-#include "xmalloc.h"
-
-static int
-extract_salt(const char *s, u_int l, char *salt, size_t salt_len)
-{
- char *p, *b64salt;
- u_int b64len;
- int ret;
-
- if (l < sizeof(HASH_MAGIC) - 1) {
- debug2("extract_salt: string too short");
- return (-1);
- }
- if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) {
- debug2("extract_salt: invalid magic identifier");
- return (-1);
- }
- s += sizeof(HASH_MAGIC) - 1;
- l -= sizeof(HASH_MAGIC) - 1;
- if ((p = memchr(s, HASH_DELIM, l)) == NULL) {
- debug2("extract_salt: missing salt termination character");
- return (-1);
- }
-
- b64len = p - s;
- /* Sanity check */
- if (b64len == 0 || b64len > 1024) {
- debug2("extract_salt: bad encoded salt length %u", b64len);
- return (-1);
- }
- b64salt = xmalloc(1 + b64len);
- memcpy(b64salt, s, b64len);
- b64salt[b64len] = '\0';
-
- ret = __b64_pton(b64salt, salt, salt_len);
- xfree(b64salt);
- if (ret == -1) {
- debug2("extract_salt: salt decode error");
- return (-1);
- }
- if (ret != SHA_DIGEST_LENGTH) {
- debug2("extract_salt: expected salt len %u, got %u",
- salt_len, ret);
- return (-1);
- }
-
- return (0);
-}
-
-char *
-host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
-{
- const EVP_MD *md = EVP_sha1();
- HMAC_CTX mac_ctx;
- char salt[256], result[256], uu_salt[512], uu_result[512];
- static char encoded[1024];
- u_int i, len;
-
- len = EVP_MD_size(md);
-
- if (name_from_hostfile == NULL) {
- /* Create new salt */
- for (i = 0; i < len; i++)
- salt[i] = arc4random();
- } else {
- /* Extract salt from known host entry */
- if (extract_salt(name_from_hostfile, src_len, salt,
- sizeof(salt)) == -1)
- return (NULL);
- }
-
- HMAC_Init(&mac_ctx, salt, len, md);
- HMAC_Update(&mac_ctx, host, strlen(host));
- HMAC_Final(&mac_ctx, result, NULL);
- HMAC_cleanup(&mac_ctx);
-
- if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
- __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
- fatal("host_hash: __b64_ntop failed");
-
- snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
- HASH_DELIM, uu_result);
-
- return (encoded);
-}