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Refine and update blacklist support in sshd

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Adjust notification points slightly to catch all auth failures,
rather than just the ones caused by bad usernames.

Modify notification point for bad usernames to send new type of
BLACKLIST_BAD_USER. (Support in libblacklist will be forthcoming soon.)
Add guards to allow library headers to expose the enum of action values.

Reviewed by:	des
Approved by:	des
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Kurt Lidl 2017-05-12 15:20:12 +00:00
parent b168d62f00
commit 342b8b88ba
8 changed files with 23 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
crypto/openssh/auth-pam.c
View File

@ -799,7 +799,8 @@ sshpam_query(void *ctx, char **name, char **info,
free(msg);
return (0);
}
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
BLACKLIST_NOTIFY(BLACKLIST_BAD_USER,
sshpam_authctxt->user);
error("PAM: %s for %s%.100s from %.100s", msg,
sshpam_authctxt->valid ? "" : "illegal user ",
sshpam_authctxt->user,

4
crypto/openssh/auth.c
View File

@ -311,7 +311,7 @@ auth_log(Authctxt *authctxt, int authenticated, int partial,
else {
authmsg = authenticated ? "Accepted" : "Failed";
if (authenticated)
BLACKLIST_NOTIFY(BLACKLIST_AUTH_OK);
BLACKLIST_NOTIFY(BLACKLIST_AUTH_OK, "ssh");
}
authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
@ -664,7 +664,7 @@ getpwnamallow(const char *user)
}
#endif
if (pw == NULL) {
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
BLACKLIST_NOTIFY(BLACKLIST_BAD_USER, user);
logit("Invalid user %.100s from %.100s port %d",
user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
#ifdef CUSTOM_FAILED_LOGIN

5
crypto/openssh/auth1.c
View File

@ -338,7 +338,7 @@ do_authloop(Authctxt *authctxt)
char *msg;
size_t len;
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
error("Access denied for user %s by PAM account "
"configuration", authctxt->user);
len = buffer_len(&loginmsg);
@ -364,6 +364,7 @@ do_authloop(Authctxt *authctxt)
if (authenticated)
return;
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
if (++authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
@ -406,7 +407,7 @@ do_authentication(Authctxt *authctxt)
else {
debug("do_authentication: invalid user %s", user);
authctxt->pw = fakepw();
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
BLACKLIST_NOTIFY(BLACKLIST_BAD_USER, user);
}
/* Configuration may have changed as a result of Match */

5
crypto/openssh/auth2.c
View File

@ -245,7 +245,6 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
@ -386,8 +385,10 @@ userauth_finish(Authctxt *authctxt, int authenticated, const char *method,
/* Allow initial try of "none" auth without failure penalty */
if (!partial && !authctxt->server_caused_failure &&
(authctxt->attempt > 1 || strcmp(method, "none") != 0))
(authctxt->attempt > 1 || strcmp(method, "none") != 0)) {
authctxt->failures++;
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
}
if (authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));

6
crypto/openssh/blacklist.c
View File

@ -46,8 +46,8 @@
#include "log.h"
#include "misc.h"
#include "servconf.h"
#include "blacklist_client.h"
#include <blacklist.h>
#include "blacklist_client.h"
static struct blacklist *blstate = NULL;
@ -88,10 +88,10 @@ blacklist_init(void)
}
void
blacklist_notify(int action)
blacklist_notify(int action, const char *msg)
{
if (blstate != NULL && packet_connection_is_on_socket())
(void)blacklist_r(blstate, action,
packet_get_connection_in(), "ssh");
packet_get_connection_in(), msg);
}

12
crypto/openssh/blacklist_client.h
View File

@ -34,22 +34,26 @@
#ifndef BLACKLIST_CLIENT_H
#define BLACKLIST_CLIENT_H
#ifndef BLACKLIST_API_ENUM
enum {
BLACKLIST_AUTH_OK = 0,
BLACKLIST_AUTH_FAIL
BLACKLIST_AUTH_FAIL,
BLACKLIST_ABUSIVE_BEHAVIOR,
BLACKLIST_BAD_USER
};
#endif
#ifdef USE_BLACKLIST
void blacklist_init(void);
void blacklist_notify(int);
void blacklist_notify(int, const char *);
#define BLACKLIST_INIT() blacklist_init()
#define BLACKLIST_NOTIFY(x) blacklist_notify(x)
#define BLACKLIST_NOTIFY(x,msg) blacklist_notify(x,msg)
#else
#define BLACKLIST_INIT()
#define BLACKLIST_NOTIFY(x)
#define BLACKLIST_NOTIFY(x,msg)
#endif

2
crypto/openssh/packet.c
View File

@ -2104,7 +2104,7 @@ sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
case SSH_ERR_NO_KEX_ALG_MATCH:
case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
if (ssh && ssh->kex && ssh->kex->failed_choice) {
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
logdie("Unable to negotiate with %.200s port %d: %s. "
"Their offer: %s", ssh_remote_ipaddr(ssh),
ssh_remote_port(ssh), ssh_err(r),

2
crypto/openssh/sshd.c
View File

@ -371,7 +371,7 @@ grace_alarm_handler(int sig)
kill(0, SIGTERM);
}
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
/* Log error and exit. */
sigdie("Timeout before authentication for %s port %d",