From 6c249f7ae890694f061bfde7a3ab52bf367be110 Mon Sep 17 00:00:00 2001
From: Doug Zongker <dougz@android.com>
Date: Fri, 2 Nov 2012 15:04:05 -0700
Subject: move key loading to verifier code

Add an option to verifier_test to load keys from a file, the way the
recovery does.

Change-Id: Icba0e391164f2c1a9fefeab4b0bcb878e91d17b4
---
 verifier.cpp | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)

(limited to 'verifier.cpp')

diff --git a/verifier.cpp b/verifier.cpp
index 1c5a41d1b..5f4c981e5 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -179,9 +179,111 @@ int verify_file(const char* path, const RSAPublicKey *pKeys, unsigned int numKey
             LOGI("whole-file signature verified against key %d\n", i);
             free(eocd);
             return VERIFY_SUCCESS;
+        } else {
+            LOGI("failed to verify against key %d\n", i);
         }
     }
     free(eocd);
     LOGE("failed to verify whole-file signature\n");
     return VERIFY_FAILURE;
 }
+
+// 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}}"
+//
+// For key versions newer than the original 2048-bit e=3 keys
+// supported by Android, the string is preceded by a version
+// identifier, eg:
+//
+//  "v2 {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.
+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 = (RSAPublicKey*)realloc(out, *numKeys * sizeof(RSAPublicKey));
+            RSAPublicKey* key = out + (*numKeys - 1);
+
+            char start_char;
+            if (fscanf(f, " %c", &start_char) != 1) goto exit;
+            if (start_char == '{') {
+                // a version 1 key has no version specifier.
+                key->exponent = 3;
+            } else if (start_char == 'v') {
+                int version;
+                if (fscanf(f, "%d {", &version) != 1) goto exit;
+                if (version == 2) {
+                    key->exponent = 65537;
+                } else {
+                    goto exit;
+                }
+            }
+
+            if (fscanf(f, " %i , 0x%x , { %u",
+                       &(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, " , %u", &(key->n[i])) != 1) goto exit;
+            }
+            if (fscanf(f, " } , { %u", &(key->rr[0])) != 1) goto exit;
+            for (i = 1; i < key->len; ++i) {
+                if (fscanf(f, " , %u", &(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;
+            }
+
+            LOGI("read key e=%d\n", key->exponent);
+        }
+    }
+
+    fclose(f);
+    return out;
+
+exit:
+    if (f) fclose(f);
+    free(out);
+    *numKeys = 0;
+    return NULL;
+}
-- 
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