103 lines
3.6 KiB
Diff
103 lines
3.6 KiB
Diff
diff -up openssh-8.7p1/kex.c.minsha1 openssh-8.7p1/kex.c
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--- openssh-8.7p1/kex.c.minsha1 2021-12-20 17:38:51.438294309 +0100
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+++ openssh-8.7p1/kex.c 2021-12-21 11:02:48.379991319 +0100
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@@ -994,6 +994,35 @@ kex_choose_conf(struct ssh *ssh)
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free(ext);
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}
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+ /* Check whether client supports rsa-sha2 algorithms */
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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("rsa-sha2-256", peer[PROPOSAL_SERVER_HOST_KEY_ALGS], NULL);
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+ if (ext) {
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+ kex->flags |= KEX_RSA_SHA2_256_SUPPORTED;
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+ free(ext);
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+ }
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+
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+ ext = match_list("rsa-sha2-512", peer[PROPOSAL_SERVER_HOST_KEY_ALGS], NULL);
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+ if (ext) {
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+ kex->flags |= KEX_RSA_SHA2_512_SUPPORTED;
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+ free(ext);
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+ }
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+
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+ ext = match_list("rsa-sha2-256-cert-v01@openssh.com", peer[PROPOSAL_SERVER_HOST_KEY_ALGS], NULL);
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+ if (ext) {
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+ kex->flags |= KEX_RSA_SHA2_256_SUPPORTED;
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+ free(ext);
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+ }
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+
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+ ext = match_list("rsa-sha2-512-cert-v01@openssh.com", peer[PROPOSAL_SERVER_HOST_KEY_ALGS], NULL);
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+ if (ext) {
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+ kex->flags |= KEX_RSA_SHA2_512_SUPPORTED;
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+ free(ext);
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+ }
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+ }
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+
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/* Algorithm Negotiation */
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if ((r = choose_kex(kex, cprop[PROPOSAL_KEX_ALGS],
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sprop[PROPOSAL_KEX_ALGS])) != 0) {
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diff -up openssh-8.7p1/kex.h.minsha1 openssh-8.7p1/kex.h
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--- openssh-8.7p1/kex.h.minsha1 2021-12-20 17:38:51.430294240 +0100
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+++ openssh-8.7p1/kex.h 2021-12-21 10:56:29.066735608 +0100
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@@ -116,6 +116,8 @@ enum kex_exchange {
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#define KEX_INIT_SENT 0x0001
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#define KEX_INITIAL 0x0002
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+#define KEX_RSA_SHA2_256_SUPPORTED 0x0004
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+#define KEX_RSA_SHA2_512_SUPPORTED 0x0008
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struct sshenc {
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char *name;
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diff -up openssh-8.7p1/serverloop.c.minsha1 openssh-8.7p1/serverloop.c
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--- openssh-8.7p1/serverloop.c.minsha1 2021-08-20 06:03:49.000000000 +0200
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+++ openssh-8.7p1/serverloop.c 2021-12-21 11:01:00.594047538 +0100
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@@ -684,7 +685,7 @@ server_input_hostkeys_prove(struct ssh *
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struct sshbuf *resp = NULL;
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struct sshbuf *sigbuf = NULL;
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struct sshkey *key = NULL, *key_pub = NULL, *key_prv = NULL;
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- int r, ndx, kexsigtype, use_kexsigtype, success = 0;
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+ int r, ndx, success = 0;
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const u_char *blob;
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u_char *sig = 0;
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size_t blen, slen;
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@@ -692,9 +693,11 @@ server_input_hostkeys_prove(struct ssh *
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if ((resp = sshbuf_new()) == NULL || (sigbuf = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new");
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- kexsigtype = sshkey_type_plain(
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- sshkey_type_from_name(ssh->kex->hostkey_alg));
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while (ssh_packet_remaining(ssh) > 0) {
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+ const char *pkexstr = NULL;
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+ const char *rsa_sha2_256 = "rsa-sha2-256";
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+ const char *rsa_sha2_512 = "rsa-sha2-512";
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+
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sshkey_free(key);
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key = NULL;
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if ((r = sshpkt_get_string_direct(ssh, &blob, &blen)) != 0 ||
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@@ -726,8 +729,13 @@ server_input_hostkeys_prove(struct ssh *
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* For RSA keys, prefer to use the signature type negotiated
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* during KEX to the default (SHA1).
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*/
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- use_kexsigtype = kexsigtype == KEY_RSA &&
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- sshkey_type_plain(key->type) == KEY_RSA;
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+ if (sshkey_type_plain(key->type) == KEY_RSA) {
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+ if (ssh->kex->flags & KEX_RSA_SHA2_512_SUPPORTED)
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+ pkexstr = rsa_sha2_512;
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+ else if (ssh->kex->flags & KEX_RSA_SHA2_256_SUPPORTED)
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+ pkexstr = rsa_sha2_256;
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+ }
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+
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if ((r = sshbuf_put_cstring(sigbuf,
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"hostkeys-prove-00@openssh.com")) != 0 ||
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(r = sshbuf_put_stringb(sigbuf,
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@@ -735,7 +743,7 @@ server_input_hostkeys_prove(struct ssh *
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(r = sshkey_puts(key, sigbuf)) != 0 ||
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(r = ssh->kex->sign(ssh, key_prv, key_pub, &sig, &slen,
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sshbuf_ptr(sigbuf), sshbuf_len(sigbuf),
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- use_kexsigtype ? ssh->kex->hostkey_alg : NULL)) != 0 ||
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+ pkexstr)) != 0 ||
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(r = sshbuf_put_string(resp, sig, slen)) != 0) {
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error_fr(r, "assemble signature");
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goto out;
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