Return ECMR public key (tang_pub) in /rec/$kid response

src/tangd.c

@@ -178,6 +178,13 @@ rec(http_method_t method, const char *path, const char *body,
     if (json_object_set_new(rep, "key_ops", json_pack("[s]", "deriveKey")) < 0)
         return http_reply(HTTP_STATUS_INTERNAL_SERVER_ERROR, NULL);
 
+    json_auto_t *pub = json_deep_copy(jwk);
+    if (!pub || !jose_jwk_pub(NULL, pub))
+        return http_reply(HTTP_STATUS_INTERNAL_SERVER_ERROR, NULL);
+
+    if (json_object_set(rep, "tang_pub", pub) < 0)
+        return http_reply(HTTP_STATUS_INTERNAL_SERVER_ERROR, NULL);
+
     enc = json_dumps(rep, JSON_SORT_KEYS | JSON_COMPACT);
     if (!enc)
         return http_reply(HTTP_STATUS_INTERNAL_SERVER_ERROR, NULL);
@@ -188,10 +195,32 @@ rec(http_method_t method, const char *path, const char *body,
                       "\r\n%s", strlen(enc), enc);
 }
 
+static int
+tang_version(http_method_t method, const char *path, const char *body,
+             regmatch_t matches[], void *misc)
+{
+    __attribute__((cleanup(str_cleanup))) char *out = NULL;
+    json_auto_t *ver = json_pack("{s:s, s:{s:b}}",
+                                 "tang_version", VERSION,
+                                 "features", "tang_pub", 1);
+    if (!ver)
+        return http_reply(HTTP_STATUS_INTERNAL_SERVER_ERROR, NULL);
+
+    out = json_dumps(ver, JSON_SORT_KEYS | JSON_COMPACT);
+    if (!out)
+        return http_reply(HTTP_STATUS_INTERNAL_SERVER_ERROR, NULL);
+
+    return http_reply(HTTP_STATUS_OK,
+                      "Content-Type: application/json\r\n"
+                      "Content-Length: %zu\r\n"
+                      "\r\n%s", strlen(out), out);
+}
+
 static struct http_dispatch s_dispatch[] = {
-    { adv, 1 << HTTP_GET,  2, "^/+adv/+([0-9A-Za-z_-]+)$" },
-    { adv, 1 << HTTP_GET,  2, "^/+adv/*$" },
-    { rec, 1 << HTTP_POST, 2, "^/+rec/+([0-9A-Za-z_-]+)$" },
+    { adv,          1 << HTTP_GET,  2, "^/+adv/+([0-9A-Za-z_-]+)$" },
+    { adv,          1 << HTTP_GET,  2, "^/+adv/*$" },
+    { rec,          1 << HTTP_POST, 2, "^/+rec/+([0-9A-Za-z_-]+)$" },
+    { tang_version, 1 << HTTP_GET,  1, "^/+version/*$" },
     {}
 };
 
@@ -327,6 +356,7 @@ main(int argc, char *argv[])
     char adv_thp_endpoint[MAX_URL] = {};
     char adv_endpoint[MAX_URL] = {};
     char rec_endpoint[MAX_URL] = {};
+    char ver_endpoint[MAX_URL] = {};
     if (endpoint != NULL) {
         char *endpoint_ptr = (char*)endpoint;
         while (*endpoint_ptr == '/') {
@@ -335,9 +365,11 @@ main(int argc, char *argv[])
         snprintf(adv_thp_endpoint, MAX_URL, "^/%s/+adv/+([0-9A-Za-z_-]+)$", endpoint_ptr);
         snprintf(adv_endpoint, MAX_URL, "^/%s/+adv/*$", endpoint_ptr);
         snprintf(rec_endpoint, MAX_URL, "^/%s/+rec/+([0-9A-Za-z_-]+)$", endpoint_ptr);
+        snprintf(ver_endpoint, MAX_URL, "^/%s/+version/*$", endpoint_ptr);
         s_dispatch[0].re = adv_thp_endpoint;
         s_dispatch[1].re = adv_endpoint;
         s_dispatch[2].re = rec_endpoint;
+        s_dispatch[3].re = ver_endpoint;
     }
     if (listen == 0) { /* process one-shot query from stdin */
         return process_request(jwkdir, STDIN_FILENO);

tests/adv

@@ -47,6 +47,11 @@ adv_second_phase () {
     fetch "${ENDPOINT}"/adv | ver $TMP/db/sig.jwk
     fetch "${ENDPOINT}"/adv/ | ver $TMP/db/sig.jwk
 
+    # Verify /version endpoint reports tang_pub capability
+    ver_resp=$(fetch "${ENDPOINT}"/version)
+    printf '%s' "$ver_resp" | jose fmt -j- -Og tang_version -u- >/dev/null
+    printf '%s' "$ver_resp" | jose fmt -j- -Og features -Og tang_pub >/dev/null
+
     # Fetching by any thumbprint should work
     fetch "${ENDPOINT}"/adv/`jose jwk thp -i $TMP/db/sig.jwk` | ver $TMP/db/sig.jwk
     fetch "${ENDPOINT}"/adv/`jose jwk thp -a S512 -i $TMP/db/sig.jwk` | ver $TMP/db/sig.jwk

tests/rec

@@ -45,11 +45,21 @@ rec_second_phase () {
 
     # Make a recovery request (NOTE: this is insecure! Don't do this in real code!)
     good=`jose jwk exc -i '{"alg":"ECMR","key_ops":["deriveKey"]}' -l $TMP/exc.jwk -r $TMP/db/exc.jwk`
-    test=`curl -sf -X POST \
+    full_resp=`curl -sf -X POST \
            -H "Content-Type: application/jwk+json" \
            --data-binary @- \
            http://127.0.0.1:$PORT/rec/${exc_kid} < $TMP/exc.pub.jwk`
+
+    # Strip tang_pub from response and verify the exchange result
+    test=`printf '%s' "$full_resp" | jose fmt -j- -Od tang_pub -o-`
     [ "$good" = "$test" ]
+
+    # Verify tang_pub is present and contains no private material
+    printf '%s' "$full_resp" | jose fmt -j- -Og tang_pub -o- > $TMP/tang_pub.jwk
+    ! jose fmt -j $TMP/tang_pub.jwk -Og d 2>/dev/null
+
+    # Verify tang_pub thumbprint matches the requested key identifier
+    [ "$(jose jwk thp -i $TMP/tang_pub.jwk)" = "$exc_kid" ]
 }
 
 rec_second_phase_endpoint () {
@@ -59,9 +69,19 @@ rec_second_phase_endpoint () {
 
     # Make a recovery request (NOTE: this is insecure! Don't do this in real code!)
     good=`jose jwk exc -i '{"alg":"ECMR","key_ops":["deriveKey"]}' -l $TMP/exc.jwk -r $TMP/db/exc.jwk`
-    test=`curl -sf -X POST \
+    full_resp=`curl -sf -X POST \
            -H "Content-Type: application/jwk+json" \
            --data-binary @- \
            http://127.0.0.1:$PORT/$ENDPOINT/rec/${exc_kid} < $TMP/exc.pub.jwk`
+
+    # Strip tang_pub from response and verify the exchange result
+    test=`printf '%s' "$full_resp" | jose fmt -j- -Od tang_pub -o-`
     [ "$good" = "$test" ]
+
+    # Verify tang_pub is present and contains no private material
+    printf '%s' "$full_resp" | jose fmt -j- -Og tang_pub -o- > $TMP/tang_pub.jwk
+    ! jose fmt -j $TMP/tang_pub.jwk -Og d 2>/dev/null
+
+    # Verify tang_pub thumbprint matches the requested key identifier
+    [ "$(jose jwk thp -i $TMP/tang_pub.jwk)" = "$exc_kid" ]
 }

tests/verify-tang-pub

@@ -0,0 +1,78 @@
+#!/bin/sh -e
+# vim: set tabstop=8 shiftwidth=4 softtabstop=4 expandtab smarttab colorcolumn=80:
+#
+# Verify that a running Tang server returns tang_pub in /rec/$kid responses.
+#
+# Usage: verify-tang-pub [jwkdir] [url]
+#   jwkdir: path to Tang key directory (default: /var/db/tang)
+#   url:    Tang server URL (default: http://localhost)
+
+JWKDIR="${1:-/var/db/tang}"
+URL="${2:-http://localhost}"
+
+if [ ! -d "$JWKDIR" ]; then
+    echo "Error: key directory $JWKDIR does not exist" >&2
+    exit 1
+fi
+
+exc_file=""
+for f in "$JWKDIR"/*.jwk; do
+    [ -f "$f" ] || continue
+    alg=$(jose fmt -j "$f" -Og alg -u- 2>/dev/null) || continue
+    if [ "$alg" = "ECMR" ]; then
+        exc_file="$f"
+        break
+    fi
+done
+
+if [ -z "$exc_file" ]; then
+    echo "Error: no ECMR exchange key found in $JWKDIR" >&2
+    exit 1
+fi
+
+exc_kid=$(jose jwk thp -i "$exc_file")
+echo "Exchange key: $(basename "$exc_file")"
+echo "Thumbprint:   $exc_kid"
+
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+ver_resp=$(curl -sf "$URL/version" 2>/dev/null) || {
+    echo "FAIL: /version endpoint not available (server may not support tang_pub)" >&2
+    exit 1
+}
+
+if ! printf '%s' "$ver_resp" | jose fmt -j- -Og features -Og tang_pub >/dev/null 2>&1; then
+    echo "FAIL: /version does not report tang_pub capability" >&2
+    exit 1
+fi
+echo "OK: /version reports tang_pub capability"
+
+jose jwk gen -i '{"alg":"ECMR"}' -o "$TMP/client.jwk"
+jose jwk pub -i "$TMP/client.jwk" -o "$TMP/client.pub.jwk"
+
+resp=$(curl -sf -X POST \
+    -H "Content-Type: application/jwk+json" \
+    --data-binary @"$TMP/client.pub.jwk" \
+    "$URL/rec/$exc_kid" 2>/dev/null) || {
+    echo "Error: /rec/$exc_kid request failed" >&2
+    exit 1
+}
+
+tang_pub=$(printf '%s' "$resp" | jose fmt -j- -Og tang_pub -o- 2>/dev/null) || {
+    echo "FAIL: tang_pub not present in /rec/$exc_kid response" >&2
+    exit 1
+}
+
+if printf '%s' "$tang_pub" | jose fmt -j- -Og d 2>/dev/null >/dev/null; then
+    echo "FAIL: tang_pub contains private material" >&2
+    exit 1
+fi
+
+tang_pub_thp=$(printf '%s' "$tang_pub" | jose jwk thp -i-)
+if [ "$tang_pub_thp" != "$exc_kid" ]; then
+    echo "FAIL: tang_pub thumbprint ($tang_pub_thp) does not match key identifier ($exc_kid)" >&2
+    exit 1
+fi
+
+echo "OK: tang_pub is present, public-only, and matches key identifier"