2 changed files with 22 additions and 0 deletions
@@ -157,6 +157,21 @@ public cloud metadata addresses: currently only `168.63.129.16`, Azure's
 WireServer, which serves an Azure VM its credentials. Because it is a
 public address, listing it in `ALLOWED_EGRESS_CIDRS` reopens it.
 That is all the default blocklist covers: the IPv4 private and reserved
 ranges; of IPv6, only loopback (`::1`), unique local addresses
 (`fc00::/7`) and link-local addresses (`fe80::/10`); and certain public
 addresses. A public address belongs on the default blocklist only if it
 hands credentials, user data or bootstrap material to whatever can reach
 it, without the caller presenting anything. A provider's other public
 addresses are not refused. IBM Cloud, for example, serves its package
 mirrors, time servers and object storage on `161.26.0.0/16`, and the
 private endpoints of its own cloud services on `166.8.0.0/14`. Neither
 range hands out credentials that way: the token service among those
 endpoints issues a token only in exchange for something the caller
 presents, such as an API key. Reaching these services can be a
 legitimate delivery, and every cloud has some, so a partial list would
 promise coverage it does not give.
 That default is also inconvenient for the thing webhooker is mostly
 for: taking a public webhook and forwarding it to something on your own
 network. A container on the same Docker network, a box on `10.x`, a
@@ -43,6 +43,13 @@ var (
 // permit specific blocks out of this set with
 // ALLOWED_EGRESS_CIDRS; see Guard.
 //
 // A public address belongs on the default blocklist only if it
 // hands credentials, user data or bootstrap material to whatever
 // can reach it, without the caller presenting anything. A
 // provider's other public addresses are not refused, since
 // reaching them can be legitimate and no list of them could be
 // complete.
 //
 //nolint:gochecknoglobals // package-level network list is appropriate here
 var blockedNetworks []*net.IPNet