audit.c

Go to the documentation of this file.

/*
 * security/tomoyo/audit.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 */

#include "common.h"
#include <linux/slab.h>

static char *tomoyo_print_bprm(struct linux_binprm *bprm,
                   struct tomoyo_page_dump *dump)
{
    static const int tomoyo_buffer_len = 4096 * 2;
    char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
    char *cp;
    char *last_start;
    int len;
    unsigned long pos = bprm->p;
    int offset = pos % PAGE_SIZE;
    int argv_count = bprm->argc;
    int envp_count = bprm->envc;
    bool truncated = false;
    if (!buffer)
        return NULL;
    len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
    cp = buffer + len;
    if (!argv_count) {
        memmove(cp, "} envp[]={ ", 11);
        cp += 11;
    }
    last_start = cp;
    while (argv_count || envp_count) {
        if (!tomoyo_dump_page(bprm, pos, dump))
            goto out;
        pos += PAGE_SIZE - offset;
        /* Read. */
        while (offset < PAGE_SIZE) {
            const char *kaddr = dump->data;
            const unsigned char c = kaddr[offset++];
            if (cp == last_start)
                *cp++ = '"';
            if (cp >= buffer + tomoyo_buffer_len - 32) {
                /* Reserve some room for "..." string. */
                truncated = true;
            } else if (c == '\\') {
                *cp++ = '\\';
                *cp++ = '\\';
            } else if (c > ' ' && c < 127) {
                *cp++ = c;
            } else if (!c) {
                *cp++ = '"';
                *cp++ = ' ';
                last_start = cp;
            } else {
                *cp++ = '\\';
                *cp++ = (c >> 6) + '0';
                *cp++ = ((c >> 3) & 7) + '0';
                *cp++ = (c & 7) + '0';
            }
            if (c)
                continue;
            if (argv_count) {
                if (--argv_count == 0) {
                    if (truncated) {
                        cp = last_start;
                        memmove(cp, "... ", 4);
                        cp += 4;
                    }
                    memmove(cp, "} envp[]={ ", 11);
                    cp += 11;
                    last_start = cp;
                    truncated = false;
                }
            } else if (envp_count) {
                if (--envp_count == 0) {
                    if (truncated) {
                        cp = last_start;
                        memmove(cp, "... ", 4);
                        cp += 4;
                    }
                }
            }
            if (!argv_count && !envp_count)
                break;
        }
        offset = 0;
    }
    *cp++ = '}';
    *cp = '\0';
    return buffer;
out:
    snprintf(buffer, tomoyo_buffer_len - 1,
         "argv[]={ ... } envp[]= { ... }");
    return buffer;
}

static inline const char *tomoyo_filetype(const umode_t mode)
{
    switch (mode & S_IFMT) {
    case S_IFREG:
    case 0:
        return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
    case S_IFDIR:
        return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
    case S_IFLNK:
        return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
    case S_IFIFO:
        return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
    case S_IFSOCK:
        return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
    case S_IFBLK:
        return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
    case S_IFCHR:
        return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
    }
    return "unknown"; /* This should not happen. */
}

static char *tomoyo_print_header(struct tomoyo_request_info *r)
{
    struct tomoyo_time stamp;
    const pid_t gpid = task_pid_nr(current);
    struct tomoyo_obj_info *obj = r->obj;
    static const int tomoyo_buffer_len = 4096;
    char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
    int pos;
    u8 i;
    if (!buffer)
        return NULL;
    {
        struct timeval tv;
        do_gettimeofday(&tv);
        tomoyo_convert_time(tv.tv_sec, &stamp);
    }
    pos = snprintf(buffer, tomoyo_buffer_len - 1,
               "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
               "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
               "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
               "fsuid=%u fsgid=%u }", stamp.year, stamp.month,
               stamp.day, stamp.hour, stamp.min, stamp.sec, r->profile,
               tomoyo_mode[r->mode], tomoyo_yesno(r->granted), gpid,
               tomoyo_sys_getpid(), tomoyo_sys_getppid(),
               from_kuid(&init_user_ns, current_uid()),
               from_kgid(&init_user_ns, current_gid()),
               from_kuid(&init_user_ns, current_euid()),
               from_kgid(&init_user_ns, current_egid()),
               from_kuid(&init_user_ns, current_suid()),
               from_kgid(&init_user_ns, current_sgid()),
               from_kuid(&init_user_ns, current_fsuid()),
               from_kgid(&init_user_ns, current_fsgid()));
    if (!obj)
        goto no_obj_info;
    if (!obj->validate_done) {
        tomoyo_get_attributes(obj);
        obj->validate_done = true;
    }
    for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
        struct tomoyo_mini_stat *stat;
        unsigned int dev;
        umode_t mode;
        if (!obj->stat_valid[i])
            continue;
        stat = &obj->stat[i];
        dev = stat->dev;
        mode = stat->mode;
        if (i & 1) {
            pos += snprintf(buffer + pos,
                    tomoyo_buffer_len - 1 - pos,
                    " path%u.parent={ uid=%u gid=%u "
                    "ino=%lu perm=0%o }", (i >> 1) + 1,
                    from_kuid(&init_user_ns, stat->uid),
                    from_kgid(&init_user_ns, stat->gid),
                    (unsigned long)stat->ino,
                    stat->mode & S_IALLUGO);
            continue;
        }
        pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
                " path%u={ uid=%u gid=%u ino=%lu major=%u"
                " minor=%u perm=0%o type=%s", (i >> 1) + 1,
                from_kuid(&init_user_ns, stat->uid),
                from_kgid(&init_user_ns, stat->gid),
                (unsigned long)stat->ino,
                MAJOR(dev), MINOR(dev),
                mode & S_IALLUGO, tomoyo_filetype(mode));
        if (S_ISCHR(mode) || S_ISBLK(mode)) {
            dev = stat->rdev;
            pos += snprintf(buffer + pos,
                    tomoyo_buffer_len - 1 - pos,
                    " dev_major=%u dev_minor=%u",
                    MAJOR(dev), MINOR(dev));
        }
        pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
                " }");
    }
no_obj_info:
    if (pos < tomoyo_buffer_len - 1)
        return buffer;
    kfree(buffer);
    return NULL;
}

char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
              va_list args)
{
    char *buf = NULL;
    char *bprm_info = NULL;
    const char *header = NULL;
    char *realpath = NULL;
    const char *symlink = NULL;
    int pos;
    const char *domainname = r->domain->domainname->name;
    header = tomoyo_print_header(r);
    if (!header)
        return NULL;
    /* +10 is for '\n' etc. and '\0'. */
    len += strlen(domainname) + strlen(header) + 10;
    if (r->ee) {
        struct file *file = r->ee->bprm->file;
        realpath = tomoyo_realpath_from_path(&file->f_path);
        bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
        if (!realpath || !bprm_info)
            goto out;
        /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
        len += strlen(realpath) + 80 + strlen(bprm_info);
    } else if (r->obj && r->obj->symlink_target) {
        symlink = r->obj->symlink_target->name;
        /* +18 is for " symlink.target=\"%s\"" */
        len += 18 + strlen(symlink);
    }
    len = tomoyo_round2(len);
    buf = kzalloc(len, GFP_NOFS);
    if (!buf)
        goto out;
    len--;
    pos = snprintf(buf, len, "%s", header);
    if (realpath) {
        struct linux_binprm *bprm = r->ee->bprm;
        pos += snprintf(buf + pos, len - pos,
                " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
                realpath, bprm->argc, bprm->envc, bprm_info);
    } else if (symlink)
        pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
                symlink);
    pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
    vsnprintf(buf + pos, len - pos, fmt, args);
out:
    kfree(realpath);
    kfree(bprm_info);
    kfree(header);
    return buf;
}

/* Wait queue for /sys/kernel/security/tomoyo/audit. */
static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);

/* Structure for audit log. */
struct tomoyo_log {
    struct list_head list;
    char *log;
    int size;
};

/* The list for "struct tomoyo_log". */
static LIST_HEAD(tomoyo_log);

/* Lock for "struct list_head tomoyo_log". */
static DEFINE_SPINLOCK(tomoyo_log_lock);

/* Length of "stuct list_head tomoyo_log". */
static unsigned int tomoyo_log_count;

static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
                 const u8 profile, const u8 index,
                 const struct tomoyo_acl_info *matched_acl,
                 const bool is_granted)
{
    u8 mode;
    const u8 category = tomoyo_index2category[index] +
        TOMOYO_MAX_MAC_INDEX;
    struct tomoyo_profile *p;
    if (!tomoyo_policy_loaded)
        return false;
    p = tomoyo_profile(ns, profile);
    if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
        return false;
    if (is_granted && matched_acl && matched_acl->cond &&
        matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
        return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
    mode = p->config[index];
    if (mode == TOMOYO_CONFIG_USE_DEFAULT)
        mode = p->config[category];
    if (mode == TOMOYO_CONFIG_USE_DEFAULT)
        mode = p->default_config;
    if (is_granted)
        return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
    return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
}

void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
               va_list args)
{
    char *buf;
    struct tomoyo_log *entry;
    bool quota_exceeded = false;
    if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
                  r->matched_acl, r->granted))
        goto out;
    buf = tomoyo_init_log(r, len, fmt, args);
    if (!buf)
        goto out;
    entry = kzalloc(sizeof(*entry), GFP_NOFS);
    if (!entry) {
        kfree(buf);
        goto out;
    }
    entry->log = buf;
    len = tomoyo_round2(strlen(buf) + 1);
    /*
     * The entry->size is used for memory quota checks.
     * Don't go beyond strlen(entry->log).
     */
    entry->size = len + tomoyo_round2(sizeof(*entry));
    spin_lock(&tomoyo_log_lock);
    if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
        tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
        tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
        quota_exceeded = true;
    } else {
        tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
        list_add_tail(&entry->list, &tomoyo_log);
        tomoyo_log_count++;
    }
    spin_unlock(&tomoyo_log_lock);
    if (quota_exceeded) {
        kfree(buf);
        kfree(entry);
        goto out;
    }
    wake_up(&tomoyo_log_wait);
out:
    return;
}

void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
{
    va_list args;
    int len;
    va_start(args, fmt);
    len = vsnprintf((char *) &len, 1, fmt, args) + 1;
    va_end(args);
    va_start(args, fmt);
    tomoyo_write_log2(r, len, fmt, args);
    va_end(args);
}

void tomoyo_read_log(struct tomoyo_io_buffer *head)
{
    struct tomoyo_log *ptr = NULL;
    if (head->r.w_pos)
        return;
    kfree(head->read_buf);
    head->read_buf = NULL;
    spin_lock(&tomoyo_log_lock);
    if (!list_empty(&tomoyo_log)) {
        ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
        list_del(&ptr->list);
        tomoyo_log_count--;
        tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
    }
    spin_unlock(&tomoyo_log_lock);
    if (ptr) {
        head->read_buf = ptr->log;
        head->r.w[head->r.w_pos++] = head->read_buf;
        kfree(ptr);
    }
}

unsigned int tomoyo_poll_log(struct file *file, poll_table *wait)
{
    if (tomoyo_log_count)
        return POLLIN | POLLRDNORM;
    poll_wait(file, &tomoyo_log_wait, wait);
    if (tomoyo_log_count)
        return POLLIN | POLLRDNORM;
    return 0;
}