Bug 4748: r15240 broke IP-based URLs, twice. (#41)

r15240 broke ipcacheCheckNumeric() because that function's static
storage was no longer reset properly between calls.

This bug is very different from bug 4741, but their symptoms (e.g.,
false "Host header forgery" SECURITY ALERTs) can be the same.

I did not realize that std::vector::resize(n, x) ignores x when the
vector size is already at least n. It is not a reset()-like method. My
tests did not have enough different IP-based URLs to expose this bug.

diff --git a/src/ipcache.cc b/src/ipcache.cc
index c3d4a2d37638d0865e9a89d940364acc78fbb2aa..e6d52ac181f6f3d23e69517b2cc98eac296cbaca 100644 (file)
--- a/src/ipcache.cc
+++ b/src/ipcache.cc
@@ -947,7 +947,8 @@ Dns::CachedIps::seekNewGood(const char *name)
 void
 Dns::CachedIps::reset(const Ip::Address &ip)
 {
-    ips.resize(1, Dns::CachedIp(ip));
+    ips.clear();
+    ips.emplace_back(ip);
     goodPosition = 0;
     // Assume that the given IP is good because CachedIps are designed to never
     // run out of good IPs.
@@ -978,10 +979,12 @@ Dns::CachedIps::have(const Ip::Address &ip, size_t *positionOrNil) const
         if (cachedIp.ip == ip) {
             if (auto position = positionOrNil)
                 *position = pos;
+            debugs(14, 7, ip << " at " << pos << " in " << *this);
             return true;
         }
     }
     // no such address; leave *position as is
+    debugs(14, 7, " no " << ip << " in " << *this);
     return false;
 }