From 38d98fd3aa80f864d8f2ecb9a0a3393462d3caa2 Mon Sep 17 00:00:00 2001 From: Simo Sorce Date: Fri, 6 Jul 2012 16:18:29 -0400 Subject: Add special modify op to regen ipaNTHash The NT Hash is the same thing as the RC4-HMAC key, so we add a function to extract it from krb5 keys if they are available to avoid forcing a password change when configuring trust relationships. --- .../ipa-pwd-extop/ipapwd_prepost.c | 146 ++++++++++++++++++++- 1 file changed, 143 insertions(+), 3 deletions(-) diff --git a/daemons/ipa-slapi-plugins/ipa-pwd-extop/ipapwd_prepost.c b/daemons/ipa-slapi-plugins/ipa-pwd-extop/ipapwd_prepost.c index deae64777..e4909c945 100644 --- a/daemons/ipa-slapi-plugins/ipa-pwd-extop/ipapwd_prepost.c +++ b/daemons/ipa-slapi-plugins/ipa-pwd-extop/ipapwd_prepost.c @@ -41,7 +41,12 @@ # include #endif -#define _XOPEN_SOURCE /* strptime needs this */ +/* strptime needs _XOPEN_SOURCE and endian.h needs __USE_BSD + * _GNU_SOURCE imply both, and we use it elsewhere, so use this */ +#ifndef _GNU_SOURCE +#define _GNU_SOURCE 1 +#endif + #include #include #include @@ -53,6 +58,7 @@ #include #include #include +#include #include "ipapwd.h" #include "util.h" @@ -379,6 +385,12 @@ done: return 0; } +#define NTHASH_REGEN_VAL "MagicRegen" +#define NTHASH_REGEN_LEN sizeof(NTHASH_REGEN_VAL) +static int ipapwd_regen_nthash(Slapi_PBlock *pb, Slapi_Mods *smods, + char *dn, struct slapi_entry *entry, + struct ipapwd_krbcfg *krbcfg); + /* PRE MOD Operation: * Gets the clean text password (fail the operation if the password came * pre-hashed, unless this is a replicated operation). @@ -407,6 +419,7 @@ static int ipapwd_pre_mod(Slapi_PBlock *pb) int has_krb_keys = 0; int has_history = 0; int gen_krb_keys = 0; + int is_magic_regen = 0; int ret, rc; LOG_TRACE( "=>\n"); @@ -447,6 +460,27 @@ static int ipapwd_pre_mod(Slapi_PBlock *pb) default: break; } + } else if (slapi_attr_types_equivalent(lmod->mod_type, "ipaNTHash")) { + /* check op filtering out LDAP_MOD_BVALUES */ + switch (lmod->mod_op & 0x0f) { + case LDAP_MOD_ADD: + if (!lmod->mod_bvalues || + !lmod->mod_bvalues[0]) { + rc = LDAP_OPERATIONS_ERROR; + goto done; + } + bv = lmod->mod_bvalues[0]; + if ((bv->bv_len >= NTHASH_REGEN_LEN -1) && + (bv->bv_len <= NTHASH_REGEN_LEN) && + (strncmp(NTHASH_REGEN_VAL, + bv->bv_val, bv->bv_len) == 0)) { + is_magic_regen = 1; + /* make sure the database will later ignore this mod */ + slapi_mods_remove(smods); + } + default: + break; + } } else if (slapi_attr_types_equivalent(lmod->mod_type, "unhashed#user#password")) { /* we check for unahsehd password here so that we are sure to @@ -472,8 +506,9 @@ static int ipapwd_pre_mod(Slapi_PBlock *pb) lmod = slapi_mods_get_next_mod(smods); } - /* If userPassword is not modified we are done here */ - if (! is_pwd_op) { + /* If userPassword is not modified check if this is a request to generate + * NT hashes otherwise we are done here */ + if (!is_pwd_op && !is_magic_regen) { rc = LDAP_SUCCESS; goto done; } @@ -522,6 +557,22 @@ static int ipapwd_pre_mod(Slapi_PBlock *pb) goto done; } + if (!is_pwd_op) { + /* This may be a magic op to ask us to generate the NT hashes */ + if (is_magic_regen) { + /* Make sense to call only if this entry has krb keys to source + * the nthash from */ + if (is_krb) { + rc = ipapwd_regen_nthash(pb, smods, dn, e, krbcfg); + } else { + rc = LDAP_UNWILLING_TO_PERFORM; + } + } else { + rc = LDAP_OPERATIONS_ERROR; + } + goto done; + } + /* run through the mods again and adjust flags if operations affect them */ lmod = slapi_mods_get_first_mod(smods); while (lmod) { @@ -831,6 +882,95 @@ done: return 0; } +static int ipapwd_regen_nthash(Slapi_PBlock *pb, Slapi_Mods *smods, + char *dn, struct slapi_entry *entry, + struct ipapwd_krbcfg *krbcfg) +{ + Slapi_Attr *attr; + Slapi_Value *value; + const struct berval *val; + struct berval *ntvals[2] = { NULL, NULL }; + struct berval bval; + krb5_key_data *keys; + int num_keys; + int mkvno; + int ret; + int i; + + ret = slapi_entry_attr_find(entry, "ipaNTHash", &attr); + if (ret == 0) { + /* We refuse to regen if there is already a value */ + return LDAP_CONSTRAINT_VIOLATION; + } + + /* ok let's see if we can find the RC4 hash in the keys */ + ret = slapi_entry_attr_find(entry, "krbPrincipalKey", &attr); + if (ret) { + return LDAP_UNWILLING_TO_PERFORM; + } + + ret = slapi_attr_first_value(attr, &value); + if (ret) { + return LDAP_OPERATIONS_ERROR; + } + + val = slapi_value_get_berval(value); + if (!val) { + return LDAP_OPERATIONS_ERROR; + } + + ret = ber_decode_krb5_key_data((struct berval *)val, + &mkvno, &num_keys, &keys); + if (ret) { + return LDAP_OPERATIONS_ERROR; + } + + ret = LDAP_UNWILLING_TO_PERFORM; + + for (i = 0; i < num_keys; i++) { + char nthash[16]; + krb5_enc_data cipher; + krb5_data plain; + krb5_int16 t; + + if (keys[i].key_data_type[0] != ENCTYPE_ARCFOUR_HMAC) { + continue; + } + + memcpy(&t, keys[i].key_data_contents[0], 2); + plain.length = le16toh(t); + if (plain.length != 16) { + continue; + } + plain.data = nthash; + + memset(&cipher, 0, sizeof(krb5_enc_data)); + cipher.enctype = krbcfg->kmkey->enctype; + cipher.ciphertext.length = keys[i].key_data_length[0] - 2; + cipher.ciphertext.data = ((char *)keys[i].key_data_contents[0]) + 2; + + ret = krb5_c_decrypt(krbcfg->krbctx, krbcfg->kmkey, + 0, NULL, &cipher, &plain); + if (ret) { + ret = LDAP_OPERATIONS_ERROR; + break; + } + + bval.bv_val = nthash; + bval.bv_len = 16; + ntvals[0] = &bval; + + slapi_mods_add_modbvps(smods, LDAP_MOD_ADD, "ipaNTHash", ntvals); + + ret = LDAP_SUCCESS; + break; + } + + ipa_krb5_free_key_data(keys, num_keys); + + return ret; +} + static int ipapwd_post_op(Slapi_PBlock *pb) { void *op; -- cgit