This issue was researched by glebius, and this patch was

incorporated by ISC into the next version of BIND.

The patch addresses a problem with high-load resolvers which
hit memory barriers. Without this patch, running the resolving
name server out of memory would lead to "unpredictable results."

Of course, the canonical answer to this problem is to put more
memory into the system, however that is not always possible, and
the code should be able to handle this situation gracefully in
any case.

Approved by:	portmgr (krion)

4 files changed, 92 insertions, 0 deletions

diff --git a/dns/bind9/files/patch-lib_dns_resolver.c b/dns/bind9/files/patch-lib_dns_resolver.c
new file mode 100644
index 000000000000..5605bb71f3ec
--- /dev/null
+++ b/dns/bind9/files/patch-lib_dns_resolver.c
@@ -0,0 +1,23 @@
+--- lib/dns/resolver.c.orig	Tue Feb  8 15:59:44 2005
++++ lib/dns/resolver.c	Wed Aug 17 02:42:48 2005
+@@ -2665,7 +2665,7 @@
+ 	    unsigned int options, unsigned int bucketnum, fetchctx_t **fctxp)
+ {
+ 	fetchctx_t *fctx;
+-	isc_result_t result = ISC_R_SUCCESS;
++	isc_result_t result;
+ 	isc_result_t iresult;
+ 	isc_interval_t interval;
+ 	dns_fixedname_t qdomain;
+@@ -2687,8 +2687,10 @@
+ 	strcat(buf, "/");	/* checked */
+ 	strcat(buf, typebuf);	/* checked */
+ 	fctx->info = isc_mem_strdup(res->mctx, buf);
+-	if (fctx->info == NULL)
++	if (fctx->info == NULL) {
++		result = ISC_R_NOMEMORY;
+ 		goto cleanup_fetch;
++	}
+ 	FCTXTRACE("create");
+ 	dns_name_init(&fctx->name, NULL);
+ 	result = dns_name_dup(name, res->mctx, &fctx->name);
diff --git a/dns/bind94/files/patch-lib_dns_resolver.c b/dns/bind94/files/patch-lib_dns_resolver.c
new file mode 100644
index 000000000000..5605bb71f3ec
--- /dev/null
+++ b/dns/bind94/files/patch-lib_dns_resolver.c
@@ -0,0 +1,23 @@
+--- lib/dns/resolver.c.orig	Tue Feb  8 15:59:44 2005
++++ lib/dns/resolver.c	Wed Aug 17 02:42:48 2005
+@@ -2665,7 +2665,7 @@
+ 	    unsigned int options, unsigned int bucketnum, fetchctx_t **fctxp)
+ {
+ 	fetchctx_t *fctx;
+-	isc_result_t result = ISC_R_SUCCESS;
++	isc_result_t result;
+ 	isc_result_t iresult;
+ 	isc_interval_t interval;
+ 	dns_fixedname_t qdomain;
+@@ -2687,8 +2687,10 @@
+ 	strcat(buf, "/");	/* checked */
+ 	strcat(buf, typebuf);	/* checked */
+ 	fctx->info = isc_mem_strdup(res->mctx, buf);
+-	if (fctx->info == NULL)
++	if (fctx->info == NULL) {
++		result = ISC_R_NOMEMORY;
+ 		goto cleanup_fetch;
++	}
+ 	FCTXTRACE("create");
+ 	dns_name_init(&fctx->name, NULL);
+ 	result = dns_name_dup(name, res->mctx, &fctx->name);
diff --git a/dns/bind95/files/patch-lib_dns_resolver.c b/dns/bind95/files/patch-lib_dns_resolver.c
new file mode 100644
index 000000000000..5605bb71f3ec
--- /dev/null
+++ b/dns/bind95/files/patch-lib_dns_resolver.c
@@ -0,0 +1,23 @@
+--- lib/dns/resolver.c.orig	Tue Feb  8 15:59:44 2005
++++ lib/dns/resolver.c	Wed Aug 17 02:42:48 2005
+@@ -2665,7 +2665,7 @@
+ 	    unsigned int options, unsigned int bucketnum, fetchctx_t **fctxp)
+ {
+ 	fetchctx_t *fctx;
+-	isc_result_t result = ISC_R_SUCCESS;
++	isc_result_t result;
+ 	isc_result_t iresult;
+ 	isc_interval_t interval;
+ 	dns_fixedname_t qdomain;
+@@ -2687,8 +2687,10 @@
+ 	strcat(buf, "/");	/* checked */
+ 	strcat(buf, typebuf);	/* checked */
+ 	fctx->info = isc_mem_strdup(res->mctx, buf);
+-	if (fctx->info == NULL)
++	if (fctx->info == NULL) {
++		result = ISC_R_NOMEMORY;
+ 		goto cleanup_fetch;
++	}
+ 	FCTXTRACE("create");
+ 	dns_name_init(&fctx->name, NULL);
+ 	result = dns_name_dup(name, res->mctx, &fctx->name);
diff --git a/dns/bind96/files/patch-lib_dns_resolver.c b/dns/bind96/files/patch-lib_dns_resolver.c
new file mode 100644
index 000000000000..5605bb71f3ec
--- /dev/null
+++ b/dns/bind96/files/patch-lib_dns_resolver.c
@@ -0,0 +1,23 @@
+--- lib/dns/resolver.c.orig	Tue Feb  8 15:59:44 2005
++++ lib/dns/resolver.c	Wed Aug 17 02:42:48 2005
+@@ -2665,7 +2665,7 @@
+ 	    unsigned int options, unsigned int bucketnum, fetchctx_t **fctxp)
+ {
+ 	fetchctx_t *fctx;
+-	isc_result_t result = ISC_R_SUCCESS;
++	isc_result_t result;
+ 	isc_result_t iresult;
+ 	isc_interval_t interval;
+ 	dns_fixedname_t qdomain;
+@@ -2687,8 +2687,10 @@
+ 	strcat(buf, "/");	/* checked */
+ 	strcat(buf, typebuf);	/* checked */
+ 	fctx->info = isc_mem_strdup(res->mctx, buf);
+-	if (fctx->info == NULL)
++	if (fctx->info == NULL) {
++		result = ISC_R_NOMEMORY;
+ 		goto cleanup_fetch;
++	}
+ 	FCTXTRACE("create");
+ 	dns_name_init(&fctx->name, NULL);
+ 	result = dns_name_dup(name, res->mctx, &fctx->name);