AppArmor: misc. base functions and defines

Miscellaneous functions and defines needed by AppArmor, including
the base path resolution routines.

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

security/apparmor/include/apparmor.h

@@ -0,0 +1,92 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor basic global and lib definitions
+ *
+ * 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.
+ */
+
+#ifndef __APPARMOR_H
+#define __APPARMOR_H
+
+#include <linux/fs.h>
+
+#include "match.h"
+
+/* Control parameters settable through module/boot flags */
+extern enum audit_mode aa_g_audit;
+extern int aa_g_audit_header;
+extern int aa_g_debug;
+extern int aa_g_lock_policy;
+extern int aa_g_logsyscall;
+extern int aa_g_paranoid_load;
+extern unsigned int aa_g_path_max;
+
+/*
+ * DEBUG remains global (no per profile flag) since it is mostly used in sysctl
+ * which is not related to profile accesses.
+ */
+
+#define AA_DEBUG(fmt, args...)						\
+	do {								\
+		if (aa_g_debug && printk_ratelimit())			\
+			printk(KERN_DEBUG "AppArmor: " fmt, ##args);	\
+	} while (0)
+
+#define AA_ERROR(fmt, args...)						\
+	do {								\
+		if (printk_ratelimit())					\
+			printk(KERN_ERR "AppArmor: " fmt, ##args);	\
+	} while (0)
+
+/* Flag indicating whether initialization completed */
+extern int apparmor_initialized __initdata;
+
+/* fn's in lib */
+char *aa_split_fqname(char *args, char **ns_name);
+void aa_info_message(const char *str);
+void *kvmalloc(size_t size);
+void kvfree(void *buffer);
+
+
+/**
+ * aa_strneq - compare null terminated @str to a non null terminated substring
+ * @str: a null terminated string
+ * @sub: a substring, not necessarily null terminated
+ * @len: length of @sub to compare
+ *
+ * The @str string must be full consumed for this to be considered a match
+ */
+static inline bool aa_strneq(const char *str, const char *sub, int len)
+{
+	return !strncmp(str, sub, len) && !str[len];
+}
+
+/**
+ * aa_dfa_null_transition - step to next state after null character
+ * @dfa: the dfa to match against
+ * @start: the state of the dfa to start matching in
+ *
+ * aa_dfa_null_transition transitions to the next state after a null
+ * character which is not used in standard matching and is only
+ * used to separate pairs.
+ */
+static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa,
+						  unsigned int start)
+{
+	/* the null transition only needs the string's null terminator byte */
+	return aa_dfa_match_len(dfa, start, "", 1);
+}
+
+static inline bool mediated_filesystem(struct inode *inode)
+{
+	return !(inode->i_sb->s_flags & MS_NOUSER);
+}
+
+#endif /* __APPARMOR_H */

security/apparmor/include/path.h

@@ -0,0 +1,31 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor basic path manipulation function definitions.
+ *
+ * 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.
+ */
+
+#ifndef __AA_PATH_H
+#define __AA_PATH_H
+
+
+enum path_flags {
+	PATH_IS_DIR = 0x1,		/* path is a directory */
+	PATH_CONNECT_PATH = 0x4,	/* connect disconnected paths to / */
+	PATH_CHROOT_REL = 0x8,		/* do path lookup relative to chroot */
+	PATH_CHROOT_NSCONNECT = 0x10,	/* connect paths that are at ns root */
+
+	PATH_DELEGATE_DELETED = 0x08000, /* delegate deleted files */
+	PATH_MEDIATE_DELETED = 0x10000,	/* mediate deleted paths */
+};
+
+int aa_get_name(struct path *path, int flags, char **buffer, const char **name);
+
+#endif /* __AA_PATH_H */

security/apparmor/lib.c

@@ -0,0 +1,133 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains basic common functions used in AppArmor
+ *
+ * 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 <linux/slab.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+
+#include "include/audit.h"
+
+
+/**
+ * aa_split_fqname - split a fqname into a profile and namespace name
+ * @fqname: a full qualified name in namespace profile format (NOT NULL)
+ * @ns_name: pointer to portion of the string containing the ns name (NOT NULL)
+ *
+ * Returns: profile name or NULL if one is not specified
+ *
+ * Split a namespace name from a profile name (see policy.c for naming
+ * description).  If a portion of the name is missing it returns NULL for
+ * that portion.
+ *
+ * NOTE: may modify the @fqname string.  The pointers returned point
+ *       into the @fqname string.
+ */
+char *aa_split_fqname(char *fqname, char **ns_name)
+{
+	char *name = strim(fqname);
+
+	*ns_name = NULL;
+	if (name[0] == ':') {
+		char *split = strchr(&name[1], ':');
+		if (split) {
+			/* overwrite ':' with \0 */
+			*split = 0;
+			name = skip_spaces(split + 1);
+		} else
+			/* a ns name without a following profile is allowed */
+			name = NULL;
+		*ns_name = &name[1];
+	}
+	if (name && *name == 0)
+		name = NULL;
+
+	return name;
+}
+
+/**
+ * aa_info_message - log a none profile related status message
+ * @str: message to log
+ */
+void aa_info_message(const char *str)
+{
+	if (audit_enabled) {
+		struct common_audit_data sa;
+		COMMON_AUDIT_DATA_INIT(&sa, NONE);
+		sa.aad.info = str;
+		aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, NULL);
+	}
+	printk(KERN_INFO "AppArmor: %s\n", str);
+}
+
+/**
+ * kvmalloc - do allocation preferring kmalloc but falling back to vmalloc
+ * @size: size of allocation
+ *
+ * Return: allocated buffer or NULL if failed
+ *
+ * It is possible that policy being loaded from the user is larger than
+ * what can be allocated by kmalloc, in those cases fall back to vmalloc.
+ */
+void *kvmalloc(size_t size)
+{
+	void *buffer = NULL;
+
+	if (size == 0)
+		return NULL;
+
+	/* do not attempt kmalloc if we need more than 16 pages at once */
+	if (size <= (16*PAGE_SIZE))
+		buffer = kmalloc(size, GFP_NOIO | __GFP_NOWARN);
+	if (!buffer) {
+		/* see kvfree for why size must be at least work_struct size
+		 * when allocated via vmalloc
+		 */
+		if (size < sizeof(struct work_struct))
+			size = sizeof(struct work_struct);
+		buffer = vmalloc(size);
+	}
+	return buffer;
+}
+
+/**
+ * do_vfree - workqueue routine for freeing vmalloced memory
+ * @work: data to be freed
+ *
+ * The work_struct is overlaid to the data being freed, as at the point
+ * the work is scheduled the data is no longer valid, be its freeing
+ * needs to be delayed until safe.
+ */
+static void do_vfree(struct work_struct *work)
+{
+	vfree(work);
+}
+
+/**
+ * kvfree - free an allocation do by kvmalloc
+ * @buffer: buffer to free (MAYBE_NULL)
+ *
+ * Free a buffer allocated by kvmalloc
+ */
+void kvfree(void *buffer)
+{
+	if (is_vmalloc_addr(buffer)) {
+		/* Data is no longer valid so just use the allocated space
+		 * as the work_struct
+		 */
+		struct work_struct *work = (struct work_struct *) buffer;
+		INIT_WORK(work, do_vfree);
+		schedule_work(work);
+	} else
+		kfree(buffer);
+}