KDC denial of service attacks [MITKRB5-SA-2011-002 CVE-2011-0281 CVE-2011-0282]

pull up r24622 from trunk, minus the fix for CVE-2011-0283, which is
only applicable to krb5-1.9 and later.

 ------------------------------------------------------------------------
 r24622 | tlyu | 2011-02-09 15:25:08 -0500 (Wed, 09 Feb 2011) | 10 lines

 ticket: 6860
 subject: KDC denial of service attacks [MITKRB5-SA-2011-002 CVE-2011-0281 CVE-2011-0282 CVE-2011-0283]
 tags: pullup
 target_version: 1.9.1

 [CVE-2011-0281 CVE-2011-0282] Fix some LDAP back end principal name
 handling that could cause the KDC to hang or crash.

 [CVE-2011-0283] Fix a KDC null pointer dereference introduced in krb5-1.9.

ticket: 6862
version_fixed: 1.8.4
status: resolved

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-8@24626 dc483132-0cff-0310-8789-dd5450dbe970

4 files changed, 30 insertions, 17 deletions

diff --git a/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap.h b/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap.h
index 1ca09b4..60caf3d 100644
--- a/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap.h
+++ b/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap.h
@@ -102,14 +102,18 @@ extern void prepend_err_str (krb5_context ctx, const char *s, krb5_error_code er
 #define LDAP_SEARCH(base, scope, filter, attrs)   LDAP_SEARCH_1(base, scope, filter, attrs, CHECK_STATUS)
 
 #define LDAP_SEARCH_1(base, scope, filter, attrs, status_check)         \
-    do {                                                                \
-        st = ldap_search_ext_s(ld, base, scope, filter, attrs, 0, NULL, NULL, &timelimit, LDAP_NO_LIMIT, &result); \
-        if (translate_ldap_error(st, OP_SEARCH) == KRB5_KDB_ACCESS_ERROR) { \
-            tempst = krb5_ldap_rebind(ldap_context, &ldap_server_handle); \
-            if (ldap_server_handle)                                     \
-                ld = ldap_server_handle->ldap_handle;                   \
-        }                                                               \
-    }while (translate_ldap_error(st, OP_SEARCH) == KRB5_KDB_ACCESS_ERROR && tempst == 0); \
+    tempst = 0;                                                         \
+    st = ldap_search_ext_s(ld, base, scope, filter, attrs, 0, NULL,     \
+                           NULL, &timelimit, LDAP_NO_LIMIT, &result);   \
+    if (translate_ldap_error(st, OP_SEARCH) == KRB5_KDB_ACCESS_ERROR) { \
+        tempst = krb5_ldap_rebind(ldap_context, &ldap_server_handle);   \
+        if (ldap_server_handle)                                         \
+            ld = ldap_server_handle->ldap_handle;                       \
+        if (tempst == 0)                                                \
+            st = ldap_search_ext_s(ld, base, scope, filter, attrs, 0,   \
+                                   NULL, NULL, &timelimit,              \
+                                   LDAP_NO_LIMIT, &result);             \
+    }                                                                   \
                                                                         \
     if (status_check != IGNORE_STATUS) {                                \
         if (tempst != 0) {                                              \
diff --git a/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap_conn.c b/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap_conn.c
index 82b0333..84e80ee 100644
--- a/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap_conn.c
+++ b/src/plugins/kdb/ldap/libkdb_ldap/kdb_ldap_conn.c
@@ -302,6 +302,7 @@ krb5_ldap_rebind(krb5_ldap_context *ldap_context,
 {
     krb5_ldap_server_handle     *handle = *ldap_server_handle;
 
+    ldap_unbind_ext_s(handle->ldap_handle, NULL, NULL);
     if ((ldap_initialize(&handle->ldap_handle, handle->server_info->server_name) != LDAP_SUCCESS)
         || (krb5_ldap_bind(ldap_context, handle) != LDAP_SUCCESS))
         return krb5_ldap_request_next_handle_from_pool(ldap_context, ldap_server_handle);
diff --git a/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c b/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c
index f549e23..b70940f 100644
--- a/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c
+++ b/src/plugins/kdb/ldap/libkdb_ldap/ldap_misc.c
@@ -446,12 +446,11 @@ is_principal_in_realm(krb5_ldap_context *ldap_context,
      * portion, then the first portion of the principal name SHOULD be
      * "krbtgt".  All this check is done in the immediate block.
      */
-    if (searchfor->length == 2)
-        if ((strncasecmp(searchfor->data[0].data, "krbtgt",
-                         FIND_MAX(searchfor->data[0].length, strlen("krbtgt"))) == 0) &&
-            (strncasecmp(searchfor->data[1].data, defrealm,
-                         FIND_MAX(searchfor->data[1].length, defrealmlen)) == 0))
+    if (searchfor->length == 2) {
+        if (data_eq_string(searchfor->data[0], "krbtgt") &&
+            data_eq_string(searchfor->data[1], defrealm))
             return 0;
+    }
 
     /* first check the length, if they are not equal, then they are not same */
     if (strlen(defrealm) != searchfor->realm.length)
diff --git a/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c b/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c
index 7ad31da..626ed1f 100644
--- a/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c
+++ b/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c
@@ -103,10 +103,10 @@ krb5_ldap_get_principal(krb5_context context, krb5_const_principal searchfor,
                         unsigned int flags, krb5_db_entry *entries,
                         int *nentries, krb5_boolean *more)
 {
-    char                        *user=NULL, *filter=NULL, **subtree=NULL;
+    char                        *user=NULL, *filter=NULL, *filtuser=NULL;
     unsigned int                tree=0, ntrees=1, princlen=0;
     krb5_error_code             tempst=0, st=0;
-    char                        **values=NULL, *cname=NULL;
+    char                        **values=NULL, **subtree=NULL, *cname=NULL;
     LDAP                        *ld=NULL;
     LDAPMessage                 *result=NULL, *ent=NULL;
     krb5_ldap_context           *ldap_context=NULL;
@@ -142,12 +142,18 @@ krb5_ldap_get_principal(krb5_context context, krb5_const_principal searchfor,
     if ((st=krb5_ldap_unparse_principal_name(user)) != 0)
         goto cleanup;
 
-    princlen = strlen(FILTER) + strlen(user) + 2 + 1;      /* 2 for closing brackets */
+    filtuser = ldap_filter_correct(user);
+    if (filtuser == NULL) {
+        st = ENOMEM;
+        goto cleanup;
+    }
+
+    princlen = strlen(FILTER) + strlen(filtuser) + 2 + 1;  /* 2 for closing brackets */
     if ((filter = malloc(princlen)) == NULL) {
         st = ENOMEM;
         goto cleanup;
     }
-    snprintf(filter, princlen, FILTER"%s))", user);
+    snprintf(filter, princlen, FILTER"%s))", filtuser);
 
     if ((st = krb5_get_subtree_info(ldap_context, &subtree, &ntrees)) != 0)
         goto cleanup;
@@ -231,6 +237,9 @@ cleanup:
     if (user)
         free(user);
 
+    if (filtuser)
+        free(filtuser);
+
     if (cname)
         free(cname);