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/*-
* Copyright (c) 2011 Dag-Erling Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: openpam_subst.c 461 2011-11-02 14:00:38Z des $
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <security/pam_appl.h>
#include "openpam_impl.h"
#define subst_char(ch) do { \
int ch_ = (ch); \
if (buf && len < *bufsize) \
*buf++ = ch_; \
++len; \
} while (0)
#define subst_string(s) do { \
const char *s_ = (s); \
while (*s_) \
subst_char(*s_++); \
} while (0)
#define subst_item(i) do { \
int i_ = (i); \
const void *p_; \
ret = pam_get_item(pamh, i_, &p_); \
if (ret == PAM_SUCCESS && p_ != NULL) \
subst_string(p_); \
} while (0)
/*
* OpenPAM internal
*
* Substitute PAM item values in a string
*/
int
openpam_subst(const pam_handle_t *pamh,
char *buf, size_t *bufsize, const char *template)
{
size_t len;
int ret;
ENTERS(template);
if (template == NULL)
template = "(null)";
len = 1; /* initialize to 1 for terminating NUL */
ret = PAM_SUCCESS;
while (*template && ret == PAM_SUCCESS) {
if (template[0] == '%') {
++template;
switch (*template) {
case 's':
subst_item(PAM_SERVICE);
break;
case 't':
subst_item(PAM_TTY);
break;
case 'h':
subst_item(PAM_HOST);
break;
case 'u':
subst_item(PAM_USER);
break;
case 'H':
subst_item(PAM_RHOST);
break;
case 'U':
subst_item(PAM_RUSER);
break;
case '\0':
subst_char('%');
break;
default:
subst_char('%');
subst_char(*template);
}
++template;
} else {
subst_char(*template++);
}
}
if (buf)
*buf = '\0';
if (ret == PAM_SUCCESS) {
if (len > *bufsize)
ret = PAM_TRY_AGAIN;
*bufsize = len;
}
RETURNC(ret);
}
/*
* Error codes:
*
* =pam_get_item
* !PAM_SYMBOL_ERR
* PAM_TRY_AGAIN
*/
/**
* The =openpam_subst function expands a string, substituting PAM item
* values for all occurrences of specific substitution codes.
* The =template argument points to the initial string.
* The result is stored in the buffer pointed to by the =buf argument; the
* =bufsize argument specifies the size of that buffer.
* The actual size of the resulting string, including the terminating NUL
* character, is stored in the location pointed to by the =bufsize
* argument.
*
* If =buf is NULL, or if the buffer is too small to hold the expanded
* string, =bufsize is updated to reflect the amount of space required to
* hold the entire string, and =openpam_subst returns =PAM_TRY_AGAIN.
*
* If =openpam_subst fails for any other reason, the =bufsize argument is
* untouched, but part of the buffer may still have been overwritten.
*
* Substitution codes are introduced by a percent character and correspond
* to PAM items:
*
* %H:
* Replaced by the current value of the =PAM_RHOST item.
* %h:
* Replaced by the current value of the =PAM_HOST item.
* %s:
* Replaced by the current value of the =PAM_SERVICE item.
* %t:
* Replaced by the current value of the =PAM_TTY item.
* %U:
* Replaced by the current value of the =PAM_RUSER item.
* %u:
* Replaced by the current value of the =PAM_USER item.
*
* >pam_get_authtok
* >pam_get_item
* >pam_get_user
*
* AUTHOR DES
*/
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