Damien Miller | 8029775 | 1999-11-19 13:03:25 +1100 | [diff] [blame] | 1 | #ifdef SKEY |
| 2 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 3 | #include "includes.h" |
| 4 | RCSID("$Id: auth-skey.c,v 1.2 1999/10/16 20:57:52 deraadt Exp $"); |
| 5 | |
| 6 | #include "ssh.h" |
| 7 | #include <sha1.h> |
| 8 | |
| 9 | /* from %OpenBSD: skeylogin.c,v 1.32 1999/08/16 14:46:56 millert Exp % */ |
| 10 | |
| 11 | |
| 12 | #define ROUND(x) (((x)[0] << 24) + (((x)[1]) << 16) + (((x)[2]) << 8) + \ |
| 13 | ((x)[3])) |
| 14 | |
| 15 | /* |
| 16 | * hash_collapse() |
| 17 | */ |
| 18 | static u_int32_t |
| 19 | hash_collapse(s) |
| 20 | u_char *s; |
| 21 | { |
| 22 | int len, target; |
| 23 | u_int32_t i; |
| 24 | |
| 25 | if ((strlen(s) % sizeof(u_int32_t)) == 0) |
| 26 | target = strlen(s); /* Multiple of 4 */ |
| 27 | else |
| 28 | target = strlen(s) - (strlen(s) % sizeof(u_int32_t)); |
| 29 | |
| 30 | for (i = 0, len = 0; len < target; len += 4) |
| 31 | i ^= ROUND(s + len); |
| 32 | |
| 33 | return i; |
| 34 | } |
| 35 | char * |
| 36 | skey_fake_keyinfo(char *username) |
| 37 | { |
| 38 | int i; |
| 39 | u_int ptr; |
| 40 | u_char hseed[SKEY_MAX_SEED_LEN], flg = 1, *up; |
| 41 | char pbuf[SKEY_MAX_PW_LEN+1]; |
| 42 | static char skeyprompt[SKEY_MAX_CHALLENGE+1]; |
| 43 | char *secret = NULL; |
| 44 | size_t secretlen = 0; |
| 45 | SHA1_CTX ctx; |
| 46 | char *p, *u; |
| 47 | |
| 48 | /* |
| 49 | * Base first 4 chars of seed on hostname. |
| 50 | * Add some filler for short hostnames if necessary. |
| 51 | */ |
| 52 | if (gethostname(pbuf, sizeof(pbuf)) == -1) |
| 53 | *(p = pbuf) = '.'; |
| 54 | else |
| 55 | for (p = pbuf; *p && isalnum(*p); p++) |
| 56 | if (isalpha(*p) && isupper(*p)) |
| 57 | *p = tolower(*p); |
| 58 | if (*p && pbuf - p < 4) |
| 59 | (void)strncpy(p, "asjd", 4 - (pbuf - p)); |
| 60 | pbuf[4] = '\0'; |
| 61 | |
| 62 | /* Hash the username if possible */ |
| 63 | if ((up = SHA1Data(username, strlen(username), NULL)) != NULL) { |
| 64 | struct stat sb; |
| 65 | time_t t; |
| 66 | int fd; |
| 67 | |
| 68 | /* Collapse the hash */ |
| 69 | ptr = hash_collapse(up); |
| 70 | memset(up, 0, strlen(up)); |
| 71 | |
| 72 | /* See if the random file's there, else use ctime */ |
| 73 | if ((fd = open(_SKEY_RAND_FILE_PATH_, O_RDONLY)) != -1 |
| 74 | && fstat(fd, &sb) == 0 && |
| 75 | sb.st_size > (off_t)SKEY_MAX_SEED_LEN && |
| 76 | lseek(fd, ptr % (sb.st_size - SKEY_MAX_SEED_LEN), |
| 77 | SEEK_SET) != -1 && read(fd, hseed, |
| 78 | SKEY_MAX_SEED_LEN) == SKEY_MAX_SEED_LEN) { |
| 79 | close(fd); |
| 80 | secret = hseed; |
| 81 | secretlen = SKEY_MAX_SEED_LEN; |
| 82 | flg = 0; |
| 83 | } else if (!stat(_PATH_MEM, &sb) || !stat("/", &sb)) { |
| 84 | t = sb.st_ctime; |
| 85 | secret = ctime(&t); |
| 86 | secretlen = strlen(secret); |
| 87 | flg = 0; |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | /* Put that in your pipe and smoke it */ |
| 92 | if (flg == 0) { |
| 93 | /* Hash secret value with username */ |
| 94 | SHA1Init(&ctx); |
| 95 | SHA1Update(&ctx, secret, secretlen); |
| 96 | SHA1Update(&ctx, username, strlen(username)); |
| 97 | SHA1End(&ctx, up); |
| 98 | |
| 99 | /* Zero out */ |
| 100 | memset(secret, 0, secretlen); |
| 101 | |
| 102 | /* Now hash the hash */ |
| 103 | SHA1Init(&ctx); |
| 104 | SHA1Update(&ctx, up, strlen(up)); |
| 105 | SHA1End(&ctx, up); |
| 106 | |
| 107 | ptr = hash_collapse(up + 4); |
| 108 | |
| 109 | for (i = 4; i < 9; i++) { |
| 110 | pbuf[i] = (ptr % 10) + '0'; |
| 111 | ptr /= 10; |
| 112 | } |
| 113 | pbuf[i] = '\0'; |
| 114 | |
| 115 | /* Sequence number */ |
| 116 | ptr = ((up[2] + up[3]) % 99) + 1; |
| 117 | |
| 118 | memset(up, 0, 20); /* SHA1 specific */ |
| 119 | free(up); |
| 120 | |
| 121 | (void)snprintf(skeyprompt, sizeof skeyprompt, |
| 122 | "otp-%.*s %d %.*s", |
| 123 | SKEY_MAX_HASHNAME_LEN, |
| 124 | skey_get_algorithm(), |
| 125 | ptr, SKEY_MAX_SEED_LEN, |
| 126 | pbuf); |
| 127 | } else { |
| 128 | /* Base last 8 chars of seed on username */ |
| 129 | u = username; |
| 130 | i = 8; |
| 131 | p = &pbuf[4]; |
| 132 | do { |
| 133 | if (*u == 0) { |
| 134 | /* Pad remainder with zeros */ |
| 135 | while (--i >= 0) |
| 136 | *p++ = '0'; |
| 137 | break; |
| 138 | } |
| 139 | |
| 140 | *p++ = (*u++ % 10) + '0'; |
| 141 | } while (--i != 0); |
| 142 | pbuf[12] = '\0'; |
| 143 | |
| 144 | (void)snprintf(skeyprompt, sizeof skeyprompt, |
| 145 | "otp-%.*s %d %.*s", |
| 146 | SKEY_MAX_HASHNAME_LEN, |
| 147 | skey_get_algorithm(), |
| 148 | 99, SKEY_MAX_SEED_LEN, pbuf); |
| 149 | } |
| 150 | return skeyprompt; |
| 151 | } |
Damien Miller | 8029775 | 1999-11-19 13:03:25 +1100 | [diff] [blame] | 152 | |
| 153 | #endif SKEY |