[PPAPI] Quarantine files that are writeable by a Pepper plugin.

content/common/quarantine/quarantine_linux.cc

 // Copyright (c) 2012 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.
 
-#include "content/browser/download/quarantine.h"
+#include "content/public/common/quarantine.h"
 
 #include <stddef.h>
 #include <sys/types.h>
 #include <sys/xattr.h>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/threading/thread_restrictions.h"
-#include "content/browser/download/quarantine_constants_linux.h"
+#include "content/common/quarantine/quarantine_constants_linux.h"
 #include "url/gurl.h"
 
 namespace content {
 
 const char kSourceURLExtendedAttrName[] = "user.xdg.origin.url";
 const char kReferrerURLExtendedAttrName[] = "user.xdg.referrer.url";
 
 namespace {
 
 bool SetExtendedFileAttribute(const char* path,
                               const char* name,
                               const char* value,
                               size_t value_size,
                               int flags) {
   base::ThreadRestrictions::AssertIOAllowed();
   int result = setxattr(path, name, value, value_size, flags);
   if (result) {
     DPLOG(ERROR) << "Could not set extended attribute " << name << " on file "
                  << path;
     return false;
   }
   return true;
 }
 
+std::string GetExtendedFileAttribute(const char* path, const char* name) {
+  base::ThreadRestrictions::AssertIOAllowed();
+  ssize_t len = getxattr(path, name, nullptr, 0);
+  if (len <= 0)
+    return std::string();
+
+  std::vector<char> buffer(len);
+  len = getxattr(path, name, buffer.data(), buffer.size());
+  if (len < static_cast<ssize_t>(buffer.size()))
+    return std::string();
+  return std::string(buffer.begin(), buffer.end());
+}
+
 }  // namespace
 
 QuarantineFileResult QuarantineFile(const base::FilePath& file,
                                     const GURL& source_url,
                                     const GURL& referrer_url,
                                     const std::string& client_guid) {
   DCHECK(base::PathIsWritable(file));
 
   bool source_succeeded =
       source_url.is_valid() &&
       SetExtendedFileAttribute(file.value().c_str(), kSourceURLExtendedAttrName,
                                source_url.spec().c_str(),
                                source_url.spec().length(), 0);
 
   // Referrer being empty is not considered an error. This could happen if the
   // referrer policy resulted in an empty referrer for the download request.
   bool referrer_succeeded =
       !referrer_url.is_valid() ||
       SetExtendedFileAttribute(
           file.value().c_str(), kReferrerURLExtendedAttrName,
           referrer_url.spec().c_str(), referrer_url.spec().length(), 0);
   return source_succeeded && referrer_succeeded
              ? QuarantineFileResult::OK
              : QuarantineFileResult::ANNOTATION_FAILED;
 }
 
+bool IsFileQuarantined(const base::FilePath& file,
+                       const GURL& source_url,
+                       const GURL& referrer_url) {
+  if (!base::PathExists(file))
+    return false;
+
+  std::string url_value = GetExtendedFileAttribute(file.value().c_str(),
+                                                   kSourceURLExtendedAttrName);
+  if (source_url.is_empty())
+    return !url_value.empty();
+
+  if (source_url != GURL(url_value))
+    return false;
+
+  return !referrer_url.is_valid() ||
+         GURL(GetExtendedFileAttribute(file.value().c_str(),
+                                       kReferrerURLExtendedAttrName)) ==
+             referrer_url;
+}
+
 }  // namespace content