.

Process B does an NFS access which results in an upcall to gssd.
When gssd attempts to instantiate the context key (to be linked
into the process session keyring), it is denied access even though it
has an authorization key.

The order of calls is:

   keyctl_instantiate_key()
      lookup_user_key()				    (the default: case)
         search_process_keyrings(current)
	    search_process_keyrings(rka-&gt;context)   (recursive call)
	       keyring_search_aux()

keyring_search_aux() verifies the keys and keyrings underneath the
top-level keyring it is given, but that top-level keyring is neither
fully validated nor checked to see if it is the thing being searched for.

This patch changes keyring_search_aux() to:
1) do more validation on the top keyring it is given and
2) check whether that top-level keyring is the thing being searched for


Signed-off-by: Kevin Coffman &lt;kwc@citi.umich.edu&gt;
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
---

 security/keys/keyring.c |   35 +++++++++++++++++++++++++++++++----
 1 files changed, 31 insertions(+), 4 deletions(-)


diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 88292e3..76b89b2 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -292,7 +292,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref,
 
 	struct keyring_list *keylist;
 	struct timespec now;
-	unsigned long possessed;
+	unsigned long possessed, kflags;
 	struct key *keyring, *key;
 	key_ref_t key_ref;
 	long err;
@@ -318,6 +318,32 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref,
 	now = current_kernel_time();
 	err = ...[ message continues ]

[view original message]

From: David Howells

Subject: [PATCH 03/27] KEYS: Allow the callout data to be passed as a blob rather than a string [try #2]

Date: Wednesday, January 23, 2008 - 10:20 am

Allow the callout data to be passed as a blob rather than a string for internal
kernel services that call any request_key_*() interface other than
request_key().  request_key() itself still takes a NUL-terminated string.

The functions that change are:

	request_key_with_auxdata()
	request_key_async()
	request_key_async_with_auxdata()

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
---

 Documentation/keys-request-key.txt |   11 +++++---
 Documentation/keys.txt             |   14 +++++++---
 include/linux/key.h                |    9 ++++---
 security/keys/internal.h           |    9 ++++---
 security/keys/keyctl.c             |    7 ++++-
 security/keys/request_key.c        |   49 ++++++++++++++++++++++--------------
 security/keys/request_key_auth.c   |   12 +++++----
 7 files changed, 70 insertions(+), 41 deletions(-)


diff --git a/Documentation/keys-request-key.txt b/Documentation/keys-request-key.txt
index 266955d..09b55e4 100644
--- a/Documentation/keys-request-key.txt
+++ b/Documentation/keys-request-key.txt
@@ -11,26 +11,29 @@ request_key*():
 
 	struct key *request_key(const struct key_type *type,
 				const char *description,
-				const char *callout_string);
+				const char *callout_info);
 
 or:
 
 	struct key *request_key_with_auxdata(const struct key_type *type,
 					     const char *description,
-					     const char *callout_string,
+					     const char *callout_info,
+					     size_t callout_len,
 					     void *aux);
 
 or:
 
 	struct key *request_key_async(const struct key_type *type,
 				      const char *description,
-				      const char *callout_string);
+				      const char *callout_info,
+				      size_t callout_len);
 
 or:
 
 	struct key *request_key_async_with_auxdata(const struct key_type *type,
 						   const char *description,
-						   const char *callout_string,
+						   const char *callout_info,
+					     	   size_t callout_len,
 						   void *aux);
 
 Or by userspace invoking the request_key system ...[ message continues ]

[view original message]

From: David Howells

Subject: [PATCH 01/27] KEYS: Increase the payload size when instantiating a key [try #2]

Date: Wednesday, January 23, 2008 - 10:20 am

Increase the size of a payload that can be used to instantiate a key in
add_key() and keyctl_instantiate_key().  This permits huge CIFS SPNEGO blobs to
be passed around.  The limit is raised to 1MB.  If kmalloc() can't allocate a
buffer of sufficient size, vmalloc() will be tried instead.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
---

 security/keys/keyctl.c |   38 ++++++++++++++++++++++++++++++--------
 1 files changed, 30 insertions(+), 8 deletions(-)


diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index d9ca15c..8ec8432 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -19,6 +19,7 @@
 #include &lt;linux/capability.h&gt;
 #include &lt;linux/string.h&gt;
 #include &lt;linux/err.h&gt;
+#include &lt;linux/vmalloc.h&gt;
 #include &lt;asm/uaccess.h&gt;
 #include &quot;internal.h&quot;
 
@@ -62,9 +63,10 @@ asmlinkage long sys_add_key(const char __user *_type,
 	char type[32], *description;
 	void *payload;
 	long ret;
+	bool vm;
 
 	ret = -EINVAL;
-	if (plen &gt; 32767)
+	if (plen &gt; 1024 * 1024 - 1)
 		goto error;
 
 	/* draw all the data into kernel space */
@@ -81,11 +83,18 @@ asmlinkage long sys_add_key(const char __user *_type,
 	/* pull the payload in if one was supplied */
 	payload = NULL;
 
+	vm = false;
 	if (_payload) {
 		ret = -ENOMEM;
 		payload = kmalloc(plen, GFP_KERNEL);
-		if (!payload)
-			goto error2;
+		if (!payload) {
+			if (plen &lt;= PAGE_SIZE)
+				goto error2;
+			vm = true;
+			payload = vmalloc(plen);
+			if (!payload)
+				goto error2;
+		}
 
 		ret = -EFAULT;
 		if (copy_from_user(payload, _payload, plen) != 0)
@@ -113,7 +122,10 @@ asmlinkage long sys_add_key(const char __user *_type,
 
 	key_ref_put(keyring_ref);
  error3:
-	kfree(payload);
+	if (!vm)
+		kfree(payload);
+	else
+		vfree(payload);
  error2:
 	kfree(description);
  error:
@@ -821,9 +833,10 @@ long keyctl_instantiate_key(key_serial_t id,
 	key_ref_t keyring_ref;
 	void *payload;
 	long ret;
+	bool vm = false;
 
 	ret = -EINVAL;
-	if (plen &gt; ...[ message continues ]

[view original message]

From: David Howells

Subject: [PATCH 04/27] KEYS: Add keyctl function to get a security label [try #2]