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authorMichael Adam <obnox@samba.org>2010-01-06 17:29:04 +0100
committerMichael Adam <obnox@samba.org>2010-01-07 16:51:18 +0100
commitdc689827114c46b3ca2a75082421dc2d98001ce7 (patch)
tree1e4798afa2904b75021ef05854bd7aed8b258081
parent46111dc4e437f9cd4df1dbf2ecfe6a56eaf1ae39 (diff)
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s3:auth: don't update the bad pw count if pw is among last 2 history entries
This conforms to the behaviour of Windows 2003: http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/security/bpactlck.mspx This is supposed to fixes Bug #4347 . Michael
-rw-r--r--source3/auth/auth_sam.c74
1 files changed, 73 insertions, 1 deletions
diff --git a/source3/auth/auth_sam.c b/source3/auth/auth_sam.c
index 4c3f552ee6..ef0cd97c52 100644
--- a/source3/auth/auth_sam.c
+++ b/source3/auth/auth_sam.c
@@ -281,6 +281,75 @@ static NTSTATUS sam_account_ok(TALLOC_CTX *mem_ctx,
return NT_STATUS_OK;
}
+/**
+ * Check whether the given password is one of the last two
+ * password history entries. If so, the bad pwcount should
+ * not be incremented even thought the actual password check
+ * failed.
+ */
+static bool need_to_increment_bad_pw_count(
+ const struct auth_context *auth_context,
+ struct samu* sampass,
+ const auth_usersupplied_info *user_info)
+{
+ uint8_t i;
+ const uint8_t *pwhistory;
+ uint32_t pwhistory_len;
+ uint32_t policy_pwhistory_len;
+ uint32_t acct_ctrl;
+ const char *username;
+ TALLOC_CTX *mem_ctx = talloc_stackframe();
+ bool result = true;
+
+ pdb_get_account_policy(PDB_POLICY_PASSWORD_HISTORY,
+ &policy_pwhistory_len);
+ if (policy_pwhistory_len == 0) {
+ goto done;
+ }
+
+ pwhistory = pdb_get_pw_history(sampass, &pwhistory_len);
+ if (!pwhistory || pwhistory_len == 0) {
+ goto done;
+ }
+
+ acct_ctrl = pdb_get_acct_ctrl(sampass);
+ username = pdb_get_username(sampass);
+
+ for (i=1; i < MIN(MIN(3, policy_pwhistory_len), pwhistory_len); i++) {
+ static const uint8_t zero16[SALTED_MD5_HASH_LEN];
+ const uint8_t *salt;
+ const uint8_t *nt_pw;
+ NTSTATUS status;
+ DATA_BLOB user_sess_key = data_blob_null;
+ DATA_BLOB lm_sess_key = data_blob_null;
+
+ salt = &pwhistory[i*PW_HISTORY_ENTRY_LEN];
+ nt_pw = salt + PW_HISTORY_SALT_LEN;
+
+ if (memcmp(zero16, nt_pw, NT_HASH_LEN) == 0) {
+ /* skip zero password hash */
+ continue;
+ }
+
+ if (memcmp(zero16, salt, PW_HISTORY_SALT_LEN) != 0) {
+ /* skip nonzero salt (old format entry) */
+ continue;
+ }
+
+ status = sam_password_ok(auth_context, mem_ctx,
+ username, acct_ctrl, NULL, nt_pw,
+ user_info, &user_sess_key, &lm_sess_key);
+ if (NT_STATUS_IS_OK(status)) {
+ result = false;
+ break;
+ }
+ }
+
+done:
+ TALLOC_FREE(mem_ctx);
+ return result;
+}
+
/****************************************************************************
check if a username/password is OK assuming the password is a 24 byte
SMB hash supplied in the user_info structure
@@ -360,7 +429,10 @@ static NTSTATUS check_sam_security(const struct auth_context *auth_context,
acct_ctrl & ACB_NORMAL &&
NT_STATUS_IS_OK(update_login_attempts_status))
{
- increment_bad_pw_count = true;
+ increment_bad_pw_count =
+ need_to_increment_bad_pw_count(auth_context,
+ sampass,
+ user_info);
}
if (increment_bad_pw_count) {