* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
+/*
+ * Copyright (c) 2003,2004 Damien Miller <djm@mindrot.org>
+ * Copyright (c) 2003,2004 Darren Tucker <dtucker@zip.com.au>
+ *
+ * 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.
+ */
/* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
#include "includes.h"
#include "monitor_wrap.h"
#include "msg.h"
#include "packet.h"
-#include "readpass.h"
+#include "misc.h"
#include "servconf.h"
#include "ssh2.h"
#include "xmalloc.h"
static void
sshpam_sigchld_handler(int sig)
{
+ signal(SIGCHLD, SIG_DFL);
if (cleanup_ctxt == NULL)
return; /* handler called after PAM cleanup, shouldn't happen */
- if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) == -1)
- return; /* couldn't wait for process */
+ if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
+ <= 0) {
+ /* PAM thread has not exitted, privsep slave must have */
+ kill(cleanup_ctxt->pam_thread, SIGTERM);
+ if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0)
+ <= 0)
+ return; /* could not wait */
+ }
if (WIFSIGNALED(sshpam_thread_status) &&
WTERMSIG(sshpam_thread_status) == SIGTERM)
return; /* terminated by pthread_cancel */
static int sshpam_account_status = -1;
static char **sshpam_env = NULL;
static Authctxt *sshpam_authctxt = NULL;
+static const char *sshpam_password = NULL;
+static char badpw[] = "\b\n\r\177INCORRECT";
/* Some PAM implementations don't implement this */
#ifndef HAVE_PAM_GETENVLIST
}
#endif
+/*
+ * Some platforms, notably Solaris, do not enforce password complexity
+ * rules during pam_chauthtok() if the real uid of the calling process
+ * is 0, on the assumption that it's being called by "passwd" run by root.
+ * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
+ * the right thing.
+ */
+#ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
+static int
+sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
+{
+ int result;
+
+ if (sshpam_authctxt == NULL)
+ fatal("PAM: sshpam_authctxt not initialized");
+ if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
+ fatal("%s: setreuid failed: %s", __func__, strerror(errno));
+ result = pam_chauthtok(pamh, flags);
+ if (setreuid(0, -1) == -1)
+ fatal("%s: setreuid failed: %s", __func__, strerror(errno));
+ return result;
+}
+# define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b)))
+#endif
+
void
-pam_password_change_required(int reqd)
+sshpam_password_change_required(int reqd)
{
debug3("%s %d", __func__, reqd);
if (sshpam_authctxt == NULL)
#ifndef USE_POSIX_THREADS
/* Import variables set by do_pam_account */
sshpam_account_status = buffer_get_int(b);
- pam_password_change_required(buffer_get_int(b));
+ sshpam_password_change_required(buffer_get_int(b));
/* Import environment from subprocess */
num_env = buffer_get_int(b);
* Conversation function for authentication thread.
*/
static int
-sshpam_thread_conv(int n, const struct pam_message **msg,
+sshpam_thread_conv(int n, struct pam_message **msg,
struct pam_response **resp, void *data)
{
Buffer buffer;
debug3("PAM: %s entering, %d messages", __func__, n);
*resp = NULL;
+ if (data == NULL) {
+ error("PAM: conversation function passed a null context");
+ return (PAM_CONV_ERR);
+ }
ctxt = data;
if (n <= 0 || n > PAM_MAX_NUM_MSG)
return (PAM_CONV_ERR);
struct pam_ctxt *ctxt = ctxtp;
Buffer buffer;
struct pam_conv sshpam_conv;
+ int flags = (options.permit_empty_passwd == 0 ?
+ PAM_DISALLOW_NULL_AUTHTOK : 0);
#ifndef USE_POSIX_THREADS
extern char **environ;
char **env_from_pam;
u_int i;
const char *pam_user;
- pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
- setproctitle("%s [pam]", pam_user);
+ pam_get_item(sshpam_handle, PAM_USER, (void **)&pam_user);
environ[0] = NULL;
+
+ if (sshpam_authctxt != NULL) {
+ setproctitle("%s [pam]",
+ sshpam_authctxt->valid ? pam_user : "unknown");
+ }
#endif
sshpam_conv.conv = sshpam_thread_conv;
(const void *)&sshpam_conv);
if (sshpam_err != PAM_SUCCESS)
goto auth_fail;
- sshpam_err = pam_authenticate(sshpam_handle, 0);
+ sshpam_err = pam_authenticate(sshpam_handle, flags);
if (sshpam_err != PAM_SUCCESS)
goto auth_fail;
PAM_CHANGE_EXPIRED_AUTHTOK);
if (sshpam_err != PAM_SUCCESS)
goto auth_fail;
- pam_password_change_required(0);
+ sshpam_password_change_required(0);
}
}
}
static int
-sshpam_null_conv(int n, const struct pam_message **msg,
+sshpam_null_conv(int n, struct pam_message **msg,
struct pam_response **resp, void *data)
{
debug3("PAM: %s entering, %d messages", __func__, n);
static struct pam_conv null_conv = { sshpam_null_conv, NULL };
+static int
+sshpam_store_conv(int n, struct pam_message **msg,
+ struct pam_response **resp, void *data)
+{
+ struct pam_response *reply;
+ int i;
+ size_t len;
+
+ debug3("PAM: %s called with %d messages", __func__, n);
+ *resp = NULL;
+
+ if (n <= 0 || n > PAM_MAX_NUM_MSG)
+ return (PAM_CONV_ERR);
+
+ if ((reply = malloc(n * sizeof(*reply))) == NULL)
+ return (PAM_CONV_ERR);
+ memset(reply, 0, n * sizeof(*reply));
+
+ for (i = 0; i < n; ++i) {
+ switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
+ case PAM_ERROR_MSG:
+ case PAM_TEXT_INFO:
+ len = strlen(PAM_MSG_MEMBER(msg, i, msg));
+ buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
+ buffer_append(&loginmsg, "\n", 1 );
+ reply[i].resp_retcode = PAM_SUCCESS;
+ break;
+ default:
+ goto fail;
+ }
+ }
+ *resp = reply;
+ return (PAM_SUCCESS);
+
+ fail:
+ for(i = 0; i < n; i++) {
+ if (reply[i].resp != NULL)
+ xfree(reply[i].resp);
+ }
+ xfree(reply);
+ return (PAM_CONV_ERR);
+}
+
+static struct pam_conv store_conv = { sshpam_store_conv, NULL };
+
void
sshpam_cleanup(void)
{
if (sshpam_handle != NULL) {
/* We already have a PAM context; check if the user matches */
sshpam_err = pam_get_item(sshpam_handle,
- PAM_USER, (const void **)&pam_user);
+ PAM_USER, (void **)&pam_user);
if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
return (0);
pam_end(sshpam_handle, sshpam_err);
}
debug("PAM: initializing for \"%s\"", user);
sshpam_err =
- pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
+ pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
sshpam_authctxt = authctxt;
if (sshpam_err != PAM_SUCCESS) {
size_t plen;
u_char type;
char *msg;
- size_t len;
+ size_t len, mlen;
debug3("PAM: %s entering", __func__);
buffer_init(&buffer);
while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
type = buffer_get_char(&buffer);
msg = buffer_get_string(&buffer, NULL);
+ mlen = strlen(msg);
switch (type) {
case PAM_PROMPT_ECHO_ON:
case PAM_PROMPT_ECHO_OFF:
*num = 1;
- len = plen + strlen(msg) + 1;
+ len = plen + mlen + 1;
**prompts = xrealloc(**prompts, len);
- plen += snprintf(**prompts + plen, len, "%s", msg);
+ strlcpy(**prompts + plen, msg, len - plen);
+ plen += mlen;
**echo_on = (type == PAM_PROMPT_ECHO_ON);
xfree(msg);
return (0);
case PAM_ERROR_MSG:
case PAM_TEXT_INFO:
/* accumulate messages */
- len = plen + strlen(msg) + 2;
+ len = plen + mlen + 2;
**prompts = xrealloc(**prompts, len);
- plen += snprintf(**prompts + plen, len, "%s\n", msg);
+ strlcpy(**prompts + plen, msg, len - plen);
+ plen += mlen;
+ strlcat(**prompts + plen, "\n", len - plen);
+ plen++;
xfree(msg);
break;
case PAM_SUCCESS:
**prompts = NULL;
}
if (type == PAM_SUCCESS) {
+ if (!sshpam_authctxt->valid ||
+ (sshpam_authctxt->pw->pw_uid == 0 &&
+ options.permit_root_login != PERMIT_YES))
+ fatal("Internal error: PAM auth "
+ "succeeded when it should have "
+ "failed");
import_environments(&buffer);
*num = 0;
**echo_on = 0;
return (-1);
}
buffer_init(&buffer);
- buffer_put_cstring(&buffer, *resp);
+ if (sshpam_authctxt->valid &&
+ (sshpam_authctxt->pw->pw_uid != 0 ||
+ options.permit_root_login == PERMIT_YES))
+ buffer_put_cstring(&buffer, *resp);
+ else
+ buffer_put_cstring(&buffer, badpw);
if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
buffer_free(&buffer);
return (-1);
u_int
do_pam_account(void)
{
+ debug("%s: called", __func__);
if (sshpam_account_status != -1)
return (sshpam_account_status);
sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
- debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
+ debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err,
+ pam_strerror(sshpam_handle, sshpam_err));
if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
sshpam_account_status = 0;
}
if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
- pam_password_change_required(1);
+ sshpam_password_change_required(1);
sshpam_account_status = 1;
return (sshpam_account_status);
do_pam_setcred(int init)
{
sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
- (const void *)&null_conv);
+ (const void *)&store_conv);
if (sshpam_err != PAM_SUCCESS)
fatal("PAM: failed to set PAM_CONV: %s",
pam_strerror(sshpam_handle, sshpam_err));
}
static int
-pam_tty_conv(int n, const struct pam_message **msg,
+sshpam_tty_conv(int n, struct pam_message **msg,
struct pam_response **resp, void *data)
{
char input[PAM_MAX_MSG_SIZE];
case PAM_PROMPT_ECHO_ON:
fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
fgets(input, sizeof input, stdin);
- reply[i].resp = xstrdup(input);
+ if ((reply[i].resp = strdup(input)) == NULL)
+ goto fail;
reply[i].resp_retcode = PAM_SUCCESS;
break;
case PAM_ERROR_MSG:
return (PAM_CONV_ERR);
}
-static struct pam_conv tty_conv = { pam_tty_conv, NULL };
+static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
/*
* XXX this should be done in the authentication phase, but ssh1 doesn't
pam_strerror(sshpam_handle, sshpam_err));
}
-static int
-pam_store_conv(int n, const struct pam_message **msg,
- struct pam_response **resp, void *data)
-{
- struct pam_response *reply;
- int i;
- size_t len;
-
- debug3("PAM: %s called with %d messages", __func__, n);
- *resp = NULL;
-
- if (n <= 0 || n > PAM_MAX_NUM_MSG)
- return (PAM_CONV_ERR);
-
- if ((reply = malloc(n * sizeof(*reply))) == NULL)
- return (PAM_CONV_ERR);
- memset(reply, 0, n * sizeof(*reply));
-
- for (i = 0; i < n; ++i) {
- switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
- case PAM_ERROR_MSG:
- case PAM_TEXT_INFO:
- len = strlen(PAM_MSG_MEMBER(msg, i, msg));
- buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
- buffer_append(&loginmsg, "\n", 1 );
- reply[i].resp_retcode = PAM_SUCCESS;
- break;
- default:
- goto fail;
- }
- }
- *resp = reply;
- return (PAM_SUCCESS);
-
- fail:
- for(i = 0; i < n; i++) {
- if (reply[i].resp != NULL)
- xfree(reply[i].resp);
- }
- xfree(reply);
- return (PAM_CONV_ERR);
-}
-
-static struct pam_conv store_conv = { pam_store_conv, NULL };
-
void
do_pam_session(void)
{
fatal("PAM: failed to set PAM_CONV: %s",
pam_strerror(sshpam_handle, sshpam_err));
sshpam_err = pam_open_session(sshpam_handle, 0);
- if (sshpam_err != PAM_SUCCESS)
- fatal("PAM: pam_open_session(): %s",
+ if (sshpam_err == PAM_SUCCESS)
+ sshpam_session_open = 1;
+ else {
+ sshpam_session_open = 0;
+ disable_forwarding();
+ error("PAM: pam_open_session(): %s",
pam_strerror(sshpam_handle, sshpam_err));
- sshpam_session_open = 1;
+ }
+
+}
+
+int
+is_pam_session_open(void)
+{
+ return sshpam_session_open;
}
/*
xfree(env);
}
+/*
+ * "Blind" conversation function for password authentication. Assumes that
+ * echo-off prompts are for the password and stores messages for later
+ * display.
+ */
+static int
+sshpam_passwd_conv(int n, struct pam_message **msg,
+ struct pam_response **resp, void *data)
+{
+ struct pam_response *reply;
+ int i;
+ size_t len;
+
+ debug3("PAM: %s called with %d messages", __func__, n);
+
+ *resp = NULL;
+
+ if (n <= 0 || n > PAM_MAX_NUM_MSG)
+ return (PAM_CONV_ERR);
+
+ if ((reply = malloc(n * sizeof(*reply))) == NULL)
+ return (PAM_CONV_ERR);
+ memset(reply, 0, n * sizeof(*reply));
+
+ for (i = 0; i < n; ++i) {
+ switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
+ case PAM_PROMPT_ECHO_OFF:
+ if (sshpam_password == NULL)
+ goto fail;
+ if ((reply[i].resp = strdup(sshpam_password)) == NULL)
+ goto fail;
+ reply[i].resp_retcode = PAM_SUCCESS;
+ break;
+ case PAM_ERROR_MSG:
+ case PAM_TEXT_INFO:
+ len = strlen(PAM_MSG_MEMBER(msg, i, msg));
+ if (len > 0) {
+ buffer_append(&loginmsg,
+ PAM_MSG_MEMBER(msg, i, msg), len);
+ buffer_append(&loginmsg, "\n", 1);
+ }
+ if ((reply[i].resp = strdup("")) == NULL)
+ goto fail;
+ reply[i].resp_retcode = PAM_SUCCESS;
+ break;
+ default:
+ goto fail;
+ }
+ }
+ *resp = reply;
+ return (PAM_SUCCESS);
+
+ fail:
+ for(i = 0; i < n; i++) {
+ if (reply[i].resp != NULL)
+ xfree(reply[i].resp);
+ }
+ xfree(reply);
+ return (PAM_CONV_ERR);
+}
+
+static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL };
+
+/*
+ * Attempt password authentication via PAM
+ */
+int
+sshpam_auth_passwd(Authctxt *authctxt, const char *password)
+{
+ int flags = (options.permit_empty_passwd == 0 ?
+ PAM_DISALLOW_NULL_AUTHTOK : 0);
+
+ if (!options.use_pam || sshpam_handle == NULL)
+ fatal("PAM: %s called when PAM disabled or failed to "
+ "initialise.", __func__);
+
+ sshpam_password = password;
+ sshpam_authctxt = authctxt;
+
+ /*
+ * If the user logging in is invalid, or is root but is not permitted
+ * by PermitRootLogin, use an invalid password to prevent leaking
+ * information via timing (eg if the PAM config has a delay on fail).
+ */
+ if (!authctxt->valid || (authctxt->pw->pw_uid == 0 &&
+ options.permit_root_login != PERMIT_YES))
+ sshpam_password = badpw;
+
+ sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
+ (const void *)&passwd_conv);
+ if (sshpam_err != PAM_SUCCESS)
+ fatal("PAM: %s: failed to set PAM_CONV: %s", __func__,
+ pam_strerror(sshpam_handle, sshpam_err));
+
+ sshpam_err = pam_authenticate(sshpam_handle, flags);
+ sshpam_password = NULL;
+ if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
+ debug("PAM: password authentication accepted for %.100s",
+ authctxt->user);
+ return 1;
+ } else {
+ debug("PAM: password authentication failed for %.100s: %s",
+ authctxt->valid ? authctxt->user : "an illegal user",
+ pam_strerror(sshpam_handle, sshpam_err));
+ return 0;
+ }
+}
#endif /* USE_PAM */
andersk / openssh.git / blobdiff