fix(gateway): normalization of DNSLink inlining (#462)

Co-authored-by: Henrique Dias <hacdias@gmail.com>

.github/workflows/gateway-conformance.yml

@@ -25,7 +25,7 @@ jobs:
  - name: Setup Go
  uses: actions/setup-go@v3
  with:
- go-version: 1.19.x
+ go-version: 1.21.x
  - name: Checkout boxo
  uses: actions/checkout@v3
  with:

.github/workflows/gateway-sharness.yml

@@ -18,7 +18,7 @@ jobs:
  - name: Setup Go
  uses: actions/setup-go@v4
  with:
- go-version: 1.19.1
+ go-version: 1.21.x
  - name: Checkout boxo
  uses: actions/checkout@v3
  with:

CHANGELOG.md

@@ -38,6 +38,9 @@ The following emojis are used to highlight certain changes:
 
 ### Fixed
 
+* The normalization of DNSLink identifiers in `gateway` has been corrected in the edge
+ case where the value passed to the path component of the URL is already normalized.
+
 ### Security
 
 ## [v0.12.0]

gateway/hostname.go

@@ -300,7 +300,7 @@ func isHTTPSRequest(r *http.Request) bool {
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto
  xproto := r.Header.Get("X-Forwarded-Proto")
  // Is request a native TLS (not used atm, but future-proofing)
- // or a proxied HTTPS (eg. go-ipfs behind nginx at a public gw)?
+ // or a proxied HTTPS (eg. Kubo behind nginx at a public gw)?
  return r.URL.Scheme == "https" || xproto == "https"
 }
 
@@ -396,27 +396,40 @@ func toSubdomainURL(hostname, path string, r *http.Request, inlineDNSLink bool,
  }
  } else { // rootID is not a CID
 
- // Check if rootID is a FQDN with DNSLink and convert it to TLS-safe
- // representation that fits in a single DNS label. We support this so
- // loading DNSLink names over TLS "just works" on public HTTP gateways
- // that pass 'https' in X-Forwarded-Proto to go-ipfs.
- //
- // Rationale can be found under "Option C"
- // at: https://github.com/ipfs/in-web-browsers/issues/169
- //
- // TLDR is:
- // /ipns/my.v-long.example.com
- // can be loaded from a subdomain gateway with a wildcard TLS cert if
- // represented as a single DNS label:
- // https://my-v--long-example-com.ipns.dweb.link
+ // If rootID is an inlined notation of a FQDN with DNSLink we need to
+ // un-inline it first, to make it work in contexts where subdomain
+ // identifier is used on a path (/ipns/my-v--long-example-com)
+ // e.g. when ipfs-companion extension passes value from subdomain gateway
+ // for further normalization: https://github.com/ipfs/ipfs-companion/issues/1278#issuecomment-1724550623
+ if ns == "ipns" && !strings.Contains(rootID, ".") && strings.Contains(rootID, "-") {
+  dnsLinkFqdn := toDNSLinkFQDN(rootID) // my-v--long-example-com → my.v-long.example.com
+  if hasDNSLinkRecord(r.Context(), backend, dnsLinkFqdn) {
+  // update path prefix to use real FQDN with DNSLink
+  rootID = dnsLinkFqdn
+  }
+ }
+
  if (inlineDNSLink || isHTTPS) && ns == "ipns" && strings.Contains(rootID, ".") {
+ // If rootID is a FQDN with DNSLink we need to inline it to make it TLS-safe
+ // representation that fits in a single DNS label. We support this so
+ // loading DNSLink names over TLS "just works" on public HTTP gateways
+ // that pass 'https' in X-Forwarded-Proto to Kubo.
+ //
+ // Rationale can be found under "Option C"
+ // at: https://github.com/ipfs/in-web-browsers/issues/169
+ //
+ // TLDR is:
+ // /ipns/my.v-long.example.com
+ // can be loaded from a subdomain gateway with a wildcard TLS cert if
+ // represented as a single DNS label:
+ // https://my-v--long-example-com.ipns.dweb.link
  if hasDNSLinkRecord(r.Context(), backend, rootID) {
  // my.v-long.example.com → my-v--long-example-com
  dnsLabel, err := toDNSLinkDNSLabel(rootID)
  if err != nil {
  return "", err
  }
- // update path prefix to use real FQDN with DNSLink
+ // update path prefix to use inlined FQDN with DNSLink as a single DNS label
  rootID = dnsLabel
  }
  } else if ns == "ipfs" {

gateway/hostname_test.go

@@ -55,9 +55,12 @@ func TestToSubdomainURL(t *testing.T) {
  {httpRequest, "dweb.link", false, "/ipns/dnslink.long-name.example.com", "http://dnslink.long-name.example.com.ipns.dweb.link/", nil},
  {httpsRequest, "dweb.link", false, "/ipns/dnslink.long-name.example.com", "https://dnslink-long--name-example-com.ipns.dweb.link/", nil},
  {httpsProxiedRequest, "dweb.link", false, "/ipns/dnslink.long-name.example.com", "https://dnslink-long--name-example-com.ipns.dweb.link/", nil},
- // HTTP requests can also be converted to fit into a single DNS label - https://github.com/ipfs/kubo/issues/9243
+ // Enabling DNS label inlining: HTTP requests can also be converted to fit into a single DNS label when it matters - https://github.com/ipfs/kubo/issues/9243
  {httpRequest, "localhost", true, "/ipns/dnslink.long-name.example.com", "http://dnslink-long--name-example-com.ipns.localhost/", nil},
  {httpRequest, "dweb.link", true, "/ipns/dnslink.long-name.example.com", "http://dnslink-long--name-example-com.ipns.dweb.link/", nil},
+ // Disabling DNS label inlining: should un-inline any inlined DNS labels put in a path
+ {httpRequest, "localhost", false, "/ipns/dnslink-long--name-example-com", "http://dnslink.long-name.example.com.ipns.localhost/", nil},
+ {httpRequest, "dweb.link", false, "/ipns/dnslink-long--name-example-com", "http://dnslink.long-name.example.com.ipns.dweb.link/", nil},
  // Correctly redirects paths when there is a ? (question mark) character - https://github.com/ipfs/kubo/issues/9882
  {httpRequest, "localhost", false, "/ipns/example.com/this is a file with some spaces . dots and - but also a ?.png", "http://example.com.ipns.localhost/this%20is%20a%20file%20with%20some%20spaces%20.%20dots%20and%20-%20but%20also%20a%20%3F.png", nil},
  {httpRequest, "localhost", false, "/ipfs/QmbCMUZw6JFeZ7Wp9jkzbye3Fzp2GGcPgC3nmeUjfVF87n/this is a file with some spaces . dots and - but also a ?.png", "http://bafybeif7a7gdklt6hodwdrmwmxnhksctcuav6lfxlcyfz4khzl3qfmvcgu.ipfs.localhost/this%20is%20a%20file%20with%20some%20spaces%20.%20dots%20and%20-%20but%20also%20a%20%3F.png", nil},