root/session/mod_files.c

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DEFINITIONS

This source file includes following definitions.
  1. ps_files_valid_key
  2. ps_files_path_create
  3. ps_files_close
  4. ps_files_open
  5. ps_files_cleanup_dir
  6. PS_OPEN_FUNC
  7. PS_CLOSE_FUNC
  8. PS_READ_FUNC
  9. PS_WRITE_FUNC
  10. PS_DESTROY_FUNC
  11. PS_GC_FUNC

/*
   +----------------------------------------------------------------------+
   | PHP Version 5                                                        |
   +----------------------------------------------------------------------+
   | Copyright (c) 1997-2013 The PHP Group                                |
   +----------------------------------------------------------------------+
   | This source file is subject to version 3.01 of the PHP license,      |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.php.net/license/3_01.txt                                  |
   | If you did not receive a copy of the PHP license and are unable to   |
   | obtain it through the world-wide-web, please send a note to          |
   | license@php.net so we can mail you a copy immediately.               |
   +----------------------------------------------------------------------+
   | Author: Sascha Schumann <sascha@schumann.cx>                         |
   +----------------------------------------------------------------------+
 */

/* $Id$ */

#include "php.h"

#include <sys/stat.h>
#include <sys/types.h>

#if HAVE_SYS_FILE_H
#include <sys/file.h>
#endif

#if HAVE_DIRENT_H
#include <dirent.h>
#endif

#ifdef PHP_WIN32
#include "win32/readdir.h"
#endif
#include <time.h>

#include <fcntl.h>
#include <errno.h>

#if HAVE_UNISTD_H
#include <unistd.h>
#endif

#include "php_session.h"
#include "mod_files.h"
#include "ext/standard/flock_compat.h"
#include "php_open_temporary_file.h"

#define FILE_PREFIX "sess_"

typedef struct {
        int fd;
        char *lastkey;
        char *basedir;
        size_t basedir_len;
        size_t dirdepth;
        size_t st_size;
        int filemode;
} ps_files;

ps_module ps_mod_files = {
        PS_MOD(files)
};

/* If you change the logic here, please also update the error message in
 * ps_files_open() appropriately */
static int ps_files_valid_key(const char *key)
{
        size_t len;
        const char *p;
        char c;
        int ret = 1;

        for (p = key; (c = *p); p++) {
                /* valid characters are a..z,A..Z,0..9 */
                if (!((c >= 'a' && c <= 'z')
                                || (c >= 'A' && c <= 'Z')
                                || (c >= '0' && c <= '9')
                                || c == ','
                                || c == '-')) {
                        ret = 0;
                        break;
                }
        }

        len = p - key;

        /* Somewhat arbitrary length limit here, but should be way more than
           anyone needs and avoids file-level warnings later on if we exceed MAX_PATH */
        if (len == 0 || len > 128) {
                ret = 0;
        }

        return ret;
}

static char *ps_files_path_create(char *buf, size_t buflen, ps_files *data, const char *key)
{
        size_t key_len;
        const char *p;
        int i;
        int n;

        key_len = strlen(key);
        if (key_len <= data->dirdepth ||
                buflen < (strlen(data->basedir) + 2 * data->dirdepth + key_len + 5 + sizeof(FILE_PREFIX))) {
                return NULL;
        }

        p = key;
        memcpy(buf, data->basedir, data->basedir_len);
        n = data->basedir_len;
        buf[n++] = PHP_DIR_SEPARATOR;
        for (i = 0; i < (int)data->dirdepth; i++) {
                buf[n++] = *p++;
                buf[n++] = PHP_DIR_SEPARATOR;
        }
        memcpy(buf + n, FILE_PREFIX, sizeof(FILE_PREFIX) - 1);
        n += sizeof(FILE_PREFIX) - 1;
        memcpy(buf + n, key, key_len);
        n += key_len;
        buf[n] = '\0';

        return buf;
}

#ifndef O_BINARY
# define O_BINARY 0
#endif

static void ps_files_close(ps_files *data)
{
        if (data->fd != -1) {
#ifdef PHP_WIN32
                /* On Win32 locked files that are closed without being explicitly unlocked
                   will be unlocked only when "system resources become available". */
                flock(data->fd, LOCK_UN);
#endif
                close(data->fd);
                data->fd = -1;
        }
}

static void ps_files_open(ps_files *data, const char *key TSRMLS_DC)
{
        char buf[MAXPATHLEN];

        if (data->fd < 0 || !data->lastkey || strcmp(key, data->lastkey)) {
                if (data->lastkey) {
                        efree(data->lastkey);
                        data->lastkey = NULL;
                }

                ps_files_close(data);

                if (!ps_files_valid_key(key)) {
                        php_error_docref(NULL TSRMLS_CC, E_WARNING, "The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,'");
                        PS(invalid_session_id) = 1;
                        return;
                }
                if (!ps_files_path_create(buf, sizeof(buf), data, key)) {
                        return;
                }

                data->lastkey = estrdup(key);

                data->fd = VCWD_OPEN_MODE(buf, O_CREAT | O_RDWR | O_BINARY, data->filemode);

                if (data->fd != -1) {
#ifndef PHP_WIN32
                        /* check to make sure that the opened file is not a symlink, linking to data outside of allowable dirs */
                        if (PG(open_basedir)) {
                                struct stat sbuf;

                                if (fstat(data->fd, &sbuf)) {
                                        close(data->fd);
                                        return;
                                }
                                if (S_ISLNK(sbuf.st_mode) && php_check_open_basedir(buf TSRMLS_CC)) {
                                        close(data->fd);
                                        return;
                                }
                        }
#endif
                        flock(data->fd, LOCK_EX);

#ifdef F_SETFD
# ifndef FD_CLOEXEC
#  define FD_CLOEXEC 1
# endif
                        if (fcntl(data->fd, F_SETFD, FD_CLOEXEC)) {
                                php_error_docref(NULL TSRMLS_CC, E_WARNING, "fcntl(%d, F_SETFD, FD_CLOEXEC) failed: %s (%d)", data->fd, strerror(errno), errno);
                        }
#endif
                } else {
                        php_error_docref(NULL TSRMLS_CC, E_WARNING, "open(%s, O_RDWR) failed: %s (%d)", buf, strerror(errno), errno);
                }
        }
}

static int ps_files_cleanup_dir(const char *dirname, int maxlifetime TSRMLS_DC)
{
        DIR *dir;
        char dentry[sizeof(struct dirent) + MAXPATHLEN];
        struct dirent *entry = (struct dirent *) &dentry;
        struct stat sbuf;
        char buf[MAXPATHLEN];
        time_t now;
        int nrdels = 0;
        size_t dirname_len;

        dir = opendir(dirname);
        if (!dir) {
                php_error_docref(NULL TSRMLS_CC, E_NOTICE, "ps_files_cleanup_dir: opendir(%s) failed: %s (%d)", dirname, strerror(errno), errno);
                return (0);
        }

        time(&now);

        dirname_len = strlen(dirname);

        /* Prepare buffer (dirname never changes) */
        memcpy(buf, dirname, dirname_len);
        buf[dirname_len] = PHP_DIR_SEPARATOR;

        while (php_readdir_r(dir, (struct dirent *) dentry, &entry) == 0 && entry) {
                /* does the file start with our prefix? */
                if (!strncmp(entry->d_name, FILE_PREFIX, sizeof(FILE_PREFIX) - 1)) {
                        size_t entry_len = strlen(entry->d_name);

                        /* does it fit into our buffer? */
                        if (entry_len + dirname_len + 2 < MAXPATHLEN) {
                                /* create the full path.. */
                                memcpy(buf + dirname_len + 1, entry->d_name, entry_len);

                                /* NUL terminate it and */
                                buf[dirname_len + entry_len + 1] = '\0';

                                /* check whether its last access was more than maxlifet ago */
                                if (VCWD_STAT(buf, &sbuf) == 0 &&
                                                (now - sbuf.st_mtime) > maxlifetime) {
                                        VCWD_UNLINK(buf);
                                        nrdels++;
                                }
                        }
                }
        }

        closedir(dir);

        return (nrdels);
}

#define PS_FILES_DATA ps_files *data = PS_GET_MOD_DATA()

PS_OPEN_FUNC(files)
{
        ps_files *data;
        const char *p, *last;
        const char *argv[3];
        int argc = 0;
        size_t dirdepth = 0;
        int filemode = 0600;

        if (*save_path == '\0') {
                /* if save path is an empty string, determine the temporary dir */
                save_path = php_get_temporary_directory();

                if (php_check_open_basedir(save_path TSRMLS_CC)) {
                        return FAILURE;
                }
        }

        /* split up input parameter */
        last = save_path;
        p = strchr(save_path, ';');
        while (p) {
                argv[argc++] = last;
                last = ++p;
                p = strchr(p, ';');
                if (argc > 1) break;
        }
        argv[argc++] = last;

        if (argc > 1) {
                errno = 0;
                dirdepth = (size_t) strtol(argv[0], NULL, 10);
                if (errno == ERANGE) {
                        php_error(E_WARNING, "The first parameter in session.save_path is invalid");
                        return FAILURE;
                }
        }

        if (argc > 2) {
                errno = 0;
                filemode = strtol(argv[1], NULL, 8);
                if (errno == ERANGE || filemode < 0 || filemode > 07777) {
                        php_error(E_WARNING, "The second parameter in session.save_path is invalid");
                        return FAILURE;
                }
        }
        save_path = argv[argc - 1];

        data = ecalloc(1, sizeof(*data));

        data->fd = -1;
        data->dirdepth = dirdepth;
        data->filemode = filemode;
        data->basedir_len = strlen(save_path);
        data->basedir = estrndup(save_path, data->basedir_len);

        if (PS_GET_MOD_DATA()) {
                ps_close_files(mod_data TSRMLS_CC);
        }
        PS_SET_MOD_DATA(data);

        return SUCCESS;
}

PS_CLOSE_FUNC(files)
{
        PS_FILES_DATA;

        ps_files_close(data);

        if (data->lastkey) {
                efree(data->lastkey);
        }

        efree(data->basedir);
        efree(data);
        *mod_data = NULL;

        return SUCCESS;
}

PS_READ_FUNC(files)
{
        long n;
        struct stat sbuf;
        PS_FILES_DATA;

        ps_files_open(data, key TSRMLS_CC);
        if (data->fd < 0) {
                return FAILURE;
        }

        if (fstat(data->fd, &sbuf)) {
                return FAILURE;
        }

        data->st_size = *vallen = sbuf.st_size;

        if (sbuf.st_size == 0) {
                *val = STR_EMPTY_ALLOC();
                return SUCCESS;
        }

        *val = emalloc(sbuf.st_size);

#if defined(HAVE_PREAD)
        n = pread(data->fd, *val, sbuf.st_size, 0);
#else
        lseek(data->fd, 0, SEEK_SET);
        n = read(data->fd, *val, sbuf.st_size);
#endif

        if (n != sbuf.st_size) {
                if (n == -1) {
                        php_error_docref(NULL TSRMLS_CC, E_WARNING, "read failed: %s (%d)", strerror(errno), errno);
                } else {
                        php_error_docref(NULL TSRMLS_CC, E_WARNING, "read returned less bytes than requested");
                }
                efree(*val);
                return FAILURE;
        }

        return SUCCESS;
}

PS_WRITE_FUNC(files)
{
        long n;
        PS_FILES_DATA;

        ps_files_open(data, key TSRMLS_CC);
        if (data->fd < 0) {
                return FAILURE;
        }

        /* Truncate file if the amount of new data is smaller than the existing data set. */

        if (vallen < (int)data->st_size) {
                php_ignore_value(ftruncate(data->fd, 0));
        }

#if defined(HAVE_PWRITE)
        n = pwrite(data->fd, val, vallen, 0);
#else
        lseek(data->fd, 0, SEEK_SET);
        n = write(data->fd, val, vallen);
#endif

        if (n != vallen) {
                if (n == -1) {
                        php_error_docref(NULL TSRMLS_CC, E_WARNING, "write failed: %s (%d)", strerror(errno), errno);
                } else {
                        php_error_docref(NULL TSRMLS_CC, E_WARNING, "write wrote less bytes than requested");
                }
                return FAILURE;
        }

        return SUCCESS;
}

PS_DESTROY_FUNC(files)
{
        char buf[MAXPATHLEN];
        PS_FILES_DATA;

        if (!ps_files_path_create(buf, sizeof(buf), data, key)) {
                return FAILURE;
        }

        if (data->fd != -1) {
                ps_files_close(data);

                if (VCWD_UNLINK(buf) == -1) {
                        /* This is a little safety check for instances when we are dealing with a regenerated session
                         * that was not yet written to disk. */
                        if (!VCWD_ACCESS(buf, F_OK)) {
                                return FAILURE;
                        }
                }
        }

        return SUCCESS;
}

PS_GC_FUNC(files)
{
        PS_FILES_DATA;

        /* we don't perform any cleanup, if dirdepth is larger than 0.
           we return SUCCESS, since all cleanup should be handled by
           an external entity (i.e. find -ctime x | xargs rm) */

        if (data->dirdepth == 0) {
                *nrdels = ps_files_cleanup_dir(data->basedir, maxlifetime TSRMLS_CC);
        }

        return SUCCESS;
}

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 * vim600: sw=4 ts=4 fdm=marker
 * vim<600: sw=4 ts=4
 */

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