Adding upstream version 1:9.2p1.upstream/1%9.2p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 526 insertions, 0 deletions

diff --git a/cipher.c b/cipher.c
new file mode 100644
index 0000000..02aea40
--- /dev/null
+++ b/cipher.c
@@ -0,0 +1,526 @@
+/* $OpenBSD: cipher.c,v 1.119 2021/04/03 06:18:40 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ *
+ * Copyright (c) 1999 Niels Provos.  All rights reserved.
+ * Copyright (c) 1999, 2000 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+
+#include <string.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "cipher.h"
+#include "misc.h"
+#include "sshbuf.h"
+#include "ssherr.h"
+#include "digest.h"
+
+#include "openbsd-compat/openssl-compat.h"
+
+#ifndef WITH_OPENSSL
+#define EVP_CIPHER_CTX void
+#endif
+
+struct sshcipher_ctx {
+	int	plaintext;
+	int	encrypt;
+	EVP_CIPHER_CTX *evp;
+	struct chachapoly_ctx *cp_ctx;
+	struct aesctr_ctx ac_ctx; /* XXX union with evp? */
+	const struct sshcipher *cipher;
+};
+
+struct sshcipher {
+	char	*name;
+	u_int	block_size;
+	u_int	key_len;
+	u_int	iv_len;		/* defaults to block_size */
+	u_int	auth_len;
+	u_int	flags;
+#define CFLAG_CBC		(1<<0)
+#define CFLAG_CHACHAPOLY	(1<<1)
+#define CFLAG_AESCTR		(1<<2)
+#define CFLAG_NONE		(1<<3)
+#define CFLAG_INTERNAL		CFLAG_NONE /* Don't use "none" for packets */
+#ifdef WITH_OPENSSL
+	const EVP_CIPHER	*(*evptype)(void);
+#else
+	void	*ignored;
+#endif
+};
+
+static const struct sshcipher ciphers[] = {
+#ifdef WITH_OPENSSL
+#ifndef OPENSSL_NO_DES
+	{ "3des-cbc",		8, 24, 0, 0, CFLAG_CBC, EVP_des_ede3_cbc },
+#endif
+	{ "aes128-cbc",		16, 16, 0, 0, CFLAG_CBC, EVP_aes_128_cbc },
+	{ "aes192-cbc",		16, 24, 0, 0, CFLAG_CBC, EVP_aes_192_cbc },
+	{ "aes256-cbc",		16, 32, 0, 0, CFLAG_CBC, EVP_aes_256_cbc },
+	{ "aes128-ctr",		16, 16, 0, 0, 0, EVP_aes_128_ctr },
+	{ "aes192-ctr",		16, 24, 0, 0, 0, EVP_aes_192_ctr },
+	{ "aes256-ctr",		16, 32, 0, 0, 0, EVP_aes_256_ctr },
+	{ "aes128-gcm@openssh.com",
+				16, 16, 12, 16, 0, EVP_aes_128_gcm },
+	{ "aes256-gcm@openssh.com",
+				16, 32, 12, 16, 0, EVP_aes_256_gcm },
+#else
+	{ "aes128-ctr",		16, 16, 0, 0, CFLAG_AESCTR, NULL },
+	{ "aes192-ctr",		16, 24, 0, 0, CFLAG_AESCTR, NULL },
+	{ "aes256-ctr",		16, 32, 0, 0, CFLAG_AESCTR, NULL },
+#endif
+	{ "chacha20-poly1305@openssh.com",
+				8, 64, 0, 16, CFLAG_CHACHAPOLY, NULL },
+	{ "none",		8, 0, 0, 0, CFLAG_NONE, NULL },
+
+	{ NULL,			0, 0, 0, 0, 0, NULL }
+};
+
+/*--*/
+
+/* Returns a comma-separated list of supported ciphers. */
+char *
+cipher_alg_list(char sep, int auth_only)
+{
+	char *tmp, *ret = NULL;
+	size_t nlen, rlen = 0;
+	const struct sshcipher *c;
+
+	for (c = ciphers; c->name != NULL; c++) {
+		if ((c->flags & CFLAG_INTERNAL) != 0)
+			continue;
+		if (auth_only && c->auth_len == 0)
+			continue;
+		if (ret != NULL)
+			ret[rlen++] = sep;
+		nlen = strlen(c->name);
+		if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
+			free(ret);
+			return NULL;
+		}
+		ret = tmp;
+		memcpy(ret + rlen, c->name, nlen + 1);
+		rlen += nlen;
+	}
+	return ret;
+}
+
+const char *
+compression_alg_list(int compression)
+{
+#ifdef WITH_ZLIB
+	return compression ? "zlib@openssh.com,zlib,none" :
+	    "none,zlib@openssh.com,zlib";
+#else
+	return "none";
+#endif
+}
+
+u_int
+cipher_blocksize(const struct sshcipher *c)
+{
+	return (c->block_size);
+}
+
+u_int
+cipher_keylen(const struct sshcipher *c)
+{
+	return (c->key_len);
+}
+
+u_int
+cipher_seclen(const struct sshcipher *c)
+{
+	if (strcmp("3des-cbc", c->name) == 0)
+		return 14;
+	return cipher_keylen(c);
+}
+
+u_int
+cipher_authlen(const struct sshcipher *c)
+{
+	return (c->auth_len);
+}
+
+u_int
+cipher_ivlen(const struct sshcipher *c)
+{
+	/*
+	 * Default is cipher block size, except for chacha20+poly1305 that
+	 * needs no IV. XXX make iv_len == -1 default?
+	 */
+	return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ?
+	    c->iv_len : c->block_size;
+}
+
+u_int
+cipher_is_cbc(const struct sshcipher *c)
+{
+	return (c->flags & CFLAG_CBC) != 0;
+}
+
+u_int
+cipher_ctx_is_plaintext(struct sshcipher_ctx *cc)
+{
+	return cc->plaintext;
+}
+
+const struct sshcipher *
+cipher_by_name(const char *name)
+{
+	const struct sshcipher *c;
+	for (c = ciphers; c->name != NULL; c++)
+		if (strcmp(c->name, name) == 0)
+			return c;
+	return NULL;
+}
+
+#define	CIPHER_SEP	","
+int
+ciphers_valid(const char *names)
+{
+	const struct sshcipher *c;
+	char *cipher_list, *cp;
+	char *p;
+
+	if (names == NULL || strcmp(names, "") == 0)
+		return 0;
+	if ((cipher_list = cp = strdup(names)) == NULL)
+		return 0;
+	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
+	    (p = strsep(&cp, CIPHER_SEP))) {
+		c = cipher_by_name(p);
+		if (c == NULL || (c->flags & CFLAG_INTERNAL) != 0) {
+			free(cipher_list);
+			return 0;
+		}
+	}
+	free(cipher_list);
+	return 1;
+}
+
+const char *
+cipher_warning_message(const struct sshcipher_ctx *cc)
+{
+	if (cc == NULL || cc->cipher == NULL)
+		return NULL;
+	/* XXX repurpose for CBC warning */
+	return NULL;
+}
+
+int
+cipher_init(struct sshcipher_ctx **ccp, const struct sshcipher *cipher,
+    const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
+    int do_encrypt)
+{
+	struct sshcipher_ctx *cc = NULL;
+	int ret = SSH_ERR_INTERNAL_ERROR;
+#ifdef WITH_OPENSSL
+	const EVP_CIPHER *type;
+	int klen;
+#endif
+
+	*ccp = NULL;
+	if ((cc = calloc(sizeof(*cc), 1)) == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+
+	cc->plaintext = (cipher->flags & CFLAG_NONE) != 0;
+	cc->encrypt = do_encrypt;
+
+	if (keylen < cipher->key_len ||
+	    (iv != NULL && ivlen < cipher_ivlen(cipher))) {
+		ret = SSH_ERR_INVALID_ARGUMENT;
+		goto out;
+	}
+
+	cc->cipher = cipher;
+	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
+		cc->cp_ctx = chachapoly_new(key, keylen);
+		ret = cc->cp_ctx != NULL ? 0 : SSH_ERR_INVALID_ARGUMENT;
+		goto out;
+	}
+	if ((cc->cipher->flags & CFLAG_NONE) != 0) {
+		ret = 0;
+		goto out;
+	}
+#ifndef WITH_OPENSSL
+	if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
+		aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen);
+		aesctr_ivsetup(&cc->ac_ctx, iv);
+		ret = 0;
+		goto out;
+	}
+	ret = SSH_ERR_INVALID_ARGUMENT;
+	goto out;
+#else /* WITH_OPENSSL */
+	type = (*cipher->evptype)();
+	if ((cc->evp = EVP_CIPHER_CTX_new()) == NULL) {
+		ret = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if (EVP_CipherInit(cc->evp, type, NULL, (u_char *)iv,
+	    (do_encrypt == CIPHER_ENCRYPT)) == 0) {
+		ret = SSH_ERR_LIBCRYPTO_ERROR;
+		goto out;
+	}
+	if (cipher_authlen(cipher) &&
+	    !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_IV_FIXED,
+	    -1, (u_char *)iv)) {
+		ret = SSH_ERR_LIBCRYPTO_ERROR;
+		goto out;
+	}
+	klen = EVP_CIPHER_CTX_key_length(cc->evp);
+	if (klen > 0 && keylen != (u_int)klen) {
+		if (EVP_CIPHER_CTX_set_key_length(cc->evp, keylen) == 0) {
+			ret = SSH_ERR_LIBCRYPTO_ERROR;
+			goto out;
+		}
+	}
+	if (EVP_CipherInit(cc->evp, NULL, (u_char *)key, NULL, -1) == 0) {
+		ret = SSH_ERR_LIBCRYPTO_ERROR;
+		goto out;
+	}
+	ret = 0;
+#endif /* WITH_OPENSSL */
+ out:
+	if (ret == 0) {
+		/* success */
+		*ccp = cc;
+	} else {
+		if (cc != NULL) {
+#ifdef WITH_OPENSSL
+			EVP_CIPHER_CTX_free(cc->evp);
+#endif /* WITH_OPENSSL */
+			freezero(cc, sizeof(*cc));
+		}
+	}
+	return ret;
+}
+
+/*
+ * cipher_crypt() operates as following:
+ * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'.
+ * These bytes are treated as additional authenticated data for
+ * authenticated encryption modes.
+ * En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'.
+ * Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag.
+ * This tag is written on encryption and verified on decryption.
+ * Both 'aadlen' and 'authlen' can be set to 0.
+ */
+int
+cipher_crypt(struct sshcipher_ctx *cc, u_int seqnr, u_char *dest,
+   const u_char *src, u_int len, u_int aadlen, u_int authlen)
+{
+	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
+		return chachapoly_crypt(cc->cp_ctx, seqnr, dest, src,
+		    len, aadlen, authlen, cc->encrypt);
+	}
+	if ((cc->cipher->flags & CFLAG_NONE) != 0) {
+		memcpy(dest, src, aadlen + len);
+		return 0;
+	}
+#ifndef WITH_OPENSSL
+	if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
+		if (aadlen)
+			memcpy(dest, src, aadlen);
+		aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen,
+		    dest + aadlen, len);
+		return 0;
+	}
+	return SSH_ERR_INVALID_ARGUMENT;
+#else
+	if (authlen) {
+		u_char lastiv[1];
+
+		if (authlen != cipher_authlen(cc->cipher))
+			return SSH_ERR_INVALID_ARGUMENT;
+		/* increment IV */
+		if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN,
+		    1, lastiv))
+			return SSH_ERR_LIBCRYPTO_ERROR;
+		/* set tag on decyption */
+		if (!cc->encrypt &&
+		    !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_TAG,
+		    authlen, (u_char *)src + aadlen + len))
+			return SSH_ERR_LIBCRYPTO_ERROR;
+	}
+	if (aadlen) {
+		if (authlen &&
+		    EVP_Cipher(cc->evp, NULL, (u_char *)src, aadlen) < 0)
+			return SSH_ERR_LIBCRYPTO_ERROR;
+		memcpy(dest, src, aadlen);
+	}
+	if (len % cc->cipher->block_size)
+		return SSH_ERR_INVALID_ARGUMENT;
+	if (EVP_Cipher(cc->evp, dest + aadlen, (u_char *)src + aadlen,
+	    len) < 0)
+		return SSH_ERR_LIBCRYPTO_ERROR;
+	if (authlen) {
+		/* compute tag (on encrypt) or verify tag (on decrypt) */
+		if (EVP_Cipher(cc->evp, NULL, NULL, 0) < 0)
+			return cc->encrypt ?
+			    SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID;
+		if (cc->encrypt &&
+		    !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_GET_TAG,
+		    authlen, dest + aadlen + len))
+			return SSH_ERR_LIBCRYPTO_ERROR;
+	}
+	return 0;
+#endif
+}
+
+/* Extract the packet length, including any decryption necessary beforehand */
+int
+cipher_get_length(struct sshcipher_ctx *cc, u_int *plenp, u_int seqnr,
+    const u_char *cp, u_int len)
+{
+	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
+		return chachapoly_get_length(cc->cp_ctx, plenp, seqnr,
+		    cp, len);
+	if (len < 4)
+		return SSH_ERR_MESSAGE_INCOMPLETE;
+	*plenp = PEEK_U32(cp);
+	return 0;
+}
+
+void
+cipher_free(struct sshcipher_ctx *cc)
+{
+	if (cc == NULL)
+		return;
+	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
+		chachapoly_free(cc->cp_ctx);
+		cc->cp_ctx = NULL;
+	} else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
+		explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx));
+#ifdef WITH_OPENSSL
+	EVP_CIPHER_CTX_free(cc->evp);
+	cc->evp = NULL;
+#endif
+	freezero(cc, sizeof(*cc));
+}
+
+/*
+ * Exports an IV from the sshcipher_ctx required to export the key
+ * state back from the unprivileged child to the privileged parent
+ * process.
+ */
+int
+cipher_get_keyiv_len(const struct sshcipher_ctx *cc)
+{
+	const struct sshcipher *c = cc->cipher;
+
+	if ((c->flags & CFLAG_CHACHAPOLY) != 0)
+		return 0;
+	else if ((c->flags & CFLAG_AESCTR) != 0)
+		return sizeof(cc->ac_ctx.ctr);
+#ifdef WITH_OPENSSL
+	return EVP_CIPHER_CTX_iv_length(cc->evp);
+#else
+	return 0;
+#endif
+}
+
+int
+cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, size_t len)
+{
+#ifdef WITH_OPENSSL
+	const struct sshcipher *c = cc->cipher;
+	int evplen;
+#endif
+
+	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
+		if (len != 0)
+			return SSH_ERR_INVALID_ARGUMENT;
+		return 0;
+	}
+	if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
+		if (len != sizeof(cc->ac_ctx.ctr))
+			return SSH_ERR_INVALID_ARGUMENT;
+		memcpy(iv, cc->ac_ctx.ctr, len);
+		return 0;
+	}
+	if ((cc->cipher->flags & CFLAG_NONE) != 0)
+		return 0;
+
+#ifdef WITH_OPENSSL
+	evplen = EVP_CIPHER_CTX_iv_length(cc->evp);
+	if (evplen == 0)
+		return 0;
+	else if (evplen < 0)
+		return SSH_ERR_LIBCRYPTO_ERROR;
+	if ((size_t)evplen != len)
+		return SSH_ERR_INVALID_ARGUMENT;
+	if (cipher_authlen(c)) {
+		if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN,
+		    len, iv))
+			return SSH_ERR_LIBCRYPTO_ERROR;
+	} else if (!EVP_CIPHER_CTX_get_iv(cc->evp, iv, len))
+		return SSH_ERR_LIBCRYPTO_ERROR;
+#endif
+	return 0;
+}
+
+int
+cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv, size_t len)
+{
+#ifdef WITH_OPENSSL
+	const struct sshcipher *c = cc->cipher;
+	int evplen = 0;
+#endif
+
+	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
+		return 0;
+	if ((cc->cipher->flags & CFLAG_NONE) != 0)
+		return 0;
+
+#ifdef WITH_OPENSSL
+	evplen = EVP_CIPHER_CTX_iv_length(cc->evp);
+	if (evplen <= 0)
+		return SSH_ERR_LIBCRYPTO_ERROR;
+	if ((size_t)evplen != len)
+		return SSH_ERR_INVALID_ARGUMENT;
+	if (cipher_authlen(c)) {
+		/* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */
+		if (!EVP_CIPHER_CTX_ctrl(cc->evp,
+		    EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv))
+			return SSH_ERR_LIBCRYPTO_ERROR;
+	} else if (!EVP_CIPHER_CTX_set_iv(cc->evp, iv, evplen))
+		return SSH_ERR_LIBCRYPTO_ERROR;
+#endif
+	return 0;
+}