Excerpts from the release notes: * ssh-agent(1): PKCS#11 modules must now be specified by their full paths. Previously dlopen(3) could search for them in system library directories. * ssh(1): allow forwarding Unix Domain sockets via ssh -W. * ssh(1): add support for configuration tags to ssh(1). This adds a ssh_config(5) "Tag" directive and corresponding "Match tag" predicate that may be used to select blocks of configuration similar to the pf.conf(5) keywords of the same name. * ssh(1): add a "match localnetwork" predicate. This allows matching on the addresses of available network interfaces and may be used to vary the effective client configuration based on network location. * ssh-agent(1): improve isolation between loaded PKCS#11 modules by running separate ssh-pkcs11-helpers for each loaded provider. * ssh-agent(1), ssh(1): improve defences against invalid PKCS#11 modules being loaded by checking that the requested module contains the required symbol before loading it. * ssh(1): don't incorrectly disable hostname canonicalization when CanonicalizeHostname=yes and ProxyJump was expicitly set to "none". bz3567 Full release notes at https://www.openssh.com/txt/release-9.4 Relnotes: Yes Sponsored by: The FreeBSD Foundation
166 lines
4.9 KiB
C
166 lines
4.9 KiB
C
/* $OpenBSD: cipher-chachapoly-libcrypto.c,v 1.2 2023/07/17 05:26:38 djm Exp $ */
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/*
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* Copyright (c) 2013 Damien Miller <djm@mindrot.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#ifdef WITH_OPENSSL
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#include "openbsd-compat/openssl-compat.h"
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#endif
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#if defined(HAVE_EVP_CHACHA20) && !defined(HAVE_BROKEN_CHACHA20)
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#include <sys/types.h>
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#include <stdarg.h> /* needed for log.h */
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#include <string.h>
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#include <stdio.h> /* needed for misc.h */
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#include <openssl/evp.h>
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#include "log.h"
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#include "sshbuf.h"
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#include "ssherr.h"
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#include "cipher-chachapoly.h"
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struct chachapoly_ctx {
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EVP_CIPHER_CTX *main_evp, *header_evp;
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};
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struct chachapoly_ctx *
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chachapoly_new(const u_char *key, u_int keylen)
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{
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struct chachapoly_ctx *ctx;
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if (keylen != (32 + 32)) /* 2 x 256 bit keys */
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return NULL;
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if ((ctx = calloc(1, sizeof(*ctx))) == NULL)
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return NULL;
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if ((ctx->main_evp = EVP_CIPHER_CTX_new()) == NULL ||
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(ctx->header_evp = EVP_CIPHER_CTX_new()) == NULL)
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goto fail;
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if (!EVP_CipherInit(ctx->main_evp, EVP_chacha20(), key, NULL, 1))
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goto fail;
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if (!EVP_CipherInit(ctx->header_evp, EVP_chacha20(), key + 32, NULL, 1))
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goto fail;
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if (EVP_CIPHER_CTX_iv_length(ctx->header_evp) != 16)
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goto fail;
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return ctx;
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fail:
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chachapoly_free(ctx);
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return NULL;
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}
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void
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chachapoly_free(struct chachapoly_ctx *cpctx)
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{
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if (cpctx == NULL)
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return;
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EVP_CIPHER_CTX_free(cpctx->main_evp);
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EVP_CIPHER_CTX_free(cpctx->header_evp);
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freezero(cpctx, sizeof(*cpctx));
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}
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/*
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* chachapoly_crypt() operates as following:
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* En/decrypt with header key 'aadlen' bytes from 'src', storing result
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* to 'dest'. The ciphertext here is treated as additional authenticated
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* data for MAC calculation.
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* En/decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'. Use
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* POLY1305_TAGLEN bytes at offset 'len'+'aadlen' as the authentication
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* tag. This tag is written on encryption and verified on decryption.
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*/
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int
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chachapoly_crypt(struct chachapoly_ctx *ctx, u_int seqnr, u_char *dest,
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const u_char *src, u_int len, u_int aadlen, u_int authlen, int do_encrypt)
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{
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u_char seqbuf[16]; /* layout: u64 counter || u64 seqno */
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int r = SSH_ERR_INTERNAL_ERROR;
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u_char expected_tag[POLY1305_TAGLEN], poly_key[POLY1305_KEYLEN];
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/*
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* Run ChaCha20 once to generate the Poly1305 key. The IV is the
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* packet sequence number.
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*/
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memset(seqbuf, 0, sizeof(seqbuf));
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POKE_U64(seqbuf + 8, seqnr);
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memset(poly_key, 0, sizeof(poly_key));
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if (!EVP_CipherInit(ctx->main_evp, NULL, NULL, seqbuf, 1) ||
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EVP_Cipher(ctx->main_evp, poly_key,
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poly_key, sizeof(poly_key)) < 0) {
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r = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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/* If decrypting, check tag before anything else */
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if (!do_encrypt) {
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const u_char *tag = src + aadlen + len;
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poly1305_auth(expected_tag, src, aadlen + len, poly_key);
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if (timingsafe_bcmp(expected_tag, tag, POLY1305_TAGLEN) != 0) {
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r = SSH_ERR_MAC_INVALID;
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goto out;
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}
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}
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/* Crypt additional data */
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if (aadlen) {
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if (!EVP_CipherInit(ctx->header_evp, NULL, NULL, seqbuf, 1) ||
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EVP_Cipher(ctx->header_evp, dest, src, aadlen) < 0) {
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r = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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}
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/* Set Chacha's block counter to 1 */
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seqbuf[0] = 1;
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if (!EVP_CipherInit(ctx->main_evp, NULL, NULL, seqbuf, 1) ||
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EVP_Cipher(ctx->main_evp, dest + aadlen, src + aadlen, len) < 0) {
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r = SSH_ERR_LIBCRYPTO_ERROR;
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goto out;
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}
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/* If encrypting, calculate and append tag */
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if (do_encrypt) {
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poly1305_auth(dest + aadlen + len, dest, aadlen + len,
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poly_key);
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}
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r = 0;
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out:
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explicit_bzero(expected_tag, sizeof(expected_tag));
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explicit_bzero(seqbuf, sizeof(seqbuf));
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explicit_bzero(poly_key, sizeof(poly_key));
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return r;
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}
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/* Decrypt and extract the encrypted packet length */
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int
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chachapoly_get_length(struct chachapoly_ctx *ctx,
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u_int *plenp, u_int seqnr, const u_char *cp, u_int len)
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{
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u_char buf[4], seqbuf[16];
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if (len < 4)
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return SSH_ERR_MESSAGE_INCOMPLETE;
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memset(seqbuf, 0, sizeof(seqbuf));
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POKE_U64(seqbuf + 8, seqnr);
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if (!EVP_CipherInit(ctx->header_evp, NULL, NULL, seqbuf, 0))
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return SSH_ERR_LIBCRYPTO_ERROR;
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if (EVP_Cipher(ctx->header_evp, buf, (u_char *)cp, sizeof(buf)) < 0)
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return SSH_ERR_LIBCRYPTO_ERROR;
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*plenp = PEEK_U32(buf);
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return 0;
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}
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#endif /* defined(HAVE_EVP_CHACHA20) && !defined(HAVE_BROKEN_CHACHA20) */
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