sudo/lib/util/getusershell.c

146 lines
3.3 KiB
C

/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2019-2020 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sudo_compat.h>
#include <sudo_debug.h>
#include <sudo_util.h>
#ifdef TESTSUDOERS
# include <tsgetgrpw.h>
#endif
static const char *shellfile = "/etc/shell";
static char **allowed_shells, * const *current_shell;
static const char *default_shells[] = {
"/bin/sh",
"/bin/ksh",
"/bin/ksh93",
"/bin/bash",
"/bin/dash",
"/bin/zsh",
"/bin/csh",
"/bin/tcsh",
NULL
};
static char **
read_shells(void)
{
size_t maxshells = 16, nshells = 0;
size_t linesize = 0;
char *line = NULL;
FILE *fp;
debug_decl(read_shells, SUDO_DEBUG_UTIL);
if ((fp = fopen(shellfile, "r")) == NULL)
goto bad;
free(allowed_shells);
allowed_shells = reallocarray(NULL, maxshells, sizeof(char *));
if (allowed_shells == NULL)
goto bad;
while (sudo_parseln(&line, &linesize, NULL, fp, PARSELN_CONT_IGN) != -1) {
if (nshells + 1 >= maxshells) {
char **new_shells;
new_shells = reallocarray(NULL, maxshells + 16, sizeof(char *));
if (new_shells == NULL)
goto bad;
allowed_shells = new_shells;
maxshells += 16;
}
if ((allowed_shells[nshells] = strdup(line)) == NULL)
goto bad;
nshells++;
}
allowed_shells[nshells] = NULL;
free(line);
fclose(fp);
debug_return_ptr(allowed_shells);
bad:
free(line);
if (fp != NULL)
fclose(fp);
while (nshells != 0)
free(allowed_shells[--nshells]);
free(allowed_shells);
allowed_shells = NULL;
debug_return_ptr(default_shells);
}
void
sudo_setusershell(void)
{
debug_decl(setusershell, SUDO_DEBUG_UTIL);
current_shell = read_shells();
debug_return;
}
void
sudo_endusershell(void)
{
debug_decl(endusershell, SUDO_DEBUG_UTIL);
if (allowed_shells != NULL) {
char **shell;
for (shell = allowed_shells; *shell != NULL; shell++)
free(*shell);
free(allowed_shells);
allowed_shells = NULL;
}
current_shell = NULL;
debug_return;
}
char *
sudo_getusershell(void)
{
debug_decl(getusershell, SUDO_DEBUG_UTIL);
if (current_shell == NULL)
current_shell = read_shells();
debug_return_str(*current_shell++);
}
#ifdef TESTSUDOERS
void
testsudoers_setshellfile(const char *file)
{
testsudoers_endusershell();
shellfile = file;
}
#endif /* TESTSUDOERS */