| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef EXTENSIONS_BROWSER_VERIFIED_CONTENTS_H_ |
| #define EXTENSIONS_BROWSER_VERIFIED_CONTENTS_H_ |
| |
| #include <map> |
| #include <string> |
| #include <vector> |
| |
| #include "base/files/file_path.h" |
| #include "base/version.h" |
| |
| namespace extensions { |
| |
| // This class encapsulates the data in a "verified_contents.json" file |
| // generated by the webstore for a .crx file. That data includes a set of |
| // signed expected hashes of file content which can be used to check for |
| // corruption of extension files on local disk. |
| class VerifiedContents { |
| public: |
| // This function fixes up a string in base64url encoding to be in standard |
| // base64. |
| // |
| // The JSON signing spec we're following uses "base64url" encoding (RFC 4648 |
| // section 5 without padding). The slight differences from regular base64 |
| // encoding are: |
| // 1. uses '_' instead of '/' |
| // 2. uses '-' instead of '+' |
| // 3. omits trailing '=' padding |
| static bool FixupBase64Encoding(std::string* input); |
| |
| // Note: the public_key must remain valid for the lifetime of this object. |
| VerifiedContents(const uint8* public_key, int public_key_size); |
| ~VerifiedContents(); |
| |
| // Returns true if we successfully parsed the verified_contents.json file at |
| // |path| and validated the enclosed signature. The |
| // |ignore_invalid_signature| argument can be set to make this still succeed |
| // if the contents of the file were parsed successfully but the signature did |
| // not validate. (Use with caution!) |
| bool InitFrom(const base::FilePath& path, bool ignore_invalid_signature); |
| |
| int block_size() const { return block_size_; } |
| const std::string& extension_id() const { return extension_id_; } |
| const base::Version& version() const { return version_; } |
| |
| bool HasTreeHashRoot(const base::FilePath& relative_path) const; |
| |
| bool TreeHashRootEquals(const base::FilePath& relative_path, |
| const std::string& expected) const; |
| |
| // If InitFrom has not been called yet, or was used in "ignore invalid |
| // signature" mode, this can return false. |
| bool valid_signature() { return valid_signature_; } |
| |
| private: |
| // Returns the base64url-decoded "payload" field from the json at |path|, if |
| // the signature was valid (or ignore_invalid_signature was set to true). |
| bool GetPayload(const base::FilePath& path, |
| std::string* payload, |
| bool ignore_invalid_signature); |
| |
| // The |protected_value| and |payload| arguments should be base64url encoded |
| // strings, and |signature_bytes| should be a byte array. See comments in the |
| // .cc file on GetPayload for where these come from in the overall input |
| // file. |
| bool VerifySignature(const std::string& protected_value, |
| const std::string& payload, |
| const std::string& signature_bytes); |
| |
| // The public key we should use for signature verification. |
| const uint8* public_key_; |
| const int public_key_size_; |
| |
| // Indicates whether the signature was successfully validated or not. |
| bool valid_signature_; |
| |
| // The block size used for computing the treehash root hashes. |
| int block_size_; |
| |
| // Information about which extension these signed hashes are for. |
| std::string extension_id_; |
| base::Version version_; |
| |
| // The expected treehash root hashes for each file, lower cased so we can do |
| // case-insensitive lookups. |
| // |
| // We use a multi-map here so that we can do fast lookups of paths from |
| // requests on case-insensitive systems (windows, mac) where the request path |
| // might not have the exact right capitalization, but not break |
| // case-sensitive systems (linux, chromeos). TODO(asargent) - we should give |
| // developers client-side warnings in each of those cases, and have the |
| // webstore reject the cases they can statically detect. See crbug.com/29941 |
| typedef std::multimap<base::FilePath::StringType, std::string> RootHashes; |
| RootHashes root_hashes_; |
| |
| DISALLOW_COPY_AND_ASSIGN(VerifiedContents); |
| }; |
| |
| } // namespace extensions |
| |
| #endif // EXTENSIONS_BROWSER_VERIFIED_CONTENTS_H_ |