DP: Fix bugs in sss_dp_get_account_int

The conversion to the tevent_req style introduced numerous bugs
related to memory management of the various client requests. In
some circumstances, this could cause memory corruption and
segmentation faults in the NSS responder. This patch makes the
following changes:

1) Rename the internal lookup from subreq to sidereq, to indicate
that it is not a sub-request of the current lookup (and therefore
is not cancelled if the current request is).

2) Change the handling of the callback loops since they call
tevent_req_[done|error], which results in them being freed (and
therefore removed from the cb_list. This was the source of the
memory corruption that would occasionally result in dereferencing
an unreadable request.

3) Remove the unnecessary sss_dp_get_account_int_recv() function
and change sss_dp_get_account_done() so that it only frees the
sidereq. All of the waiting processes have already been signaled
with the final results from sss_dp_get_account_int_done()

1 files changed, 1 insertions, 0 deletions

diff --git a/src/responder/pam/pamsrv_cmd.c b/src/responder/pam/pamsrv_cmd.c
index 8cb64221..0f9fd5ed 100644
--- a/src/responder/pam/pamsrv_cmd.c
+++ b/src/responder/pam/pamsrv_cmd.c
@@ -994,6 +994,7 @@ static void pam_dp_send_acct_req_done(struct tevent_req *req)
     ret = sss_dp_get_account_recv(cb_ctx->mem_ctx, req,
                                   &err_maj, &err_min,
                                   &err_msg);
+    talloc_zfree(req);
     if (ret != EOK) {
         DEBUG(SSSDBG_CRIT_FAILURE,
               ("Fatal error, killing connection!\n"));