X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/fb396518eb4e209d9047da3b35f315de59f072df..cc365543c473fc49be6e02687ce43d16ef918e67:/hostfile.c diff --git a/hostfile.c b/hostfile.c index cefff8d6..cd28bf44 100644 --- a/hostfile.c +++ b/hostfile.c @@ -1,3 +1,4 @@ +/* $OpenBSD: hostfile.c,v 1.46 2009/10/11 23:03:15 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -36,14 +37,110 @@ */ #include "includes.h" -RCSID("$OpenBSD: hostfile.c,v 1.29 2001/12/18 10:04:21 jakob Exp $"); -#include "packet.h" +#include + +#include + +#include +#include + +#include +#include +#include +#include +#include + +#include "xmalloc.h" #include "match.h" #include "key.h" #include "hostfile.h" #include "log.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 %d, got %d", + SHA_DIGEST_LENGTH, 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); +} + /* * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the * pointer over the key. Skips any whitespace at the beginning and at end. @@ -72,15 +169,15 @@ hostfile_read_key(char **cpp, u_int *bitsp, Key *ret) } static int -hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum) +hostfile_check_key(int bits, const Key *key, const char *host, const char *filename, int linenum) { if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL) return 1; if (bits != BN_num_bits(key->rsa->n)) { - log("Warning: %s, line %d: keysize mismatch for host %s: " + logit("Warning: %s, line %d: keysize mismatch for host %s: " "actual %d vs. announced %d.", filename, linenum, host, BN_num_bits(key->rsa->n), bits); - log("Warning: replace %d with %d in %s, line %d.", + logit("Warning: replace %d with %d in %s, line %d.", bits, BN_num_bits(key->rsa->n), filename, linenum); } return 1; @@ -91,22 +188,24 @@ hostfile_check_key(int bits, Key *key, const char *host, const char *filename, i * in the list of our known hosts. Returns HOST_OK if the host is known and * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED * if the host is known but used to have a different host key. + * + * If no 'key' has been specified and a key of type 'keytype' is known + * for the specified host, then HOST_FOUND is returned. */ -HostStatus -check_host_in_hostfile(const char *filename, const char *host, Key *key, - Key *found, int *numret) +static HostStatus +check_host_in_hostfile_by_key_or_type(const char *filename, + const char *host, const Key *key, int keytype, Key *found, int *numret) { FILE *f; char line[8192]; int linenum = 0; u_int kbits; - char *cp, *cp2; + char *cp, *cp2, *hashed_host; HostStatus end_return; - debug3("check_host_in_hostfile: filename %s", filename); - if (key == NULL) - fatal("no key to look up"); + debug3("check_host_in_hostfile: host %s filename %s", host, filename); + /* Open the file containing the list of known hosts. */ f = fopen(filename, "r"); if (!f) @@ -135,8 +234,18 @@ check_host_in_hostfile(const char *filename, const char *host, Key *key, ; /* Check if the host name matches. */ - if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1) - continue; + if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1) { + if (*cp != HASH_DELIM) + continue; + hashed_host = host_hash(host, cp, (u_int) (cp2 - cp)); + if (hashed_host == NULL) { + debug("Invalid hashed host line %d of %s", + linenum, filename); + continue; + } + if (strncmp(hashed_host, cp, (u_int) (cp2 - cp)) != 0) + continue; + } /* Got a match. Skip host name. */ cp = cp2; @@ -147,12 +256,22 @@ check_host_in_hostfile(const char *filename, const char *host, Key *key, */ if (!hostfile_read_key(&cp, &kbits, found)) continue; - if (!hostfile_check_key(kbits, found, host, filename, linenum)) - continue; if (numret != NULL) *numret = linenum; + if (key == NULL) { + /* we found a key of the requested type */ + if (found->type == keytype) { + fclose(f); + return HOST_FOUND; + } + continue; + } + + if (!hostfile_check_key(kbits, found, host, filename, linenum)) + continue; + /* Check if the current key is the same as the given key. */ if (key_equal(key, found)) { /* Ok, they match. */ @@ -177,22 +296,52 @@ check_host_in_hostfile(const char *filename, const char *host, Key *key, return end_return; } +HostStatus +check_host_in_hostfile(const char *filename, const char *host, const Key *key, + Key *found, int *numret) +{ + if (key == NULL) + fatal("no key to look up"); + return (check_host_in_hostfile_by_key_or_type(filename, host, key, 0, + found, numret)); +} + +int +lookup_key_in_hostfile_by_type(const char *filename, const char *host, + int keytype, Key *found, int *numret) +{ + return (check_host_in_hostfile_by_key_or_type(filename, host, NULL, + keytype, found, numret) == HOST_FOUND); +} + /* * Appends an entry to the host file. Returns false if the entry could not * be appended. */ int -add_host_to_hostfile(const char *filename, const char *host, Key *key) +add_host_to_hostfile(const char *filename, const char *host, const Key *key, + int store_hash) { FILE *f; int success = 0; + char *hashed_host = NULL; + if (key == NULL) return 1; /* XXX ? */ f = fopen(filename, "a"); if (!f) return 0; - fprintf(f, "%s ", host); + + if (store_hash) { + if ((hashed_host = host_hash(host, NULL, 0)) == NULL) { + error("add_host_to_hostfile: host_hash failed"); + fclose(f); + return 0; + } + } + fprintf(f, "%s ", store_hash ? hashed_host : host); + if (key_write(key, f)) { success = 1; } else {