openssh/openssh-8.0p1-openssl-kdf.patch

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commit 2c3ef499bfffce3cfd315edeebf202850ba4e00a
Author: Jakub Jelen <jjelen@redhat.com>
Date: Tue Apr 16 15:35:18 2019 +0200
Use the new OpenSSL KDF
diff --git a/configure.ac b/configure.ac
index 2a455e4e..e01c3d43 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2712,6 +2712,7 @@ if test "x$openssl" = "xyes" ; then
HMAC_CTX_init \
RSA_generate_key_ex \
RSA_get_default_method \
+ EVP_KDF_CTX_new \
])
# OpenSSL_add_all_algorithms may be a macro.
diff --git a/kex.c b/kex.c
index b6f041f4..1fbce2bb 100644
--- a/kex.c
+++ b/kex.c
@@ -38,6 +38,11 @@
#ifdef WITH_OPENSSL
#include <openssl/crypto.h>
#include <openssl/dh.h>
+# ifdef HAVE_EVP_KDF_CTX_NEW
+# include <openssl/kdf.h>
+# include <openssl/param_build.h>
+# include <openssl/core_names.h>
+# endif
#endif
#include "ssh.h"
@@ -942,6 +945,112 @@ kex_choose_conf(struct ssh *ssh)
return r;
}
+#ifdef HAVE_EVP_KDF_CTX_NEW
+static const char *
+digest_to_md(int digest_type)
+{
+ switch (digest_type) {
+ case SSH_DIGEST_SHA1:
+ return SN_sha1;
+ case SSH_DIGEST_SHA256:
+ return SN_sha256;
+ case SSH_DIGEST_SHA384:
+ return SN_sha384;
+ case SSH_DIGEST_SHA512:
+ return SN_sha512;
+ }
+ return NULL;
+}
+
+static int
+derive_key(struct ssh *ssh, int id, u_int need, u_char *hash, u_int hashlen,
+ const struct sshbuf *shared_secret, u_char **keyp)
+{
+ struct kex *kex = ssh->kex;
+ u_char *key = NULL;
+ int r, key_len;
+
+ EVP_KDF *kdf = EVP_KDF_fetch(NULL, "SSHKDF", NULL);
+ EVP_KDF_CTX *ctx = NULL;
+ OSSL_PARAM_BLD *param_bld = OSSL_PARAM_BLD_new();
+ OSSL_PARAM *params = NULL;
+ const char *md = digest_to_md(kex->hash_alg);
+ char keytype = (char)id;
+
+ if (!kdf) {
+ r = SSH_ERR_LIBCRYPTO_ERROR;
+ goto out;
+ }
+ ctx = EVP_KDF_CTX_new(kdf);
+ EVP_KDF_free(kdf);
+ if (!ctx) {
+ r = SSH_ERR_LIBCRYPTO_ERROR;
+ goto out;
+ }
+ if (md == NULL) {
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto out;
+ }
+
+ if (param_bld == NULL) {
+ EVP_KDF_CTX_free(ctx);
+ return -1;
+ }
+ if ((key_len = ssh_digest_bytes(kex->hash_alg)) == 0) {
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto out;
+ }
+
+ key_len = ROUNDUP(need, key_len);
+ if ((key = calloc(1, key_len)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+
+ r = OSSL_PARAM_BLD_push_utf8_string(param_bld, OSSL_KDF_PARAM_DIGEST,
+ md, strlen(md)) && /* SN */
+ OSSL_PARAM_BLD_push_octet_string(param_bld, OSSL_KDF_PARAM_KEY,
+ sshbuf_ptr(shared_secret), sshbuf_len(shared_secret)) &&
+ OSSL_PARAM_BLD_push_octet_string(param_bld, OSSL_KDF_PARAM_SSHKDF_XCGHASH,
+ hash, hashlen) &&
+ OSSL_PARAM_BLD_push_octet_string(param_bld, OSSL_KDF_PARAM_SSHKDF_SESSION_ID,
+ sshbuf_ptr(kex->session_id), sshbuf_len(kex->session_id)) &&
+ OSSL_PARAM_BLD_push_utf8_string(param_bld, OSSL_KDF_PARAM_SSHKDF_TYPE,
+ &keytype, 1);
+ if (r != 1) {
+ r = SSH_ERR_LIBCRYPTO_ERROR;
+ goto out;
+ }
+
+ params = OSSL_PARAM_BLD_to_param(param_bld);
+ if (params == NULL) {
+ r = SSH_ERR_LIBCRYPTO_ERROR;
+ goto out;
+ }
+ r = EVP_KDF_derive(ctx, key, key_len, params);
+ if (r != 1) {
+ r = SSH_ERR_LIBCRYPTO_ERROR;
+ goto out;
+ }
+#ifdef DEBUG_KEX
+ fprintf(stderr, "key '%c'== ", id);
+ dump_digest("key", key, key_len);
+#endif
+ *keyp = key;
+ key = NULL;
+ r = 0;
+
+out:
+ OSSL_PARAM_BLD_free(param_bld);
+ OSSL_PARAM_free(params);
+ free (key);
+ EVP_KDF_CTX_free(ctx);
+ if (r < 0) {
+ return r;
+ }
+ return 0;
+}
+#else
static int
derive_key(struct ssh *ssh, int id, u_int need, u_char *hash, u_int hashlen,
const struct sshbuf *shared_secret, u_char **keyp)
@@ -1004,6 +1096,7 @@ derive_key(struct ssh *ssh, int id, u_int need, u_char *hash, u_int hashlen,
ssh_digest_free(hashctx);
return r;
}
+#endif /* HAVE_OPENSSL_EVP_KDF_CTX_NEW */
#define NKEYS 6
int