1 files changed, 344 insertions, 0 deletions

diff --git a/verifierold.cpp b/verifierold.cpp
new file mode 100644
index 000000000..4387ab5a4
--- /dev/null
+++ b/verifierold.cpp
@@ -0,0 +1,344 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "common.h"
+#include "verifierold.h"
+#include "ui.h"
+
+#include "mincrypt/rsa.h"
+#include "mincrypt/sha.h"
+#include "mincrypt/sha256.h"
+
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+//extern RecoveryUI* ui;
+
+#define PUBLIC_KEYS_FILE "/res/keys"
+
+// Look for an RSA signature embedded in the .ZIP file comment given
+// the path to the zip.  Verify it matches one of the given public
+// keys.
+//
+// Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered
+// or no key matches the signature).
+int verify_file(const char* path) {
+    //ui->SetProgress(0.0);
+
+    int numKeys;
+    Certificate* pKeys = load_keys(PUBLIC_KEYS_FILE, &numKeys);
+    if (pKeys == NULL) {
+        LOGE("Failed to load keys\n");
+        return INSTALL_CORRUPT;
+    }
+    LOGI("%d key(s) loaded from %s\n", numKeys, PUBLIC_KEYS_FILE);
+
+    FILE* f = fopen(path, "rb");
+    if (f == NULL) {
+        LOGE("failed to open %s (%s)\n", path, strerror(errno));
+        return VERIFY_FAILURE;
+    }
+
+    // An archive with a whole-file signature will end in six bytes:
+    //
+    //   (2-byte signature start) $ff $ff (2-byte comment size)
+    //
+    // (As far as the ZIP format is concerned, these are part of the
+    // archive comment.)  We start by reading this footer, this tells
+    // us how far back from the end we have to start reading to find
+    // the whole comment.
+
+#define FOOTER_SIZE 6
+
+    if (fseek(f, -FOOTER_SIZE, SEEK_END) != 0) {
+        LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+    unsigned char footer[FOOTER_SIZE];
+    if (fread(footer, 1, FOOTER_SIZE, f) != FOOTER_SIZE) {
+        LOGE("failed to read footer from %s (%s)\n", path, strerror(errno));
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+    if (footer[2] != 0xff || footer[3] != 0xff) {
+        LOGE("footer is wrong\n");
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+    size_t comment_size = footer[4] + (footer[5] << 8);
+    size_t signature_start = footer[0] + (footer[1] << 8);
+    LOGI("comment is %d bytes; signature %d bytes from end\n",
+         comment_size, signature_start);
+
+    if (signature_start - FOOTER_SIZE < RSANUMBYTES) {
+        // "signature" block isn't big enough to contain an RSA block.
+        LOGE("signature is too short\n");
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+#define EOCD_HEADER_SIZE 22
+
+    // The end-of-central-directory record is 22 bytes plus any
+    // comment length.
+    size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
+
+    if (fseek(f, -eocd_size, SEEK_END) != 0) {
+        LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+    // Determine how much of the file is covered by the signature.
+    // This is everything except the signature data and length, which
+    // includes all of the EOCD except for the comment length field (2
+    // bytes) and the comment data.
+    size_t signed_len = ftell(f) + EOCD_HEADER_SIZE - 2;
+
+    unsigned char* eocd = (unsigned char*)malloc(eocd_size);
+    if (eocd == NULL) {
+        LOGE("malloc for EOCD record failed\n");
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+    if (fread(eocd, 1, eocd_size, f) != eocd_size) {
+        LOGE("failed to read eocd from %s (%s)\n", path, strerror(errno));
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+    // If this is really is the EOCD record, it will begin with the
+    // magic number $50 $4b $05 $06.
+    if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
+        eocd[2] != 0x05 || eocd[3] != 0x06) {
+        LOGE("signature length doesn't match EOCD marker\n");
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+    size_t i;
+    for (i = 4; i < eocd_size-3; ++i) {
+        if (eocd[i  ] == 0x50 && eocd[i+1] == 0x4b &&
+            eocd[i+2] == 0x05 && eocd[i+3] == 0x06) {
+            // if the sequence $50 $4b $05 $06 appears anywhere after
+            // the real one, minzip will find the later (wrong) one,
+            // which could be exploitable.  Fail verification if
+            // this sequence occurs anywhere after the real one.
+            LOGE("EOCD marker occurs after start of EOCD\n");
+            fclose(f);
+            return VERIFY_FAILURE;
+        }
+    }
+
+#define BUFFER_SIZE 4096
+
+    bool need_sha1 = false;
+    bool need_sha256 = false;
+    for (i = 0; i < numKeys; ++i) {
+        switch (pKeys[i].hash_len) {
+            case SHA_DIGEST_SIZE: need_sha1 = true; break;
+            case SHA256_DIGEST_SIZE: need_sha256 = true; break;
+        }
+    }
+
+    SHA_CTX sha1_ctx;
+    SHA256_CTX sha256_ctx;
+    SHA_init(&sha1_ctx);
+    SHA256_init(&sha256_ctx);
+    unsigned char* buffer = (unsigned char*)malloc(BUFFER_SIZE);
+    if (buffer == NULL) {
+        LOGE("failed to alloc memory for sha1 buffer\n");
+        fclose(f);
+        return VERIFY_FAILURE;
+    }
+
+    double frac = -1.0;
+    size_t so_far = 0;
+    fseek(f, 0, SEEK_SET);
+    while (so_far < signed_len) {
+        size_t size = BUFFER_SIZE;
+        if (signed_len - so_far < size) size = signed_len - so_far;
+        if (fread(buffer, 1, size, f) != size) {
+            LOGE("failed to read data from %s (%s)\n", path, strerror(errno));
+            fclose(f);
+            return VERIFY_FAILURE;
+        }
+        if (need_sha1) SHA_update(&sha1_ctx, buffer, size);
+        if (need_sha256) SHA256_update(&sha256_ctx, buffer, size);
+        so_far += size;
+        double f = so_far / (double)signed_len;
+        if (f > frac + 0.02 || size == so_far) {
+            //ui->SetProgress(f);
+            frac = f;
+        }
+    }
+    fclose(f);
+    free(buffer);
+
+    const uint8_t* sha1 = SHA_final(&sha1_ctx);
+    const uint8_t* sha256 = SHA256_final(&sha256_ctx);
+
+    for (i = 0; i < numKeys; ++i) {
+        const uint8_t* hash;
+        switch (pKeys[i].hash_len) {
+            case SHA_DIGEST_SIZE: hash = sha1; break;
+            case SHA256_DIGEST_SIZE: hash = sha256; break;
+            default: continue;
+        }
+
+        // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that
+        // the signing tool appends after the signature itself.
+        if (RSA_verify(pKeys[i].public_key, eocd + eocd_size - 6 - RSANUMBYTES,
+                       RSANUMBYTES, hash, pKeys[i].hash_len)) {
+            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);
+        }
+		LOGI("i: %i, eocd_size: %i, RSANUMBYTES: %i\n", i, eocd_size, RSANUMBYTES);
+    }
+    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.
+//
+// A Certificate is a pair of an RSAPublicKey and a particular hash
+// (we support SHA-1 and SHA-256; we store the hash length to signify
+// which is being used).  The hash used is implied by the version number.
+//
+//       1: 2048-bit RSA key with e=3 and SHA-1 hash
+//       2: 2048-bit RSA key with e=65537 and SHA-1 hash
+//       3: 2048-bit RSA key with e=3 and SHA-256 hash
+//       4: 2048-bit RSA key with e=65537 and SHA-256 hash
+//
+// Returns NULL if the file failed to parse, or if it contain zero keys.
+Certificate*
+load_keys(const char* filename, int* numKeys) {
+    Certificate* 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 = (Certificate*)realloc(out, *numKeys * sizeof(Certificate));
+            Certificate* cert = out + (*numKeys - 1);
+            cert->public_key = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
+
+            char start_char;
+            if (fscanf(f, " %c", &start_char) != 1) goto exit;
+            if (start_char == '{') {
+                // a version 1 key has no version specifier.
+                cert->public_key->exponent = 3;
+                cert->hash_len = SHA_DIGEST_SIZE;
+            } else if (start_char == 'v') {
+                int version;
+                if (fscanf(f, "%d {", &version) != 1) goto exit;
+                switch (version) {
+                    case 2:
+                        cert->public_key->exponent = 65537;
+                        cert->hash_len = SHA_DIGEST_SIZE;
+                        break;
+                    case 3:
+                        cert->public_key->exponent = 3;
+                        cert->hash_len = SHA256_DIGEST_SIZE;
+                        break;
+                    case 4:
+                        cert->public_key->exponent = 65537;
+                        cert->hash_len = SHA256_DIGEST_SIZE;
+                        break;
+                    default:
+                        goto exit;
+                }
+            }
+
+            RSAPublicKey* key = cert->public_key;
+            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 hash=%d\n", key->exponent, cert->hash_len);
+        }
+    }
+
+    fclose(f);
+    return out;
+
+exit:
+    if (f) fclose(f);
+    free(out);
+    *numKeys = 0;
+    return NULL;
+}