MSVSphere Packaging Team
8 months ago
parent
8d72e3530d
commit
467228ea54
@ -0,0 +1,447 @@
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diff --git a/PROTOCOL b/PROTOCOL
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index d453c779..ded935eb 100644
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--- a/PROTOCOL
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+++ b/PROTOCOL
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@@ -137,6 +137,32 @@ than as a named global or channel request to allow pings with very
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described at:
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http://git.libssh.org/users/aris/libssh.git/plain/doc/curve25519-sha256@libssh.org.txt?h=curve25519
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+1.9 transport: strict key exchange extension
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+
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+OpenSSH supports a number of transport-layer hardening measures under
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+a "strict KEX" feature. This feature is signalled similarly to the
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+RFC8308 ext-info feature: by including a additional algorithm in the
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+initiial SSH2_MSG_KEXINIT kex_algorithms field. The client may append
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+"kex-strict-c-v00@openssh.com" to its kex_algorithms and the server
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+may append "kex-strict-s-v00@openssh.com". These pseudo-algorithms
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+are only valid in the initial SSH2_MSG_KEXINIT and MUST be ignored
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+if they are present in subsequent SSH2_MSG_KEXINIT packets.
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+
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+When an endpoint that supports this extension observes this algorithm
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+name in a peer's KEXINIT packet, it MUST make the following changes to
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+the the protocol:
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+
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+a) During initial KEX, terminate the connection if any unexpected or
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+ out-of-sequence packet is received. This includes terminating the
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+ connection if the first packet received is not SSH2_MSG_KEXINIT.
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+ Unexpected packets for the purpose of strict KEX include messages
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+ that are otherwise valid at any time during the connection such as
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+ SSH2_MSG_DEBUG and SSH2_MSG_IGNORE.
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+b) After sending or receiving a SSH2_MSG_NEWKEYS message, reset the
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+ packet sequence number to zero. This behaviour persists for the
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+ duration of the connection (i.e. not just the first
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+ SSH2_MSG_NEWKEYS).
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+
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2. Connection protocol changes
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2.1. connection: Channel write close extension "eow@openssh.com"
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diff --git a/kex.c b/kex.c
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index aa5e792d..d478ff6e 100644
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--- a/kex.c
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+++ b/kex.c
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@@ -65,7 +65,7 @@
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#endif
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/* prototype */
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-static int kex_choose_conf(struct ssh *);
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+static int kex_choose_conf(struct ssh *, uint32_t seq);
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static int kex_input_newkeys(int, u_int32_t, struct ssh *);
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static const char *proposal_names[PROPOSAL_MAX] = {
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@@ -177,6 +177,18 @@ kex_names_valid(const char *names)
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return 1;
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}
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+/* returns non-zero if proposal contains any algorithm from algs */
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+static int
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+has_any_alg(const char *proposal, const char *algs)
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+{
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+ char *cp;
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+
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+ if ((cp = match_list(proposal, algs, NULL)) == NULL)
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+ return 0;
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+ free(cp);
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+ return 1;
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+}
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+
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/*
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* Concatenate algorithm names, avoiding duplicates in the process.
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* Caller must free returned string.
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@@ -184,7 +196,7 @@ kex_names_valid(const char *names)
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char *
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kex_names_cat(const char *a, const char *b)
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{
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- char *ret = NULL, *tmp = NULL, *cp, *p, *m;
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+ char *ret = NULL, *tmp = NULL, *cp, *p;
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size_t len;
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if (a == NULL || *a == '\0')
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@@ -201,10 +213,8 @@ kex_names_cat(const char *a, const char *b)
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}
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strlcpy(ret, a, len);
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for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) {
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- if ((m = match_list(ret, p, NULL)) != NULL) {
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- free(m);
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+ if (has_any_alg(ret, p))
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continue; /* Algorithm already present */
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- }
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if (strlcat(ret, ",", len) >= len ||
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strlcat(ret, p, len) >= len) {
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free(tmp);
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@@ -466,7 +485,12 @@ kex_protocol_error(int type, u_int32_t seq, struct ssh *ssh)
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{
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int r;
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- error("kex protocol error: type %d seq %u", type, seq);
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+ /* If in strict mode, any unexpected message is an error */
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+ if ((ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict) {
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+ ssh_packet_disconnect(ssh, "strict KEX violation: "
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+ "unexpected packet type %u (seqnr %u)", type, seq);
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+ }
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+ error_f("type %u seq %u", type, seq);
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if ((r = sshpkt_start(ssh, SSH2_MSG_UNIMPLEMENTED)) != 0 ||
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(r = sshpkt_put_u32(ssh, seq)) != 0 ||
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(r = sshpkt_send(ssh)) != 0)
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@@ -548,6 +572,11 @@ kex_input_ext_info(int type, u_int32_t seq, struct ssh *ssh)
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ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &kex_protocol_error);
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if ((r = sshpkt_get_u32(ssh, &ninfo)) != 0)
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return r;
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+ if (ninfo >= 1024) {
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+ error("SSH2_MSG_EXT_INFO with too many entries, expected "
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+ "<=1024, received %u", ninfo);
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+ return dispatch_protocol_error(type, seq, ssh);
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+ }
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for (i = 0; i < ninfo; i++) {
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if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0)
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return r;
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@@ -681,7 +705,7 @@ kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)
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error_f("no kex");
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return SSH_ERR_INTERNAL_ERROR;
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}
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- ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, NULL);
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+ ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_protocol_error);
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ptr = sshpkt_ptr(ssh, &dlen);
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if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
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return r;
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@@ -717,7 +741,7 @@ kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)
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if (!(kex->flags & KEX_INIT_SENT))
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if ((r = kex_send_kexinit(ssh)) != 0)
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return r;
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- if ((r = kex_choose_conf(ssh)) != 0)
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+ if ((r = kex_choose_conf(ssh, seq)) != 0)
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return r;
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if (kex->kex_type < KEX_MAX && kex->kex[kex->kex_type] != NULL)
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@@ -981,20 +1005,14 @@ proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
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return (1);
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}
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-/* returns non-zero if proposal contains any algorithm from algs */
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static int
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-has_any_alg(const char *proposal, const char *algs)
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+kexalgs_contains(char **peer, const char *ext)
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{
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- char *cp;
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-
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- if ((cp = match_list(proposal, algs, NULL)) == NULL)
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- return 0;
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- free(cp);
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- return 1;
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+ return has_any_alg(peer[PROPOSAL_KEX_ALGS], ext);
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}
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static int
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-kex_choose_conf(struct ssh *ssh)
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+kex_choose_conf(struct ssh *ssh, uint32_t seq)
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{
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struct kex *kex = ssh->kex;
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struct newkeys *newkeys;
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@@ -1019,13 +1037,23 @@ kex_choose_conf(struct ssh *ssh)
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sprop=peer;
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}
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- /* Check whether client supports ext_info_c */
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- if (kex->server && (kex->flags & KEX_INITIAL)) {
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- char *ext;
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-
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- ext = match_list("ext-info-c", peer[PROPOSAL_KEX_ALGS], NULL);
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- kex->ext_info_c = (ext != NULL);
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- free(ext);
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+ /* Check whether peer supports ext_info/kex_strict */
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+ if ((kex->flags & KEX_INITIAL) != 0) {
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+ if (kex->server) {
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+ kex->ext_info_c = kexalgs_contains(peer, "ext-info-c");
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+ kex->kex_strict = kexalgs_contains(peer,
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+ "kex-strict-c-v00@openssh.com");
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+ } else {
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+ kex->kex_strict = kexalgs_contains(peer,
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+ "kex-strict-s-v00@openssh.com");
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+ }
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+ if (kex->kex_strict) {
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+ debug3_f("will use strict KEX ordering");
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+ if (seq != 0)
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+ ssh_packet_disconnect(ssh,
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+ "strict KEX violation: "
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+ "KEXINIT was not the first packet");
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+ }
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}
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/* Check whether client supports rsa-sha2 algorithms */
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diff --git a/kex.h b/kex.h
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index 5f7ef784..272ebb43 100644
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--- a/kex.h
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+++ b/kex.h
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@@ -149,6 +149,7 @@ struct kex {
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u_int kex_type;
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char *server_sig_algs;
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int ext_info_c;
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+ int kex_strict;
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struct sshbuf *my;
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struct sshbuf *peer;
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struct sshbuf *client_version;
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diff --git a/packet.c b/packet.c
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index 52017def..beb214f9 100644
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--- a/packet.c
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+++ b/packet.c
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@@ -1207,8 +1207,13 @@ ssh_packet_send2_wrapped(struct ssh *ssh)
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sshbuf_dump(state->output, stderr);
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#endif
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/* increment sequence number for outgoing packets */
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- if (++state->p_send.seqnr == 0)
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+ if (++state->p_send.seqnr == 0) {
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+ if ((ssh->kex->flags & KEX_INITIAL) != 0) {
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+ ssh_packet_disconnect(ssh, "outgoing sequence number "
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+ "wrapped during initial key exchange");
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+ }
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logit("outgoing seqnr wraps around");
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+ }
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if (++state->p_send.packets == 0)
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if (!(ssh->compat & SSH_BUG_NOREKEY))
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return SSH_ERR_NEED_REKEY;
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@@ -1216,6 +1221,11 @@ ssh_packet_send2_wrapped(struct ssh *ssh)
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state->p_send.bytes += len;
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sshbuf_reset(state->outgoing_packet);
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+ if (type == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
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+ debug_f("resetting send seqnr %u", state->p_send.seqnr);
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+ state->p_send.seqnr = 0;
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+ }
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+
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if (type == SSH2_MSG_NEWKEYS)
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r = ssh_set_newkeys(ssh, MODE_OUT);
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else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
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@@ -1344,8 +1354,7 @@ ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
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/* Stay in the loop until we have received a complete packet. */
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for (;;) {
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/* Try to read a packet from the buffer. */
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- r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
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- if (r != 0)
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+ if ((r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p)) != 0)
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break;
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/* If we got a packet, return it. */
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if (*typep != SSH_MSG_NONE)
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@@ -1629,10 +1615,16 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
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if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
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goto out;
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}
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+
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if (seqnr_p != NULL)
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*seqnr_p = state->p_read.seqnr;
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- if (++state->p_read.seqnr == 0)
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+ if (++state->p_read.seqnr == 0) {
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+ if ((ssh->kex->flags & KEX_INITIAL) != 0) {
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+ ssh_packet_disconnect(ssh, "incoming sequence number "
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+ "wrapped during initial key exchange");
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+ }
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logit("incoming seqnr wraps around");
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+ }
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if (++state->p_read.packets == 0)
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if (!(ssh->compat & SSH_BUG_NOREKEY))
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return SSH_ERR_NEED_REKEY;
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@@ -1698,6 +1690,10 @@ ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
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#endif
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/* reset for next packet */
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state->packlen = 0;
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+ if (*typep == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
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+ debug_f("resetting read seqnr %u", state->p_read.seqnr);
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+ state->p_read.seqnr = 0;
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+ }
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if ((r = ssh_packet_check_rekey(ssh)) != 0)
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return r;
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@@ -1720,10 +1716,39 @@ ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
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r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
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if (r != 0)
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return r;
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- if (*typep) {
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- state->keep_alive_timeouts = 0;
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- DBG(debug("received packet type %d", *typep));
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+ if (*typep == 0) {
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+ /* no message ready */
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+ return 0;
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}
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+ state->keep_alive_timeouts = 0;
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+ DBG(debug("received packet type %d", *typep));
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+
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+ /* Always process disconnect messages */
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+ if (*typep == SSH2_MSG_DISCONNECT) {
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+ if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
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+ (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
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+ return r;
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+ /* Ignore normal client exit notifications */
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+ do_log2(ssh->state->server_side &&
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+ reason == SSH2_DISCONNECT_BY_APPLICATION ?
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+ SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
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+ "Received disconnect from %s port %d:"
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+ "%u: %.400s", ssh_remote_ipaddr(ssh),
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+ ssh_remote_port(ssh), reason, msg);
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+ free(msg);
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+ return SSH_ERR_DISCONNECTED;
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+ }
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+
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+ /*
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+ * Do not implicitly handle any messages here during initial
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+ * KEX when in strict mode. They will be need to be allowed
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+ * explicitly by the KEX dispatch table or they will generate
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+ * protocol errors.
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+ */
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+ if (ssh->kex != NULL &&
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+ (ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict)
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+ return 0;
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+ /* Implicitly handle transport-level messages */
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switch (*typep) {
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case SSH2_MSG_IGNORE:
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debug3("Received SSH2_MSG_IGNORE");
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@@ -1738,19 +1763,6 @@ ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
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debug("Remote: %.900s", msg);
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free(msg);
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|
break;
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- case SSH2_MSG_DISCONNECT:
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- if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
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- (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
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|
- return r;
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- /* Ignore normal client exit notifications */
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|
- do_log2(ssh->state->server_side &&
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- reason == SSH2_DISCONNECT_BY_APPLICATION ?
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- SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
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- "Received disconnect from %s port %d:"
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- "%u: %.400s", ssh_remote_ipaddr(ssh),
|
||||||
|
- ssh_remote_port(ssh), reason, msg);
|
||||||
|
- free(msg);
|
||||||
|
- return SSH_ERR_DISCONNECTED;
|
||||||
|
case SSH2_MSG_UNIMPLEMENTED:
|
||||||
|
if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
|
||||||
|
return r;
|
||||||
|
@@ -2242,6 +2254,7 @@ kex_to_blob(struct sshbuf *m, struct kex *kex)
|
||||||
|
(r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
|
||||||
|
(r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
|
||||||
|
(r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
|
||||||
|
+ (r = sshbuf_put_u32(m, kex->kex_strict)) != 0 ||
|
||||||
|
(r = sshbuf_put_stringb(m, kex->my)) != 0 ||
|
||||||
|
(r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
|
||||||
|
(r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
|
||||||
|
@@ -2404,6 +2417,7 @@ kex_from_blob(struct sshbuf *m, struct kex **kexp)
|
||||||
|
(r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
|
||||||
|
(r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
|
||||||
|
(r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
|
||||||
|
+ (r = sshbuf_get_u32(m, &kex->kex_strict)) != 0 ||
|
||||||
|
(r = sshbuf_get_stringb(m, kex->my)) != 0 ||
|
||||||
|
(r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
|
||||||
|
(r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
|
||||||
|
@@ -2732,6 +2746,7 @@ sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
|
||||||
|
vsnprintf(buf, sizeof(buf), fmt, args);
|
||||||
|
va_end(args);
|
||||||
|
|
||||||
|
+ debug2_f("sending SSH2_MSG_DISCONNECT: %s", buf);
|
||||||
|
if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
|
||||||
|
(r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
|
||||||
|
(r = sshpkt_put_cstring(ssh, buf)) != 0 ||
|
||||||
|
diff --git a/sshconnect2.c b/sshconnect2.c
|
||||||
|
index df6caf81..0cccbcc4 100644
|
||||||
|
--- a/sshconnect2.c
|
||||||
|
+++ b/sshconnect2.c
|
||||||
|
@@ -253,7 +253,8 @@ ssh_kex2(struct ssh *ssh, char *host, st
|
||||||
|
fatal_fr(r, "kex_assemble_namelist");
|
||||||
|
free(all_key);
|
||||||
|
|
||||||
|
- if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL)
|
||||||
|
+ if ((s = kex_names_cat(options.kex_algorithms,
|
||||||
|
+ "ext-info-c,kex-strict-c-v00@openssh.com")) == NULL)
|
||||||
|
fatal_f("kex_names_cat");
|
||||||
|
myproposal[PROPOSAL_KEX_ALGS] = prop_kex = compat_kex_proposal(ssh, s);
|
||||||
|
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
|
||||||
|
@@ -358,7 +358,6 @@ struct cauthmethod {
|
||||||
|
};
|
||||||
|
|
||||||
|
static int input_userauth_service_accept(int, u_int32_t, struct ssh *);
|
||||||
|
-static int input_userauth_ext_info(int, u_int32_t, struct ssh *);
|
||||||
|
static int input_userauth_success(int, u_int32_t, struct ssh *);
|
||||||
|
static int input_userauth_failure(int, u_int32_t, struct ssh *);
|
||||||
|
static int input_userauth_banner(int, u_int32_t, struct ssh *);
|
||||||
|
@@ -472,7 +471,7 @@ ssh_userauth2(struct ssh *ssh, const char *local_user,
|
||||||
|
|
||||||
|
ssh->authctxt = &authctxt;
|
||||||
|
ssh_dispatch_init(ssh, &input_userauth_error);
|
||||||
|
- ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info);
|
||||||
|
+ ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, kex_input_ext_info);
|
||||||
|
ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept);
|
||||||
|
ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */
|
||||||
|
pubkey_cleanup(ssh);
|
||||||
|
@@ -531,12 +530,6 @@ input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh)
|
||||||
|
}
|
||||||
|
|
||||||
|
/* ARGSUSED */
|
||||||
|
-static int
|
||||||
|
-input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh)
|
||||||
|
-{
|
||||||
|
- return kex_input_ext_info(type, seqnr, ssh);
|
||||||
|
-}
|
||||||
|
-
|
||||||
|
void
|
||||||
|
userauth(struct ssh *ssh, char *authlist)
|
||||||
|
{
|
||||||
|
@@ -615,6 +608,7 @@ input_userauth_success(int type, u_int32_t seq, struct ssh *ssh)
|
||||||
|
free(authctxt->methoddata);
|
||||||
|
authctxt->methoddata = NULL;
|
||||||
|
authctxt->success = 1; /* break out */
|
||||||
|
+ ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, dispatch_protocol_error);
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
diff -up openssh-8.7p1/sshd.c.kexstrict openssh-8.7p1/sshd.c
|
||||||
|
--- openssh-8.7p1/sshd.c.kexstrict 2023-11-27 13:19:18.855433602 +0100
|
||||||
|
+++ openssh-8.7p1/sshd.c 2023-11-27 13:28:10.441325314 +0100
|
||||||
|
@@ -2531,10 +2531,14 @@ do_ssh2_kex(struct ssh *ssh)
|
||||||
|
struct kex *kex;
|
||||||
|
char *hostkey_types = NULL;
|
||||||
|
char *prop_kex = NULL, *prop_enc = NULL, *prop_hostkey = NULL;
|
||||||
|
+ char *cp;
|
||||||
|
int r;
|
||||||
|
|
||||||
|
- myproposal[PROPOSAL_KEX_ALGS] = prop_kex = compat_kex_proposal(ssh,
|
||||||
|
- options.kex_algorithms);
|
||||||
|
+ if ((cp = kex_names_cat(options.kex_algorithms,
|
||||||
|
+ "kex-strict-s-v00@openssh.com")) == NULL)
|
||||||
|
+ fatal_f("kex_names_cat");
|
||||||
|
+
|
||||||
|
+ myproposal[PROPOSAL_KEX_ALGS] = prop_kex = compat_kex_proposal(ssh, cp);
|
||||||
|
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
|
||||||
|
myproposal[PROPOSAL_ENC_ALGS_STOC] = prop_enc =
|
||||||
|
compat_cipher_proposal(ssh, options.ciphers);
|
||||||
|
@@ -2586,7 +2586,7 @@ do_ssh2_kex(struct ssh *ssh)
|
||||||
|
if (gss && orig)
|
||||||
|
xasprintf(&newstr, "%s,%s", gss, orig);
|
||||||
|
else if (gss)
|
||||||
|
- newstr = gss;
|
||||||
|
+ xasprintf(&newstr, "%s,%s", gss, "kex-strict-s-v00@openssh.com");
|
||||||
|
else if (orig)
|
||||||
|
newstr = orig;
|
||||||
|
|
||||||
|
@@ -2650,6 +2654,7 @@ do_ssh2_kex(struct ssh *ssh)
|
||||||
|
#endif
|
||||||
|
free(prop_kex);
|
||||||
|
free(prop_enc);
|
||||||
|
+ free(cp);
|
||||||
|
free(prop_hostkey);
|
||||||
|
debug("KEX done");
|
||||||
|
}
|
||||||
@ -0,0 +1,57 @@
|
|||||||
|
diff --git a/ssh.c b/ssh.c
|
||||||
|
index 35c48e62..48d93ddf 100644
|
||||||
|
--- a/ssh.c
|
||||||
|
+++ b/ssh.c
|
||||||
|
@@ -626,6 +626,41 @@ ssh_conn_info_free(struct ssh_conn_info *cinfo)
|
||||||
|
free(cinfo);
|
||||||
|
}
|
||||||
|
|
||||||
|
+static int
|
||||||
|
+valid_hostname(const char *s)
|
||||||
|
+{
|
||||||
|
+ size_t i;
|
||||||
|
+
|
||||||
|
+ if (*s == '-')
|
||||||
|
+ return 0;
|
||||||
|
+ for (i = 0; s[i] != 0; i++) {
|
||||||
|
+ if (strchr("'`\"$\\;&<>|(){}", s[i]) != NULL ||
|
||||||
|
+ isspace((u_char)s[i]) || iscntrl((u_char)s[i]))
|
||||||
|
+ return 0;
|
||||||
|
+ }
|
||||||
|
+ return 1;
|
||||||
|
+}
|
||||||
|
+
|
||||||
|
+static int
|
||||||
|
+valid_ruser(const char *s)
|
||||||
|
+{
|
||||||
|
+ size_t i;
|
||||||
|
+
|
||||||
|
+ if (*s == '-')
|
||||||
|
+ return 0;
|
||||||
|
+ for (i = 0; s[i] != 0; i++) {
|
||||||
|
+ if (strchr("'`\";&<>|(){}", s[i]) != NULL)
|
||||||
|
+ return 0;
|
||||||
|
+ /* Disallow '-' after whitespace */
|
||||||
|
+ if (isspace((u_char)s[i]) && s[i + 1] == '-')
|
||||||
|
+ return 0;
|
||||||
|
+ /* Disallow \ in last position */
|
||||||
|
+ if (s[i] == '\\' && s[i + 1] == '\0')
|
||||||
|
+ return 0;
|
||||||
|
+ }
|
||||||
|
+ return 1;
|
||||||
|
+}
|
||||||
|
+
|
||||||
|
/*
|
||||||
|
* Main program for the ssh client.
|
||||||
|
*/
|
||||||
|
@@ -1118,6 +1153,10 @@ main(int ac, char **av)
|
||||||
|
if (!host)
|
||||||
|
usage();
|
||||||
|
|
||||||
|
+ if (!valid_hostname(host))
|
||||||
|
+ fatal("hostname contains invalid characters");
|
||||||
|
+ if (options.user != NULL && !valid_ruser(options.user))
|
||||||
|
+ fatal("remote username contains invalid characters");
|
||||||
|
host_arg = xstrdup(host);
|
||||||
|
|
||||||
|
/* Initialize the command to execute on remote host. */
|
||||||
Loading…
Reference in new issue