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DES pointed out that the PAM layer may change the target user name

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during authentication.  Thus we need to call getpwnam *after* the user
has been authenticated.  Colin mentioned that we should also move the
check for root in that case.
This commit is contained in:
Jacques Vidrine 2005-04-05 14:55:33 +00:00
parent bbccd83251
commit 5251901c93
1 changed files with 32 additions and 15 deletions
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47
libexec/rexecd/rexecd.c
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@ -86,6 +86,8 @@ char default_shell[] = _PATH_BSHELL;
static void doit(struct sockaddr *);
static void getstr(char *, int, const char *);
static void error(const char *fmt, ...);
static struct passwd *xgetpwnam(const char *, struct passwd *, char **,
size_t *);
int no_uid_0 = 1;
@ -192,25 +194,16 @@ doit(struct sockaddr *fromp)
getstr(cmdbuf, maxcmdlen, "command");
(void) alarm(0);
pwdbuflen = BUFSIZ;
pwdbuflen = 0;
pwdbuf = NULL;
pwd = NULL;
r = ERANGE;
while (pwd == NULL && r == ERANGE) {
pwdbuflen <<= 1;
if ((pwdbuf = reallocf(pwdbuf, pwdbuflen)) == NULL) {
syslog(LOG_ERR, "Cannot allocate memory");
error("Cannot allocate memory.\n");
exit(1);
}
r = getpwnam_r(user, &pwd_storage, pwdbuf, pwdbuflen, &pwd);
}
if (pwd == NULL || (pwd->pw_uid == 0 && no_uid_0) ||
!pam_ok(pam_start("rexecd", user, &pamc, &pamh)) ||
if (!pam_ok(pam_start("rexecd", user, &pamc, &pamh)) ||
!pam_ok(pam_set_item(pamh, PAM_RHOST, remote)) ||
!pam_ok(pam_set_item(pamh, PAM_AUTHTOK, pass)) ||
!pam_ok(pam_authenticate(pamh, pam_flags)) ||
!pam_ok(pam_acct_mgmt(pamh, pam_flags))) {
!pam_ok(pam_acct_mgmt(pamh, pam_flags)) ||
!pam_ok(pam_get_item(pamh, PAM_USER, (const void **)&user)) ||
(pwd = xgetpwnam(user, &pwd_storage, &pwdbuf,
&pwdbuflen)) == NULL || (pwd->pw_uid == 0 && no_uid_0)) {
syslog(LOG_ERR, "%s LOGIN REFUSED from %s", user, remote);
error("Login incorrect.\n");
exit(1);
@ -335,3 +328,27 @@ getstr(char *buf, int cnt, const char *field)
}
} while (c != 0);
}
static struct passwd *
xgetpwnam(const char *user, struct passwd *pwd_storage, char **pwdbuf,
size_t *pwdbuflen)
{
struct passwd *pwd;
size_t needed;
int rv;
needed = (*pwdbuflen == 0) ? BUFSIZ : *pwdbuflen;
pwd = NULL;
do {
if (needed != *pwdbuflen) {
if ((*pwdbuf = reallocf(*pwdbuf, needed)) == NULL) {
syslog(LOG_ERR, "Cannot allocate memory");
error("Cannot allocate memory.\n");
exit(1);
} else
*pwdbuflen = needed;
}
rv = getpwnam_r(user, pwd_storage, *pwdbuf, *pwdbuflen, &pwd);
} while (pwd == NULL && rv == ERANGE && (needed <<= 1));
return pwd;
}