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PJPROJECT 2.5.5 introduced a race condition with the -r5349 IPv6 DNS patch. The patches below fix the DNS lookup race condition crash caused by attempting to send the same message twice for the single DNS lookup. 0006-r5471-svn-backport-Various-fixes-for-DNS-IPv6.patch 0006-r5473-svn-backport-Fix-pending-query.patch The patch below removes a cached DNS response from the hash table when another thread is referencing the old entry. The table still contained the entry when it was destroyed which can result in inexplicable crashes. 0006-r5475-svn-backport-Remove-DNS-cache-entry.patch ASTERISK-26344 #close Reported by: Ian Gilmour ASTERISK-26387 #close Reported by: Harley Peters Change-Id: I17fde80359e66f65a91341ceca58d914d0f61cc4
71 lines
2.5 KiB
Diff
71 lines
2.5 KiB
Diff
From 46e1cfa18853a38b7fcdebad782710c5db676657 Mon Sep 17 00:00:00 2001
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From: Richard Mudgett <rmudgett@digium.com>
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Date: Fri, 28 Oct 2016 12:15:44 -0500
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Subject: [PATCH 3/3] r5475 svn backport Remove DNS cache entry
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Re #1974: Remove DNS cache entry from resolver's hash table when app callback has a reference.
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Thanks to Richard Mudgett for the patch.
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---
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pjlib-util/src/pjlib-util/resolver.c | 29 +++++++++++++++--------------
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1 file changed, 15 insertions(+), 14 deletions(-)
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diff --git a/pjlib-util/src/pjlib-util/resolver.c b/pjlib-util/src/pjlib-util/resolver.c
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index fe687b7..52b7655 100644
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--- a/pjlib-util/src/pjlib-util/resolver.c
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+++ b/pjlib-util/src/pjlib-util/resolver.c
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@@ -1444,10 +1444,12 @@ static void update_res_cache(pj_dns_resolver *resolver,
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if (ttl > resolver->settings.cache_max_ttl)
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ttl = resolver->settings.cache_max_ttl;
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+ /* Get a cache response entry */
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+ cache = (struct cached_res *) pj_hash_get(resolver->hrescache, key,
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+ sizeof(*key), &hval);
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+
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/* If TTL is zero, clear the same entry in the hash table */
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if (ttl == 0) {
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- cache = (struct cached_res *) pj_hash_get(resolver->hrescache, key,
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- sizeof(*key), &hval);
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/* Remove the entry before releasing its pool (see ticket #1710) */
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pj_hash_set(NULL, resolver->hrescache, key, sizeof(*key), hval, NULL);
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@@ -1457,24 +1459,23 @@ static void update_res_cache(pj_dns_resolver *resolver,
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return;
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}
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- /* Get a cache response entry */
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- cache = (struct cached_res *) pj_hash_get(resolver->hrescache, key,
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- sizeof(*key), &hval);
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if (cache == NULL) {
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cache = alloc_entry(resolver);
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- } else if (cache->ref_cnt > 1) {
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- /* When cache entry is being used by callback (to app), just decrement
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- * ref_cnt so it will be freed after the callback returns and allocate
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- * new entry.
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- */
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- cache->ref_cnt--;
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- cache = alloc_entry(resolver);
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} else {
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/* Remove the entry before resetting its pool (see ticket #1710) */
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pj_hash_set(NULL, resolver->hrescache, key, sizeof(*key), hval, NULL);
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- /* Reset cache to avoid bloated cache pool */
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- reset_entry(&cache);
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+ if (cache->ref_cnt > 1) {
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+ /* When cache entry is being used by callback (to app),
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+ * just decrement ref_cnt so it will be freed after
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+ * the callback returns and allocate new entry.
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+ */
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+ cache->ref_cnt--;
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+ cache = alloc_entry(resolver);
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+ } else {
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+ /* Reset cache to avoid bloated cache pool */
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+ reset_entry(&cache);
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+ }
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}
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/* Duplicate the packet.
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--
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1.7.9.5
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