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-rw-r--r--mac.c127
1 files changed, 95 insertions, 32 deletions
diff --git a/mac.c b/mac.c
index e5d5bfa88..34464659a 100644
--- a/mac.c
+++ b/mac.c
@@ -1,4 +1,4 @@
1/* $OpenBSD: mac.c,v 1.12 2006/08/03 03:34:42 deraadt Exp $ */ 1/* $OpenBSD: mac.c,v 1.14 2007/06/07 19:37:34 pvalchev Exp $ */
2/* 2/*
3 * Copyright (c) 2001 Markus Friedl. All rights reserved. 3 * Copyright (c) 2001 Markus Friedl. All rights reserved.
4 * 4 *
@@ -42,63 +42,126 @@
42#include "mac.h" 42#include "mac.h"
43#include "misc.h" 43#include "misc.h"
44 44
45#include "umac.h"
46
47#define SSH_EVP 1 /* OpenSSL EVP-based MAC */
48#define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
49
45struct { 50struct {
46 char *name; 51 char *name;
52 int type;
47 const EVP_MD * (*mdfunc)(void); 53 const EVP_MD * (*mdfunc)(void);
48 int truncatebits; /* truncate digest if != 0 */ 54 int truncatebits; /* truncate digest if != 0 */
55 int key_len; /* just for UMAC */
56 int len; /* just for UMAC */
49} macs[] = { 57} macs[] = {
50 { "hmac-sha1", EVP_sha1, 0, }, 58 { "hmac-sha1", SSH_EVP, EVP_sha1, 0, -1, -1 },
51 { "hmac-sha1-96", EVP_sha1, 96 }, 59 { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, -1, -1 },
52 { "hmac-md5", EVP_md5, 0 }, 60 { "hmac-md5", SSH_EVP, EVP_md5, 0, -1, -1 },
53 { "hmac-md5-96", EVP_md5, 96 }, 61 { "hmac-md5-96", SSH_EVP, EVP_md5, 96, -1, -1 },
54 { "hmac-ripemd160", EVP_ripemd160, 0 }, 62 { "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
55 { "hmac-ripemd160@openssh.com", EVP_ripemd160, 0 }, 63 { "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
56 { NULL, NULL, 0 } 64 { "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64 },
65 { NULL, 0, NULL, 0, -1, -1 }
57}; 66};
58 67
68static void
69mac_setup_by_id(Mac *mac, int which)
70{
71 int evp_len;
72 mac->type = macs[which].type;
73 if (mac->type == SSH_EVP) {
74 mac->evp_md = (*macs[which].mdfunc)();
75 if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
76 fatal("mac %s len %d", mac->name, evp_len);
77 mac->key_len = mac->mac_len = (u_int)evp_len;
78 } else {
79 mac->mac_len = macs[which].len / 8;
80 mac->key_len = macs[which].key_len / 8;
81 mac->umac_ctx = NULL;
82 }
83 if (macs[which].truncatebits != 0)
84 mac->mac_len = macs[which].truncatebits / 8;
85}
86
59int 87int
60mac_init(Mac *mac, char *name) 88mac_setup(Mac *mac, char *name)
61{ 89{
62 int i, evp_len; 90 int i;
63 91
64 for (i = 0; macs[i].name; i++) { 92 for (i = 0; macs[i].name; i++) {
65 if (strcmp(name, macs[i].name) == 0) { 93 if (strcmp(name, macs[i].name) == 0) {
66 if (mac != NULL) { 94 if (mac != NULL)
67 mac->md = (*macs[i].mdfunc)(); 95 mac_setup_by_id(mac, i);
68 if ((evp_len = EVP_MD_size(mac->md)) <= 0) 96 debug2("mac_setup: found %s", name);
69 fatal("mac %s len %d", name, evp_len);
70 mac->key_len = mac->mac_len = (u_int)evp_len;
71 if (macs[i].truncatebits != 0)
72 mac->mac_len = macs[i].truncatebits/8;
73 }
74 debug2("mac_init: found %s", name);
75 return (0); 97 return (0);
76 } 98 }
77 } 99 }
78 debug2("mac_init: unknown %s", name); 100 debug2("mac_setup: unknown %s", name);
79 return (-1); 101 return (-1);
80} 102}
81 103
104int
105mac_init(Mac *mac)
106{
107 if (mac->key == NULL)
108 fatal("mac_init: no key");
109 switch (mac->type) {
110 case SSH_EVP:
111 if (mac->evp_md == NULL)
112 return -1;
113 HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
114 return 0;
115 case SSH_UMAC:
116 mac->umac_ctx = umac_new(mac->key);
117 return 0;
118 default:
119 return -1;
120 }
121}
122
82u_char * 123u_char *
83mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen) 124mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
84{ 125{
85 HMAC_CTX c;
86 static u_char m[EVP_MAX_MD_SIZE]; 126 static u_char m[EVP_MAX_MD_SIZE];
87 u_char b[4]; 127 u_char b[4], nonce[8];
88 128
89 if (mac->key == NULL)
90 fatal("mac_compute: no key");
91 if (mac->mac_len > sizeof(m)) 129 if (mac->mac_len > sizeof(m))
92 fatal("mac_compute: mac too long"); 130 fatal("mac_compute: mac too long %u %lu",
93 HMAC_Init(&c, mac->key, mac->key_len, mac->md); 131 mac->mac_len, sizeof(m));
94 put_u32(b, seqno); 132
95 HMAC_Update(&c, b, sizeof(b)); 133 switch (mac->type) {
96 HMAC_Update(&c, data, datalen); 134 case SSH_EVP:
97 HMAC_Final(&c, m, NULL); 135 put_u32(b, seqno);
98 HMAC_cleanup(&c); 136 /* reset HMAC context */
137 HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
138 HMAC_Update(&mac->evp_ctx, b, sizeof(b));
139 HMAC_Update(&mac->evp_ctx, data, datalen);
140 HMAC_Final(&mac->evp_ctx, m, NULL);
141 break;
142 case SSH_UMAC:
143 put_u64(nonce, seqno);
144 umac_update(mac->umac_ctx, data, datalen);
145 umac_final(mac->umac_ctx, m, nonce);
146 break;
147 default:
148 fatal("mac_compute: unknown MAC type");
149 }
99 return (m); 150 return (m);
100} 151}
101 152
153void
154mac_clear(Mac *mac)
155{
156 if (mac->type == SSH_UMAC) {
157 if (mac->umac_ctx != NULL)
158 umac_delete(mac->umac_ctx);
159 } else if (mac->evp_md != NULL)
160 HMAC_cleanup(&mac->evp_ctx);
161 mac->evp_md = NULL;
162 mac->umac_ctx = NULL;
163}
164
102/* XXX copied from ciphers_valid */ 165/* XXX copied from ciphers_valid */
103#define MAC_SEP "," 166#define MAC_SEP ","
104int 167int
@@ -111,7 +174,7 @@ mac_valid(const char *names)
111 maclist = cp = xstrdup(names); 174 maclist = cp = xstrdup(names);
112 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0'; 175 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
113 (p = strsep(&cp, MAC_SEP))) { 176 (p = strsep(&cp, MAC_SEP))) {
114 if (mac_init(NULL, p) < 0) { 177 if (mac_setup(NULL, p) < 0) {
115 debug("bad mac %s [%s]", p, names); 178 debug("bad mac %s [%s]", p, names);
116 xfree(maclist); 179 xfree(maclist);
117 return (0); 180 return (0);