AppArmor: userspace interfaces

The /proc/<pid>/attr/* interface is used for process introspection and
commands.  While the apparmorfs interface is used for global introspection
and loading and removing policy.

The interface currently only contains the files necessary for loading
policy, and will be extended in the future to include sysfs style
single per file introspection inteface.

The old AppArmor 2.4 interface files have been removed into a compatibility
patch, that distros can use to maintain backwards compatibility.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 170 insertions, 0 deletions

diff --git a/security/apparmor/procattr.c b/security/apparmor/procattr.c
new file mode 100644
index 000000000000..04a2cf8d1b65
--- /dev/null
+++ b/security/apparmor/procattr.c
@@ -0,0 +1,170 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor /proc/<pid>/attr/ interface functions
+ *
+ * Copyright (C) 1998-2008 Novell/SUSE
+ * Copyright 2009-2010 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ */
+
+#include "include/apparmor.h"
+#include "include/context.h"
+#include "include/policy.h"
+#include "include/domain.h"
+
+
+/**
+ * aa_getprocattr - Return the profile information for @profile
+ * @profile: the profile to print profile info about  (NOT NULL)
+ * @string: Returns - string containing the profile info (NOT NULL)
+ *
+ * Returns: length of @string on success else error on failure
+ *
+ * Requires: profile != NULL
+ *
+ * Creates a string containing the namespace_name://profile_name for
+ * @profile.
+ *
+ * Returns: size of string placed in @string else error code on failure
+ */
+int aa_getprocattr(struct aa_profile *profile, char **string)
+{
+	char *str;
+	int len = 0, mode_len = 0, ns_len = 0, name_len;
+	const char *mode_str = profile_mode_names[profile->mode];
+	const char *ns_name = NULL;
+	struct aa_namespace *ns = profile->ns;
+	struct aa_namespace *current_ns = __aa_current_profile()->ns;
+	char *s;
+
+	if (!aa_ns_visible(current_ns, ns))
+		return -EACCES;
+
+	ns_name = aa_ns_name(current_ns, ns);
+	ns_len = strlen(ns_name);
+
+	/* if the visible ns_name is > 0 increase size for : :// seperator */
+	if (ns_len)
+		ns_len += 4;
+
+	/* unconfined profiles don't have a mode string appended */
+	if (!unconfined(profile))
+		mode_len = strlen(mode_str) + 3;	/* + 3 for _() */
+
+	name_len = strlen(profile->base.hname);
+	len = mode_len + ns_len + name_len + 1;	    /* + 1 for \n */
+	s = str = kmalloc(len + 1, GFP_KERNEL);	    /* + 1 \0 */
+	if (!str)
+		return -ENOMEM;
+
+	if (ns_len) {
+		/* skip over prefix current_ns->base.hname and separating // */
+		sprintf(s, ":%s://", ns_name);
+		s += ns_len;
+	}
+	if (unconfined(profile))
+		/* mode string not being appended */
+		sprintf(s, "%s\n", profile->base.hname);
+	else
+		sprintf(s, "%s (%s)\n", profile->base.hname, mode_str);
+	*string = str;
+
+	/* NOTE: len does not include \0 of string, not saved as part of file */
+	return len;
+}
+
+/**
+ * split_token_from_name - separate a string of form  <token>^<name>
+ * @op: operation being checked
+ * @args: string to parse  (NOT NULL)
+ * @token: stores returned parsed token value  (NOT NULL)
+ *
+ * Returns: start position of name after token else NULL on failure
+ */
+static char *split_token_from_name(int op, char *args, u64 * token)
+{
+	char *name;
+
+	*token = simple_strtoull(args, &name, 16);
+	if ((name == args) || *name != '^') {
+		AA_ERROR("%s: Invalid input '%s'", op_table[op], args);
+		return ERR_PTR(-EINVAL);
+	}
+
+	name++;			/* skip ^ */
+	if (!*name)
+		name = NULL;
+	return name;
+}
+
+/**
+ * aa_setprocattr_chagnehat - handle procattr interface to change_hat
+ * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
+ * @size: size of the args
+ * @test: true if this is a test of change_hat permissions
+ *
+ * Returns: %0 or error code if change_hat fails
+ */
+int aa_setprocattr_changehat(char *args, size_t size, int test)
+{
+	char *hat;
+	u64 token;
+	const char *hats[16];		/* current hard limit on # of names */
+	int count = 0;
+
+	hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
+	if (IS_ERR(hat))
+		return PTR_ERR(hat);
+
+	if (!hat && !token) {
+		AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
+		return -EINVAL;
+	}
+
+	if (hat) {
+		/* set up hat name vector, args guaranteed null terminated
+		 * at args[size] by setprocattr.
+		 *
+		 * If there are multiple hat names in the buffer each is
+		 * separated by a \0.  Ie. userspace writes them pre tokenized
+		 */
+		char *end = args + size;
+		for (count = 0; (hat < end) && count < 16; ++count) {
+			char *next = hat + strlen(hat) + 1;
+			hats[count] = hat;
+			hat = next;
+		}
+	}
+
+	AA_DEBUG("%s: Magic 0x%llx Hat '%s'\n",
+		 __func__, token, hat ? hat : NULL);
+
+	return aa_change_hat(hats, count, token, test);
+}
+
+/**
+ * aa_setprocattr_changeprofile - handle procattr interface to changeprofile
+ * @fqname: args received from writting to /proc/<pid>/attr/current (NOT NULL)
+ * @onexec: true if change_profile should be delayed until exec
+ * @test: true if this is a test of change_profile permissions
+ *
+ * Returns: %0 or error code if change_profile fails
+ */
+int aa_setprocattr_changeprofile(char *fqname, bool onexec, int test)
+{
+	char *name, *ns_name;
+
+	name = aa_split_fqname(fqname, &ns_name);
+	return aa_change_profile(ns_name, name, onexec, test);
+}
+
+int aa_setprocattr_permipc(char *fqname)
+{
+	/* TODO: add ipc permission querying */
+	return -ENOTSUPP;
+}