AI 144130: Don't build OTA package keys into the recovery binary; read

them from an external file in the recovery image.  Use the
  test-keys for all builds.

Automated import of CL 144130

Android.mk

@@ -33,21 +33,8 @@ LOCAL_STATIC_LIBRARIES := libminzip libunz libamend libmtdutils libmincrypt
 LOCAL_STATIC_LIBRARIES += libminui libpixelflinger_static libpng libcutils
 LOCAL_STATIC_LIBRARIES += libstdc++ libc
 
-# Specify a C-includable file containing the OTA public keys.
-# This is built in config/Makefile.
-# *** THIS IS A TOTAL HACK; EXECUTABLES MUST NOT CHANGE BETWEEN DIFFERENT
-#     PRODUCTS/BUILD TYPES. ***
-# TODO: make recovery read the keys from an external file.
-RECOVERY_INSTALL_OTA_KEYS_INC := \
-	$(call intermediates-dir-for,PACKAGING,ota_keys_inc)/keys.inc
-# Let install.c say #include "keys.inc"
-LOCAL_C_INCLUDES += $(dir $(RECOVERY_INSTALL_OTA_KEYS_INC))
-
 include $(BUILD_EXECUTABLE)
 
-# Depend on the generated keys.inc containing the OTA public keys.
-$(intermediates)/install.o: $(RECOVERY_INSTALL_OTA_KEYS_INC)
-
 include $(commands_recovery_local_path)/minui/Android.mk
 
 endif   # TARGET_ARCH == arm

install.c

@@ -31,12 +31,8 @@
 #include "roots.h"
 #include "verifier.h"
 
-/* List of public keys */
-static const RSAPublicKey keys[] = {
-#include "keys.inc"
-};
-
 #define ASSUMED_UPDATE_SCRIPT_NAME  "META-INF/com/google/android/update-script"
+#define PUBLIC_KEYS_FILE "/res/keys"
 
 static const ZipEntry *
 find_update_script(ZipArchive *zip)
@@ -114,7 +110,8 @@ handle_update_script(ZipArchive *zip, const ZipEntry *update_script_entry)
 }
 
 static int
-handle_update_package(const char *path, ZipArchive *zip)
+handle_update_package(const char *path, ZipArchive *zip,
+                      const RSAPublicKey *keys, int numKeys)
 {
     // Give verification half the progress bar...
     ui_print("Verifying update package...\n");
@@ -122,7 +119,7 @@ handle_update_package(const char *path, ZipArchive *zip)
             VERIFICATION_PROGRESS_FRACTION,
             VERIFICATION_PROGRESS_TIME);
 
-    if (!verify_jar_signature(zip, keys, sizeof(keys) / sizeof(keys[0]))) {
+    if (!verify_jar_signature(zip, keys, numKeys)) {
         LOGE("Verification failed\n");
         return INSTALL_CORRUPT;
     }
@@ -147,6 +144,80 @@ handle_update_package(const char *path, ZipArchive *zip)
     return ret;
 }
 
+// Reads a file containing one or more public keys as produced by
+// DumpPublicKey:  this is an RSAPublicKey struct as it would appear
+// as a C source literal, eg:
+//
+//  "{64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
+//
+// (Note that the braces and commas in this example are actual
+// characters the parser expects to find in the file; the ellipses
+// indicate more numbers omitted from this example.)
+//
+// The file may contain multiple keys in this format, separated by
+// commas.  The last key must not be followed by a comma.
+//
+// Returns NULL if the file failed to parse, or if it contain zero keys.
+static RSAPublicKey*
+load_keys(const char* filename, int* numKeys) {
+    RSAPublicKey* out = NULL;
+    *numKeys = 0;
+
+    FILE* f = fopen(filename, "r");
+    if (f == NULL) {
+        LOGE("opening %s: %s\n", filename, strerror(errno));
+        goto exit;
+    }
+
+    int i;
+    bool done = false;
+    while (!done) {
+        ++*numKeys;
+        out = realloc(out, *numKeys * sizeof(RSAPublicKey));
+        RSAPublicKey* key = out + (*numKeys - 1);
+        if (fscanf(f, " { %i , %i , { %i",
+                   &(key->len), &(key->n0inv), &(key->n[0])) != 3) {
+            goto exit;
+        }
+        if (key->len != RSANUMWORDS) {
+            LOGE("key length (%d) does not match expected size\n", key->len);
+            goto exit;
+        }
+        for (i = 1; i < key->len; ++i) {
+            if (fscanf(f, " , %i", &(key->n[i])) != 1) goto exit;
+        }
+        if (fscanf(f, " } , { %i", &(key->rr[0])) != 1) goto exit;
+        for (i = 1; i < key->len; ++i) {
+            if (fscanf(f, " , %i", &(key->rr[i])) != 1) goto exit;
+        }
+        fscanf(f, " } } ");
+
+        // if the line ends in a comma, this file has more keys.
+        switch (fgetc(f)) {
+            case ',':
+                // more keys to come.
+                break;
+
+            case EOF:
+                done = true;
+                break;
+
+            default:
+                LOGE("unexpected character between keys\n");
+                goto exit;
+        }
+    }
+
+    fclose(f);
+    return out;
+
+exit:
+    if (f) fclose(f);
+    free(out);
+    *numKeys = 0;
+    return NULL;
+}
+
 int
 install_package(const char *root_path)
 {
@@ -169,6 +240,14 @@ install_package(const char *root_path)
     ui_print("Opening update package...\n");
     LOGI("Update file path: %s\n", path);
 
+    int numKeys;
+    RSAPublicKey* loadedKeys = load_keys(PUBLIC_KEYS_FILE, &numKeys);
+    if (loadedKeys == NULL) {
+        LOGE("Failed to load keys\n");
+        return INSTALL_CORRUPT;
+    }
+    LOGI("%d key(s) loaded from %s\n", numKeys, PUBLIC_KEYS_FILE);
+
     /* Try to open the package.
      */
     ZipArchive zip;
@@ -180,7 +259,8 @@ install_package(const char *root_path)
 
     /* Verify and install the contents of the package.
      */
-    int status = handle_update_package(path, &zip);
+    int status = handle_update_package(path, &zip, loadedKeys, numKeys);
     mzCloseZipArchive(&zip);
+    free(loadedKeys);
     return status;
 }