ComputerSurge/bind9
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don't set DNS_DISPATCHSTATE_CONNECTED until attaching handle

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there was a race possible in which a dispatch was put into
the 'connected' state before it had a TCP handle attached,
which could cause an assertion failure in dns_dispatch_gettcp().
This commit is contained in:
Evan Hunt
2021-10-20 11:39:13 -07:00
parent d4e04abb73
commit c5a8454436
1 changed files with 4 additions and 4 deletions
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8
lib/dns/dispatch.c
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@@ -1603,6 +1603,10 @@ startrecv(isc_nmhandle_t *handle, dns_dispatch_t *disp, dns_dispentry_t *resp) {
REQUIRE(disp != NULL);
LOCK(&disp->lock);
REQUIRE(disp->handle == NULL);
REQUIRE(atomic_compare_exchange_strong(
&disp->state,
&(uint_fast32_t){ DNS_DISPATCHSTATE_CONNECTING },
DNS_DISPATCHSTATE_CONNECTED));
isc_nmhandle_attach(handle, &disp->handle);
dns_dispatch_attach(disp, &(dns_dispatch_t *){ NULL });
@@ -1633,10 +1637,6 @@ tcp_connected(isc_nmhandle_t *handle, isc_result_t eresult, void *arg) {
}
if (eresult == ISC_R_SUCCESS) {
REQUIRE(atomic_compare_exchange_strong(
&disp->state,
&(uint_fast32_t){ DNS_DISPATCHSTATE_CONNECTING },
DNS_DISPATCHSTATE_CONNECTED));
startrecv(handle, disp, NULL);
}