view src/os/unix/ngx_user.c @ 5356:acd51b0f6fd4

Disable symlinks: use O_PATH to open path components. It was introduced in Linux 2.6.39, glibc 2.14 and allows to obtain file descriptors without actually opening files. Thus made it possible to traverse path with openat() syscalls without the need to have read permissions for path components. It is effectively emulates O_SEARCH which is missing on Linux. O_PATH is used in combination with O_RDONLY. The last one is ignored if O_PATH is used, but it allows nginx to not fail when it was built on modern system (i.e. glibc 2.14+) and run with a kernel older than 2.6.39. Then O_PATH is unknown to the kernel and ignored, while O_RDONLY is used. Sadly, fstat() is not working with O_PATH descriptors till Linux 3.6. As a workaround we fallback to fstatat() with the AT_EMPTY_PATH flag that was introduced at the same time as O_PATH.
author Valentin Bartenev <vbart@nginx.com>
date Mon, 02 Sep 2013 08:07:59 +0400
parents 6ccd3a50b40f
children fd6fd02f6a4d
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


/*
 * Solaris has thread-safe crypt()
 * Linux has crypt_r(); "struct crypt_data" is more than 128K
 * FreeBSD needs the mutex to protect crypt()
 *
 * TODO:
 *     ngx_crypt_init() to init mutex
 */


#if (NGX_CRYPT)

#if (NGX_HAVE_GNU_CRYPT_R)

ngx_int_t
ngx_libc_crypt(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
{
    char               *value;
    size_t              len;
    struct crypt_data   cd;

    cd.initialized = 0;
    /* work around the glibc bug */
    cd.current_salt[0] = ~salt[0];

    value = crypt_r((char *) key, (char *) salt, &cd);

    if (value) {
        len = ngx_strlen(value) + 1;

        *encrypted = ngx_pnalloc(pool, len);
        if (*encrypted == NULL) {
            return NGX_ERROR;
        }

        ngx_memcpy(*encrypted, value, len);
        return NGX_OK;
    }

    ngx_log_error(NGX_LOG_CRIT, pool->log, ngx_errno, "crypt_r() failed");

    return NGX_ERROR;
}

#else

ngx_int_t
ngx_libc_crypt(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
{
    char       *value;
    size_t      len;
    ngx_err_t   err;

#if (NGX_THREADS && NGX_NONREENTRANT_CRYPT)

    /* crypt() is a time consuming function, so we only try to lock */

    if (ngx_mutex_trylock(ngx_crypt_mutex) != NGX_OK) {
        return NGX_AGAIN;
    }

#endif

    value = crypt((char *) key, (char *) salt);

    if (value) {
        len = ngx_strlen(value) + 1;

        *encrypted = ngx_pnalloc(pool, len);
        if (*encrypted == NULL) {
#if (NGX_THREADS && NGX_NONREENTRANT_CRYPT)
            ngx_mutex_unlock(ngx_crypt_mutex);
#endif
            return NGX_ERROR;
        }

        ngx_memcpy(*encrypted, value, len);
#if (NGX_THREADS && NGX_NONREENTRANT_CRYPT)
        ngx_mutex_unlock(ngx_crypt_mutex);
#endif
        return NGX_OK;
    }

    err = ngx_errno;

#if (NGX_THREADS && NGX_NONREENTRANT_CRYPT)
    ngx_mutex_unlock(ngx_crypt_mutex);
#endif

    ngx_log_error(NGX_LOG_CRIT, pool->log, err, "crypt() failed");

    return NGX_ERROR;
}

#endif

#endif /* NGX_CRYPT */