/*
  Copyright 2024 Northern.tech AS

  This file is part of CFEngine 3 - written and maintained by Northern.tech AS.

  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 3.

  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

  To the extent this program is licensed as part of the Enterprise
  versions of CFEngine, the applicable Commercial Open Source License
  (COSL) may apply to this file if you as a licensee so wish it. See
  included file COSL.txt.
*/

#include <files_properties.h>

#include <files_names.h>
#include <files_interfaces.h>
#include <file_lib.h>                                      /* IsFileSep */
#include <item_lib.h>

static Item *SUSPICIOUSLIST = NULL; /* GLOBAL_P */

void AddFilenameToListOfSuspicious(const char *pattern)
{
    PrependItem(&SUSPICIOUSLIST, pattern, NULL);
}

static const char *const SKIPFILES[] =
{
    ".",
    "..",
    "lost+found",
    ".cfengine.rm",
    NULL
};

/* TODO rework to accept only one param: path+nodename */
static bool ConsiderFile(const char *nodename, const char *path, struct stat *stat)
{
    int i;

    if (nodename[0] == '\0')
    {
        Log(LOG_LEVEL_ERR, "Empty (null) filename detected in '%s', skipping", path);
        return false;
    }

    if (stat != NULL && (S_ISREG(stat->st_mode) || S_ISLNK(stat->st_mode)) &&
        IsItemIn(SUSPICIOUSLIST, nodename))
    {
        Log(LOG_LEVEL_WARNING, "Filename '%s/%s' is classified as suspiscious, skipping", path, nodename);
        return false;
    }

    /* A file named '...' is likely to be a path traversal attempt, see http://cwe.mitre.org/data/definitions/32.html */
    if (strcmp(nodename, "...") == 0)
    {
        Log(LOG_LEVEL_WARNING, "Possible path traversal attempt detected in '%s/%s', skipping", path, nodename);
        return false;
    }

    /* A directory entry is a single path component and never contains a
     * separator. One that does (e.g. "../x" from a hostile server's listing)
     * would escape 'path' when the two are joined, see
     * http://cwe.mitre.org/data/definitions/32.html */
    for (const char *s = nodename; *s != '\0'; s++)
    {
        if (IsFileSep(*s))
        {
            Log(LOG_LEVEL_WARNING, "Path separator in directory entry '%s/%s', skipping", path, nodename);
            return false;
        }
    }

    for (i = 0; SKIPFILES[i] != NULL; i++)
    {
        if (strcmp(nodename, SKIPFILES[i]) == 0)
        {
            Log(LOG_LEVEL_VERBOSE, "Filename '%s/%s' is classified as ignorable, skipping", path, nodename);
            return false;
        }
    }

    return true;
}

bool ConsiderLocalFile(const char *filename, const char *directory)
{
    struct stat stat;
    if (lstat(filename, &stat) == -1)
    {
        return ConsiderFile(filename, directory, NULL);
    }
    else
    {
        return ConsiderFile(filename, directory, &stat);
    }
}

bool ConsiderAbstractFile(const char *filename, const char *directory, const FileCopy *fc, AgentConnection *conn)
{
    /* First check if the file should be avoided, e.g. ".." - before sending
     * anything over the network*/

    if (!ConsiderFile(filename, directory, NULL))
    {
        return false;
    }

    /* TODO this function should accept the joined path in the first place
     * since it's joined elsewhere as well, if split needed do it here. */
    char buf[CF_BUFSIZE];
    int ret = snprintf(buf, sizeof(buf), "%s/%s", directory, filename);
    if (ret < 0)
    {
        Log(LOG_LEVEL_ERR, 
            "Unexpected failure from snprintf (%d - %s) on '%s' "
            "(ConsiderAbstractFile)", errno, GetErrorStr(), buf);
        return false;
    }
    else if ((size_t) ret >= sizeof(buf))
    {
        Log(LOG_LEVEL_ERR,
            "Filename too long! Directory '%s' filename '%s'",
            directory, filename);
        return false;
    }

    /* Second, send the STAT command. */

    struct stat stat;
    if (cf_lstat(buf, &stat, fc, conn) == -1)
    {
        return false;                                      /* stat() failed */
    }
    else
    {
        /* Reconsider, but using stat info this time. */
        return ConsiderFile(filename, directory, &stat);
    }
}
