/* auditsc.c -- System-call auditing support
 * Handles all system-call specific auditing features.
 *
 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
 * Copyright 2005 Hewlett-Packard Development Company, L.P.
 * Copyright (C) 2005, 2006 IBM Corporation
 * All Rights Reserved.
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
 *
 * Many of the ideas implemented here are from Stephen C. Tweedie,
 * especially the idea of avoiding a copy by using getname.
 *
 * The method for actual interception of syscall entry and exit (not in
 * this file -- see entry.S) is based on a GPL'd patch written by
 * okir@suse.de and Copyright 2003 SuSE Linux AG.
 *
 * POSIX message queue support added by George Wilson <ltcgcw@us.ibm.com>,
 * 2006.
 *
 * The support of additional filter rules compares (>, <, >=, <=) was
 * added by Dustin Kirkland <dustin.kirkland@us.ibm.com>, 2005.
 *
 * Modified by Amy Griffis <amy.griffis@hp.com> to collect additional
 * filesystem information.
 *
 * Subject and object context labeling support added by <danjones@us.ibm.com>
 * and <dustin.kirkland@us.ibm.com> for LSPP certification compliance.
 */

#include <linux/init.h>
#include <asm/types.h>
#include <asm/atomic.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/socket.h>
#include <linux/mqueue.h>
#include <linux/audit.h>
#include <linux/personality.h>
#include <linux/time.h>
#include <linux/netlink.h>
#include <linux/compiler.h>
#include <asm/unistd.h>
#include <linux/security.h>
#include <linux/list.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/highmem.h>
#include <linux/syscalls.h>
#include <linux/inotify.h>
#include <linux/capability.h>
#include <linux/fs_struct.h>

#include "audit.h"

/* AUDIT_NAMES is the number of slots we reserve in the audit_context
 * for saving names from getname(). */
#define AUDIT_NAMES    20

/* Indicates that audit should log the full pathname. */
#define AUDIT_NAME_FULL -1

/* no execve audit message should be longer than this (userspace limits) */
#define MAX_EXECVE_AUDIT_LEN 7500

/* number of audit rules */
int audit_n_rules;

/* determines whether we collect data for signals sent */
int audit_signals;

struct audit_cap_data {
        kernel_cap_t            permitted;
        kernel_cap_t            inheritable;
        union {
                unsigned int    fE;             /* effective bit of a file capability */
                kernel_cap_t    effective;      /* effective set of a process */
        };
};

/* When fs/namei.c:getname() is called, we store the pointer in name and
 * we don't let putname() free it (instead we free all of the saved
 * pointers at syscall exit time).
 *
 * Further, in fs/namei.c:path_lookup() we store the inode and device. */
struct audit_names {
        const char      *name;
        int             name_len;       /* number of name's characters to log */
        unsigned        name_put;       /* call __putname() for this name */
        unsigned long   ino;
        dev_t           dev;
        umode_t         mode;
        uid_t           uid;
        gid_t           gid;
        dev_t           rdev;
        u32             osid;
        struct audit_cap_data fcap;
        unsigned int    fcap_ver;
};

struct audit_aux_data {
        struct audit_aux_data   *next;
        int                     type;
};

#define AUDIT_AUX_IPCPERM       0

/* Number of target pids per aux struct. */
#define AUDIT_AUX_PIDS  16

struct audit_aux_data_execve {
        struct audit_aux_data   d;
        int argc;
        int envc;
        struct mm_struct *mm;
};

struct audit_aux_data_pids {
        struct audit_aux_data   d;
        pid_t                   target_pid[AUDIT_AUX_PIDS];
        uid_t                   target_auid[AUDIT_AUX_PIDS];
        uid_t                   target_uid[AUDIT_AUX_PIDS];
        unsigned int            target_sessionid[AUDIT_AUX_PIDS];
        u32                     target_sid[AUDIT_AUX_PIDS];
        char                    target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
        int                     pid_count;
};

struct audit_aux_data_bprm_fcaps {
        struct audit_aux_data   d;
        struct audit_cap_data   fcap;
        unsigned int            fcap_ver;
        struct audit_cap_data   old_pcap;
        struct audit_cap_data   new_pcap;
};

struct audit_aux_data_capset {
        struct audit_aux_data   d;
        pid_t                   pid;
        struct audit_cap_data   cap;
};

struct audit_tree_refs {
        struct audit_tree_refs *next;
        struct audit_chunk *c[31];
};

/* The per-task audit context. */
struct audit_context {
        int                 dummy;      /* must be the first element */
        int                 in_syscall; /* 1 if task is in a syscall */
        enum audit_state    state, current_state;
        unsigned int        serial;     /* serial number for record */
        struct timespec     ctime;      /* time of syscall entry */
        int                 major;      /* syscall number */
        unsigned long       argv[4];    /* syscall arguments */
        int                 return_valid; /* return code is valid */
        long                return_code;/* syscall return code */
        u64                 prio;
        int                 name_count;
        struct audit_names  names[AUDIT_NAMES];
        char *              filterkey;  /* key for rule that triggered record */
        struct path         pwd;
        struct audit_context *previous; /* For nested syscalls */
        struct audit_aux_data *aux;
        struct audit_aux_data *aux_pids;
        struct sockaddr_storage *sockaddr;
        size_t sockaddr_len;
                                /* Save things to print about task_struct */
        pid_t               pid, ppid;
        uid_t               uid, euid, suid, fsuid;
        gid_t               gid, egid, sgid, fsgid;
        unsigned long       personality;
        int                 arch;

        pid_t               target_pid;
        uid_t               target_auid;
        uid_t               target_uid;
        unsigned int        target_sessionid;
        u32                 target_sid;
        char                target_comm[TASK_COMM_LEN];

        struct audit_tree_refs *trees, *first_trees;
        int tree_count;

        int type;
        union {
                struct {
                        int nargs;
                        long args[6];
                } socketcall;
                struct {
                        uid_t                   uid;
                        gid_t                   gid;
                        mode_t                  mode;
                        u32                     osid;
                        int                     has_perm;
                        uid_t                   perm_uid;
                        gid_t                   perm_gid;
                        mode_t                  perm_mode;
                        unsigned long           qbytes;
                } ipc;
                struct {
                        mqd_t                   mqdes;
                        struct mq_attr          mqstat;
                } mq_getsetattr;
                struct {
                        mqd_t                   mqdes;
                        int                     sigev_signo;
                } mq_notify;
                struct {
                        mqd_t                   mqdes;
                        size_t                  msg_len;
                        unsigned int            msg_prio;
                        struct timespec         abs_timeout;
                } mq_sendrecv;
                struct {
                        int                     oflag;
                        mode_t                  mode;
                        struct mq_attr          attr;
                } mq_open;
                struct {
                        pid_t                   pid;
                        struct audit_cap_data   cap;
                } capset;
        };
        int fds[2];

#if AUDIT_DEBUG
        int                 put_count;
        int                 ino_count;
#endif
};

#define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
static inline int open_arg(int flags, int mask)
{
        int n = ACC_MODE(flags);
        if (flags & (O_TRUNC | O_CREAT))
                n |= AUDIT_PERM_WRITE;
        return n & mask;
}

static int audit_match_perm(struct audit_context *ctx, int mask)
{
        unsigned n;
        if (unlikely(!ctx))
                return 0;
        n = ctx->major;

        switch (audit_classify_syscall(ctx->arch, n)) {
        case 0: /* native */
                if ((mask & AUDIT_PERM_WRITE) &&
                     audit_match_class(AUDIT_CLASS_WRITE, n))
                        return 1;
                if ((mask & AUDIT_PERM_READ) &&
                     audit_match_class(AUDIT_CLASS_READ, n))
                        return 1;
                if ((mask & AUDIT_PERM_ATTR) &&
                     audit_match_class(AUDIT_CLASS_CHATTR, n))
                        return 1;
                return 0;
        case 1: /* 32bit on biarch */
                if ((mask & AUDIT_PERM_WRITE) &&
                     audit_match_class(AUDIT_CLASS_WRITE_32, n))
                        return 1;
                if ((mask & AUDIT_PERM_READ) &&
                     audit_match_class(AUDIT_CLASS_READ_32, n))
                        return 1;
                if ((mask & AUDIT_PERM_ATTR) &&
                     audit_match_class(AUDIT_CLASS_CHATTR_32, n))
                        return 1;
                return 0;
        case 2: /* open */
                return mask & ACC_MODE(ctx->argv[1]);
        case 3: /* openat */
                return mask & ACC_MODE(ctx->argv[2]);
        case 4: /* socketcall */
                return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
        case 5: /* execve */
                return mask & AUDIT_PERM_EXEC;
        default:
                return 0;
        }
}

static int audit_match_filetype(struct audit_context *ctx, int which)
{
        unsigned index = which & ~S_IFMT;
        mode_t mode = which & S_IFMT;

        if (unlikely(!ctx))
                return 0;

        if (index >= ctx->name_count)
                return 0;
        if (ctx->names[index].ino == -1)
                return 0;
        if ((ctx->names[index].mode ^ mode) & S_IFMT)
                return 0;
        return 1;
}

/*
 * We keep a linked list of fixed-sized (31 pointer) arrays of audit_chunk *;
 * ->first_trees points to its beginning, ->trees - to the current end of data.
 * ->tree_count is the number of free entries in array pointed to by ->trees.
 * Original condition is (NULL, NULL, 0); as soon as it grows we never revert to NULL,
 * "empty" becomes (p, p, 31) afterwards.  We don't shrink the list (and seriously,
 * it's going to remain 1-element for almost any setup) until we free context itself.
 * References in it _are_ dropped - at the same time we free/drop aux stuff.
 */

#ifdef CONFIG_AUDIT_TREE
static void audit_set_auditable(struct audit_context *ctx)
{
        if (!ctx->prio) {
                ctx->prio = 1;
                ctx->current_state = AUDIT_RECORD_CONTEXT;
        }
}

static int put_tree_ref(struct audit_context *ctx, struct audit_chunk *chunk)
{
        struct audit_tree_refs *p = ctx->trees;
        int left = ctx->tree_count;
        if (likely(left)) {
                p->c[--left] = chunk;
                ctx->tree_count = left;
                return 1;
        }
        if (!p)
                return 0;
        p = p->next;
        if (p) {
                p->c[30] = chunk;
                ctx->trees = p;
                ctx->tree_count = 30;
                return 1;
        }
        return 0;
}

static int grow_tree_refs(struct audit_context *ctx)
{
        struct audit_tree_refs *p = ctx->trees;
        ctx->trees = kzalloc(sizeof(struct audit_tree_refs), GFP_KERNEL);
        if (!ctx->trees) {
                ctx->trees = p;
                return 0;
        }
        if (p)
                p->next = ctx->trees;
        else
                ctx->first_trees = ctx->trees;
        ctx->tree_count = 31;
        return 1;
}
#endif

static void unroll_tree_refs(struct audit_context *ctx,
                      struct audit_tree_refs *p, int count)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_tree_refs *q;
        int n;
        if (!p) {
                /* we started with empty chain */
                p = ctx->first_trees;
                count = 31;
                /* if the very first allocation has failed, nothing to do */
                if (!p)
                        return;
        }
        n = count;
        for (q = p; q != ctx->trees; q = q->next, n = 31) {
                while (n--) {
                        audit_put_chunk(q->c[n]);
                        q->c[n] = NULL;
                }
        }
        while (n-- > ctx->tree_count) {
                audit_put_chunk(q->c[n]);
                q->c[n] = NULL;
        }
        ctx->trees = p;
        ctx->tree_count = count;
#endif
}

static void free_tree_refs(struct audit_context *ctx)
{
        struct audit_tree_refs *p, *q;
        for (p = ctx->first_trees; p; p = q) {
                q = p->next;
                kfree(p);
        }
}

static int match_tree_refs(struct audit_context *ctx, struct audit_tree *tree)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_tree_refs *p;
        int n;
        if (!tree)
                return 0;
        /* full ones */
        for (p = ctx->first_trees; p != ctx->trees; p = p->next) {
                for (n = 0; n < 31; n++)
                        if (audit_tree_match(p->c[n], tree))
                                return 1;
        }
        /* partial */
        if (p) {
                for (n = ctx->tree_count; n < 31; n++)
                        if (audit_tree_match(p->c[n], tree))
                                return 1;
        }
#endif
        return 0;
}

/* Determine if any context name data matches a rule's watch data */
/* Compare a task_struct with an audit_rule.  Return 1 on match, 0
 * otherwise. */
static int audit_filter_rules(struct task_struct *tsk,
                              struct audit_krule *rule,
                              struct audit_context *ctx,
                              struct audit_names *name,
                              enum audit_state *state)
{
        const struct cred *cred = get_task_cred(tsk);
        int i, j, need_sid = 1;
        u32 sid;

        for (i = 0; i < rule->field_count; i++) {
                struct audit_field *f = &rule->fields[i];
                int result = 0;

                switch (f->type) {
                case AUDIT_PID:
                        result = audit_comparator(tsk->pid, f->op, f->val);
                        break;
                case AUDIT_PPID:
                        if (ctx) {
                                if (!ctx->ppid)
                                        ctx->ppid = sys_getppid();
                                result = audit_comparator(ctx->ppid, f->op, f->val);
                        }
                        break;
                case AUDIT_UID:
                        result = audit_comparator(cred->uid, f->op, f->val);
                        break;
                case AUDIT_EUID:
                        result = audit_comparator(cred->euid, f->op, f->val);
                        break;
                case AUDIT_SUID:
                        result = audit_comparator(cred->suid, f->op, f->val);
                        break;
                case AUDIT_FSUID:
                        result = audit_comparator(cred->fsuid, f->op, f->val);
                        break;
                case AUDIT_GID:
                        result = audit_comparator(cred->gid, f->op, f->val);
                        break;
                case AUDIT_EGID:
                        result = audit_comparator(cred->egid, f->op, f->val);
                        break;
                case AUDIT_SGID:
                        result = audit_comparator(cred->sgid, f->op, f->val);
                        break;
                case AUDIT_FSGID:
                        result = audit_comparator(cred->fsgid, f->op, f->val);
                        break;
                case AUDIT_PERS:
                        result = audit_comparator(tsk->personality, f->op, f->val);
                        break;
                case AUDIT_ARCH:
                        if (ctx)
                                result = audit_comparator(ctx->arch, f->op, f->val);
                        break;

                case AUDIT_EXIT:
                        if (ctx && ctx->return_valid)
                                result = audit_comparator(ctx->return_code, f->op, f->val);
                        break;
                case AUDIT_SUCCESS:
                        if (ctx && ctx->return_valid) {
                                if (f->val)
                                        result = audit_comparator(ctx->return_valid, f->op, AUDITSC_SUCCESS);
                                else
                                        result = audit_comparator(ctx->return_valid, f->op, AUDITSC_FAILURE);
                        }
                        break;
                case AUDIT_DEVMAJOR:
                        if (name)
                                result = audit_comparator(MAJOR(name->dev),
                                                          f->op, f->val);
                        else if (ctx) {
                                for (j = 0; j < ctx->name_count; j++) {
                                        if (audit_comparator(MAJOR(ctx->names[j].dev),  f->op, f->val)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_DEVMINOR:
                        if (name)
                                result = audit_comparator(MINOR(name->dev),
                                                          f->op, f->val);
                        else if (ctx) {
                                for (j = 0; j < ctx->name_count; j++) {
                                        if (audit_comparator(MINOR(ctx->names[j].dev), f->op, f->val)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_INODE:
                        if (name)
                                result = (name->ino == f->val);
                        else if (ctx) {
                                for (j = 0; j < ctx->name_count; j++) {
                                        if (audit_comparator(ctx->names[j].ino, f->op, f->val)) {
                                                ++result;
                                                break;
                                        }
                                }
                        }
                        break;
                case AUDIT_WATCH:
                        if (name && rule->watch->ino != (unsigned long)-1)
                                result = (name->dev == rule->watch->dev &&
                                          name->ino == rule->watch->ino);
                        break;
                case AUDIT_DIR:
                        if (ctx)
                                result = match_tree_refs(ctx, rule->tree);
                        break;
                case AUDIT_LOGINUID:
                        result = 0;
                        if (ctx)
                                result = audit_comparator(tsk->loginuid, f->op, f->val);
                        break;
                case AUDIT_SUBJ_USER:
                case AUDIT_SUBJ_ROLE:
                case AUDIT_SUBJ_TYPE:
                case AUDIT_SUBJ_SEN:
                case AUDIT_SUBJ_CLR:
                        /* NOTE: this may return negative values indicating
                           a temporary error.  We simply treat this as a
                           match for now to avoid losing information that
                           may be wanted.   An error message will also be
                           logged upon error */
                        if (f->lsm_rule) {
                                if (need_sid) {
                                        security_task_getsecid(tsk, &sid);
                                        need_sid = 0;
                                }
                                result = security_audit_rule_match(sid, f->type,
                                                                  f->op,
                                                                  f->lsm_rule,
                                                                  ctx);
                        }
                        break;
                case AUDIT_OBJ_USER:
                case AUDIT_OBJ_ROLE:
                case AUDIT_OBJ_TYPE:
                case AUDIT_OBJ_LEV_LOW:
                case AUDIT_OBJ_LEV_HIGH:
                        /* The above note for AUDIT_SUBJ_USER...AUDIT_SUBJ_CLR
                           also applies here */
                        if (f->lsm_rule) {
                                /* Find files that match */
                                if (name) {
                                        result = security_audit_rule_match(
                                                   name->osid, f->type, f->op,
                                                   f->lsm_rule, ctx);
                                } else if (ctx) {
                                        for (j = 0; j < ctx->name_count; j++) {
                                                if (security_audit_rule_match(
                                                      ctx->names[j].osid,
                                                      f->type, f->op,
                                                      f->lsm_rule, ctx)) {
                                                        ++result;
                                                        break;
                                                }
                                        }
                                }
                                /* Find ipc objects that match */
                                if (!ctx || ctx->type != AUDIT_IPC)
                                        break;
                                if (security_audit_rule_match(ctx->ipc.osid,
                                                              f->type, f->op,
                                                              f->lsm_rule, ctx))
                                        ++result;
                        }
                        break;
                case AUDIT_ARG0:
                case AUDIT_ARG1:
                case AUDIT_ARG2:
                case AUDIT_ARG3:
                        if (ctx)
                                result = audit_comparator(ctx->argv[f->type-AUDIT_ARG0], f->op, f->val);
                        break;
                case AUDIT_FILTERKEY:
                        /* ignore this field for filtering */
                        result = 1;
                        break;
                case AUDIT_PERM:
                        result = audit_match_perm(ctx, f->val);
                        break;
                case AUDIT_FILETYPE:
                        result = audit_match_filetype(ctx, f->val);
                        break;
                }

                if (!result) {
                        put_cred(cred);
                        return 0;
                }
        }

        if (ctx) {
                if (rule->prio <= ctx->prio)
                        return 0;
                if (rule->filterkey) {
                        kfree(ctx->filterkey);
                        ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
                }
                ctx->prio = rule->prio;
        }
        switch (rule->action) {
        case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
        case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
        }
        put_cred(cred);
        return 1;
}

/* At process creation time, we can determine if system-call auditing is
 * completely disabled for this task.  Since we only have the task
 * structure at this point, we can only check uid and gid.
 */
static enum audit_state audit_filter_task(struct task_struct *tsk, char **key)
{
        struct audit_entry *e;
        enum audit_state   state;

        rcu_read_lock();
        list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TASK], list) {
                if (audit_filter_rules(tsk, &e->rule, NULL, NULL, &state)) {
                        if (state == AUDIT_RECORD_CONTEXT)
                                *key = kstrdup(e->rule.filterkey, GFP_ATOMIC);
                        rcu_read_unlock();
                        return state;
                }
        }
        rcu_read_unlock();
        return AUDIT_BUILD_CONTEXT;
}

/* At syscall entry and exit time, this filter is called if the
 * audit_state is not low enough that auditing cannot take place, but is
 * also not high enough that we already know we have to write an audit
 * record (i.e., the state is AUDIT_SETUP_CONTEXT or AUDIT_BUILD_CONTEXT).
 */
static enum audit_state audit_filter_syscall(struct task_struct *tsk,
                                             struct audit_context *ctx,
                                             struct list_head *list)
{
        struct audit_entry *e;
        enum audit_state state;

        if (audit_pid && tsk->tgid == audit_pid)
                return AUDIT_DISABLED;

        rcu_read_lock();
        if (!list_empty(list)) {
                int word = AUDIT_WORD(ctx->major);
                int bit  = AUDIT_BIT(ctx->major);

                list_for_each_entry_rcu(e, list, list) {
                        if ((e->rule.mask[word] & bit) == bit &&
                            audit_filter_rules(tsk, &e->rule, ctx, NULL,
                                               &state)) {
                                rcu_read_unlock();
                                ctx->current_state = state;
                                return state;
                        }
                }
        }
        rcu_read_unlock();
        return AUDIT_BUILD_CONTEXT;
}

/* At syscall exit time, this filter is called if any audit_names[] have been
 * collected during syscall processing.  We only check rules in sublists at hash
 * buckets applicable to the inode numbers in audit_names[].
 * Regarding audit_state, same rules apply as for audit_filter_syscall().
 */
void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx)
{
        int i;
        struct audit_entry *e;
        enum audit_state state;

        if (audit_pid && tsk->tgid == audit_pid)
                return;

        rcu_read_lock();
        for (i = 0; i < ctx->name_count; i++) {
                int word = AUDIT_WORD(ctx->major);
                int bit  = AUDIT_BIT(ctx->major);
                struct audit_names *n = &ctx->names[i];
                int h = audit_hash_ino((u32)n->ino);
                struct list_head *list = &audit_inode_hash[h];

                if (list_empty(list))
                        continue;

                list_for_each_entry_rcu(e, list, list) {
                        if ((e->rule.mask[word] & bit) == bit &&
                            audit_filter_rules(tsk, &e->rule, ctx, n, &state)) {
                                rcu_read_unlock();
                                ctx->current_state = state;
                                return;
                        }
                }
        }
        rcu_read_unlock();
}

static inline struct audit_context *audit_get_context(struct task_struct *tsk,
                                                      int return_valid,
                                                      long return_code)
{
        struct audit_context *context = tsk->audit_context;

        if (likely(!context))
                return NULL;
        context->return_valid = return_valid;

        /*
         * we need to fix up the return code in the audit logs if the actual
         * return codes are later going to be fixed up by the arch specific
         * signal handlers
         *
         * This is actually a test for:
         * (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) ||
         * (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK)
         *
         * but is faster than a bunch of ||
         */
        if (unlikely(return_code <= -ERESTARTSYS) &&
            (return_code >= -ERESTART_RESTARTBLOCK) &&
            (return_code != -ENOIOCTLCMD))
                context->return_code = -EINTR;
        else
                context->return_code  = return_code;

        if (context->in_syscall && !context->dummy) {
                audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_EXIT]);
                audit_filter_inodes(tsk, context);
        }

        tsk->audit_context = NULL;
        return context;
}

static inline void audit_free_names(struct audit_context *context)
{
        int i;

#if AUDIT_DEBUG == 2
        if (context->put_count + context->ino_count != context->name_count) {
                printk(KERN_ERR "%s:%d(:%d): major=%d in_syscall=%d"
                       " name_count=%d put_count=%d"
                       " ino_count=%d [NOT freeing]\n",
                       __FILE__, __LINE__,
                       context->serial, context->major, context->in_syscall,
                       context->name_count, context->put_count,
                       context->ino_count);
                for (i = 0; i < context->name_count; i++) {
                        printk(KERN_ERR "names[%d] = %p = %s\n", i,
                               context->names[i].name,
                               context->names[i].name ?: "(null)");
                }
                dump_stack();
                return;
        }
#endif
#if AUDIT_DEBUG
        context->put_count  = 0;
        context->ino_count  = 0;
#endif

        for (i = 0; i < context->name_count; i++) {
                if (context->names[i].name && context->names[i].name_put)
                        __putname(context->names[i].name);
        }
        context->name_count = 0;
        path_put(&context->pwd);
        context->pwd.dentry = NULL;
        context->pwd.mnt = NULL;
}

static inline void audit_free_aux(struct audit_context *context)
{
        struct audit_aux_data *aux;

        while ((aux = context->aux)) {
                context->aux = aux->next;
                kfree(aux);
        }
        while ((aux = context->aux_pids)) {
                context->aux_pids = aux->next;
                kfree(aux);
        }
}

static inline void audit_zero_context(struct audit_context *context,
                                      enum audit_state state)
{
        memset(context, 0, sizeof(*context));
        context->state      = state;
        context->prio = state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0;
}

static inline struct audit_context *audit_alloc_context(enum audit_state state)
{
        struct audit_context *context;

        if (!(context = kmalloc(sizeof(*context), GFP_KERNEL)))
                return NULL;
        audit_zero_context(context, state);
        return context;
}

/**
 * audit_alloc - allocate an audit context block for a task
 * @tsk: task
 *
 * Filter on the task information and allocate a per-task audit context
 * if necessary.  Doing so turns on system call auditing for the
 * specified task.  This is called from copy_process, so no lock is
 * needed.
 */
int audit_alloc(struct task_struct *tsk)
{
        struct audit_context *context;
        enum audit_state     state;
        char *key = NULL;

        if (likely(!audit_ever_enabled))
                return 0; /* Return if not auditing. */

        state = audit_filter_task(tsk, &key);
        if (likely(state == AUDIT_DISABLED))
                return 0;

        if (!(context = audit_alloc_context(state))) {
                kfree(key);
                audit_log_lost("out of memory in audit_alloc");
                return -ENOMEM;
        }
        context->filterkey = key;

        tsk->audit_context  = context;
        set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
        return 0;
}

static inline void audit_free_context(struct audit_context *context)
{
        struct audit_context *previous;
        int                  count = 0;

        do {
                previous = context->previous;
                if (previous || (count &&  count < 10)) {
                        ++count;
                        printk(KERN_ERR "audit(:%d): major=%d name_count=%d:"
                               " freeing multiple contexts (%d)\n",
                               context->serial, context->major,
                               context->name_count, count);
                }
                audit_free_names(context);
                unroll_tree_refs(context, NULL, 0);
                free_tree_refs(context);
                audit_free_aux(context);
                kfree(context->filterkey);
                kfree(context->sockaddr);
                kfree(context);
                context  = previous;
        } while (context);
        if (count >= 10)
                printk(KERN_ERR "audit: freed %d contexts\n", count);
}

void audit_log_task_context(struct audit_buffer *ab)
{
        char *ctx = NULL;
        unsigned len;
        int error;
        u32 sid;

        security_task_getsecid(current, &sid);
        if (!sid)
                return;

        error = security_secid_to_secctx(sid, &ctx, &len);
        if (error) {
                if (error != -EINVAL)
                        goto error_path;
                return;
        }

        audit_log_format(ab, " subj=%s", ctx);
        security_release_secctx(ctx, len);
        return;

error_path:
        audit_panic("error in audit_log_task_context");
        return;
}

EXPORT_SYMBOL(audit_log_task_context);

static void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
{
        char name[sizeof(tsk->comm)];
        struct mm_struct *mm = tsk->mm;
        struct vm_area_struct *vma;

        /* tsk == current */

        get_task_comm(name, tsk);
        audit_log_format(ab, " comm=");
        audit_log_untrustedstring(ab, name);

        if (mm) {
                down_read(&mm->mmap_sem);
                vma = mm->mmap;
                while (vma) {
                        if ((vma->vm_flags & VM_EXECUTABLE) &&
                            vma->vm_file) {
                                audit_log_d_path(ab, "exe=",
                                                 &vma->vm_file->f_path);
                                break;
                        }
                        vma = vma->vm_next;
                }
                up_read(&mm->mmap_sem);
        }
        audit_log_task_context(ab);
}

static int audit_log_pid_context(struct audit_context *context, pid_t pid,
                                 uid_t auid, uid_t uid, unsigned int sessionid,
                                 u32 sid, char *comm)
{
        struct audit_buffer *ab;
        char *ctx = NULL;
        u32 len;
        int rc = 0;

        ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
        if (!ab)
                return rc;

        audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid, auid,
                         uid, sessionid);
        if (security_secid_to_secctx(sid, &ctx, &len)) {
                audit_log_format(ab, " obj=(none)");
                rc = 1;
        } else {
                audit_log_format(ab, " obj=%s", ctx);
                security_release_secctx(ctx, len);
        }
        audit_log_format(ab, " ocomm=");

        audit_log_untrustedstring(ab, comm);
        audit_log_end(ab);

        return rc;
}

/*
 * to_send and len_sent accounting are very loose estimates.  We aren't
 * really worried about a hard cap to MAX_EXECVE_AUDIT_LEN so much as being
 * within about 500 bytes (next page boundry)
 *
 * why snprintf?  an int is up to 12 digits long.  if we just assumed when
 * logging that a[%d]= was going to be 16 characters long we would be wasting
 * space in every audit message.  In one 7500 byte message we can log up to
 * about 1000 min size arguments.  That comes down to about 50% waste of space
 * if we didn't do the snprintf to find out how long arg_num_len was.
 */
static int audit_log_single_execve_arg(struct audit_context *context,
                                        struct audit_buffer **ab,
                                        int arg_num,
                                        size_t *len_sent,
                                        const char __user *p,
                                        char *buf)
{
        char arg_num_len_buf[12];
        const char __user *tmp_p = p;
        /* how many digits are in arg_num? 3 is the length of " a=" */
        size_t arg_num_len = snprintf(arg_num_len_buf, 12, "%d", arg_num) + 3;
        size_t len, len_left, to_send;
        size_t max_execve_audit_len = MAX_EXECVE_AUDIT_LEN;
        unsigned int i, has_cntl = 0, too_long = 0;
        int ret;

        /* strnlen_user includes the null we don't want to send */
        len_left = len = strnlen_user(p, MAX_ARG_STRLEN) - 1;

        /*
         * We just created this mm, if we can't find the strings
         * we just copied into it something is _very_ wrong. Similar
         * for strings that are too long, we should not have created
         * any.
         */
        if (unlikely((len == -1) || len > MAX_ARG_STRLEN - 1)) {
                WARN_ON(1);
                send_sig(SIGKILL, current, 0);
                return -1;
        }

        /* walk the whole argument looking for non-ascii chars */
        do {
                if (len_left > MAX_EXECVE_AUDIT_LEN)
                        to_send = MAX_EXECVE_AUDIT_LEN;
                else
                        to_send = len_left;
                ret = copy_from_user(buf, tmp_p, to_send);
                /*
                 * There is no reason for this copy to be short. We just
                 * copied them here, and the mm hasn't been exposed to user-
                 * space yet.
                 */
                if (ret) {
                        WARN_ON(1);
                        send_sig(SIGKILL, current, 0);
                        return -1;
                }
                buf[to_send] = '\0';
                has_cntl = audit_string_contains_control(buf, to_send);
                if (has_cntl) {
                        /*
                         * hex messages get logged as 2 bytes, so we can only
                         * send half as much in each message
                         */
                        max_execve_audit_len = MAX_EXECVE_AUDIT_LEN / 2;
                        break;
                }
                len_left -= to_send;
                tmp_p += to_send;
        } while (len_left > 0);

        len_left = len;

        if (len > max_execve_audit_len)
                too_long = 1;

        /* rewalk the argument actually logging the message */
        for (i = 0; len_left > 0; i++) {
                int room_left;

                if (len_left > max_execve_audit_len)
                        to_send = max_execve_audit_len;
                else
                        to_send = len_left;

                /* do we have space left to send this argument in this ab? */
                room_left = MAX_EXECVE_AUDIT_LEN - arg_num_len - *len_sent;
                if (has_cntl)
                        room_left -= (to_send * 2);
                else
                        room_left -= to_send;
                if (room_left < 0) {
                        *len_sent = 0;
                        audit_log_end(*ab);
                        *ab = audit_log_start(context, GFP_KERNEL, AUDIT_EXECVE);
                        if (!*ab)
                                return 0;
                }

                /*
                 * first record needs to say how long the original string was
                 * so we can be sure nothing was lost.
                 */
                if ((i == 0) && (too_long))
                        audit_log_format(*ab, " a%d_len=%zu", arg_num,
                                         has_cntl ? 2*len : len);

                /*
                 * normally arguments are small enough to fit and we already
                 * filled buf above when we checked for control characters
                 * so don't bother with another copy_from_user
                 */
                if (len >= max_execve_audit_len)
                        ret = copy_from_user(buf, p, to_send);
                else
                        ret = 0;
                if (ret) {
                        WARN_ON(1);
                        send_sig(SIGKILL, current, 0);
                        return -1;
                }
                buf[to_send] = '\0';

                /* actually log it */
                audit_log_format(*ab, " a%d", arg_num);
                if (too_long)
                        audit_log_format(*ab, "[%d]", i);
                audit_log_format(*ab, "=");
                if (has_cntl)
                        audit_log_n_hex(*ab, buf, to_send);
                else
                        audit_log_format(*ab, "\"%s\"", buf);

                p += to_send;
                len_left -= to_send;
                *len_sent += arg_num_len;
                if (has_cntl)
                        *len_sent += to_send * 2;
                else
                        *len_sent += to_send;
        }
        /* include the null we didn't log */
        return len + 1;
}

static void audit_log_execve_info(struct audit_context *context,
                                  struct audit_buffer **ab,
                                  struct audit_aux_data_execve *axi)
{
        int i;
        size_t len, len_sent = 0;
        const char __user *p;
        char *buf;

        if (axi->mm != current->mm)
                return; /* execve failed, no additional info */

        p = (const char __user *)axi->mm->arg_start;

        audit_log_format(*ab, "argc=%d", axi->argc);

        /*
         * we need some kernel buffer to hold the userspace args.  Just
         * allocate one big one rather than allocating one of the right size
         * for every single argument inside audit_log_single_execve_arg()
         * should be <8k allocation so should be pretty safe.
         */
        buf = kmalloc(MAX_EXECVE_AUDIT_LEN + 1, GFP_KERNEL);
        if (!buf) {
                audit_panic("out of memory for argv string\n");
                return;
        }

        for (i = 0; i < axi->argc; i++) {
                len = audit_log_single_execve_arg(context, ab, i,
                                                  &len_sent, p, buf);
                if (len <= 0)
                        break;
                p += len;
        }
        kfree(buf);
}

static void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
{
        int i;

        audit_log_format(ab, " %s=", prefix);
        CAP_FOR_EACH_U32(i) {
                audit_log_format(ab, "%08x", cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]);
        }
}

static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
{
        kernel_cap_t *perm = &name->fcap.permitted;
        kernel_cap_t *inh = &name->fcap.inheritable;
        int log = 0;

        if (!cap_isclear(*perm)) {
                audit_log_cap(ab, "cap_fp", perm);
                log = 1;
        }
        if (!cap_isclear(*inh)) {
                audit_log_cap(ab, "cap_fi", inh);
                log = 1;
        }

        if (log)
                audit_log_format(ab, " cap_fe=%d cap_fver=%x", name->fcap.fE, name->fcap_ver);
}

static void show_special(struct audit_context *context, int *call_panic)
{
        struct audit_buffer *ab;
        int i;

        ab = audit_log_start(context, GFP_KERNEL, context->type);
        if (!ab)
                return;

        switch (context->type) {
        case AUDIT_SOCKETCALL: {
                int nargs = context->socketcall.nargs;
                audit_log_format(ab, "nargs=%d", nargs);
                for (i = 0; i < nargs; i++)
                        audit_log_format(ab, " a%d=%lx", i,
                                context->socketcall.args[i]);
                break; }
        case AUDIT_IPC: {
                u32 osid = context->ipc.osid;

                audit_log_format(ab, "ouid=%u ogid=%u mode=%#o",
                         context->ipc.uid, context->ipc.gid, context->ipc.mode);
                if (osid) {
                        char *ctx = NULL;
                        u32 len;
                        if (security_secid_to_secctx(osid, &ctx, &len)) {
                                audit_log_format(ab, " osid=%u", osid);
                                *call_panic = 1;
                        } else {
                                audit_log_format(ab, " obj=%s", ctx);
                                security_release_secctx(ctx, len);
                        }
                }
                if (context->ipc.has_perm) {
                        audit_log_end(ab);
                        ab = audit_log_start(context, GFP_KERNEL,
                                             AUDIT_IPC_SET_PERM);
                        audit_log_format(ab,
                                "qbytes=%lx ouid=%u ogid=%u mode=%#o",
                                context->ipc.qbytes,
                                context->ipc.perm_uid,
                                context->ipc.perm_gid,
                                context->ipc.perm_mode);
                        if (!ab)
                                return;
                }
                break; }
        case AUDIT_MQ_OPEN: {
                audit_log_format(ab,
                        "oflag=0x%x mode=%#o mq_flags=0x%lx mq_maxmsg=%ld "
                        "mq_msgsize=%ld mq_curmsgs=%ld",
                        context->mq_open.oflag, context->mq_open.mode,
                        context->mq_open.attr.mq_flags,
                        context->mq_open.attr.mq_maxmsg,
                        context->mq_open.attr.mq_msgsize,
                        context->mq_open.attr.mq_curmsgs);
                break; }
        case AUDIT_MQ_SENDRECV: {
                audit_log_format(ab,
                        "mqdes=%d msg_len=%zd msg_prio=%u "
                        "abs_timeout_sec=%ld abs_timeout_nsec=%ld",
                        context->mq_sendrecv.mqdes,
                        context->mq_sendrecv.msg_len,
                        context->mq_sendrecv.msg_prio,
                        context->mq_sendrecv.abs_timeout.tv_sec,
                        context->mq_sendrecv.abs_timeout.tv_nsec);
                break; }
        case AUDIT_MQ_NOTIFY: {
                audit_log_format(ab, "mqdes=%d sigev_signo=%d",
                                context->mq_notify.mqdes,
                                context->mq_notify.sigev_signo);
                break; }
        case AUDIT_MQ_GETSETATTR: {
                struct mq_attr *attr = &context->mq_getsetattr.mqstat;
                audit_log_format(ab,
                        "mqdes=%d mq_flags=0x%lx mq_maxmsg=%ld mq_msgsize=%ld "
                        "mq_curmsgs=%ld ",
                        context->mq_getsetattr.mqdes,
                        attr->mq_flags, attr->mq_maxmsg,
                        attr->mq_msgsize, attr->mq_curmsgs);
                break; }
        case AUDIT_CAPSET: {
                audit_log_format(ab, "pid=%d", context->capset.pid);
                audit_log_cap(ab, "cap_pi", &context->capset.cap.inheritable);
                audit_log_cap(ab, "cap_pp", &context->capset.cap.permitted);
                audit_log_cap(ab, "cap_pe", &context->capset.cap.effective);
                break; }
        }
        audit_log_end(ab);
}

static void audit_log_exit(struct audit_context *context, struct task_struct *tsk)
{
        const struct cred *cred;
        int i, call_panic = 0;
        struct audit_buffer *ab;
        struct audit_aux_data *aux;
        const char *tty;

        /* tsk == current */
        context->pid = tsk->pid;
        if (!context->ppid)
                context->ppid = sys_getppid();
        cred = current_cred();
        context->uid   = cred->uid;
        context->gid   = cred->gid;
        context->euid  = cred->euid;
        context->suid  = cred->suid;
        context->fsuid = cred->fsuid;
        context->egid  = cred->egid;
        context->sgid  = cred->sgid;
        context->fsgid = cred->fsgid;
        context->personality = tsk->personality;

        ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL);
        if (!ab)
                return;         /* audit_panic has been called */
        audit_log_format(ab, "arch=%x syscall=%d",
                         context->arch, context->major);
        if (context->personality != PER_LINUX)
                audit_log_format(ab, " per=%lx", context->personality);
        if (context->return_valid)
                audit_log_format(ab, " success=%s exit=%ld",
                                 (context->return_valid==AUDITSC_SUCCESS)?"yes":"no",
                                 context->return_code);

        spin_lock_irq(&tsk->sighand->siglock);
        if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
                tty = tsk->signal->tty->name;
        else
                tty = "(none)";
        spin_unlock_irq(&tsk->sighand->siglock);

        audit_log_format(ab,
                  " a0=%lx a1=%lx a2=%lx a3=%lx items=%d"
                  " ppid=%d pid=%d auid=%u uid=%u gid=%u"
                  " euid=%u suid=%u fsuid=%u"
                  " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
                  context->argv[0],
                  context->argv[1],
                  context->argv[2],
                  context->argv[3],
                  context->name_count,
                  context->ppid,
                  context->pid,
                  tsk->loginuid,
                  context->uid,
                  context->gid,
                  context->euid, context->suid, context->fsuid,
                  context->egid, context->sgid, context->fsgid, tty,
                  tsk->sessionid);


        audit_log_task_info(ab, tsk);
        if (context->filterkey) {
                audit_log_format(ab, " key=");
                audit_log_untrustedstring(ab, context->filterkey);
        } else
                audit_log_format(ab, " key=(null)");
        audit_log_end(ab);

        for (aux = context->aux; aux; aux = aux->next) {

                ab = audit_log_start(context, GFP_KERNEL, aux->type);
                if (!ab)
                        continue; /* audit_panic has been called */

                switch (aux->type) {

                case AUDIT_EXECVE: {
                        struct audit_aux_data_execve *axi = (void *)aux;
                        audit_log_execve_info(context, &ab, axi);
                        break; }

                case AUDIT_BPRM_FCAPS: {
                        struct audit_aux_data_bprm_fcaps *axs = (void *)aux;
                        audit_log_format(ab, "fver=%x", axs->fcap_ver);
                        audit_log_cap(ab, "fp", &axs->fcap.permitted);
                        audit_log_cap(ab, "fi", &axs->fcap.inheritable);
                        audit_log_format(ab, " fe=%d", axs->fcap.fE);
                        audit_log_cap(ab, "old_pp", &axs->old_pcap.permitted);
                        audit_log_cap(ab, "old_pi", &axs->old_pcap.inheritable);
                        audit_log_cap(ab, "old_pe", &axs->old_pcap.effective);
                        audit_log_cap(ab, "new_pp", &axs->new_pcap.permitted);
                        audit_log_cap(ab, "new_pi", &axs->new_pcap.inheritable);
                        audit_log_cap(ab, "new_pe", &axs->new_pcap.effective);
                        break; }

                }
                audit_log_end(ab);
        }

        if (context->type)
                show_special(context, &call_panic);

        if (context->fds[0] >= 0) {
                ab = audit_log_start(context, GFP_KERNEL, AUDIT_FD_PAIR);
                if (ab) {
                        audit_log_format(ab, "fd0=%d fd1=%d",
                                        context->fds[0], context->fds[1]);
                        audit_log_end(ab);
                }
        }

        if (context->sockaddr_len) {
                ab = audit_log_start(context, GFP_KERNEL, AUDIT_SOCKADDR);
                if (ab) {
                        audit_log_format(ab, "saddr=");
                        audit_log_n_hex(ab, (void *)context->sockaddr,
                                        context->sockaddr_len);
                        audit_log_end(ab);
                }
        }

        for (aux = context->aux_pids; aux; aux = aux->next) {
                struct audit_aux_data_pids *axs = (void *)aux;

                for (i = 0; i < axs->pid_count; i++)
                        if (audit_log_pid_context(context, axs->target_pid[i],
                                                  axs->target_auid[i],
                                                  axs->target_uid[i],
                                                  axs->target_sessionid[i],
                                                  axs->target_sid[i],
                                                  axs->target_comm[i]))
                                call_panic = 1;
        }

        if (context->target_pid &&
            audit_log_pid_context(context, context->target_pid,
                                  context->target_auid, context->target_uid,
                                  context->target_sessionid,
                                  context->target_sid, context->target_comm))
                        call_panic = 1;

        if (context->pwd.dentry && context->pwd.mnt) {
                ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
                if (ab) {
                        audit_log_d_path(ab, "cwd=", &context->pwd);
                        audit_log_end(ab);
                }
        }
        for (i = 0; i < context->name_count; i++) {
                struct audit_names *n = &context->names[i];

                ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
                if (!ab)
                        continue; /* audit_panic has been called */

                audit_log_format(ab, "item=%d", i);

                if (n->name) {
                        switch(n->name_len) {
                        case AUDIT_NAME_FULL:
                                /* log the full path */
                                audit_log_format(ab, " name=");
                                audit_log_untrustedstring(ab, n->name);
                                break;
                        case 0:
                                /* name was specified as a relative path and the
                                 * directory component is the cwd */
                                audit_log_d_path(ab, "name=", &context->pwd);
                                break;
                        default:
                                /* log the name's directory component */
                                audit_log_format(ab, " name=");
                                audit_log_n_untrustedstring(ab, n->name,
                                                            n->name_len);
                        }
                } else
                        audit_log_format(ab, " name=(null)");

                if (n->ino != (unsigned long)-1) {
                        audit_log_format(ab, " inode=%lu"
                                         " dev=%02x:%02x mode=%#o"
                                         " ouid=%u ogid=%u rdev=%02x:%02x",
                                         n->ino,
                                         MAJOR(n->dev),
                                         MINOR(n->dev),
                                         n->mode,
                                         n->uid,
                                         n->gid,
                                         MAJOR(n->rdev),
                                         MINOR(n->rdev));
                }
                if (n->osid != 0) {
                        char *ctx = NULL;
                        u32 len;
                        if (security_secid_to_secctx(
                                n->osid, &ctx, &len)) {
                                audit_log_format(ab, " osid=%u", n->osid);
                                call_panic = 2;
                        } else {
                                audit_log_format(ab, " obj=%s", ctx);
                                security_release_secctx(ctx, len);
                        }
                }

                audit_log_fcaps(ab, n);

                audit_log_end(ab);
        }

        /* Send end of event record to help user space know we are finished */
        ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
        if (ab)
                audit_log_end(ab);
        if (call_panic)
                audit_panic("error converting sid to string");
}

/**
 * audit_free - free a per-task audit context
 * @tsk: task whose audit context block to free
 *
 * Called from copy_process and do_exit
 */
void audit_free(struct task_struct *tsk)
{
        struct audit_context *context;

        context = audit_get_context(tsk, 0, 0);
        if (likely(!context))
                return;

        /* Check for system calls that do not go through the exit
         * function (e.g., exit_group), then free context block.
         * We use GFP_ATOMIC here because we might be doing this
         * in the context of the idle thread */
        /* that can happen only if we are called from do_exit() */
        if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT)
                audit_log_exit(context, tsk);

        audit_free_context(context);
}

/**
 * audit_syscall_entry - fill in an audit record at syscall entry
 * @arch: architecture type
 * @major: major syscall type (function)
 * @a1: additional syscall register 1
 * @a2: additional syscall register 2
 * @a3: additional syscall register 3
 * @a4: additional syscall register 4
 *
 * Fill in audit context at syscall entry.  This only happens if the
 * audit context was created when the task was created and the state or
 * filters demand the audit context be built.  If the state from the
 * per-task filter or from the per-syscall filter is AUDIT_RECORD_CONTEXT,
 * then the record will be written at syscall exit time (otherwise, it
 * will only be written if another part of the kernel requests that it
 * be written).
 */
void audit_syscall_entry(int arch, int major,
                         unsigned long a1, unsigned long a2,
                         unsigned long a3, unsigned long a4)
{
        struct task_struct *tsk = current;
        struct audit_context *context = tsk->audit_context;
        enum audit_state     state;

        if (unlikely(!context))
                return;

        /*
         * This happens only on certain architectures that make system
         * calls in kernel_thread via the entry.S interface, instead of
         * with direct calls.  (If you are porting to a new
         * architecture, hitting this condition can indicate that you
         * got the _exit/_leave calls backward in entry.S.)
         *
         * i386     no
         * x86_64   no
         * ppc64    yes (see arch/powerpc/platforms/iseries/misc.S)
         *
         * This also happens with vm86 emulation in a non-nested manner
         * (entries without exits), so this case must be caught.
         */
        if (context->in_syscall) {
                struct audit_context *newctx;

#if AUDIT_DEBUG
                printk(KERN_ERR
                       "audit(:%d) pid=%d in syscall=%d;"
                       " entering syscall=%d\n",
                       context->serial, tsk->pid, context->major, major);
#endif
                newctx = audit_alloc_context(context->state);
                if (newctx) {
                        newctx->previous   = context;
                        context            = newctx;
                        tsk->audit_context = newctx;
                } else  {
                        /* If we can't alloc a new context, the best we
                         * can do is to leak memory (any pending putname
                         * will be lost).  The only other alternative is
                         * to abandon auditing. */
                        audit_zero_context(context, context->state);
                }
        }
        BUG_ON(context->in_syscall || context->name_count);

        if (!audit_enabled)
                return;

        context->arch       = arch;
        context->major      = major;
        context->argv[0]    = a1;
        context->argv[1]    = a2;
        context->argv[2]    = a3;
        context->argv[3]    = a4;

        state = context->state;
        context->dummy = !audit_n_rules;
        if (!context->dummy && state == AUDIT_BUILD_CONTEXT) {
                context->prio = 0;
                state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_ENTRY]);
        }
        if (likely(state == AUDIT_DISABLED))
                return;

        context->serial     = 0;
        context->ctime      = CURRENT_TIME;
        context->in_syscall = 1;
        context->current_state  = state;
        context->ppid       = 0;
}

void audit_finish_fork(struct task_struct *child)
{
        struct audit_context *ctx = current->audit_context;
        struct audit_context *p = child->audit_context;
        if (!p || !ctx)
                return;
        if (!ctx->in_syscall || ctx->current_state != AUDIT_RECORD_CONTEXT)
                return;
        p->arch = ctx->arch;
        p->major = ctx->major;
        memcpy(p->argv, ctx->argv, sizeof(ctx->argv));
        p->ctime = ctx->ctime;
        p->dummy = ctx->dummy;
        p->in_syscall = ctx->in_syscall;
        p->filterkey = kstrdup(ctx->filterkey, GFP_KERNEL);
        p->ppid = current->pid;
        p->prio = ctx->prio;
        p->current_state = ctx->current_state;
}

/**
 * audit_syscall_exit - deallocate audit context after a system call
 * @valid: success/failure flag
 * @return_code: syscall return value
 *
 * Tear down after system call.  If the audit context has been marked as
 * auditable (either because of the AUDIT_RECORD_CONTEXT state from
 * filtering, or because some other part of the kernel write an audit
 * message), then write out the syscall information.  In call cases,
 * free the names stored from getname().
 */
void audit_syscall_exit(int valid, long return_code)
{
        struct task_struct *tsk = current;
        struct audit_context *context;

        context = audit_get_context(tsk, valid, return_code);

        if (likely(!context))
                return;

        if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT)
                audit_log_exit(context, tsk);

        context->in_syscall = 0;
        context->prio = context->state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0;

        if (context->previous) {
                struct audit_context *new_context = context->previous;
                context->previous  = NULL;
                audit_free_context(context);
                tsk->audit_context = new_context;
        } else {
                audit_free_names(context);
                unroll_tree_refs(context, NULL, 0);
                audit_free_aux(context);
                context->aux = NULL;
                context->aux_pids = NULL;
                context->target_pid = 0;
                context->target_sid = 0;
                context->sockaddr_len = 0;
                context->type = 0;
                context->fds[0] = -1;
                if (context->state != AUDIT_RECORD_CONTEXT) {
                        kfree(context->filterkey);
                        context->filterkey = NULL;
                }
                tsk->audit_context = context;
        }
}

static inline void handle_one(const struct inode *inode)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_context *context;
        struct audit_tree_refs *p;
        struct audit_chunk *chunk;
        int count;
        if (likely(list_empty(&inode->inotify_watches)))
                return;
        context = current->audit_context;
        p = context->trees;
        count = context->tree_count;
        rcu_read_lock();
        chunk = audit_tree_lookup(inode);
        rcu_read_unlock();
        if (!chunk)
                return;
        if (likely(put_tree_ref(context, chunk)))
                return;
        if (unlikely(!grow_tree_refs(context))) {
                printk(KERN_WARNING "out of memory, audit has lost a tree reference\n");
                audit_set_auditable(context);
                audit_put_chunk(chunk);
                unroll_tree_refs(context, p, count);
                return;
        }
        put_tree_ref(context, chunk);
#endif
}

static void handle_path(const struct dentry *dentry)
{
#ifdef CONFIG_AUDIT_TREE
        struct audit_context *context;
        struct audit_tree_refs *p;
        const struct dentry *d, *parent;
        struct audit_chunk *drop;
        unsigned long seq;
        int count;

        context = current->audit_context;
        p = context->trees;
        count = context->tree_count;
retry:
        drop = NULL;
        d = dentry;
        rcu_read_lock();
        seq = read_seqbegin(&rename_lock);
        for(;;) {
                struct inode *inode = d->d_inode;
                if (inode && unlikely(!list_empty(&inode->inotify_watches))) {
                        struct audit_chunk *chunk;
                        chunk = audit_tree_lookup(inode);
                        if (chunk) {
                                if (unlikely(!put_tree_ref(context, chunk))) {
                                        drop = chunk;
                                        break;
                                }
                        }
                }
                parent = d->d_parent;
                if (parent == d)
                        break;
                d = parent;
        }
        if (unlikely(read_seqretry(&rename_lock, seq) || drop)) {  /* in this order */
                rcu_read_unlock();
                if (!drop) {
                        /* just a race with rename */
                        unroll_tree_refs(context, p, count);
                        goto retry;
                }
                audit_put_chunk(drop);
                if (grow_tree_refs(context)) {
                        /* OK, got more space */
                        unroll_tree_refs(context, p, count);
                        goto retry;
                }
                /* too bad */
                printk(KERN_WARNING
                        "out of memory, audit has lost a tree reference\n");
                unroll_tree_refs(context, p, count);
                audit_set_auditable(context);
                return;
        }
        rcu_read_unlock();
#endif
}

/**
 * audit_getname - add a name to the list
 * @name: name to add
 *
 * Add a name to the list of audit names for this context.
 * Called from fs/namei.c:getname().
 */
void __audit_getname(const char *name)
{
        struct audit_context *context = current->audit_context;

        if (IS_ERR(name) || !name)
                return;

        if (!context->in_syscall) {
#if AUDIT_DEBUG == 2
                printk(KERN_ERR "%s:%d(:%d): ignoring getname(%p)\n",
                       __FILE__, __LINE__, context->serial, name);
                dump_stack();
#endif
                return;
        }
        BUG_ON(context->name_count >= AUDIT_NAMES);
        context->names[context->name_count].name = name;
        context->names[context->name_count].name_len = AUDIT_NAME_FULL;
        context->names[context->name_count].name_put = 1;
        context->names[context->name_count].ino  = (unsigned long)-1;
        context->names[context->name_count].osid = 0;
        ++context->name_count;
        if (!context->pwd.dentry) {
                read_lock(&current->fs->lock);
                context->pwd = current->fs->pwd;
                path_get(&current->fs->pwd);
                read_unlock(&current->fs->lock);
        }

}

/* audit_putname - intercept a putname request
 * @name: name to intercept and delay for putname
 *
 * If we have stored the name from getname in the audit context,
 * then we delay the putname until syscall exit.
 * Called from include/linux/fs.h:putname().
 */
void audit_putname(const char *name)
{
        struct audit_context *context = current->audit_context;

        BUG_ON(!context);
        if (!context->in_syscall) {
#if AUDIT_DEBUG == 2
                printk(KERN_ERR "%s:%d(:%d): __putname(%p)\n",
                       __FILE__, __LINE__, context->serial, name);
                if (context->name_count) {
                        int i;
                        for (i = 0; i < context->name_count; i++)
                                printk(KERN_ERR "name[%d] = %p = %s\n", i,
                                       context->names[i].name,
                                       context->names[i].name ?: "(null)");
                }
#endif
                __putname(name);
        }
#if AUDIT_DEBUG
        else {
                ++context->put_count;
                if (context->put_count > context->name_count) {
                        printk(KERN_ERR "%s:%d(:%d): major=%d"
                               " in_syscall=%d putname(%p) name_count=%d"
                               " put_count=%d\n",
                               __FILE__, __LINE__,
                               context->serial, context->major,
                               context->in_syscall, name, context->name_count,
                               context->put_count);
                        dump_stack();
                }
        }
#endif
}

static int audit_inc_name_count(struct audit_context *context,
                                const struct inode *inode)
{
        if (context->name_count >= AUDIT_NAMES) {
                if (inode)
                        printk(KERN_DEBUG "name_count maxed, losing inode data: "
                               "dev=%02x:%02x, inode=%lu\n",
                               MAJOR(inode->i_sb->s_dev),
                               MINOR(inode->i_sb->s_dev),
                               inode->i_ino);

                else
                        printk(KERN_DEBUG "name_count maxed, losing inode data\n");
                return 1;
        }
        context->name_count++;
#if AUDIT_DEBUG
        context->ino_count++;
#endif
        return 0;
}


static inline int audit_copy_fcaps(struct audit_names *name, const struct dentry *dentry)
{
        struct cpu_vfs_cap_data caps;
        int rc;

        memset(&name->fcap.permitted, 0, sizeof(kernel_cap_t));
        memset(&name->fcap.inheritable, 0, sizeof(kernel_cap_t));
        name->fcap.fE = 0;
        name->fcap_ver = 0;

        if (!dentry)
                return 0;

        rc = get_vfs_caps_from_disk(dentry, &caps);
        if (rc)
                return rc;

        name->fcap.permitted = caps.permitted;
        name->fcap.inheritable = caps.inheritable;
        name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
        name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >> VFS_CAP_REVISION_SHIFT;

        return 0;
}


/* Copy inode data into an audit_names. */
static void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
                             const struct inode *inode)
{
        name->ino   = inode->i_ino;
        name->dev   = inode->i_sb->s_dev;
        name->mode  = inode->i_mode;
        name->uid   = inode->i_uid;
        name->gid   = inode->i_gid;
        name->rdev  = inode->i_rdev;
        security_inode_getsecid(inode, &name->osid);
        audit_copy_fcaps(name, dentry);
}

/**
 * audit_inode - store the inode and device from a lookup
 * @name: name being audited
 * @dentry: dentry being audited
 *
 * Called from fs/namei.c:path_lookup().
 */
void __audit_inode(const char *name, const struct dentry *dentry)
{
        int idx;
        struct audit_context *context = current->audit_context;
        const struct inode *inode = dentry->d_inode;

        if (!context->in_syscall)
                return;
        if (context->name_count
            && context->names[context->name_count-1].name
            && context->names[context->name_count-1].name == name)
                idx = context->name_count - 1;
        else if (context->name_count > 1
                 && context->names[context->name_count-2].name
                 && context->names[context->name_count-2].name == name)
                idx = context->name_count - 2;
        else {
                /* FIXME: how much do we care about inodes that have no
                 * associated name? */
                if (audit_inc_name_count(context, inode))
                        return;
                idx = context->name_count - 1;
                context->names[idx].name = NULL;
        }
        handle_path(dentry);
        audit_copy_inode(&context->names[idx], dentry, inode);
}

/**
 * audit_inode_child - collect inode info for created/removed objects
 * @dname: inode's dentry name
 * @dentry: dentry being audited
 * @parent: inode of dentry parent
 *
 * For syscalls that create or remove filesystem objects, audit_inode
 * can only collect information for the filesystem object's parent.
 * This call updates the audit context with the child's information.
 * Syscalls that create a new filesystem object must be hooked after
 * the object is created.  Syscalls that remove a filesystem object
 * must be hooked prior, in order to capture the target inode during
 * unsuccessful attempts.
 */