upstream commit

clear session keys from memory; ok djm@

Upstream-ID: ecd178819868975affd5fd6637458b7c712b6a0f
This commit is contained in:
markus@openbsd.org 2017-05-31 08:09:45 +00:00 committed by Damien Miller
parent 92e9fe6331
commit 1e0cdf8efb
8 changed files with 92 additions and 42 deletions

View File

@ -1,4 +1,4 @@
/* $OpenBSD: monitor.c,v 1.169 2017/05/30 14:10:53 markus Exp $ */
/* $OpenBSD: monitor.c,v 1.170 2017/05/31 08:09:45 markus Exp $ */
/*
* Copyright 2002 Niels Provos <provos@citi.umich.edu>
* Copyright 2002 Markus Friedl <markus@openbsd.org>
@ -1583,6 +1583,17 @@ mm_answer_audit_command(int socket, Buffer *m)
}
#endif /* SSH_AUDIT_EVENTS */
void
monitor_clear_keystate(struct monitor *pmonitor)
{
struct ssh *ssh = active_state; /* XXX */
ssh_clear_newkeys(ssh, MODE_IN);
ssh_clear_newkeys(ssh, MODE_OUT);
sshbuf_free(child_state);
child_state = NULL;
}
void
monitor_apply_keystate(struct monitor *pmonitor)
{

View File

@ -1,4 +1,4 @@
/* $OpenBSD: monitor_wrap.h,v 1.34 2017/05/30 14:10:53 markus Exp $ */
/* $OpenBSD: monitor_wrap.h,v 1.35 2017/05/31 08:09:45 markus Exp $ */
/*
* Copyright 2002 Niels Provos <provos@citi.umich.edu>
@ -34,7 +34,6 @@ extern int use_privsep;
enum mm_keytype { MM_NOKEY, MM_HOSTKEY, MM_USERKEY };
struct monitor;
struct mm_master;
struct Authctxt;
void mm_log_handler(LogLevel, const char *, void *);
@ -86,6 +85,7 @@ void mm_session_pty_cleanup2(struct Session *);
struct newkeys *mm_newkeys_from_blob(u_char *, int);
int mm_newkeys_to_blob(int, u_char **, u_int *);
void monitor_clear_keystate(struct monitor *);
void monitor_apply_keystate(struct monitor *);
void mm_get_keystate(struct monitor *);
void mm_send_keystate(struct monitor*);

View File

@ -149,5 +149,7 @@ void packet_disconnect(const char *, ...)
ssh_packet_set_mux(active_state)
#define packet_get_mux() \
ssh_packet_get_mux(active_state)
#define packet_clear_keys() \
ssh_packet_clear_keys(active_state)
#endif /* _OPACKET_H */

View File

@ -1,4 +1,4 @@
/* $OpenBSD: packet.c,v 1.256 2017/05/08 06:03:39 djm Exp $ */
/* $OpenBSD: packet.c,v 1.257 2017/05/31 08:09:45 markus Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -559,8 +559,8 @@ ssh_local_port(struct ssh *ssh)
/* Closes the connection and clears and frees internal data structures. */
void
ssh_packet_close(struct ssh *ssh)
static void
ssh_packet_close_internal(struct ssh *ssh, int do_close)
{
struct session_state *state = ssh->state;
u_int mode;
@ -568,20 +568,26 @@ ssh_packet_close(struct ssh *ssh)
if (!state->initialized)
return;
state->initialized = 0;
if (state->connection_in == state->connection_out) {
shutdown(state->connection_out, SHUT_RDWR);
close(state->connection_out);
} else {
close(state->connection_in);
close(state->connection_out);
if (do_close) {
if (state->connection_in == state->connection_out) {
shutdown(state->connection_out, SHUT_RDWR);
close(state->connection_out);
} else {
close(state->connection_in);
close(state->connection_out);
}
}
sshbuf_free(state->input);
sshbuf_free(state->output);
sshbuf_free(state->outgoing_packet);
sshbuf_free(state->incoming_packet);
for (mode = 0; mode < MODE_MAX; mode++)
kex_free_newkeys(state->newkeys[mode]);
if (state->compression_buffer) {
for (mode = 0; mode < MODE_MAX; mode++) {
kex_free_newkeys(state->newkeys[mode]); /* current keys */
state->newkeys[mode] = NULL;
ssh_clear_newkeys(ssh, mode); /* next keys */
}
/* comression state is in shared mem, so we can only release it once */
if (do_close && state->compression_buffer) {
sshbuf_free(state->compression_buffer);
if (state->compression_out_started) {
z_streamp stream = &state->compression_out_stream;
@ -609,10 +615,24 @@ ssh_packet_close(struct ssh *ssh)
cipher_free(state->send_context);
cipher_free(state->receive_context);
state->send_context = state->receive_context = NULL;
free(ssh->remote_ipaddr);
ssh->remote_ipaddr = NULL;
free(ssh->state);
ssh->state = NULL;
if (do_close) {
free(ssh->remote_ipaddr);
ssh->remote_ipaddr = NULL;
free(ssh->state);
ssh->state = NULL;
}
}
void
ssh_packet_close(struct ssh *ssh)
{
ssh_packet_close_internal(ssh, 1);
}
void
ssh_packet_clear_keys(struct ssh *ssh)
{
ssh_packet_close_internal(ssh, 0);
}
/* Sets remote side protocol flags. */
@ -791,6 +811,15 @@ uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
/* NOTREACHED */
}
void
ssh_clear_newkeys(struct ssh *ssh, int mode)
{
if (ssh->kex && ssh->kex->newkeys) {
kex_free_newkeys(ssh->kex->newkeys[mode]);
ssh->kex->newkeys[mode] = NULL;
}
}
int
ssh_set_newkeys(struct ssh *ssh, int mode)
{
@ -820,26 +849,16 @@ ssh_set_newkeys(struct ssh *ssh, int mode)
max_blocks = &state->max_blocks_in;
}
if (state->newkeys[mode] != NULL) {
debug("%s: rekeying after %llu %s blocks"
" (%llu bytes total)", __func__,
(unsigned long long)ps->blocks, dir,
(unsigned long long)ps->bytes);
debug("set_newkeys: rekeying, input %llu bytes %llu blocks, "
"output %llu bytes %llu blocks",
(unsigned long long)state->p_read.bytes,
(unsigned long long)state->p_read.blocks,
(unsigned long long)state->p_send.bytes,
(unsigned long long)state->p_send.blocks);
cipher_free(*ccp);
*ccp = NULL;
enc = &state->newkeys[mode]->enc;
mac = &state->newkeys[mode]->mac;
comp = &state->newkeys[mode]->comp;
mac_clear(mac);
explicit_bzero(enc->iv, enc->iv_len);
explicit_bzero(enc->key, enc->key_len);
explicit_bzero(mac->key, mac->key_len);
free(enc->name);
free(enc->iv);
free(enc->key);
free(mac->name);
free(mac->key);
free(comp->name);
free(state->newkeys[mode]);
kex_free_newkeys(state->newkeys[mode]);
state->newkeys[mode] = NULL;
}
/* note that both bytes and the seqnr are not reset */
ps->packets = ps->blocks = 0;
@ -1784,15 +1803,20 @@ sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
switch (r) {
case SSH_ERR_CONN_CLOSED:
ssh_packet_clear_keys(ssh);
logdie("Connection closed by %s", remote_id);
case SSH_ERR_CONN_TIMEOUT:
ssh_packet_clear_keys(ssh);
logdie("Connection %s %s timed out",
ssh->state->server_side ? "from" : "to", remote_id);
case SSH_ERR_DISCONNECTED:
ssh_packet_clear_keys(ssh);
logdie("Disconnected from %s", remote_id);
case SSH_ERR_SYSTEM_ERROR:
if (errno == ECONNRESET)
if (errno == ECONNRESET) {
ssh_packet_clear_keys(ssh);
logdie("Connection reset by %s", remote_id);
}
/* FALLTHROUGH */
case SSH_ERR_NO_CIPHER_ALG_MATCH:
case SSH_ERR_NO_MAC_ALG_MATCH:
@ -1800,12 +1824,14 @@ 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) {
ssh_packet_clear_keys(ssh);
logdie("Unable to negotiate with %s: %s. "
"Their offer: %s", remote_id, ssh_err(r),
ssh->kex->failed_choice);
}
/* FALLTHROUGH */
default:
ssh_packet_clear_keys(ssh);
logdie("%s%sConnection %s %s: %s",
tag != NULL ? tag : "", tag != NULL ? ": " : "",
ssh->state->server_side ? "from" : "to",

View File

@ -1,4 +1,4 @@
/* $OpenBSD: packet.h,v 1.80 2017/05/30 14:18:15 markus Exp $ */
/* $OpenBSD: packet.h,v 1.81 2017/05/31 08:09:45 markus Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
@ -97,6 +97,8 @@ int ssh_packet_get_connection_in(struct ssh *);
int ssh_packet_get_connection_out(struct ssh *);
void ssh_packet_close(struct ssh *);
void ssh_packet_set_input_hook(struct ssh *, ssh_packet_hook_fn *, void *);
void ssh_packet_clear_keys(struct ssh *);
void ssh_clear_newkeys(struct ssh *, int);
int ssh_packet_is_rekeying(struct ssh *);
void ssh_packet_set_protocol_flags(struct ssh *, u_int);

View File

@ -1,4 +1,4 @@
/* $OpenBSD: session.c,v 1.286 2016/11/30 03:00:05 djm Exp $ */
/* $OpenBSD: session.c,v 1.287 2017/05/31 08:09:45 markus Exp $ */
/*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
@ -1486,6 +1486,7 @@ do_child(Session *s, const char *command)
/* remove hostkey from the child's memory */
destroy_sensitive_data();
packet_clear_keys();
/* Force a password change */
if (s->authctxt->force_pwchange) {

4
sshd.c
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@ -1,4 +1,4 @@
/* $OpenBSD: sshd.c,v 1.489 2017/05/31 07:00:13 markus Exp $ */
/* $OpenBSD: sshd.c,v 1.490 2017/05/31 08:09:45 markus Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -649,6 +649,7 @@ privsep_postauth(Authctxt *authctxt)
else if (pmonitor->m_pid != 0) {
verbose("User child is on pid %ld", (long)pmonitor->m_pid);
buffer_clear(&loginmsg);
monitor_clear_keystate(pmonitor);
monitor_child_postauth(pmonitor);
/* NEVERREACHED */
@ -2032,6 +2033,7 @@ main(int ac, char **av)
*/
if (use_privsep) {
mm_send_keystate(pmonitor);
packet_clear_keys();
exit(0);
}

8
umac.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: umac.c,v 1.11 2014/07/22 07:13:42 guenther Exp $ */
/* $OpenBSD: umac.c,v 1.12 2017/05/31 08:09:45 markus Exp $ */
/* -----------------------------------------------------------------------
*
* umac.c -- C Implementation UMAC Message Authentication
@ -203,6 +203,8 @@ static void kdf(void *bufp, aes_int_key key, UINT8 ndx, int nbytes)
aes_encryption(in_buf, out_buf, key);
memcpy(dst_buf,out_buf,nbytes);
}
explicit_bzero(in_buf, sizeof(in_buf));
explicit_bzero(out_buf, sizeof(out_buf));
}
/* The final UHASH result is XOR'd with the output of a pseudorandom
@ -227,6 +229,7 @@ static void pdf_init(pdf_ctx *pc, aes_int_key prf_key)
/* Initialize pdf and cache */
memset(pc->nonce, 0, sizeof(pc->nonce));
aes_encryption(pc->nonce, pc->cache, pc->prf_key);
explicit_bzero(buf, sizeof(buf));
}
static void pdf_gen_xor(pdf_ctx *pc, const UINT8 nonce[8], UINT8 buf[8])
@ -991,6 +994,7 @@ static void uhash_init(uhash_ctx_t ahc, aes_int_key prf_key)
kdf(ahc->ip_trans, prf_key, 4, STREAMS * sizeof(UINT32));
endian_convert_if_le(ahc->ip_trans, sizeof(UINT32),
STREAMS * sizeof(UINT32));
explicit_bzero(buf, sizeof(buf));
}
/* ---------------------------------------------------------------------- */
@ -1200,6 +1204,7 @@ int umac_delete(struct umac_ctx *ctx)
if (ctx) {
if (ALLOC_BOUNDARY)
ctx = (struct umac_ctx *)ctx->free_ptr;
explicit_bzero(ctx, sizeof(*ctx) + ALLOC_BOUNDARY);
free(ctx);
}
return (1);
@ -1227,6 +1232,7 @@ struct umac_ctx *umac_new(const u_char key[])
aes_key_setup(key, prf_key);
pdf_init(&ctx->pdf, prf_key);
uhash_init(&ctx->hash, prf_key);
explicit_bzero(prf_key, sizeof(prf_key));
}
return (ctx);