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/* See LICENSE file for copyright and license details. */
#include "common.h"
static const char *
get_expected(void)
{
struct passwd *pwd;
struct spwd *shdw;
const char *expected;
errno = 0;
pwd = getpwuid(getuid());
if (!pwd || !pwd->pw_name || !*pwd->pw_name) {
if (errno)
fprintf(stderr, "%s: getpwuid: %s\n", argv0, strerror(errno));
else
fprintf(stderr, "%s: your user does not exist\n", argv0);
exit(EXIT_ERROR);
}
shdw = getspnam(pwd->pw_name);
if (!shdw || !shdw->sp_pwdp) {
if (errno)
fprintf(stderr, "%s: getspnam: %s\n", argv0, strerror(errno));
else
fprintf(stderr, "%s: your user does not have a shadow entry\n", argv0);
exit(EXIT_ERROR);
}
expected = shdw->sp_pwdp;
if (!*expected) {
fprintf(stderr, "%s: your user does not have a password\n", argv0);
exit(EXIT_ERROR);
} else if (expected[expected[0] == '!'] == '*' || expected[expected[0] == '!'] == 'x') {
fprintf(stderr, "%s: login to your account is disabled\n", argv0);
exit(EXIT_ERROR);
} else if (expected[0] == '!') {
fprintf(stderr, "%s: your account is currently locked\n", argv0);
exit(EXIT_ERROR);
}
return expected;
}
static void
set_environ(void)
{
char *str;
size_t len;
struct passwd *pw;
errno = 0;
pw = getpwuid(0);
if (!pw) {
if (errno)
fprintf(stderr, "%s: getpwuid 0: %s\n", argv0, strerror(errno));
else
fprintf(stderr, "%s: cannot find root user\n", argv0);
exit(EXIT_ERROR);
}
libenv_select_variable_list((const char **)(void *)environ, LIBENV_SU_SAFE, LIBENV_END);
if (pw->pw_dir && *pw->pw_dir) {
if (setenv("HOME", pw->pw_dir, 1))
fprintf(stderr, "%s: setenv HOME %s 1: %s\n", argv0, pw->pw_dir, strerror(errno));
}
if (pw->pw_name && *pw->pw_name) {
if (setenv("LOGNAME", pw->pw_name, 1))
fprintf(stderr, "%s: setenv LOGNAME %s 1: %s\n", argv0, pw->pw_name, strerror(errno));
if (setenv("USER", pw->pw_name, 1))
fprintf(stderr, "%s: setenv USER %s 1: %s\n", argv0, pw->pw_name, strerror(errno));
len = sizeof("/var/spool/mail/") + strlen(pw->pw_name);
str = malloc(len);
if (!str)
fprintf(stderr, "%s: malloc %zu: %s\n", argv0, len, strerror(errno));
stpcpy(stpcpy(str, "/var/spool/mail/"), pw->pw_name);
if (setenv("MAIL", str, 1))
fprintf(stderr, "%s: setenv MAIL %s 1: %s\n", argv0, str, strerror(errno));
free(str);
}
if (pw->pw_shell && *pw->pw_shell) {
if (setenv("SHELL", pw->pw_shell, 1))
fprintf(stderr, "%s: setenv SHELL %s 1: %s\n", argv0, pw->pw_shell, strerror(errno));
}
}
static int
get_passphrase_fd(void)
{
const char *env;
long int r;
char *end;
int fd, value;
env = getenv("GASROOT_PASSFD");
if (!env) {
fprintf(stderr, "%s: GASROOT_PASSFD environment variable not set\n", argv0);
exit(EXIT_ERROR);
}
if (!isdigit(env[0])) {
invalid:
fprintf(stderr, "%s: GASROOT_PASSFD environment variable is improperly configured\n", argv0);
exit(EXIT_ERROR);
}
errno = 0;
r = strtol(env, &end, 10);
if (errno || (*end && *end != ':') || r < 0)
goto invalid;
#if INT_MAX < LONG_MAX
if (r > INT_MAX)
goto invalid;
#endif
fd = (int)r;
if (getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &value, &(socklen_t){(socklen_t)sizeof(value)})) {
if (errno == EBADF)
goto invalid;
fprintf(stderr, "%s: getsockopt ${GASROOT_PASSFD} SOL_SOCKET SO_DOMAIN: %s\n", argv0, strerror(errno));
exit(EXIT_ERROR);
}
if (value != PF_UNIX)
goto invalid;
if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &value, &(socklen_t){(socklen_t)sizeof(value)})) {
if (errno == EBADF)
goto invalid;
fprintf(stderr, "%s: getsockopt ${GASROOT_PASSFD} SOL_SOCKET SO_TYPE: %s\n", argv0, strerror(errno));
exit(EXIT_ERROR);
}
if (value != SOCK_STREAM)
goto invalid;
if (!*end) {
unsetenv("GASROOT_PASSFD");
} else if (setenv("GASROOT_PASSFD", &end[1], 1)) {
fprintf(stderr, "%s: setenv: %s\n", argv0, strerror(errno));
exit(EXIT_ERROR);
}
return fd;
}
static void
senddata(int fd, const char *text, size_t len)
{
ssize_t r;
while (len) {
r = send(fd, text, len, 0);
if (r < 0) {
if (errno == EINTR)
continue;
fprintf(stderr, "%s: send <graphical interface> %zu 0: %s\n", argv0, len, strerror(errno));
exit(EXIT_ERROR);
}
text = &text[r];
len -= (size_t)r;
}
}
#define sendtext(FD, TEXT) senddata(FD, TEXT, sizeof(TEXT))
static void
recvtext(int fd, char **bufp, size_t *sizep)
{
size_t len = 0;
ssize_t r;
do {
if (len + 2048UL > *sizep) {
*sizep = len + 2048UL;
*bufp = realloc(*bufp, *sizep);
if (!*bufp) {
fprintf(stderr, "%s: realloc %zu: %s\n", argv0, *sizep, strerror(errno));
exit(EXIT_ERROR);
}
}
again:
r = recv(fd, &(*bufp)[len], *sizep - len, 0);
if (r < 0) {
if (errno == EINTR)
goto again;
fprintf(stderr, "%s: recv <graphical interface> %zu 0: %s\n", argv0, *sizep - len, strerror(errno));
exit(EXIT_ERROR);
} else if (!r) {
exit(EXIT_ERROR);
}
if (memchr(&(*bufp)[len], 0, (size_t)r - 1U)) {
fprintf(stderr, "%s: protocol error in communication with graphical interface\n", argv0);
exit(EXIT_ERROR);
}
len += (size_t)r;
} while ((*bufp)[len - 1U]);
}
int
main(int argc, char *argv[])
{
int keep_env = 0;
int fd;
char *passphrase = NULL;
size_t passphrase_size = 0;
const char *expected;
ARGBEGIN {
case 'e':
keep_env = 1;
break;
default:
usage();
} ARGEND;
if (!argc)
usage();
fd = get_passphrase_fd();
expected = get_expected();
sendtext(fd, "HELLO");
for (;;) {
recvtext(fd, &passphrase, &passphrase_size);
if (!strcmp(crypt(passphrase, expected), expected))
break;
wipe(passphrase);
#if RETRY_SLEEP > 0
sendtext(fd, "BLOCK");
sleep(RETRY_SLEEP);
#endif
sendtext(fd, "RETRY");
}
wipe(passphrase);
free(passphrase);
sendtext(fd, "OK");
close(fd);
if (!keep_env)
set_environ();
if (setgid(0)) {
fprintf(stderr, "%s: setgid 0: %s\n", argv0, strerror(errno));
exit(EXIT_ERROR);
}
if (setuid(0)) {
fprintf(stderr, "%s: setuid 0: %s\n", argv0, strerror(errno));
exit(EXIT_ERROR);
}
execvp(argv[0], argv);
fprintf(stderr, "%s: execvpe %s: %s\n", argv0, argv[0], strerror(errno));
return errno == ENOENT ? EXIT_NOENT : EXIT_EXEC;
}
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