#include "auth/auth.h"
#include "auth/credentials/credentials.h"
#include "auth/auth_sam.h"
-#include "../lib/util/util_ldb.h"
#include "dsdb/samdb/samdb.h"
#include "dsdb/common/util.h"
#include "librpc/ndr/libndr.h"
return timegm(&tm);
}
-static HDBFlags uf2HDBFlags(krb5_context context, int userAccountControl, enum samba_kdc_ent_type ent_type)
+static HDBFlags uf2HDBFlags(krb5_context context, uint32_t userAccountControl, enum samba_kdc_ent_type ent_type)
{
HDBFlags flags = int2HDBFlags(0);
}
static krb5_error_code samba_kdc_message2entry_keys(krb5_context context,
+ struct samba_kdc_db_context *kdc_db_ctx,
TALLOC_CTX *mem_ctx,
struct ldb_message *msg,
uint32_t rid,
- unsigned int userAccountControl,
+ bool is_rodc,
+ uint32_t userAccountControl,
enum samba_kdc_ent_type ent_type,
hdb_entry_ex *entry_ex)
{
uint16_t i;
uint16_t allocated_keys = 0;
int rodc_krbtgt_number = 0;
- bool is_rodc = false;
-
- /* Supported Enc for this entry */
- uint32_t supported_enctypes = ENC_ALL_TYPES; /* by default, we support all enc types */
+ uint32_t supported_enctypes;
- /* However, if this is a TGS-REQ, then lock it down to a
- * reasonable guess as to what the server can decode. The
- * krbtgt is special - default to use what is stored for the KDC */
- if (rid != DOMAIN_RID_KRBTGT && ent_type == SAMBA_KDC_ENT_TYPE_SERVER) {
- /* This is the standard set for a server that has not declared a msDS-SupportedEncryptionTypes */
- supported_enctypes = ENC_CRC32 | ENC_RSA_MD5 | ENC_RC4_HMAC_MD5;
+ if (rid == DOMAIN_RID_KRBTGT || is_rodc) {
+ /* KDCs (and KDCs on RODCs) use AES, but not DES */
+ supported_enctypes = ENC_ALL_TYPES;
+ supported_enctypes &= ~(ENC_CRC32|ENC_RSA_MD5);
+ } else if (userAccountControl & (UF_PARTIAL_SECRETS_ACCOUNT|UF_SERVER_TRUST_ACCOUNT)) {
+ /* DCs and RODCs comptuer accounts use AES */
+ supported_enctypes = ENC_ALL_TYPES;
+ } else if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT ||
+ (ent_type == SAMBA_KDC_ENT_TYPE_ANY)) {
+ /* for AS-REQ the client chooses the enc types it
+ * supports, and this will vary between computers a
+ * user logs in from. However, some accounts may be
+ * banned from using DES, so allow the default to be
+ * overridden
+ *
+ * likewise for 'any' return as much as is supported,
+ * to export into a keytab */
+ supported_enctypes = ldb_msg_find_attr_as_uint(msg, "msDS-SupportedEncryptionTypes",
+ ENC_ALL_TYPES);
+ } else {
+ /* However, if this is a TGS-REQ, then lock it down to
+ * a reasonable guess as to what the server can decode
+ * - we must use whatever is in
+ * "msDS-SupportedEncryptionTypes", or the 'old' set
+ * of keys (ie, what Windows 2000 supported) */
+ supported_enctypes = ldb_msg_find_attr_as_uint(msg, "msDS-SupportedEncryptionTypes",
+ ENC_CRC32 | ENC_RSA_MD5 | ENC_RC4_HMAC_MD5);
}
- supported_enctypes = ldb_msg_find_attr_as_uint(msg, "msDS-SupportedEncryptionTypes",
- supported_enctypes);
- /* Is this the krbtgt or a RODC */
-
- if (ldb_msg_find_element(msg, "msDS-SecondaryKrbTgtNumber")) {
- is_rodc = true;
+ /* Is this the krbtgt or a RODC krbtgt */
+ if (is_rodc) {
rodc_krbtgt_number = ldb_msg_find_attr_as_int(msg, "msDS-SecondaryKrbTgtNumber", -1);
if (rodc_krbtgt_number == -1) {
}
}
- if (rid == DOMAIN_RID_KRBTGT || is_rodc) {
- /* Be double-sure never to use DES here */
- supported_enctypes &= ~(ENC_CRC32|ENC_RSA_MD5);
- }
-
- switch (ent_type) {
- case SAMBA_KDC_ENT_TYPE_KRBTGT:
- case SAMBA_KDC_ENT_TYPE_TRUST:
- /* Disallow krbtgt and trust tickets to be DES encrypted, it's just too dangerous */
- supported_enctypes &= ~(ENC_CRC32|ENC_RSA_MD5);
- break;
- default:
- break;
- /* No further restrictions */
- }
/* If UF_USE_DES_KEY_ONLY has been set, then don't allow use of the newer enc types */
if (userAccountControl & UF_USE_DES_KEY_ONLY) {
- /* However, don't allow use of DES, if we were told not to by msDS-SupportedEncTypes */
+ /* However, this still won't allow use of DES, if we
+ * were told not to by msDS-SupportedEncTypes */
supported_enctypes &= ENC_CRC32|ENC_RSA_MD5;
+ } else {
+ switch (ent_type) {
+ case SAMBA_KDC_ENT_TYPE_KRBTGT:
+ case SAMBA_KDC_ENT_TYPE_TRUST:
+ /* Unless a very special effort it made,
+ * disallow trust tickets to be DES encrypted,
+ * it's just too dangerous */
+ supported_enctypes &= ~(ENC_CRC32|ENC_RSA_MD5);
+ break;
+ default:
+ break;
+ /* No further restrictions */
+ }
}
entry_ex->entry.keys.val = NULL;
}
if (allocated_keys == 0) {
+ if (kdc_db_ctx->rodc) {
+ /* We are on an RODC, but don't have keys for this account. Signal this to the caller */
+ return HDB_ERR_NOT_FOUND_HERE;
+ }
+
/* oh, no password. Apparently (comment in
* hdb-ldap.c) this violates the ASN.1, but this
* allows an entry with no keys (yet). */
* Construct an hdb_entry from a directory entry.
*/
static krb5_error_code samba_kdc_message2entry(krb5_context context,
- struct samba_kdc_db_context *kdc_db_ctx,
- TALLOC_CTX *mem_ctx, krb5_const_principal principal,
- enum samba_kdc_ent_type ent_type,
- struct ldb_dn *realm_dn,
- struct ldb_message *msg,
- hdb_entry_ex *entry_ex)
+ struct samba_kdc_db_context *kdc_db_ctx,
+ TALLOC_CTX *mem_ctx, krb5_const_principal principal,
+ enum samba_kdc_ent_type ent_type,
+ unsigned flags,
+ struct ldb_dn *realm_dn,
+ struct ldb_message *msg,
+ hdb_entry_ex *entry_ex)
{
struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx;
- unsigned int userAccountControl;
+ uint32_t userAccountControl;
unsigned int i;
krb5_error_code ret = 0;
krb5_boolean is_computer = FALSE;
- char *realm = strupper_talloc(mem_ctx, lpcfg_realm(lp_ctx));
struct samba_kdc_entry *p;
NTTIME acct_expiry;
NTSTATUS status;
uint32_t rid;
+ bool is_rodc = false;
struct ldb_message_element *objectclasses;
struct ldb_val computer_val;
const char *samAccountName = ldb_msg_find_attr_as_string(msg, "samAccountName", NULL);
computer_val.data = discard_const_p(uint8_t,"computer");
computer_val.length = strlen((const char *)computer_val.data);
+ if (ldb_msg_find_element(msg, "msDS-SecondaryKrbTgtNumber")) {
+ is_rodc = true;
+ }
+
if (!samAccountName) {
ret = ENOENT;
krb5_set_error_message(context, ret, "samba_kdc_message2entry: no samAccountName present");
memset(entry_ex, 0, sizeof(*entry_ex));
- if (!realm) {
- ret = ENOMEM;
- krb5_set_error_message(context, ret, "talloc_strdup: out of memory");
- goto out;
- }
-
p = talloc(mem_ctx, struct samba_kdc_entry);
if (!p) {
ret = ENOMEM;
entry_ex->entry.principal = malloc(sizeof(*(entry_ex->entry.principal)));
if (ent_type == SAMBA_KDC_ENT_TYPE_ANY && principal == NULL) {
- krb5_make_principal(context, &entry_ex->entry.principal, realm, samAccountName, NULL);
+ krb5_make_principal(context, &entry_ex->entry.principal, lpcfg_realm(lp_ctx), samAccountName, NULL);
} else {
ret = copy_Principal(principal, entry_ex->entry.principal);
if (ret) {
* we determine from our records */
/* this has to be with malloc() */
- krb5_principal_set_realm(context, entry_ex->entry.principal, realm);
+ krb5_principal_set_realm(context, entry_ex->entry.principal, lpcfg_realm(lp_ctx));
}
/* First try and figure out the flags based on the userAccountControl */
}
}
- {
+ if (flags & HDB_F_ADMIN_DATA) {
/* These (created_by, modified_by) parts of the entry are not relevant for Samba4's use
* of the Heimdal KDC. They are stored in a the traditional
* DB for audit purposes, and still form part of the structure
/* use 'kadmin' for now (needed by mit_samba) */
krb5_make_principal(context,
&entry_ex->entry.created_by.principal,
- realm, "kadmin", NULL);
+ lpcfg_realm(lp_ctx), "kadmin", NULL);
entry_ex->entry.modified_by = (Event *) malloc(sizeof(Event));
if (entry_ex->entry.modified_by == NULL) {
/* use 'kadmin' for now (needed by mit_samba) */
krb5_make_principal(context,
&entry_ex->entry.modified_by->principal,
- realm, "kadmin", NULL);
+ lpcfg_realm(lp_ctx), "kadmin", NULL);
}
entry_ex->entry.flags.client = 0;
entry_ex->entry.flags.forwardable = 1;
entry_ex->entry.flags.ok_as_delegate = 1;
+ } else if (is_rodc) {
+ /* The RODC krbtgt account is like the main krbtgt,
+ * but it does not have a changepw or kadmin
+ * service */
+
+ entry_ex->entry.valid_end = NULL;
+ entry_ex->entry.pw_end = NULL;
+
+ /* Also don't allow the RODC krbtgt to be a client (it should not be needed) */
+ entry_ex->entry.flags.client = 0;
+ entry_ex->entry.flags.invalid = 0;
+ entry_ex->entry.flags.server = 1;
+
+ entry_ex->entry.flags.client = 0;
+ entry_ex->entry.flags.forwardable = 1;
+ entry_ex->entry.flags.ok_as_delegate = 0;
} else if (entry_ex->entry.flags.server && ent_type == SAMBA_KDC_ENT_TYPE_SERVER) {
/* The account/password expiry only applies when the account is used as a
* client (ie password login), not when used as a server */
entry_ex->entry.generation = NULL;
/* Get keys from the db */
- ret = samba_kdc_message2entry_keys(context, p, msg,
- rid, userAccountControl,
+ ret = samba_kdc_message2entry_keys(context, kdc_db_ctx, p, msg,
+ rid, is_rodc, userAccountControl,
ent_type, entry_ex);
if (ret) {
/* Could be bougus data in the entry, or out of memory */
{
struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx;
const char *dnsdomain;
- char *realm = strupper_talloc(mem_ctx, lpcfg_realm(lp_ctx));
+ const char *realm = lpcfg_realm(lp_ctx);
DATA_BLOB password_utf16;
struct samr_Password password_hash;
const struct ldb_val *password_val;
} else { /* OUTBOUND */
dnsdomain = ldb_msg_find_attr_as_string(msg, "trustPartner", NULL);
/* replace realm */
- talloc_free(realm);
realm = strupper_talloc(mem_ctx, dnsdomain);
password_val = ldb_msg_find_ldb_val(msg, "trustAuthOutgoing");
}
struct samba_kdc_db_context *kdc_db_ctx,
TALLOC_CTX *mem_ctx,
krb5_const_principal principal,
+ unsigned flags,
hdb_entry_ex *entry_ex) {
struct ldb_dn *realm_dn;
krb5_error_code ret;
}
ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
- principal, SAMBA_KDC_ENT_TYPE_CLIENT,
- realm_dn, msg, entry_ex);
+ principal, SAMBA_KDC_ENT_TYPE_CLIENT,
+ flags,
+ realm_dn, msg, entry_ex);
return ret;
}
static krb5_error_code samba_kdc_fetch_krbtgt(krb5_context context,
- struct samba_kdc_db_context *kdc_db_ctx,
- TALLOC_CTX *mem_ctx,
- krb5_const_principal principal,
- hdb_entry_ex *entry_ex)
+ struct samba_kdc_db_context *kdc_db_ctx,
+ TALLOC_CTX *mem_ctx,
+ krb5_const_principal principal,
+ unsigned flags,
+ uint32_t krbtgt_number,
+ hdb_entry_ex *entry_ex)
{
struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx;
krb5_error_code ret;
if (lpcfg_is_my_domain_or_realm(lp_ctx, principal->realm)
&& lpcfg_is_my_domain_or_realm(lp_ctx, principal->name.name_string.val[1])) {
- /* us */
+ /* us, or someone quite like us */
/* Cludge, cludge cludge. If the realm part of krbtgt/realm,
* is in our db, then direct the caller at our primary
* krbtgt */
int lret;
- char *realm_fixed;
- lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx,
- &msg, realm_dn, LDB_SCOPE_SUBTREE,
- krbtgt_attrs,
- DSDB_SEARCH_SHOW_EXTENDED_DN,
- "(&(objectClass=user)(samAccountName=krbtgt))");
+ if (krbtgt_number == kdc_db_ctx->my_krbtgt_number) {
+ lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx,
+ &msg, kdc_db_ctx->krbtgt_dn, LDB_SCOPE_BASE,
+ krbtgt_attrs, 0,
+ "(objectClass=user)");
+ } else {
+ /* We need to look up an RODC krbtgt (perhaps
+ * ours, if we are an RODC, perhaps another
+ * RODC if we are a read-write DC */
+ lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx,
+ &msg, realm_dn, LDB_SCOPE_SUBTREE,
+ krbtgt_attrs,
+ DSDB_SEARCH_SHOW_EXTENDED_DN,
+ "(&(objectClass=user)(msDS-SecondaryKrbTgtNumber=%u))", (unsigned)(krbtgt_number));
+ }
+
if (lret == LDB_ERR_NO_SUCH_OBJECT) {
- krb5_warnx(context, "samba_kdc_fetch: could not find own KRBTGT in DB!");
- krb5_set_error_message(context, HDB_ERR_NOENTRY, "samba_kdc_fetch: could not find own KRBTGT in DB!");
+ krb5_warnx(context, "samba_kdc_fetch: could not find KRBTGT number %u in DB!",
+ (unsigned)(krbtgt_number));
+ krb5_set_error_message(context, HDB_ERR_NOENTRY,
+ "samba_kdc_fetch: could not find KRBTGT number %u in DB!",
+ (unsigned)(krbtgt_number));
return HDB_ERR_NOENTRY;
} else if (lret != LDB_SUCCESS) {
- krb5_warnx(context, "samba_kdc_fetch: could not find own KRBTGT in DB: %s", ldb_errstring(kdc_db_ctx->samdb));
- krb5_set_error_message(context, HDB_ERR_NOENTRY, "samba_kdc_fetch: could not find own KRBTGT in DB: %s", ldb_errstring(kdc_db_ctx->samdb));
+ krb5_warnx(context, "samba_kdc_fetch: could not find KRBTGT number %u in DB!",
+ (unsigned)(krbtgt_number));
+ krb5_set_error_message(context, HDB_ERR_NOENTRY,
+ "samba_kdc_fetch: could not find KRBTGT number %u in DB!",
+ (unsigned)(krbtgt_number));
return HDB_ERR_NOENTRY;
}
- realm_fixed = strupper_talloc(mem_ctx, lpcfg_realm(lp_ctx));
- if (!realm_fixed) {
- ret = ENOMEM;
- krb5_set_error_message(context, ret, "strupper_talloc: out of memory");
- return ret;
- }
-
- ret = krb5_copy_principal(context, principal, &alloc_principal);
- if (ret) {
- return ret;
- }
-
- free(alloc_principal->name.name_string.val[1]);
- alloc_principal->name.name_string.val[1] = strdup(realm_fixed);
- talloc_free(realm_fixed);
- if (!alloc_principal->name.name_string.val[1]) {
- ret = ENOMEM;
- krb5_set_error_message(context, ret, "samba_kdc_fetch: strdup() failed!");
- return ret;
- }
- principal = alloc_principal;
+ if (flags & HDB_F_CANON) {
+ ret = krb5_copy_principal(context, principal, &alloc_principal);
+ if (ret) {
+ return ret;
+ }
+
+ /* When requested to do so, ensure that the
+ * both realm values in the principal are set
+ * to the upper case, canonical realm */
+ free(alloc_principal->name.name_string.val[1]);
+ alloc_principal->name.name_string.val[1] = strdup(lpcfg_realm(lp_ctx));
+ if (!alloc_principal->name.name_string.val[1]) {
+ ret = ENOMEM;
+ krb5_set_error_message(context, ret, "samba_kdc_fetch: strdup() failed!");
+ return ret;
+ }
+ principal = alloc_principal;
+ }
ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
- principal, SAMBA_KDC_ENT_TYPE_KRBTGT,
- realm_dn, msg, entry_ex);
+ principal, SAMBA_KDC_ENT_TYPE_KRBTGT,
+ flags, realm_dn, msg, entry_ex);
+ if (flags & HDB_F_CANON) {
+ /* This is again copied in the message2entry call */
+ krb5_free_principal(context, alloc_principal);
+ }
if (ret != 0) {
krb5_warnx(context, "samba_kdc_fetch: self krbtgt message2entry failed");
}
struct ldb_message **msg)
{
krb5_error_code ret;
- const char *realm;
if (principal->name.name_string.len >= 2) {
/* 'normal server' case */
int ldb_ret;
int lret;
char *filter = NULL;
char *short_princ;
+ const char *realm;
/* server as client principal case, but we must not lookup userPrincipalNames */
*realm_dn = ldb_get_default_basedn(kdc_db_ctx->samdb);
realm = krb5_principal_get_realm(context, principal);
}
static krb5_error_code samba_kdc_fetch_server(krb5_context context,
- struct samba_kdc_db_context *kdc_db_ctx,
- TALLOC_CTX *mem_ctx,
- krb5_const_principal principal,
- hdb_entry_ex *entry_ex)
+ struct samba_kdc_db_context *kdc_db_ctx,
+ TALLOC_CTX *mem_ctx,
+ krb5_const_principal principal,
+ unsigned flags,
+ hdb_entry_ex *entry_ex)
{
krb5_error_code ret;
struct ldb_dn *realm_dn;
}
ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
- principal, SAMBA_KDC_ENT_TYPE_SERVER,
- realm_dn, msg, entry_ex);
+ principal, SAMBA_KDC_ENT_TYPE_SERVER,
+ flags,
+ realm_dn, msg, entry_ex);
if (ret != 0) {
krb5_warnx(context, "samba_kdc_fetch: message2entry failed");
}
struct samba_kdc_db_context *kdc_db_ctx,
krb5_const_principal principal,
unsigned flags,
+ unsigned kvno,
hdb_entry_ex *entry_ex)
{
krb5_error_code ret = HDB_ERR_NOENTRY;
- TALLOC_CTX *mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_fetch context");
+ TALLOC_CTX *mem_ctx;
+ unsigned int krbtgt_number;
+ if (flags & HDB_F_KVNO_SPECIFIED) {
+ krbtgt_number = kvno >> 16;
+ if (kdc_db_ctx->rodc) {
+ if (krbtgt_number != kdc_db_ctx->my_krbtgt_number) {
+ return HDB_ERR_NOT_FOUND_HERE;
+ }
+ }
+ } else {
+ krbtgt_number = kdc_db_ctx->my_krbtgt_number;
+ }
+ mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_fetch context");
if (!mem_ctx) {
ret = ENOMEM;
krb5_set_error_message(context, ret, "samba_kdc_fetch: talloc_named() failed!");
}
if (flags & HDB_F_GET_CLIENT) {
- ret = samba_kdc_fetch_client(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
+ ret = samba_kdc_fetch_client(context, kdc_db_ctx, mem_ctx, principal, flags, entry_ex);
if (ret != HDB_ERR_NOENTRY) goto done;
}
if (flags & HDB_F_GET_SERVER) {
/* krbtgt fits into this situation for trusted realms, and for resolving different versions of our own realm name */
- ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
+ ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, flags, krbtgt_number, entry_ex);
if (ret != HDB_ERR_NOENTRY) goto done;
/* We return 'no entry' if it does not start with krbtgt/, so move to the common case quickly */
- ret = samba_kdc_fetch_server(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
+ ret = samba_kdc_fetch_server(context, kdc_db_ctx, mem_ctx, principal, flags, entry_ex);
if (ret != HDB_ERR_NOENTRY) goto done;
}
if (flags & HDB_F_GET_KRBTGT) {
- ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, entry_ex);
+ ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, flags, krbtgt_number, entry_ex);
if (ret != HDB_ERR_NOENTRY) goto done;
}
if (priv->index < priv->count) {
ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx,
- NULL, SAMBA_KDC_ENT_TYPE_ANY,
- priv->realm_dn, priv->msgs[priv->index++], entry);
+ NULL, SAMBA_KDC_ENT_TYPE_ANY,
+ HDB_F_ADMIN_DATA|HDB_F_GET_ANY,
+ priv->realm_dn, priv->msgs[priv->index++], entry);
} else {
ret = HDB_ERR_NOENTRY;
}
NTSTATUS samba_kdc_setup_db_ctx(TALLOC_CTX *mem_ctx, struct samba_kdc_base_context *base_ctx,
struct samba_kdc_db_context **kdc_db_ctx_out)
{
- NTSTATUS nt_status;
int ldb_ret;
struct ldb_message *msg;
struct auth_session_info *session_info;
kdc_db_ctx->ev_ctx = base_ctx->ev_ctx;
kdc_db_ctx->lp_ctx = base_ctx->lp_ctx;
-#if 1
- /* we would prefer to use system_session(), as that would
- * allow us to share the samdb backend context with other parts of the
- * system. For now we can't as we need to override the
- * credentials to set CRED_DONT_USE_KERBEROS, which would
- * break other users of the system_session */
- DEBUG(0,("FIXME: Using new system session for hdb\n"));
- nt_status = auth_system_session_info(kdc_db_ctx, base_ctx->lp_ctx, &session_info);
- if (!NT_STATUS_IS_OK(nt_status)) {
- return nt_status;
- }
-#else
session_info = system_session(kdc_db_ctx->lp_ctx);
if (session_info == NULL) {
return NT_STATUS_INTERNAL_ERROR;
}
-#endif
-
- cli_credentials_set_kerberos_state(session_info->credentials,
- CRED_DONT_USE_KERBEROS);
/* Setup the link to LDB */
kdc_db_ctx->samdb = samdb_connect(kdc_db_ctx, base_ctx->ev_ctx,
- base_ctx->lp_ctx, session_info);
+ base_ctx->lp_ctx, session_info, 0);
if (kdc_db_ctx->samdb == NULL) {
DEBUG(1, ("hdb_samba4_create: Cannot open samdb for KDC backend!"));
talloc_free(kdc_db_ctx);
git.samba.org / samba.git / blobdiff