CVE-2022-2031 s4:kpasswd: Correctly generate error strings

The error_data we create already has an explicit length, and should not
be zero-terminated, so we omit the trailing null byte. Previously,
Heimdal builds would leave a superfluous trailing null byte on error
strings, while MIT builds would omit the final character.

The two bytes added to the string's length are for the prepended error
code.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15047
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15049
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15074

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andreas Schneider <asn@samba.org>

diff --git a/selftest/knownfail_heimdal_kdc b/selftest/knownfail_heimdal_kdc
index 90da53ada617ce5795542755f81153a52d23cd47..22d5656e5fb2a8c27089452736b794df43726d3e 100644 (file)
--- a/selftest/knownfail_heimdal_kdc
+++ b/selftest/knownfail_heimdal_kdc
@@ -59,24 +59,12 @@
 #
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_canonicalize.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_canonicalize_realm_case.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_change.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_change_expired_password.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_empty.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_from_rodc.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_initial.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_canonicalize.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_canonicalize_realm_case.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_seq_number.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_non_initial.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_expired_password.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_and_realm_access.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_and_realm_no_access.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_only.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_realm_only.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_ticket_lifetime.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_ticket_requester_sid_tgs.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_too_weak.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_wrong_key.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_wrong_key_server.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_wrong_key_service.ad_dc

diff --git a/selftest/knownfail_mit_kdc b/selftest/knownfail_mit_kdc
index fcf96b685975b4286aee4537a997889aa74459a1..dfe9a5c212e599e0ea3ab1d8229daab81def53fd 100644 (file)
--- a/selftest/knownfail_mit_kdc
+++ b/selftest/knownfail_mit_kdc
@@ -436,26 +436,11 @@ samba.tests.krb5.as_canonicalization_tests.samba.tests.krb5.as_canonicalization_
 #
 # Kpasswd tests
 #
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_canonicalize.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_canonicalize_realm_case.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_change.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_change_expired_password.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_empty.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_from_rodc.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_initial.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_canonicalize.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_canonicalize_realm_case.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_seq_number.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_non_initial.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_expired_password.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_and_realm_access.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_and_realm_no_access.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_only.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_realm_only.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_ticket_lifetime.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_ticket_requester_sid_tgs.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_too_weak.ad_dc
-^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_wrong_key.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_wrong_key_server.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_wrong_key_service.ad_dc

diff --git a/selftest/knownfail_mit_kdc_1_20 b/selftest/knownfail_mit_kdc_1_20
index fe6b526b9ac9159df55201014b97723d45a9cc5f..f886c36038162f35a658b5ededdf4e070aadde06 100644 (file)
--- a/selftest/knownfail_mit_kdc_1_20
+++ b/selftest/knownfail_mit_kdc_1_20
@@ -10,5 +10,20 @@
 #
 # Kpasswd tests
 #
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_canonicalize.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_change.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_change_expired_password.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_from_rodc.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_initial.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_canonicalize.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_no_seq_number.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_expired_password.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_and_realm_access.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_and_realm_no_access.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_princ_only.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_set_target_realm_only.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_ticket_requester_sid_lifetime_tgs.ad_dc
 ^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_ticket_tgs.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_too_weak.ad_dc
+^samba.tests.krb5.kpasswd_tests.samba.tests.krb5.kpasswd_tests.KpasswdTests.test_kpasswd_wrong_key.ad_dc

diff --git a/source4/kdc/kpasswd-helper.c b/source4/kdc/kpasswd-helper.c
index ffd0a1ef0608c749f1ab87a67239d70f34024e4c..83d2dabad1fbe0098a2ed154b99edd96ffd3f13a 100644 (file)
--- a/source4/kdc/kpasswd-helper.c
+++ b/source4/kdc/kpasswd-helper.c
@@ -48,17 +48,16 @@ bool kpasswd_make_error_reply(TALLOC_CTX *mem_ctx,
        }
 
        /*
-        * The string 's' has two terminating nul-bytes which are also
-        * reflected by 'slen'. Normally Kerberos doesn't expect that strings
-        * are nul-terminated, but Heimdal does!
+        * The string 's' has one terminating nul-byte which is also
+        * reflected by 'slen'. We subtract it from the length.
         */
-#ifndef SAMBA4_USES_HEIMDAL
-       if (slen < 2) {
+       if (slen < 1) {
                talloc_free(s);
                return false;
        }
-       slen -= 2;
-#endif
+       slen--;
+
+       /* Two bytes are added to the length to account for the error code. */
        if (2 + slen < slen) {
                talloc_free(s);
                return false;