forked from pool/openssh
Antonio Larrosa
b0b10ece31
- Add patch from SLE which was missing in Factory: * Mon Jun 7 20:54:09 UTC 2021 - Hans Petter Jansson <hpj@suse.com> - Add openssh-mitigate-lingering-secrets.patch (bsc#1186673), which attempts to mitigate instances of secrets lingering in memory after a session exits. (bsc#1213004 bsc#1213008) - Rebase patch: * openssh-6.6p1-privsep-selinux.patch OBS-URL: https://build.opensuse.org/request/show/1165549 OBS-URL: https://build.opensuse.org/package/show/network/openssh?expand=0&rev=259
345 lines
9.4 KiB
Diff
345 lines
9.4 KiB
Diff
Index: openssh-9.3p2/kex.c
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===================================================================
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--- openssh-9.3p2.orig/kex.c
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+++ openssh-9.3p2/kex.c
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@@ -1564,16 +1564,16 @@ enc_destroy(struct sshenc *enc)
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return;
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if (enc->key) {
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- memset(enc->key, 0, enc->key_len);
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+ explicit_bzero(enc->key, enc->key_len);
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free(enc->key);
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}
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if (enc->iv) {
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- memset(enc->iv, 0, enc->iv_len);
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+ explicit_bzero(enc->iv, enc->iv_len);
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free(enc->iv);
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}
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- memset(enc, 0, sizeof(*enc));
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+ explicit_bzero(enc, sizeof(*enc));
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}
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void
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@@ -1584,7 +1584,7 @@ newkeys_destroy(struct newkeys *newkeys)
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enc_destroy(&newkeys->enc);
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mac_destroy(&newkeys->mac);
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- memset(&newkeys->comp, 0, sizeof(newkeys->comp));
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+ explicit_bzero(&newkeys->comp, sizeof(newkeys->comp));
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}
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/*
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Index: openssh-9.3p2/mac.c
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===================================================================
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--- openssh-9.3p2.orig/mac.c
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+++ openssh-9.3p2/mac.c
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@@ -284,11 +284,11 @@ mac_destroy(struct sshmac *mac)
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return;
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if (mac->key) {
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- memset(mac->key, 0, mac->key_len);
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+ explicit_bzero(mac->key, mac->key_len);
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free(mac->key);
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}
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- memset(mac, 0, sizeof(*mac));
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+ explicit_bzero(mac, sizeof(*mac));
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}
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/* XXX copied from ciphers_valid */
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Index: openssh-9.3p2/monitor.c
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===================================================================
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--- openssh-9.3p2.orig/monitor.c
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+++ openssh-9.3p2/monitor.c
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@@ -1789,8 +1789,12 @@ mm_answer_audit_end_command(struct ssh *
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void
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monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor)
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{
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- ssh_clear_newkeys(ssh, MODE_IN);
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- ssh_clear_newkeys(ssh, MODE_OUT);
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+ u_int mode;
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+
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+ for (mode = 0; mode < MODE_MAX; mode++) {
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+ ssh_clear_curkeys(ssh, mode); /* current keys */
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+ ssh_clear_newkeys(ssh, mode); /* next keys */
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+ }
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sshbuf_free(child_state);
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child_state = NULL;
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}
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Index: openssh-9.3p2/packet.c
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===================================================================
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--- openssh-9.3p2.orig/packet.c
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+++ openssh-9.3p2/packet.c
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@@ -655,6 +655,7 @@ ssh_packet_close_internal(struct ssh *ss
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ssh->local_ipaddr = NULL;
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free(ssh->remote_ipaddr);
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ssh->remote_ipaddr = NULL;
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+ explicit_bzero(ssh->state, sizeof(*ssh->state));
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free(ssh->state);
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ssh->state = NULL;
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kex_free(ssh->kex);
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@@ -783,8 +784,10 @@ compress_buffer(struct ssh *ssh, struct
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case Z_OK:
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/* Append compressed data to output_buffer. */
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if ((r = sshbuf_put(out, buf, sizeof(buf) -
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- ssh->state->compression_out_stream.avail_out)) != 0)
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+ ssh->state->compression_out_stream.avail_out)) != 0) {
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+ explicit_bzero(buf, sizeof(buf));
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return r;
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+ }
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break;
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case Z_STREAM_ERROR:
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default:
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@@ -819,8 +822,10 @@ uncompress_buffer(struct ssh *ssh, struc
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switch (status) {
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case Z_OK:
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if ((r = sshbuf_put(out, buf, sizeof(buf) -
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- ssh->state->compression_in_stream.avail_out)) != 0)
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+ ssh->state->compression_in_stream.avail_out)) != 0) {
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+ explicit_bzero(buf, sizeof(buf));
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return r;
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+ }
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break;
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case Z_BUF_ERROR:
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/*
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@@ -870,6 +875,17 @@ uncompress_buffer(struct ssh *ssh, struc
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#endif /* WITH_ZLIB */
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void
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+ssh_clear_curkeys(struct ssh *ssh, int mode)
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+{
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+ struct session_state *state = ssh->state;
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+
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+ if (state && state->newkeys[mode]) {
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+ kex_free_newkeys(state->newkeys[mode]);
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+ state->newkeys[mode] = NULL;
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+ }
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+}
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+
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+void
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ssh_clear_newkeys(struct ssh *ssh, int mode)
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{
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if (ssh->kex && ssh->kex->newkeys[mode]) {
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@@ -1418,7 +1434,9 @@ ssh_packet_read_seqnr(struct ssh *ssh, u
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}
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/* Append it to the buffer. */
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- if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
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+ r = ssh_packet_process_incoming(ssh, buf, len);
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+ explicit_bzero(buf, len);
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+ if (r != 0)
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goto out;
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}
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out:
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@@ -2375,9 +2393,12 @@ ssh_packet_get_state(struct ssh *ssh, st
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(r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
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(r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
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(r = sshbuf_put_stringb(m, state->input)) != 0 ||
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- (r = sshbuf_put_stringb(m, state->output)) != 0)
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+ (r = sshbuf_put_stringb(m, state->output)) != 0) {
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+ sshbuf_obfuscate(m);
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return r;
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+ }
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+ sshbuf_obfuscate(m);
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return 0;
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}
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@@ -2496,6 +2517,8 @@ ssh_packet_set_state(struct ssh *ssh, st
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size_t ilen, olen;
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int r;
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+ sshbuf_unobfuscate(m);
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+
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if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
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(r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
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(r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
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@@ -2509,7 +2532,7 @@ ssh_packet_set_state(struct ssh *ssh, st
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(r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
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(r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
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(r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
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- return r;
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+ goto out;
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/*
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* We set the time here so that in post-auth privsep child we
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* count from the completion of the authentication.
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@@ -2518,10 +2541,10 @@ ssh_packet_set_state(struct ssh *ssh, st
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/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
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if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
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(r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
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- return r;
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+ goto out;
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if ((r = ssh_packet_set_postauth(ssh)) != 0)
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- return r;
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+ goto out;
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sshbuf_reset(state->input);
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sshbuf_reset(state->output);
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@@ -2529,12 +2552,19 @@ ssh_packet_set_state(struct ssh *ssh, st
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(r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
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(r = sshbuf_put(state->input, input, ilen)) != 0 ||
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(r = sshbuf_put(state->output, output, olen)) != 0)
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- return r;
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+ goto out;
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- if (sshbuf_len(m))
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- return SSH_ERR_INVALID_FORMAT;
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+ if (sshbuf_len(m)) {
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+ r = SSH_ERR_INVALID_FORMAT;
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+ goto out;
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+ }
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+
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+ r = 0;
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+out:
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+ if (r != 0)
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+ sshbuf_obfuscate(m);
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debug3_f("done");
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- return 0;
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+ return r;
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}
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/* NEW API */
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Index: openssh-9.3p2/packet.h
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===================================================================
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--- openssh-9.3p2.orig/packet.h
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+++ openssh-9.3p2/packet.h
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@@ -103,6 +103,7 @@ void ssh_packet_close(struct ssh *);
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void ssh_packet_set_input_hook(struct ssh *, ssh_packet_hook_fn *, void *);
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void ssh_packet_clear_keys(struct ssh *);
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void ssh_packet_clear_keys_noaudit(struct ssh *);
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+void ssh_clear_curkeys(struct ssh *, int);
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void ssh_clear_newkeys(struct ssh *, int);
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int ssh_packet_is_rekeying(struct ssh *);
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Index: openssh-9.3p2/sshbuf.c
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===================================================================
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--- openssh-9.3p2.orig/sshbuf.c
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+++ openssh-9.3p2/sshbuf.c
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@@ -309,6 +309,31 @@ sshbuf_mutable_ptr(const struct sshbuf *
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return buf->d + buf->off;
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}
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+/* Trivially obfuscate the buffer. This is used to make sensitive data
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+ * (e.g. keystate) slightly less obvious if found lingering in kernel
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+ * memory after being sent from the privsep child to its parent.
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+ *
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+ * Longer term we should consider using a one-time pad or a stream cipher
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+ * here. */
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+void
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+sshbuf_obfuscate(struct sshbuf *buf)
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+{
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+ size_t i;
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+
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+ if (sshbuf_check_sanity(buf) != 0 || buf->readonly || buf->refcount > 1)
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+ return;
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+
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+ for (i = buf->off; i < buf->size; i++) {
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+ buf->d [i] ^= 0xaa;
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+ }
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+}
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+
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+void
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+sshbuf_unobfuscate(struct sshbuf *buf)
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+{
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+ sshbuf_obfuscate(buf);
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+}
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+
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int
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sshbuf_check_reserve(const struct sshbuf *buf, size_t len)
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{
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Index: openssh-9.3p2/sshbuf.h
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===================================================================
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--- openssh-9.3p2.orig/sshbuf.h
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+++ openssh-9.3p2/sshbuf.h
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@@ -298,6 +298,9 @@ int sshbuf_write_file(const char *path,
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int sshbuf_read(int, struct sshbuf *, size_t, size_t *)
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__attribute__((__nonnull__ (2)));
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+void sshbuf_obfuscate(struct sshbuf *buf);
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+void sshbuf_unobfuscate(struct sshbuf *buf);
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+
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/* Macros for decoding/encoding integers */
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#define PEEK_U64(p) \
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(((u_int64_t)(((const u_char *)(p))[0]) << 56) | \
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Index: openssh-9.3p2/sshd.c
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===================================================================
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--- openssh-9.3p2.orig/sshd.c
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+++ openssh-9.3p2/sshd.c
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@@ -272,6 +272,19 @@ static void do_ssh2_kex(struct ssh *);
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static char *listener_proctitle;
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/*
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+ * Clear some stack space. This is a bit naive, but hopefully helps mitigate
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+ * information leaks due to registers and other data having been stored on
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+ * the stack. Called after fork() and before exit().
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+ */
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+static void
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+clobber_stack(void)
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+{
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+ char data [32768];
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+
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+ explicit_bzero(data, 32768);
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+}
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+
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+/*
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* Close all listening sockets
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*/
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static void
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@@ -430,6 +443,8 @@ destroy_sensitive_data(struct ssh *ssh,
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sensitive_data.host_certificates[i] = NULL;
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}
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}
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+
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+ clobber_stack();
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}
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/* Demote private to public keys for network child */
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@@ -600,6 +615,8 @@ privsep_preauth(struct ssh *ssh)
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static void
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privsep_postauth(struct ssh *ssh, Authctxt *authctxt)
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{
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+ clobber_stack();
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+
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#ifdef DISABLE_FD_PASSING
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if (1) {
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#else
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@@ -2360,6 +2377,7 @@ main(int ac, char **av)
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if (use_privsep) {
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mm_send_keystate(ssh, pmonitor);
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ssh_packet_clear_keys(ssh);
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+ clobber_stack();
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exit(0);
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}
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@@ -2436,6 +2454,7 @@ main(int ac, char **av)
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if (use_privsep)
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mm_terminate();
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+ clobber_stack();
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exit(0);
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}
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@@ -2596,8 +2615,10 @@ cleanup_exit(int i)
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/* cleanup_exit can be called at the very least from the privsep
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wrappers used for auditing. Make sure we don't recurse
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indefinitely. */
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- if (in_cleanup)
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+ if (in_cleanup) {
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+ clobber_stack();
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_exit(i);
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+ }
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in_cleanup = 1;
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if (the_active_state != NULL && the_authctxt != NULL) {
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do_cleanup(the_active_state, the_authctxt);
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@@ -2623,5 +2644,7 @@ cleanup_exit(int i)
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(!use_privsep || mm_is_monitor()))
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audit_event(the_active_state, SSH_CONNECTION_ABANDON);
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#endif
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+
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+ clobber_stack();
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_exit(i);
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}
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