From: Jeremy Allison <jra@samba.org>
Date: Fri, 25 Jul 2008 18:46:34 +0000 (-0700)
Subject: Back-port of Volkers fix.
X-Git-Tag: samba-3.0.32~8
X-Git-Url: http://git.samba.org/?p=samba.git;a=commitdiff_plain;h=c93d42969451949566327e7fdbf29bfcee2c8319

Back-port of Volkers fix.

    Fix a race condition in winbind leading to a crash

    When SIGCHLD handling is delayed for some reason, sending a request to a child
    can fail early because the child has died already. In this case
    async_main_request_sent() directly called the continuation function without
    properly removing the malfunctioning child process and the requests in the
    queue. The next request would then crash in the DLIST_ADD_END() in
    async_request() because the request pending for the child had been
    talloc_free()'ed and yet still was referenced in the list.

    This one is *old*...

    Volker

Jeremy.
---

diff --git a/source/nsswitch/winbindd_dual.c b/source/nsswitch/winbindd_dual.c
index 40ebf54cb95..396eca7beb3 100644
--- a/source/nsswitch/winbindd_dual.c
+++ b/source/nsswitch/winbindd_dual.c
@@ -102,6 +102,7 @@ struct winbindd_async_request {
 	void *private_data;
 };
 
+static void async_request_fail(struct winbindd_async_request *state);
 static void async_main_request_sent(void *private_data, BOOL success);
 static void async_request_sent(void *private_data, BOOL success);
 static void async_reply_recv(void *private_data, BOOL success);
@@ -127,6 +128,7 @@ void async_request(TALLOC_CTX *mem_ctx, struct winbindd_child *child,
 
 	state->mem_ctx = mem_ctx;
 	state->child = child;
+	state->reply_timeout_event = NULL;
 	state->request = request;
 	state->response = response;
 	state->continuation = continuation;
@@ -146,10 +148,7 @@ static void async_main_request_sent(void *private_data, BOOL success)
 
 	if (!success) {
 		DEBUG(5, ("Could not send async request\n"));
-
-		state->response->length = sizeof(struct winbindd_response);
-		state->response->result = WINBINDD_ERROR;
-		state->continuation(state->private_data, False);
+		async_request_fail(state);
 		return;
 	}