=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/cipher.c,v retrieving revision 1.61.2.2 retrieving revision 1.62 diff -u -r1.61.2.2 -r1.62 --- src/usr.bin/ssh/cipher.c 2003/09/16 21:20:25 1.61.2.2 +++ src/usr.bin/ssh/cipher.c 2002/11/21 22:45:31 1.62 @@ -35,7 +35,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: cipher.c,v 1.61.2.2 2003/09/16 21:20:25 brad Exp $"); +RCSID("$OpenBSD: cipher.c,v 1.62 2002/11/21 22:45:31 markus Exp $"); #include "xmalloc.h" #include "log.h" @@ -44,14 +44,11 @@ #include #if OPENSSL_VERSION_NUMBER < 0x00907000L -extern const EVP_CIPHER *evp_rijndael(void); -extern void ssh_rijndael_iv(EVP_CIPHER_CTX *, int, u_char *, u_int); +#include "rijndael.h" +static const EVP_CIPHER *evp_rijndael(void); #endif -extern const EVP_CIPHER *evp_ssh1_bf(void); -extern const EVP_CIPHER *evp_ssh1_3des(void); -extern void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); -extern const EVP_CIPHER *evp_aes_128_ctr(void); -extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX *, int, u_char *, u_int); +static const EVP_CIPHER *evp_ssh1_3des(void); +static const EVP_CIPHER *evp_ssh1_bf(void); struct Cipher { char *name; @@ -82,9 +79,6 @@ { "rijndael-cbc@lysator.liu.se", SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc }, #endif - { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, evp_aes_128_ctr }, - { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, evp_aes_128_ctr }, - { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, evp_aes_128_ctr }, { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL } }; @@ -275,7 +269,268 @@ memset(&md, 0, sizeof(md)); } +/* Implementations for other non-EVP ciphers */ + /* + * This is used by SSH1: + * + * What kind of triple DES are these 2 routines? + * + * Why is there a redundant initialization vector? + * + * If only iv3 was used, then, this would till effect have been + * outer-cbc. However, there is also a private iv1 == iv2 which + * perhaps makes differential analysis easier. On the other hand, the + * private iv1 probably makes the CRC-32 attack ineffective. This is a + * result of that there is no longer any known iv1 to use when + * choosing the X block. + */ +struct ssh1_3des_ctx +{ + EVP_CIPHER_CTX k1, k2, k3; +}; + +static int +ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, + int enc) +{ + struct ssh1_3des_ctx *c; + u_char *k1, *k2, *k3; + + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { + c = xmalloc(sizeof(*c)); + EVP_CIPHER_CTX_set_app_data(ctx, c); + } + if (key == NULL) + return (1); + if (enc == -1) + enc = ctx->encrypt; + k1 = k2 = k3 = (u_char *) key; + k2 += 8; + if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) { + if (enc) + k3 += 16; + else + k1 += 16; + } + EVP_CIPHER_CTX_init(&c->k1); + EVP_CIPHER_CTX_init(&c->k2); + EVP_CIPHER_CTX_init(&c->k3); + if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 || + EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 || + EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) { + memset(c, 0, sizeof(*c)); + xfree(c); + EVP_CIPHER_CTX_set_app_data(ctx, NULL); + return (0); + } + return (1); +} + +static int +ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len) +{ + struct ssh1_3des_ctx *c; + + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { + error("ssh1_3des_cbc: no context"); + return (0); + } + if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 || + EVP_Cipher(&c->k2, dest, dest, len) == 0 || + EVP_Cipher(&c->k3, dest, dest, len) == 0) + return (0); + return (1); +} + +static int +ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx) +{ + struct ssh1_3des_ctx *c; + + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { + memset(c, 0, sizeof(*c)); + xfree(c); + EVP_CIPHER_CTX_set_app_data(ctx, NULL); + } + return (1); +} + +static const EVP_CIPHER * +evp_ssh1_3des(void) +{ + static EVP_CIPHER ssh1_3des; + + memset(&ssh1_3des, 0, sizeof(EVP_CIPHER)); + ssh1_3des.nid = NID_undef; + ssh1_3des.block_size = 8; + ssh1_3des.iv_len = 0; + ssh1_3des.key_len = 16; + ssh1_3des.init = ssh1_3des_init; + ssh1_3des.cleanup = ssh1_3des_cleanup; + ssh1_3des.do_cipher = ssh1_3des_cbc; + ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH; + return (&ssh1_3des); +} + +/* + * SSH1 uses a variation on Blowfish, all bytes must be swapped before + * and after encryption/decryption. Thus the swap_bytes stuff (yuk). + */ +static void +swap_bytes(const u_char *src, u_char *dst, int n) +{ + u_char c[4]; + + /* Process 4 bytes every lap. */ + for (n = n / 4; n > 0; n--) { + c[3] = *src++; + c[2] = *src++; + c[1] = *src++; + c[0] = *src++; + + *dst++ = c[0]; + *dst++ = c[1]; + *dst++ = c[2]; + *dst++ = c[3]; + } +} + +static int (*orig_bf)(EVP_CIPHER_CTX *, u_char *, const u_char *, u_int) = NULL; + +static int +bf_ssh1_cipher(EVP_CIPHER_CTX *ctx, u_char *out, const u_char *in, u_int len) +{ + int ret; + + swap_bytes(in, out, len); + ret = (*orig_bf)(ctx, out, out, len); + swap_bytes(out, out, len); + return (ret); +} + +static const EVP_CIPHER * +evp_ssh1_bf(void) +{ + static EVP_CIPHER ssh1_bf; + + memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER)); + orig_bf = ssh1_bf.do_cipher; + ssh1_bf.nid = NID_undef; + ssh1_bf.do_cipher = bf_ssh1_cipher; + ssh1_bf.key_len = 32; + return (&ssh1_bf); +} + +#if OPENSSL_VERSION_NUMBER < 0x00907000L +/* RIJNDAEL */ +#define RIJNDAEL_BLOCKSIZE 16 +struct ssh_rijndael_ctx +{ + rijndael_ctx r_ctx; + u_char r_iv[RIJNDAEL_BLOCKSIZE]; +}; + +static int +ssh_rijndael_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, + int enc) +{ + struct ssh_rijndael_ctx *c; + + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { + c = xmalloc(sizeof(*c)); + EVP_CIPHER_CTX_set_app_data(ctx, c); + } + if (key != NULL) { + if (enc == -1) + enc = ctx->encrypt; + rijndael_set_key(&c->r_ctx, (u_char *)key, + 8*EVP_CIPHER_CTX_key_length(ctx), enc); + } + if (iv != NULL) + memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE); + return (1); +} + +static int +ssh_rijndael_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, + u_int len) +{ + struct ssh_rijndael_ctx *c; + u_char buf[RIJNDAEL_BLOCKSIZE]; + u_char *cprev, *cnow, *plain, *ivp; + int i, j, blocks = len / RIJNDAEL_BLOCKSIZE; + + if (len == 0) + return (1); + if (len % RIJNDAEL_BLOCKSIZE) + fatal("ssh_rijndael_cbc: bad len %d", len); + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { + error("ssh_rijndael_cbc: no context"); + return (0); + } + if (ctx->encrypt) { + cnow = dest; + plain = (u_char *)src; + cprev = c->r_iv; + for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE, + cnow+=RIJNDAEL_BLOCKSIZE) { + for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++) + buf[j] = plain[j] ^ cprev[j]; + rijndael_encrypt(&c->r_ctx, buf, cnow); + cprev = cnow; + } + memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE); + } else { + cnow = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE); + plain = dest+len-RIJNDAEL_BLOCKSIZE; + + memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE); + for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE, + plain-=RIJNDAEL_BLOCKSIZE) { + rijndael_decrypt(&c->r_ctx, cnow, plain); + ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE; + for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++) + plain[j] ^= ivp[j]; + } + memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE); + } + return (1); +} + +static int +ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx) +{ + struct ssh_rijndael_ctx *c; + + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { + memset(c, 0, sizeof(*c)); + xfree(c); + EVP_CIPHER_CTX_set_app_data(ctx, NULL); + } + return (1); +} + +static const EVP_CIPHER * +evp_rijndael(void) +{ + static EVP_CIPHER rijndal_cbc; + + memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER)); + rijndal_cbc.nid = NID_undef; + rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE; + rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE; + rijndal_cbc.key_len = 16; + rijndal_cbc.init = ssh_rijndael_init; + rijndal_cbc.cleanup = ssh_rijndael_cleanup; + rijndal_cbc.do_cipher = ssh_rijndael_cbc; + rijndal_cbc.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH | + EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV; + return (&rijndal_cbc); +} +#endif + +/* * Exports an IV from the CipherContext required to export the key * state back from the unprivileged child to the privileged parent * process. @@ -298,6 +553,7 @@ cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len) { Cipher *c = cc->cipher; + u_char *civ = NULL; int evplen; switch (c->number) { @@ -310,28 +566,45 @@ if (evplen != len) fatal("%s: wrong iv length %d != %d", __func__, evplen, len); + #if OPENSSL_VERSION_NUMBER < 0x00907000L - if (c->evptype == evp_rijndael) - ssh_rijndael_iv(&cc->evp, 0, iv, len); - else + if (c->evptype == evp_rijndael) { + struct ssh_rijndael_ctx *aesc; + + aesc = EVP_CIPHER_CTX_get_app_data(&cc->evp); + if (aesc == NULL) + fatal("%s: no rijndael context", __func__); + civ = aesc->r_iv; + } else #endif - if (c->evptype == evp_aes_128_ctr) - ssh_aes_ctr_iv(&cc->evp, 0, iv, len); - else - memcpy(iv, cc->evp.iv, len); + { + civ = cc->evp.iv; + } break; - case SSH_CIPHER_3DES: - ssh1_3des_iv(&cc->evp, 0, iv, 24); - break; + case SSH_CIPHER_3DES: { + struct ssh1_3des_ctx *desc; + if (len != 24) + fatal("%s: bad 3des iv length: %d", __func__, len); + desc = EVP_CIPHER_CTX_get_app_data(&cc->evp); + if (desc == NULL) + fatal("%s: no 3des context", __func__); + debug3("%s: Copying 3DES IV", __func__); + memcpy(iv, desc->k1.iv, 8); + memcpy(iv + 8, desc->k2.iv, 8); + memcpy(iv + 16, desc->k3.iv, 8); + return; + } default: fatal("%s: bad cipher %d", __func__, c->number); } + memcpy(iv, civ, len); } void cipher_set_keyiv(CipherContext *cc, u_char *iv) { Cipher *c = cc->cipher; + u_char *div = NULL; int evplen = 0; switch (c->number) { @@ -341,22 +614,36 @@ evplen = EVP_CIPHER_CTX_iv_length(&cc->evp); if (evplen == 0) return; + #if OPENSSL_VERSION_NUMBER < 0x00907000L - if (c->evptype == evp_rijndael) - ssh_rijndael_iv(&cc->evp, 1, iv, evplen); - else + if (c->evptype == evp_rijndael) { + struct ssh_rijndael_ctx *aesc; + + aesc = EVP_CIPHER_CTX_get_app_data(&cc->evp); + if (aesc == NULL) + fatal("%s: no rijndael context", __func__); + div = aesc->r_iv; + } else #endif - if (c->evptype == evp_aes_128_ctr) - ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen); - else - memcpy(cc->evp.iv, iv, evplen); + { + div = cc->evp.iv; + } break; - case SSH_CIPHER_3DES: - ssh1_3des_iv(&cc->evp, 1, iv, 24); - break; + case SSH_CIPHER_3DES: { + struct ssh1_3des_ctx *desc; + desc = EVP_CIPHER_CTX_get_app_data(&cc->evp); + if (desc == NULL) + fatal("%s: no 3des context", __func__); + debug3("%s: Installed 3DES IV", __func__); + memcpy(desc->k1.iv, iv, 8); + memcpy(desc->k2.iv, iv + 8, 8); + memcpy(desc->k3.iv, iv + 16, 8); + return; + } default: fatal("%s: bad cipher %d", __func__, c->number); } + memcpy(div, iv, evplen); } #if OPENSSL_VERSION_NUMBER < 0x00907000L