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    Subject[PATCH 01/13] AppArmor: misc. base functions and defines
    Date
    Miscellaneous functions and defines needed by AppArmor, including
    the base path resolution routines.

    Signed-off-by: John Johansen <john.johansen@canonical.com>
    ---
    security/apparmor/include/apparmor.h | 92 +++++++++++++
    security/apparmor/include/path.h | 31 +++++
    security/apparmor/lib.c | 133 +++++++++++++++++++
    security/apparmor/path.c | 235 ++++++++++++++++++++++++++++++++++
    4 files changed, 491 insertions(+), 0 deletions(-)
    create mode 100644 security/apparmor/include/apparmor.h
    create mode 100644 security/apparmor/include/path.h
    create mode 100644 security/apparmor/lib.c
    create mode 100644 security/apparmor/path.c

    diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/include/apparmor.h
    new file mode 100644
    index 0000000..38ccaea
    --- /dev/null
    +++ b/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 */
    diff --git a/security/apparmor/include/path.h b/security/apparmor/include/path.h
    new file mode 100644
    index 0000000..27b327a
    --- /dev/null
    +++ b/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 */
    diff --git a/security/apparmor/lib.c b/security/apparmor/lib.c
    new file mode 100644
    index 0000000..6e85cdb
    --- /dev/null
    +++ b/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);
    +}
    diff --git a/security/apparmor/path.c b/security/apparmor/path.c
    new file mode 100644
    index 0000000..96bab94
    --- /dev/null
    +++ b/security/apparmor/path.c
    @@ -0,0 +1,235 @@
    +/*
    + * AppArmor security module
    + *
    + * This file contains AppArmor function for pathnames
    + *
    + * 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/magic.h>
    +#include <linux/mnt_namespace.h>
    +#include <linux/mount.h>
    +#include <linux/namei.h>
    +#include <linux/nsproxy.h>
    +#include <linux/path.h>
    +#include <linux/sched.h>
    +#include <linux/slab.h>
    +#include <linux/fs_struct.h>
    +
    +#include "include/apparmor.h"
    +#include "include/path.h"
    +#include "include/policy.h"
    +
    +
    +/* modified from dcache.c */
    +static int prepend(char **buffer, int buflen, const char *str, int namelen)
    +{
    + buflen -= namelen;
    + if (buflen < 0)
    + return -ENAMETOOLONG;
    + *buffer -= namelen;
    + memcpy(*buffer, str, namelen);
    + return 0;
    +}
    +
    +#define CHROOT_NSCONNECT (PATH_CHROOT_REL | PATH_CHROOT_NSCONNECT)
    +
    +/**
    + * d_namespace_path - lookup a name associated with a given path
    + * @path: path to lookup (NOT NULL)
    + * @buf: buffer to store path to (NOT NULL)
    + * @buflen: length of @buf
    + * @name: Returns - pointer for start of path name with in @buf (NOT NULL)
    + * @flags: flags controlling path lookup
    + *
    + * Handle path name lookup.
    + *
    + * Returns: %0 else error code if path lookup fails
    + * When no error the path name is returned in @name which points to
    + * to a position in @buf
    + */
    +static int d_namespace_path(struct path *path, char *buf, int buflen,
    + char **name, int flags)
    +{
    + struct path root, tmp;
    + char *res;
    + int deleted, connected;
    + int error = 0;
    +
    + /* Get the root we want to resolve too */
    + if (flags & PATH_CHROOT_REL) {
    + /* resolve paths relative to chroot */
    + read_lock(&current->fs->lock);
    + root = current->fs->root;
    + /* released below */
    + path_get(&root);
    + read_unlock(&current->fs->lock);
    + } else {
    + /* resolve paths relative to namespace */
    + root.mnt = current->nsproxy->mnt_ns->root;
    + root.dentry = root.mnt->mnt_root;
    + /* released below */
    + path_get(&root);
    + }
    +
    + spin_lock(&dcache_lock);
    + /* There is a race window between path lookup here and the
    + * need to strip the " (deleted) string that __d_path applies
    + * Detect the race and relookup the path
    + *
    + * The stripping of (deleted) is a hack that could be removed
    + * with an updated __d_path
    + */
    + do {
    + tmp = root;
    + deleted = d_unlinked(path->dentry);
    + res = __d_path(path, &tmp, buf, buflen);
    +
    + } while (deleted != d_unlinked(path->dentry));
    + spin_unlock(&dcache_lock);
    +
    + *name = res;
    + /* handle error conditions - and still allow a partial path to
    + * be returned.
    + */
    + if (IS_ERR(res)) {
    + error = PTR_ERR(res);
    + *name = buf;
    + goto out;
    + }
    + if (deleted) {
    + /* On some filesystems, newly allocated dentries appear to the
    + * security_path hooks as a deleted dentry except without an
    + * inode allocated.
    + *
    + * Remove the appended deleted text and return as string for
    + * normal mediation, or auditing. The (deleted) string is
    + * guaranteed to be added in this case, so just strip it.
    + */
    + buf[buflen - 11] = 0; /* - (len(" (deleted)") +\0) */
    +
    + if (path->dentry->d_inode && !(flags & PATH_MEDIATE_DELETED)) {
    + error = -ENOENT;
    + goto out;
    + }
    + }
    +
    + /* Determine if the path is connected to the expected root */
    + connected = tmp.dentry == root.dentry && tmp.mnt == root.mnt;
    +
    + /* If the path is not connected,
    + * check if it is a sysctl and handle specially else remove any
    + * leading / that __d_path may have returned.
    + * Unless
    + * specifically directed to connect the path,
    + * OR
    + * if in a chroot and doing chroot relative paths and the path
    + * resolves to the namespace root (would be connected outside
    + * of chroot) and specifically directed to connect paths to
    + * namespace root.
    + */
    + if (!connected) {
    + /* is the disconnect path a sysctl? */
    + if (tmp.dentry->d_sb->s_magic == PROC_SUPER_MAGIC &&
    + strncmp(*name, "/sys/", 5) == 0) {
    + /* TODO: convert over to using a per namespace
    + * control instead of hard coded /proc
    + */
    + error = prepend(name, *name - buf, "/proc", 5);
    + } else if (!(flags & PATH_CONNECT_PATH) &&
    + !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) &&
    + (tmp.mnt == current->nsproxy->mnt_ns->root &&
    + tmp.dentry == tmp.mnt->mnt_root))) {
    + /* disconnected path, don't return pathname starting
    + * with '/'
    + */
    + error = -ESTALE;
    + if (*res == '/')
    + *name = res + 1;
    + }
    + }
    +
    +out:
    + path_put(&root);
    +
    + return error;
    +}
    +
    +/**
    + * get_name_to_buffer - get the pathname to a buffer ensure dir / is appended
    + * @path: path to get name for (NOT NULL)
    + * @flags: flags controlling path lookup
    + * @buffer: buffer to put name in (NOT NULL)
    + * @size: size of buffer
    + * @name: Returns - contains position of path name in @buffer (NOT NULL)
    + *
    + * Returns: %0 else error on failure
    + */
    +static int get_name_to_buffer(struct path *path, int flags, char *buffer,
    + int size, char **name)
    +{
    + int adjust = (flags & PATH_IS_DIR) ? 1 : 0;
    + int error = d_namespace_path(path, buffer, size - adjust, name, flags);
    +
    + if (!error && (flags & PATH_IS_DIR) && (*name)[1] != '\0')
    + /*
    + * Append "/" to the pathname. The root directory is a special
    + * case; it already ends in slash.
    + */
    + strcpy(&buffer[size - 2], "/");
    +
    + return error;
    +}
    +
    +/**
    + * aa_get_name - compute the pathname of a file
    + * @path: path the file (NOT NULL)
    + * @flags: flags controlling path name generation
    + * @buffer: buffer that aa_get_name() allocated (NOT NULL)
    + * @name: Returns - the generated path name if !error (NOT NULL)
    + *
    + * @name is a pointer to the beginning of the pathname (which usually differs
    + * from the beginning of the buffer), or NULL. If there is an error @name
    + * may contain a partial or invalid name that can be used for audit purposes,
    + * but it can not be used for mediation.
    + *
    + * We need PATH_IS_DIR to indicate whether the file is a directory or not
    + * because the file may not yet exist, and so we cannot check the inode's
    + * file type.
    + *
    + * Returns: %0 else error code if could retrieve name
    + */
    +int aa_get_name(struct path *path, int flags, char **buffer, const char **name)
    +{
    + char *buf, *str = NULL;
    + int size = 256;
    + int error;
    +
    + *name = NULL;
    + *buffer = NULL;
    + for (;;) {
    + /* freed by caller */
    + buf = kmalloc(size, GFP_KERNEL);
    + if (!buf)
    + return -ENOMEM;
    +
    + error = get_name_to_buffer(path, flags, buf, size, &str);
    + if (error != -ENAMETOOLONG)
    + break;
    +
    + kfree(buf);
    + size <<= 1;
    + if (size > aa_g_path_max)
    + return -ENAMETOOLONG;
    + }
    + *buffer = buf;
    + *name = str;
    +
    + return error;
    +}
    --
    1.7.1


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