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a864d61df9
openssh/openssh-5.8p1-audit5.patch
Jan F a864d61df9 improve session keys audit
2011-03-10 15:52:21 +01:00

500 lines
16 KiB
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diff -up openssh-5.8p1/audit-bsm.c.audit5 openssh-5.8p1/audit-bsm.c
--- openssh-5.8p1/audit-bsm.c.audit5 2011-03-10 11:58:54.075979941 +0100
+++ openssh-5.8p1/audit-bsm.c 2011-03-10 11:58:55.029855000 +0100
@@ -414,4 +414,22 @@ audit_session_key_free_body(int ctos, pi
{
/* not implemented */
}
+
+void
+audit_destroy_sensitive_data(const char *fp)
+{
+ /* not implemented */
+}
+
+void
+audit_destroy_sensitive_data(const char *fp, pid_t pid, uid_t uid)
+{
+ /* not implemented */
+}
+
+void
+audit_generate_ephemeral_server_key(const char *fp)
+{
+ /* not implemented */
+}
#endif /* BSM */
diff -up openssh-5.8p1/audit.c.audit5 openssh-5.8p1/audit.c
--- openssh-5.8p1/audit.c.audit5 2011-03-10 11:58:54.121980174 +0100
+++ openssh-5.8p1/audit.c 2011-03-10 11:58:55.077854964 +0100
@@ -290,5 +290,24 @@ audit_session_key_free_body(int ctos, pi
debug("audit session key discard euid %u direction %d from pid %ld uid %u",
(unsigned)geteuid(), ctos, (long)pid, (unsigned)uid);
}
+
+/*
+ * This will be called on destroy private part of the server key
+ */
+void
+audit_destroy_sensitive_data(const char *fp, pid_t pid, uid_t uid)
+{
+ debug("audit destroy sensitive data euid %d fingerprint %s from pid %ld uid %u",
+ geteuid(), fp, (long)pid, (unsigned)uid);
+}
+
+/*
+ * This will be called on generation of the ephemeral server key
+ */
+void
+audit_generate_ephemeral_server_key(const char *)
+{
+ debug("audit create ephemeral server key euid %d fingerprint %s", geteuid(), fp);
+}
# endif /* !defined CUSTOM_SSH_AUDIT_EVENTS */
#endif /* SSH_AUDIT_EVENTS */
diff -up openssh-5.8p1/audit.h.audit5 openssh-5.8p1/audit.h
--- openssh-5.8p1/audit.h.audit5 2011-03-10 11:58:54.167979998 +0100
+++ openssh-5.8p1/audit.h 2011-03-10 11:58:55.126854627 +0100
@@ -48,6 +48,8 @@ enum ssh_audit_event_type {
};
typedef enum ssh_audit_event_type ssh_audit_event_t;
+int listening_for_clients(void);
+
void audit_connection_from(const char *, int);
void audit_event(ssh_audit_event_t);
void audit_count_session_open(void);
@@ -64,5 +66,7 @@ void audit_unsupported_body(int);
void audit_kex_body(int, char *, char *, char *, pid_t, uid_t);
void audit_session_key_free(int ctos);
void audit_session_key_free_body(int ctos, pid_t, uid_t);
+void audit_destroy_sensitive_data(const char *, pid_t, uid_t);
+void audit_generate_ephemeral_server_key(const char *);
#endif /* _SSH_AUDIT_H */
diff -up openssh-5.8p1/audit-linux.c.audit5 openssh-5.8p1/audit-linux.c
--- openssh-5.8p1/audit-linux.c.audit5 2011-03-10 11:58:54.215855001 +0100
+++ openssh-5.8p1/audit-linux.c 2011-03-10 11:58:55.170980918 +0100
@@ -350,4 +350,50 @@ audit_session_key_free_body(int ctos, pi
error("cannot write into audit");
}
+void
+audit_destroy_sensitive_data(const char *fp, pid_t pid, uid_t uid)
+{
+ char buf[AUDIT_LOG_SIZE];
+ int audit_fd, audit_ok;
+
+ snprintf(buf, sizeof(buf), "op=destroy kind=server fp=%s direction=? spid=%jd suid=%jd",
+ fp, (intmax_t)pid, (intmax_t)uid);
+ audit_fd = audit_open();
+ if (audit_fd < 0) {
+ if (errno != EINVAL && errno != EPROTONOSUPPORT &&
+ errno != EAFNOSUPPORT)
+ error("cannot open audit");
+ return;
+ }
+ audit_ok = audit_log_user_message(audit_fd, AUDIT_CRYPTO_KEY_USER,
+ buf, NULL,
+ listening_for_clients() ? NULL : get_remote_ipaddr(),
+ NULL, 1);
+ audit_close(audit_fd);
+ /* do not abort if the error is EPERM and sshd is run as non root user */
+ if ((audit_ok < 0) && ((audit_ok != -1) || (getuid() == 0)))
+ error("cannot write into audit");
+}
+
+void
+audit_generate_ephemeral_server_key(const char *fp)
+{
+ char buf[AUDIT_LOG_SIZE];
+ int audit_fd, audit_ok;
+
+ snprintf(buf, sizeof(buf), "op=create kind=server fp=%s direction=?", fp);
+ audit_fd = audit_open();
+ if (audit_fd < 0) {
+ if (errno != EINVAL && errno != EPROTONOSUPPORT &&
+ errno != EAFNOSUPPORT)
+ error("cannot open audit");
+ return;
+ }
+ audit_ok = audit_log_user_message(audit_fd, AUDIT_CRYPTO_KEY_USER,
+ buf, NULL, 0, NULL, 1);
+ audit_close(audit_fd);
+ /* do not abort if the error is EPERM and sshd is run as non root user */
+ if ((audit_ok < 0) && ((audit_ok != -1) || (getuid() == 0)))
+ error("cannot write into audit");
+}
#endif /* USE_LINUX_AUDIT */
diff -up openssh-5.8p1/key.c.audit5 openssh-5.8p1/key.c
--- openssh-5.8p1/key.c.audit5 2011-03-10 11:58:51.406979467 +0100
+++ openssh-5.8p1/key.c 2011-03-10 11:58:55.229855219 +0100
@@ -1797,6 +1797,30 @@ key_demote(const Key *k)
}
int
+key_is_private(const Key *k)
+{
+ switch (k->type) {
+ case KEY_RSA_CERT_V00:
+ case KEY_RSA_CERT:
+ case KEY_RSA1:
+ case KEY_RSA:
+ return k->rsa->d != NULL;
+ case KEY_DSA_CERT_V00:
+ case KEY_DSA_CERT:
+ case KEY_DSA:
+ return k->dsa->priv_key != NULL;
+#ifdef OPENSSL_HAS_ECC
+ case KEY_ECDSA_CERT:
+ case KEY_ECDSA:
+ return EC_KEY_get0_private_key(k->ecdsa) != NULL;
+#endif
+ default:
+ fatal("key_is_private: bad key type %d", k->type);
+ return 1;
+ }
+}
+
+int
key_is_cert(const Key *k)
{
if (k == NULL)
diff -up openssh-5.8p1/key.h.audit5 openssh-5.8p1/key.h
--- openssh-5.8p1/key.h.audit5 2011-03-10 11:58:51.452981181 +0100
+++ openssh-5.8p1/key.h 2011-03-10 11:58:55.276854914 +0100
@@ -109,6 +109,7 @@ Key *key_generate(int, u_int);
Key *key_from_private(const Key *);
int key_type_from_name(char *);
int key_is_cert(const Key *);
+int key_is_private(const Key *k);
int key_type_plain(int);
int key_to_certified(Key *, int);
int key_drop_cert(Key *);
diff -up openssh-5.8p1/monitor.c.audit5 openssh-5.8p1/monitor.c
--- openssh-5.8p1/monitor.c.audit5 2011-03-10 11:58:54.503854586 +0100
+++ openssh-5.8p1/monitor.c 2011-03-10 11:58:55.333855125 +0100
@@ -106,6 +106,8 @@ extern Buffer auth_debug;
extern int auth_debug_init;
extern Buffer loginmsg;
+extern void destroy_sensitive_data(int);
+
/* State exported from the child */
struct {
@@ -182,6 +184,7 @@ int mm_answer_audit_end_command(int, Buf
int mm_answer_audit_unsupported_body(int, Buffer *);
int mm_answer_audit_kex_body(int, Buffer *);
int mm_answer_audit_session_key_free_body(int, Buffer *);
+int mm_answer_audit_server_key_free(int, Buffer *);
#endif
static Authctxt *authctxt;
@@ -233,6 +236,7 @@ struct mon_table mon_dispatch_proto20[]
{MONITOR_REQ_AUDIT_UNSUPPORTED, MON_PERMIT, mm_answer_audit_unsupported_body},
{MONITOR_REQ_AUDIT_KEX, MON_PERMIT, mm_answer_audit_kex_body},
{MONITOR_REQ_AUDIT_SESSION_KEY_FREE, MON_PERMIT, mm_answer_audit_session_key_free_body},
+ {MONITOR_REQ_AUDIT_SERVER_KEY_FREE, MON_PERMIT, mm_answer_audit_server_key_free},
#endif
#ifdef BSD_AUTH
{MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
@@ -273,6 +277,7 @@ struct mon_table mon_dispatch_postauth20
{MONITOR_REQ_AUDIT_UNSUPPORTED, MON_PERMIT, mm_answer_audit_unsupported_body},
{MONITOR_REQ_AUDIT_KEX, MON_PERMIT, mm_answer_audit_kex_body},
{MONITOR_REQ_AUDIT_SESSION_KEY_FREE, MON_PERMIT, mm_answer_audit_session_key_free_body},
+ {MONITOR_REQ_AUDIT_SERVER_KEY_FREE, MON_PERMIT, mm_answer_audit_server_key_free},
#endif
{0, 0, NULL}
};
@@ -307,6 +312,7 @@ struct mon_table mon_dispatch_proto15[]
{MONITOR_REQ_AUDIT_UNSUPPORTED, MON_PERMIT, mm_answer_audit_unsupported_body},
{MONITOR_REQ_AUDIT_KEX, MON_PERMIT, mm_answer_audit_kex_body},
{MONITOR_REQ_AUDIT_SESSION_KEY_FREE, MON_PERMIT, mm_answer_audit_session_key_free_body},
+ {MONITOR_REQ_AUDIT_SERVER_KEY_FREE, MON_PERMIT, mm_answer_audit_server_key_free},
#endif
{0, 0, NULL}
};
@@ -322,6 +328,7 @@ struct mon_table mon_dispatch_postauth15
{MONITOR_REQ_AUDIT_UNSUPPORTED, MON_PERMIT, mm_answer_audit_unsupported_body},
{MONITOR_REQ_AUDIT_KEX, MON_PERMIT, mm_answer_audit_kex_body},
{MONITOR_REQ_AUDIT_SESSION_KEY_FREE, MON_PERMIT, mm_answer_audit_session_key_free_body},
+ {MONITOR_REQ_AUDIT_SERVER_KEY_FREE, MON_PERMIT, mm_answer_audit_server_key_free},
#endif
{0, 0, NULL}
};
@@ -1607,6 +1614,8 @@ mm_answer_term(int sock, Buffer *req)
sshpam_cleanup();
#endif
+ destroy_sensitive_data(0);
+
while (waitpid(pmonitor->m_pid, &status, 0) == -1)
if (errno != EINTR)
exit(1);
@@ -2338,4 +2347,24 @@ mm_answer_audit_session_key_free_body(in
mm_request_send(sock, MONITOR_ANS_AUDIT_SESSION_KEY_FREE, m);
return 0;
}
+
+int
+mm_answer_audit_server_key_free(int sock, Buffer *m)
+{
+ int len;
+ char *fp;
+ pid_t pid;
+ uid_t uid;
+
+ fp = buffer_get_string(m, &len);
+ pid = buffer_get_int64(m);
+ uid = buffer_get_int64(m);
+
+ audit_destroy_sensitive_data(fp, pid, uid);
+
+ buffer_clear(m);
+
+ mm_request_send(sock, MONITOR_ANS_AUDIT_SERVER_KEY_FREE, m);
+ return 0;
+}
#endif /* SSH_AUDIT_EVENTS */
diff -up openssh-5.8p1/monitor.h.audit5 openssh-5.8p1/monitor.h
--- openssh-5.8p1/monitor.h.audit5 2011-03-10 11:58:54.545980156 +0100
+++ openssh-5.8p1/monitor.h 2011-03-10 11:58:55.378854631 +0100
@@ -70,6 +70,7 @@ enum monitor_reqtype {
MONITOR_REQ_AUDIT_UNSUPPORTED, MONITOR_ANS_AUDIT_UNSUPPORTED,
MONITOR_REQ_AUDIT_KEX, MONITOR_ANS_AUDIT_KEX,
MONITOR_REQ_AUDIT_SESSION_KEY_FREE, MONITOR_ANS_AUDIT_SESSION_KEY_FREE,
+ MONITOR_REQ_AUDIT_SERVER_KEY_FREE, MONITOR_ANS_AUDIT_SERVER_KEY_FREE,
};
struct mm_master;
diff -up openssh-5.8p1/monitor_wrap.c.audit5 openssh-5.8p1/monitor_wrap.c
--- openssh-5.8p1/monitor_wrap.c.audit5 2011-03-10 11:58:54.602854916 +0100
+++ openssh-5.8p1/monitor_wrap.c 2011-03-10 11:58:55.432980073 +0100
@@ -1501,4 +1501,20 @@ mm_audit_session_key_free_body(int ctos,
&m);
buffer_free(&m);
}
+
+void
+mm_audit_destroy_sensitive_data(const char *fp, pid_t pid, uid_t uid)
+{
+ Buffer m;
+
+ buffer_init(&m);
+ buffer_put_cstring(&m, fp);
+ buffer_put_int64(&m, pid);
+ buffer_put_int64(&m, uid);
+
+ mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_SERVER_KEY_FREE, &m);
+ mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_AUDIT_SERVER_KEY_FREE,
+ &m);
+ buffer_free(&m);
+}
#endif /* SSH_AUDIT_EVENTS */
diff -up openssh-5.8p1/monitor_wrap.h.audit5 openssh-5.8p1/monitor_wrap.h
--- openssh-5.8p1/monitor_wrap.h.audit5 2011-03-10 11:58:54.648980503 +0100
+++ openssh-5.8p1/monitor_wrap.h 2011-03-10 11:58:55.480855200 +0100
@@ -79,6 +79,7 @@ void mm_audit_end_command(int, const cha
void mm_audit_unsupported_body(int);
void mm_audit_kex_body(int, char *, char *, char *, pid_t, uid_t);
void mm_audit_session_key_free_body(int, pid_t, uid_t);
+void mm_audit_destroy_sensitive_data(const char *, pid_t, uid_t);
#endif
struct Session;
diff -up openssh-5.8p1/session.c.audit5 openssh-5.8p1/session.c
--- openssh-5.8p1/session.c.audit5 2011-03-10 11:58:54.800854988 +0100
+++ openssh-5.8p1/session.c 2011-03-10 11:58:55.540854785 +0100
@@ -132,7 +132,7 @@ extern int log_stderr;
extern int debug_flag;
extern u_int utmp_len;
extern int startup_pipe;
-extern void destroy_sensitive_data(void);
+extern void destroy_sensitive_data(int);
extern Buffer loginmsg;
/* original command from peer. */
@@ -1626,7 +1626,7 @@ do_child(Session *s, const char *command
int r = 0;
/* remove hostkey from the child's memory */
- destroy_sensitive_data();
+ destroy_sensitive_data(1);
/* Don't audit this - both us and the parent would be talking to the
monitor over a single socket, with no synchronization. */
packet_destroy_all(0, 1);
diff -up openssh-5.8p1/sshd.c.audit5 openssh-5.8p1/sshd.c
--- openssh-5.8p1/sshd.c.audit5 2011-03-10 11:58:54.856979886 +0100
+++ openssh-5.8p1/sshd.c 2011-03-10 11:58:55.728855905 +0100
@@ -253,7 +253,7 @@ Buffer loginmsg;
struct passwd *privsep_pw = NULL;
/* Prototypes for various functions defined later in this file. */
-void destroy_sensitive_data(void);
+void destroy_sensitive_data(int);
void demote_sensitive_data(void);
static void do_ssh1_kex(void);
@@ -272,6 +272,15 @@ close_listen_socks(void)
num_listen_socks = -1;
}
+/*
+ * Is this process listening for clients (i.e. not specific to any specific
+ * client connection?)
+ */
+int listening_for_clients(void)
+{
+ return num_listen_socks > 0;
+}
+
static void
close_startup_pipes(void)
{
@@ -532,22 +541,47 @@ sshd_exchange_identification(int sock_in
}
}
-/* Destroy the host and server keys. They will no longer be needed. */
+/*
+ * Destroy the host and server keys. They will no longer be needed. Careful,
+ * this can be called from cleanup_exit() - i.e. from just about anywhere.
+ */
void
-destroy_sensitive_data(void)
+destroy_sensitive_data(int privsep)
{
int i;
+ pid_t pid;
+ uid_t uid;
if (sensitive_data.server_key) {
key_free(sensitive_data.server_key);
sensitive_data.server_key = NULL;
}
+ pid = getpid();
+ uid = getuid();
for (i = 0; i < options.num_host_key_files; i++) {
if (sensitive_data.host_keys[i]) {
+ char *fp;
+
+ if (key_is_private(sensitive_data.host_keys[i]))
+ fp = key_fingerprint(sensitive_data.host_keys[i],
+ FIPS_mode() ? SSH_FP_SHA1 : SSH_FP_MD5,
+ SSH_FP_HEX);
+ else
+ fp = NULL;
key_free(sensitive_data.host_keys[i]);
sensitive_data.host_keys[i] = NULL;
+ if (fp != NULL) {
+ if (privsep)
+ PRIVSEP(audit_destroy_sensitive_data(fp,
+ pid, uid));
+ else
+ audit_destroy_sensitive_data(fp,
+ pid, uid);
+ xfree(fp);
+ }
}
- if (sensitive_data.host_certificates[i]) {
+ if (sensitive_data.host_certificates
+ && sensitive_data.host_certificates[i]) {
key_free(sensitive_data.host_certificates[i]);
sensitive_data.host_certificates[i] = NULL;
}
@@ -561,6 +595,8 @@ void
demote_sensitive_data(void)
{
Key *tmp;
+ pid_t pid;
+ uid_t uid;
int i;
if (sensitive_data.server_key) {
@@ -569,13 +605,27 @@ demote_sensitive_data(void)
sensitive_data.server_key = tmp;
}
+ pid = getpid();
+ uid = getuid();
for (i = 0; i < options.num_host_key_files; i++) {
if (sensitive_data.host_keys[i]) {
+ char *fp;
+
+ if (key_is_private(sensitive_data.host_keys[i]))
+ fp = key_fingerprint(sensitive_data.host_keys[i],
+ FIPS_mode() ? SSH_FP_SHA1 : SSH_FP_MD5,
+ SSH_FP_HEX);
+ else
+ fp = NULL;
tmp = key_demote(sensitive_data.host_keys[i]);
key_free(sensitive_data.host_keys[i]);
sensitive_data.host_keys[i] = tmp;
if (tmp->type == KEY_RSA1)
sensitive_data.ssh1_host_key = tmp;
+ if (fp != NULL) {
+ audit_destroy_sensitive_data(fp, pid, uid);
+ xfree(fp);
+ }
}
/* Certs do not need demotion */
}
@@ -1120,6 +1170,7 @@ server_accept_loop(int *sock_in, int *so
if (received_sigterm) {
logit("Received signal %d; terminating.",
(int) received_sigterm);
+ destroy_sensitive_data(0);
close_listen_socks();
unlink(options.pid_file);
exit(255);
@@ -2023,7 +2074,7 @@ main(int ac, char **av)
privsep_postauth(authctxt);
/* the monitor process [priv] will not return */
if (!compat20)
- destroy_sensitive_data();
+ destroy_sensitive_data(0);
}
packet_set_timeout(options.client_alive_interval,
@@ -2034,6 +2085,7 @@ main(int ac, char **av)
/* The connection has been terminated. */
packet_destroy_all(1, 1);
+ destroy_sensitive_data(1);
packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes);
packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes);
@@ -2262,7 +2314,7 @@ do_ssh1_kex(void)
session_id[i] = session_key[i] ^ session_key[i + 16];
}
/* Destroy the private and public keys. No longer. */
- destroy_sensitive_data();
+ destroy_sensitive_data(0);
if (use_privsep)
mm_ssh1_session_id(session_id);
@@ -2352,8 +2404,22 @@ do_ssh2_kex(void)
void
cleanup_exit(int i)
{
+ static int in_cleanup;
+
+ int is_privsep_child;
+
+ /* cleanup_exit can be called at the very least from the privsep
+ wrappers used for auditing. Make sure we don't recurse
+ indefinitely. */
+ if (in_cleanup)
+ _exit(i);
+ in_cleanup = 1;
+
if (the_authctxt)
do_cleanup(the_authctxt);
+ is_privsep_child = use_privsep && pmonitor != NULL && !mm_is_monitor();
+ if (sensitive_data.host_keys != NULL)
+ destroy_sensitive_data(is_privsep_child);
packet_destroy_all(1, is_privsep_child);
#ifdef SSH_AUDIT_EVENTS
/* done after do_cleanup so it can cancel the PAM auth 'thread' */
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