Fixed segmentation fault in ngx_resolver_create_name_query().
If name passed for resolution was { 0, NULL } (e.g. as a result
of name server returning CNAME pointing to ".") pointer wrapped
to (void *) -1 resulting in segmentation fault on an attempt to
dereference it.
Reported by Lanshun Zhou.
diff --git a/src/core/ngx_resolver.c b/src/core/ngx_resolver.c
index 02c484d..ecf97d7 100644
--- a/src/core/ngx_resolver.c
+++ b/src/core/ngx_resolver.c
@@ -1834,6 +1834,10 @@
p--;
*p-- = '\0';
+ if (ctx->name.len == 0) {
+ return NGX_DECLINED;
+ }
+
for (s = ctx->name.data + ctx->name.len - 1; s >= ctx->name.data; s--) {
if (*s != '.') {
*p = *s;
