Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/ssh/lib/../cipher.c	Lines:	51	181	28.2 %
Date:	2017-11-07	Branches:	28	154	18.2 %


/* $OpenBSD: cipher.c,v 1.107 2017/05/07 23:12:57 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 <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"


struct sshcipher_ctx {
	int	plaintext;
	int	encrypt;
	EVP_CIPHER_CTX *evp;
	struct chachapoly_ctx cp_ctx; /* XXX union with evp? */
	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
	{ "3des-cbc",		8, 24, 0, 0, CFLAG_CBC, EVP_des_ede3_cbc },
	{ "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 },
	{ "rijndael-cbc@lysator.liu.se",
				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;
}

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) {
		ret = chachapoly_init(&cc->cp_ctx, key, keylen);
		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
			if (cc->evp != NULL)
				EVP_CIPHER_CTX_free(cc->evp);
#endif /* WITH_OPENSSL */
			explicit_bzero(cc, sizeof(*cc));
			free(cc);
		}
	}
	return ret;
}

/*
 * cipher_crypt() operates as following:
 * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'.
 * Theses 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 = get_u32(cp);
	return 0;
}

void
cipher_free(struct sshcipher_ctx *cc)
{
	if (cc == NULL)
		return;
	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
		explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx));
	else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
		explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx));
#ifdef WITH_OPENSSL
	if (cc->evp != NULL) {
		EVP_CIPHER_CTX_free(cc->evp);
		cc->evp = NULL;
	}
#endif
	explicit_bzero(cc, sizeof(*cc));
	free(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, u_int len)
{
	const struct sshcipher *c = cc->cipher;
#ifdef WITH_OPENSSL
 	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 ((u_int)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
		memcpy(iv, cc->evp->iv, len);
#endif
	return 0;
}

int
cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv)
{
	const struct sshcipher *c = cc->cipher;
#ifdef WITH_OPENSSL
 	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 (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
		memcpy(cc->evp->iv, iv, evplen);
#endif
	return 0;
}



Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: cipher.c,v 1.107 2017/05/07 23:12:57 djm Exp $ */
2			/*
3			* Author: Tatu Ylonen <ylo@cs.hut.fi>
4			* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5			* All rights reserved
6			*
7			* As far as I am concerned, the code I have written for this software
8			* can be used freely for any purpose. Any derived versions of this
9			* software must be clearly marked as such, and if the derived work is
10			* incompatible with the protocol description in the RFC file, it must be
11			* called by a name other than "ssh" or "Secure Shell".
12			*
13			*
14			* Copyright (c) 1999 Niels Provos. All rights reserved.
15			* Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
16			*
17			* Redistribution and use in source and binary forms, with or without
18			* modification, are permitted provided that the following conditions
19			* are met:
20			* 1. Redistributions of source code must retain the above copyright
21			* notice, this list of conditions and the following disclaimer.
22			* 2. Redistributions in binary form must reproduce the above copyright
23			* notice, this list of conditions and the following disclaimer in the
24			* documentation and/or other materials provided with the distribution.
25			*
26			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27			* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29			* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30			* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35			* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36			*/
37
38			#include <sys/types.h>
39
40			#include <string.h>
41			#include <stdarg.h>
42			#include <stdio.h>
43
44			#include "cipher.h"
45			#include "misc.h"
46			#include "sshbuf.h"
47			#include "ssherr.h"
48			#include "digest.h"
49
50
51			struct sshcipher_ctx {
52			int plaintext;
53			int encrypt;
54			EVP_CIPHER_CTX *evp;
55			struct chachapoly_ctx cp_ctx; /* XXX union with evp? */
56			struct aesctr_ctx ac_ctx; /* XXX union with evp? */
57			const struct sshcipher *cipher;
58			};
59
60			struct sshcipher {
61			char *name;
62			u_int block_size;
63			u_int key_len;
64			u_int iv_len; /* defaults to block_size */
65			u_int auth_len;
66			u_int flags;
67			#define CFLAG_CBC (1<<0)
68			#define CFLAG_CHACHAPOLY (1<<1)
69			#define CFLAG_AESCTR (1<<2)
70			#define CFLAG_NONE (1<<3)
71			#define CFLAG_INTERNAL CFLAG_NONE /* Don't use "none" for packets */
72			#ifdef WITH_OPENSSL
73			const EVP_CIPHER (evptype)(void);
74			#else
75			void *ignored;
76			#endif
77			};
78
79			static const struct sshcipher ciphers[] = {
80			#ifdef WITH_OPENSSL
81			{ "3des-cbc", 8, 24, 0, 0, CFLAG_CBC, EVP_des_ede3_cbc },
82			{ "aes128-cbc", 16, 16, 0, 0, CFLAG_CBC, EVP_aes_128_cbc },
83			{ "aes192-cbc", 16, 24, 0, 0, CFLAG_CBC, EVP_aes_192_cbc },
84			{ "aes256-cbc", 16, 32, 0, 0, CFLAG_CBC, EVP_aes_256_cbc },
85			{ "rijndael-cbc@lysator.liu.se",
86			16, 32, 0, 0, CFLAG_CBC, EVP_aes_256_cbc },
87			{ "aes128-ctr", 16, 16, 0, 0, 0, EVP_aes_128_ctr },
88			{ "aes192-ctr", 16, 24, 0, 0, 0, EVP_aes_192_ctr },
89			{ "aes256-ctr", 16, 32, 0, 0, 0, EVP_aes_256_ctr },
90			{ "aes128-gcm@openssh.com",
91			16, 16, 12, 16, 0, EVP_aes_128_gcm },
92			{ "aes256-gcm@openssh.com",
93			16, 32, 12, 16, 0, EVP_aes_256_gcm },
94			#else
95			{ "aes128-ctr", 16, 16, 0, 0, CFLAG_AESCTR, NULL },
96			{ "aes192-ctr", 16, 24, 0, 0, CFLAG_AESCTR, NULL },
97			{ "aes256-ctr", 16, 32, 0, 0, CFLAG_AESCTR, NULL },
98			#endif
99			{ "chacha20-poly1305@openssh.com",
100			8, 64, 0, 16, CFLAG_CHACHAPOLY, NULL },
101			{ "none", 8, 0, 0, 0, CFLAG_NONE, NULL },
102
103			{ NULL, 0, 0, 0, 0, 0, NULL }
104			};
105
106			/--/
107
108			/* Returns a comma-separated list of supported ciphers. */
109			char *
110			cipher_alg_list(char sep, int auth_only)
111			{
112			char tmp, ret = NULL;
113			size_t nlen, rlen = 0;
114			const struct sshcipher *c;
115
116			for (c = ciphers; c->name != NULL; c++) {
117			if ((c->flags & CFLAG_INTERNAL) != 0)
118			continue;
119			if (auth_only && c->auth_len == 0)
120			continue;
121			if (ret != NULL)
122			ret[rlen++] = sep;
123			nlen = strlen(c->name);
124			if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
125			free(ret);
126			return NULL;
127			}
128			ret = tmp;
129			memcpy(ret + rlen, c->name, nlen + 1);
130			rlen += nlen;
131			}
132			return ret;
133			}
134
135			u_int
136			cipher_blocksize(const struct sshcipher *c)
137			{
138		56	return (c->block_size);
139			}
140
141			u_int
142			cipher_keylen(const struct sshcipher *c)
143			{
144		64	return (c->key_len);
145			}
146
147			u_int
148			cipher_seclen(const struct sshcipher *c)
149			{
150	✗✓	8	if (strcmp("3des-cbc", c->name) == 0)
151			return 14;
152		4	return cipher_keylen(c);
153		4	}
154
155			u_int
156			cipher_authlen(const struct sshcipher *c)
157			{
158		261800	return (c->auth_len);
159			}
160
161			u_int
162			cipher_ivlen(const struct sshcipher *c)
163			{
164			/*
165			* Default is cipher block size, except for chacha20+poly1305 that
166			* needs no IV. XXX make iv_len == -1 default?
167			*/
168	✓✗✓✓	280	return (c->iv_len != 0 \|\| (c->flags & CFLAG_CHACHAPOLY) != 0) ?
169		52	c->iv_len : c->block_size;
170			}
171
172			u_int
173			cipher_is_cbc(const struct sshcipher *c)
174			{
175			return (c->flags & CFLAG_CBC) != 0;
176			}
177
178			u_int
179			cipher_ctx_is_plaintext(struct sshcipher_ctx *cc)
180			{
181		85298	return cc->plaintext;
182			}
183
184			const struct sshcipher *
185			cipher_by_name(const char *name)
186			{
187			const struct sshcipher *c;
188	✓✗	721	for (c = ciphers; c->name != NULL; c++)
189	✓✓	346	if (strcmp(c->name, name) == 0)
190		29	return c;
191			return NULL;
192		29	}
193
194			#define CIPHER_SEP ","
195			int
196			ciphers_valid(const char *names)
197			{
198			const struct sshcipher *c;
199			char cipher_list, cp;
200			char *p;
201
202			if (names == NULL \|\| strcmp(names, "") == 0)
203			return 0;
204			if ((cipher_list = cp = strdup(names)) == NULL)
205			return 0;
206			for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
207			(p = strsep(&cp, CIPHER_SEP))) {
208			c = cipher_by_name(p);
209			if (c == NULL \|\| (c->flags & CFLAG_INTERNAL) != 0) {
210			free(cipher_list);
211			return 0;
212			}
213			}
214			free(cipher_list);
215			return 1;
216			}
217
218			const char *
219			cipher_warning_message(const struct sshcipher_ctx *cc)
220			{
221	✓✗✗✓	6	if (cc == NULL \|\| cc->cipher == NULL)
222			return NULL;
223			/* XXX repurpose for CBC warning */
224		2	return NULL;
225		2	}
226
227			int
228			cipher_init(struct sshcipher_ctx *ccp, const struct sshcipher cipher,
229			const u_char key, u_int keylen, const u_char iv, u_int ivlen,
230			int do_encrypt)
231			{
232			struct sshcipher_ctx *cc = NULL;
233			int ret = SSH_ERR_INTERNAL_ERROR;
234			#ifdef WITH_OPENSSL
235			const EVP_CIPHER *type;
236			int klen;
237			#endif
238
239		60	*ccp = NULL;
240	✗✓	30	if ((cc = calloc(sizeof(*cc), 1)) == NULL)
241			return SSH_ERR_ALLOC_FAIL;
242
243		30	cc->plaintext = (cipher->flags & CFLAG_NONE) != 0;
244		30	cc->encrypt = do_encrypt;
245
246	✓✗✗✓	58	if (keylen < cipher->key_len \|\|
247	✓✓	58	(iv != NULL && ivlen < cipher_ivlen(cipher))) {
248			ret = SSH_ERR_INVALID_ARGUMENT;
249			goto out;
250			}
251
252		30	cc->cipher = cipher;
253	✓✓	30	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
254		2	ret = chachapoly_init(&cc->cp_ctx, key, keylen);
255		2	goto out;
256			}
257	✓✗	28	if ((cc->cipher->flags & CFLAG_NONE) != 0) {
258			ret = 0;
259		28	goto out;
260			}
261			#ifndef WITH_OPENSSL
262			if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
263			aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen);
264			aesctr_ivsetup(&cc->ac_ctx, iv);
265			ret = 0;
266			goto out;
267			}
268			ret = SSH_ERR_INVALID_ARGUMENT;
269			goto out;
270			#else /* WITH_OPENSSL */
271			type = (*cipher->evptype)();
272			if ((cc->evp = EVP_CIPHER_CTX_new()) == NULL) {
273			ret = SSH_ERR_ALLOC_FAIL;
274			goto out;
275			}
276			if (EVP_CipherInit(cc->evp, type, NULL, (u_char *)iv,
277			(do_encrypt == CIPHER_ENCRYPT)) == 0) {
278			ret = SSH_ERR_LIBCRYPTO_ERROR;
279			goto out;
280			}
281			if (cipher_authlen(cipher) &&
282			!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_IV_FIXED,
283			-1, (u_char *)iv)) {
284			ret = SSH_ERR_LIBCRYPTO_ERROR;
285			goto out;
286			}
287			klen = EVP_CIPHER_CTX_key_length(cc->evp);
288			if (klen > 0 && keylen != (u_int)klen) {
289			if (EVP_CIPHER_CTX_set_key_length(cc->evp, keylen) == 0) {
290			ret = SSH_ERR_LIBCRYPTO_ERROR;
291			goto out;
292			}
293			}
294			if (EVP_CipherInit(cc->evp, NULL, (u_char *)key, NULL, -1) == 0) {
295			ret = SSH_ERR_LIBCRYPTO_ERROR;
296			goto out;
297			}
298			ret = 0;
299			#endif /* WITH_OPENSSL */
300			out:
301	✓✗	30	if (ret == 0) {
302			/* success */
303		30	*ccp = cc;
304		30	} else {
305			if (cc != NULL) {
306			#ifdef WITH_OPENSSL
307			if (cc->evp != NULL)
308			EVP_CIPHER_CTX_free(cc->evp);
309			#endif /* WITH_OPENSSL */
310			explicit_bzero(cc, sizeof(*cc));
311			free(cc);
312			}
313			}
314		30	return ret;
315		30	}
316
317			/*
318			* cipher_crypt() operates as following:
319			* Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'.
320			* Theses bytes are treated as additional authenticated data for
321			* authenticated encryption modes.
322			* En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'.
323			* Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag.
324			* This tag is written on encryption and verified on decryption.
325			* Both 'aadlen' and 'authlen' can be set to 0.
326			*/
327			int
328			cipher_crypt(struct sshcipher_ctx cc, u_int seqnr, u_char dest,
329			const u_char *src, u_int len, u_int aadlen, u_int authlen)
330			{
331	✓✓	115002	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
332		114932	return chachapoly_crypt(&cc->cp_ctx, seqnr, dest, src,
333		57466	len, aadlen, authlen, cc->encrypt);
334			}
335	✓✗	35	if ((cc->cipher->flags & CFLAG_NONE) != 0) {
336		35	memcpy(dest, src, aadlen + len);
337		35	return 0;
338			}
339			#ifndef WITH_OPENSSL
340			if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
341			if (aadlen)
342			memcpy(dest, src, aadlen);
343			aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen,
344			dest + aadlen, len);
345			return 0;
346			}
347			return SSH_ERR_INVALID_ARGUMENT;
348			#else
349			if (authlen) {
350			u_char lastiv[1];
351
352			if (authlen != cipher_authlen(cc->cipher))
353			return SSH_ERR_INVALID_ARGUMENT;
354			/* increment IV */
355			if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN,
356			1, lastiv))
357			return SSH_ERR_LIBCRYPTO_ERROR;
358			/* set tag on decyption */
359			if (!cc->encrypt &&
360			!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_TAG,
361			authlen, (u_char *)src + aadlen + len))
362			return SSH_ERR_LIBCRYPTO_ERROR;
363			}
364			if (aadlen) {
365			if (authlen &&
366			EVP_Cipher(cc->evp, NULL, (u_char *)src, aadlen) < 0)
367			return SSH_ERR_LIBCRYPTO_ERROR;
368			memcpy(dest, src, aadlen);
369			}
370			if (len % cc->cipher->block_size)
371			return SSH_ERR_INVALID_ARGUMENT;
372			if (EVP_Cipher(cc->evp, dest + aadlen, (u_char *)src + aadlen,
373			len) < 0)
374			return SSH_ERR_LIBCRYPTO_ERROR;
375			if (authlen) {
376			/* compute tag (on encrypt) or verify tag (on decrypt) */
377			if (EVP_Cipher(cc->evp, NULL, NULL, 0) < 0)
378			return cc->encrypt ?
379			SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID;
380			if (cc->encrypt &&
381			!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_GET_TAG,
382			authlen, dest + aadlen + len))
383			return SSH_ERR_LIBCRYPTO_ERROR;
384			}
385			return 0;
386			#endif
387		57501	}
388
389			/* Extract the packet length, including any decryption necessary beforehand */
390			int
391			cipher_get_length(struct sshcipher_ctx cc, u_int plenp, u_int seqnr,
392			const u_char *cp, u_int len)
393			{
394	✓✗	176442	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
395		88221	return chachapoly_get_length(&cc->cp_ctx, plenp, seqnr,
396			cp, len);
397			if (len < 4)
398			return SSH_ERR_MESSAGE_INCOMPLETE;
399			*plenp = get_u32(cp);
400			return 0;
401		88221	}
402
403			void
404			cipher_free(struct sshcipher_ctx *cc)
405			{
406	✓✓	114	if (cc == NULL)
407			return;
408	✓✓	28	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
409		2	explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx));
410	✗✓	26	else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
411			explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx));
412			#ifdef WITH_OPENSSL
413	✗✓	28	if (cc->evp != NULL) {
414			EVP_CIPHER_CTX_free(cc->evp);
415			cc->evp = NULL;
416			}
417			#endif
418		28	explicit_bzero(cc, sizeof(*cc));
419		28	free(cc);
420		85	}
421
422			/*
423			* Exports an IV from the sshcipher_ctx required to export the key
424			* state back from the unprivileged child to the privileged parent
425			* process.
426			*/
427			int
428			cipher_get_keyiv_len(const struct sshcipher_ctx *cc)
429			{
430			const struct sshcipher *c = cc->cipher;
431
432			if ((c->flags & CFLAG_CHACHAPOLY) != 0)
433			return 0;
434			else if ((c->flags & CFLAG_AESCTR) != 0)
435			return sizeof(cc->ac_ctx.ctr);
436			#ifdef WITH_OPENSSL
437			return EVP_CIPHER_CTX_iv_length(cc->evp);
438			#else
439			return 0;
440			#endif
441			}
442
443			int
444			cipher_get_keyiv(struct sshcipher_ctx cc, u_char iv, u_int len)
445			{
446			const struct sshcipher *c = cc->cipher;
447			#ifdef WITH_OPENSSL
448			int evplen;
449			#endif
450
451			if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
452			if (len != 0)
453			return SSH_ERR_INVALID_ARGUMENT;
454			return 0;
455			}
456			if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
457			if (len != sizeof(cc->ac_ctx.ctr))
458			return SSH_ERR_INVALID_ARGUMENT;
459			memcpy(iv, cc->ac_ctx.ctr, len);
460			return 0;
461			}
462			if ((cc->cipher->flags & CFLAG_NONE) != 0)
463			return 0;
464
465			#ifdef WITH_OPENSSL
466			evplen = EVP_CIPHER_CTX_iv_length(cc->evp);
467			if (evplen == 0)
468			return 0;
469			else if (evplen < 0)
470			return SSH_ERR_LIBCRYPTO_ERROR;
471			if ((u_int)evplen != len)
472			return SSH_ERR_INVALID_ARGUMENT;
473			if (cipher_authlen(c)) {
474			if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN,
475			len, iv))
476			return SSH_ERR_LIBCRYPTO_ERROR;
477			} else
478			memcpy(iv, cc->evp->iv, len);
479			#endif
480			return 0;
481			}
482
483			int
484			cipher_set_keyiv(struct sshcipher_ctx cc, const u_char iv)
485			{
486			const struct sshcipher *c = cc->cipher;
487			#ifdef WITH_OPENSSL
488			int evplen = 0;
489			#endif
490
491			if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
492			return 0;
493			if ((cc->cipher->flags & CFLAG_NONE) != 0)
494			return 0;
495
496			#ifdef WITH_OPENSSL
497			evplen = EVP_CIPHER_CTX_iv_length(cc->evp);
498			if (evplen <= 0)
499			return SSH_ERR_LIBCRYPTO_ERROR;
500			if (cipher_authlen(c)) {
501			/* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */
502			if (!EVP_CIPHER_CTX_ctrl(cc->evp,
503			EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv))
504			return SSH_ERR_LIBCRYPTO_ERROR;
505			} else
506			memcpy(cc->evp->iv, iv, evplen);
507			#endif
508			return 0;
509			}
510