apparmor: issue with ns name without a following profile

If we have a ns name without a following profile then in the original code it did "*ns_name = &name[1];". "name" is NULL so "*ns_name" is 0x1. That isn't useful and could cause an oops when this function is called from aa_remove_profiles().

---
I'm not very familiar with this code and I haven't tested my fix. Sorry. Please review carefully.

index 6e85cdb..da34011 100644
@@ -44,10 +44,12 @@ char *aa_split_fqname(char *fqname, char **ns_name)
 			/* overwrite ':' with \0 */
 			*split = 0;
 			name = skip_spaces(split + 1);
-		} else
+			*ns_name = &name[1];
+		} else {
 			/* a ns name without a following profile is allowed */
+			*ns_name = &name[1];
 			name = NULL;
-		*ns_name = &name[1];
+		}
 	}
 	if (name && *name = 0)
 		name = NULL;

Indeed. I am sorry to say this case was not enabled in the test suite :( However proposed patch is incorrect, in that it results in namespace name that starts at &name[1].

I've attached two patches, the first fixes this issue, and the second fixes a locking bug in namespace removal, for this case (ie. where there is no profile name specified.

Thanks for catching this

John

From 07abf5de857614c13449031b9ac9e06c8efb7765 Mon Sep 17 00:00:00 2001
From: John Johansen <[email protected]>
Date: Mon, 9 Aug 2010 08:53:51 -0400
Subject: [PATCH 1/2] AppArmor: Fix splitting an fqname into separate namespace and profile names

As per Dan Carpenter <[email protected]>
If we have a ns name without a following profile then in the original code it did "*ns_name = &name[1];". "name" is NULL so "*ns_name" is 0x1. That isn't useful and could cause an oops when this function is called from aa_remove_profiles().

Beyond this the assignment of the namespace name was wrong in the case where the profile name was provided as it was being set to &name[1] after name = skip_spaces(split + 1);

Move the ns_name assignment before updating name for the split and also add skip_spaces, making the interface more robust.

---
 security/apparmor/lib.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 6e85cdb..506d2ba 100644
@@ -40,6 +40,7 @@ char *aa_split_fqname(char *fqname, char **ns_name)
 	*ns_name = NULL;
 	if (name[0] == ':') {
 		char *split = strchr(&name[1], ':');
+		*ns_name = skip_spaces(&name[1]);
 		if (split) {
 			/* overwrite ':' with \0 */
 			*split = 0;

@@ -47,7 +48,6 @@ char *aa_split_fqname(char *fqname, char **ns_name)
 		} else
 			/* a ns name without a following profile is allowed */
 			name = NULL;
-		*ns_name = &name[1];
 	}
 	if (name && *name == 0)
 		name = NULL;

1.7.1

From 8109a95a05dd6e5349e43a2a6bb7149565cc886e Mon Sep 17 00:00:00 2001
From: John Johansen <[email protected]>
Date: Thu, 12 Aug 2010 07:49:12 -0400
Subject: [PATCH 2/2] AppArmor: Fix locking from removal of profile namespace

The locking for profile namespace removal is wrong, when removing a profile namespace, it needs to be removed from its parent's list. Lock the parent of namespace list instead of the namespace being removed.

---
 security/apparmor/policy.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

index 3cdc1ad..52cc865 100644
@@ -1151,12 +1151,14 @@ ssize_t aa_remove_profiles(char *fqname, size_t size)
 		/* released below */
 		ns = aa_get_namespace(root);
 
-	write_lock(&ns->lock);
 	if (!name) {
 		/* remove namespace - can only happen if fqname[0] == ':' */
+		write_lock(&ns->parent->lock);
 		__remove_namespace(ns);
+		write_unlock(&ns->parent->lock);
 	} else {
 		/* remove profile */
+		write_lock(&ns->lock);
 		profile = aa_get_profile(__lookup_profile(&ns->base, name));
 		if (!profile) {
 			error = -ENOENT;

@@ -1165,8 +1167,8 @@ ssize_t aa_remove_profiles(char *fqname, size_t size)
 		}
 		name = profile->base.hname;
 		__remove_profile(profile);
+		write_unlock(&ns->lock);
 	}
-	write_unlock(&ns->lock);
 
 	/* don't fail removal if audit fails */
 	(void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);

1.7.1