diff options
Diffstat (limited to 'crypto/openssh/auth2-pubkey.c')
| -rw-r--r-- | crypto/openssh/auth2-pubkey.c | 82 |
1 files changed, 67 insertions, 15 deletions
diff --git a/crypto/openssh/auth2-pubkey.c b/crypto/openssh/auth2-pubkey.c index f3ca965..d943efa 100644 --- a/crypto/openssh/auth2-pubkey.c +++ b/crypto/openssh/auth2-pubkey.c @@ -1,4 +1,4 @@ -/* $OpenBSD: auth2-pubkey.c,v 1.41 2014/07/15 15:54:14 millert Exp $ */ +/* $OpenBSD: auth2-pubkey.c,v 1.47 2015/02/17 00:14:05 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -41,6 +41,7 @@ #include <string.h> #include <time.h> #include <unistd.h> +#include <limits.h> #include "xmalloc.h" #include "ssh.h" @@ -122,6 +123,17 @@ userauth_pubkey(Authctxt *authctxt) "signature scheme"); goto done; } + if (auth2_userkey_already_used(authctxt, key)) { + logit("refusing previously-used %s key", key_type(key)); + goto done; + } + if (match_pattern_list(sshkey_ssh_name(key), options.pubkey_key_types, + strlen(options.pubkey_key_types), 0) != 1) { + logit("%s: key type %s not in PubkeyAcceptedKeyTypes", + __func__, sshkey_ssh_name(key)); + goto done; + } + if (have_sig) { sig = packet_get_string(&slen); packet_check_eom(); @@ -159,8 +171,12 @@ userauth_pubkey(Authctxt *authctxt) authenticated = 0; if (PRIVSEP(user_key_allowed(authctxt->pw, key)) && PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b), - buffer_len(&b))) == 1) + buffer_len(&b))) == 1) { authenticated = 1; + /* Record the successful key to prevent reuse */ + auth2_record_userkey(authctxt, key); + key = NULL; /* Don't free below */ + } buffer_free(&b); free(sig); } else { @@ -212,17 +228,20 @@ pubkey_auth_info(Authctxt *authctxt, const Key *key, const char *fmt, ...) } if (key_is_cert(key)) { - fp = key_fingerprint(key->cert->signature_key, - SSH_FP_MD5, SSH_FP_HEX); + fp = sshkey_fingerprint(key->cert->signature_key, + options.fingerprint_hash, SSH_FP_DEFAULT); auth_info(authctxt, "%s ID %s (serial %llu) CA %s %s%s%s", key_type(key), key->cert->key_id, (unsigned long long)key->cert->serial, - key_type(key->cert->signature_key), fp, + key_type(key->cert->signature_key), + fp == NULL ? "(null)" : fp, extra == NULL ? "" : ", ", extra == NULL ? "" : extra); free(fp); } else { - fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); - auth_info(authctxt, "%s %s%s%s", key_type(key), fp, + fp = sshkey_fingerprint(key, options.fingerprint_hash, + SSH_FP_DEFAULT); + auth_info(authctxt, "%s %s%s%s", key_type(key), + fp == NULL ? "(null)" : fp, extra == NULL ? "" : ", ", extra == NULL ? "" : extra); free(fp); } @@ -365,8 +384,9 @@ check_authkeys_file(FILE *f, char *file, Key* key, struct passwd *pw) continue; if (!key_is_cert_authority) continue; - fp = key_fingerprint(found, SSH_FP_MD5, - SSH_FP_HEX); + if ((fp = sshkey_fingerprint(found, + options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) + continue; debug("matching CA found: file %s, line %lu, %s %s", file, linenum, key_type(found), fp); /* @@ -405,11 +425,13 @@ check_authkeys_file(FILE *f, char *file, Key* key, struct passwd *pw) continue; if (key_is_cert_authority) continue; - found_key = 1; - fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX); + if ((fp = sshkey_fingerprint(found, + options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) + continue; debug("matching key found: file %s, line %lu %s %s", file, linenum, key_type(found), fp); free(fp); + found_key = 1; break; } } @@ -431,11 +453,12 @@ user_cert_trusted_ca(struct passwd *pw, Key *key) if (!key_is_cert(key) || options.trusted_user_ca_keys == NULL) return 0; - ca_fp = key_fingerprint(key->cert->signature_key, - SSH_FP_MD5, SSH_FP_HEX); + if ((ca_fp = sshkey_fingerprint(key->cert->signature_key, + options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) + return 0; - if (key_in_file(key->cert->signature_key, - options.trusted_user_ca_keys, 1) != 1) { + if (sshkey_in_file(key->cert->signature_key, + options.trusted_user_ca_keys, 1, 0) != 0) { debug2("%s: CA %s %s is not listed in %s", __func__, key_type(key->cert->signature_key), ca_fp, options.trusted_user_ca_keys); @@ -680,6 +703,35 @@ user_key_allowed(struct passwd *pw, Key *key) return success; } +/* Records a public key in the list of previously-successful keys */ +void +auth2_record_userkey(Authctxt *authctxt, struct sshkey *key) +{ + struct sshkey **tmp; + + if (authctxt->nprev_userkeys >= INT_MAX || + (tmp = reallocarray(authctxt->prev_userkeys, + authctxt->nprev_userkeys + 1, sizeof(*tmp))) == NULL) + fatal("%s: reallocarray failed", __func__); + authctxt->prev_userkeys = tmp; + authctxt->prev_userkeys[authctxt->nprev_userkeys] = key; + authctxt->nprev_userkeys++; +} + +/* Checks whether a key has already been used successfully for authentication */ +int +auth2_userkey_already_used(Authctxt *authctxt, struct sshkey *key) +{ + u_int i; + + for (i = 0; i < authctxt->nprev_userkeys; i++) { + if (sshkey_equal_public(key, authctxt->prev_userkeys[i])) { + return 1; + } + } + return 0; +} + Authmethod method_pubkey = { "publickey", userauth_pubkey, |
