diff options
Diffstat (limited to 'usr.bin/ssh/hostfile.c')
| -rw-r--r-- | usr.bin/ssh/hostfile.c | 123 |
1 files changed, 117 insertions, 6 deletions
diff --git a/usr.bin/ssh/hostfile.c b/usr.bin/ssh/hostfile.c index 88c05491278..2e1c8bcd0c4 100644 --- a/usr.bin/ssh/hostfile.c +++ b/usr.bin/ssh/hostfile.c @@ -36,13 +36,102 @@ */ #include "includes.h" -RCSID("$OpenBSD: hostfile.c,v 1.32 2003/11/10 16:23:41 jakob Exp $"); +RCSID("$OpenBSD: hostfile.c,v 1.33 2005/03/01 10:40:26 djm Exp $"); + +#include <resolv.h> +#include <openssl/hmac.h> +#include <openssl/sha.h> #include "packet.h" #include "match.h" #include "key.h" #include "hostfile.h" #include "log.h" +#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); +} /* * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the @@ -104,7 +193,7 @@ check_host_in_hostfile_by_key_or_type(const char *filename, 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); @@ -137,8 +226,18 @@ check_host_in_hostfile_by_key_or_type(const char *filename, ; /* 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; @@ -211,16 +310,28 @@ lookup_key_in_hostfile_by_type(const char *filename, const char *host, */ int -add_host_to_hostfile(const char *filename, const char *host, const 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; + 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 { |