diff options
Diffstat (limited to 'lib/openpam_subst.c')
| -rw-r--r-- | lib/openpam_subst.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/lib/openpam_subst.c b/lib/openpam_subst.c new file mode 100644 index 0000000..d54b827 --- /dev/null +++ b/lib/openpam_subst.c @@ -0,0 +1,168 @@ +/*- + * 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 + */ |
