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- // 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.
- #include "net/base/filename_util.h"
- #include <set>
- #include "base/files/file_path.h"
- #include "base/files/file_util.h"
- #include "base/path_service.h"
- #include "base/strings/escape.h"
- #include "base/strings/string_util.h"
- #include "base/strings/sys_string_conversions.h"
- #include "base/strings/utf_string_conversions.h"
- #include "base/threading/thread_restrictions.h"
- #include "build/build_config.h"
- #include "net/base/filename_util_internal.h"
- #include "net/base/net_string_util.h"
- #include "net/base/url_util.h"
- #include "net/http/http_content_disposition.h"
- #include "url/gurl.h"
- namespace net {
- // Prefix to prepend to get a file URL.
- static const char kFileURLPrefix[] = "file:///";
- GURL FilePathToFileURL(const base::FilePath& path) {
- // Produce a URL like "file:///C:/foo" for a regular file, or
- // "file://///server/path" for UNC. The URL canonicalizer will fix up the
- // latter case to be the canonical UNC form: "file://server/path"
- std::string url_string(kFileURLPrefix);
- // GURL() strips some whitespace and trailing control chars which are valid
- // in file paths. It also interprets chars such as `%;#?` and maybe `\`, so we
- // must percent encode these first. Reserve max possible length up front.
- std::string utf8_path = path.AsUTF8Unsafe();
- url_string.reserve(url_string.size() + (3 * utf8_path.size()));
- for (auto c : utf8_path) {
- if (c == '%' || c == ';' || c == '#' || c == '?' ||
- #if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
- c == '\\' ||
- #endif
- c <= ' ') {
- static const char kHexChars[] = "0123456789ABCDEF";
- url_string += '%';
- url_string += kHexChars[(c >> 4) & 0xf];
- url_string += kHexChars[c & 0xf];
- } else {
- url_string += c;
- }
- }
- return GURL(url_string);
- }
- bool FileURLToFilePath(const GURL& url, base::FilePath* file_path) {
- *file_path = base::FilePath();
- base::FilePath::StringType& file_path_str =
- const_cast<base::FilePath::StringType&>(file_path->value());
- file_path_str.clear();
- if (!url.is_valid())
- return false;
- // We may want to change this to a CHECK in the future.
- if (!url.SchemeIsFile())
- return false;
- #if BUILDFLAG(IS_WIN)
- std::string path;
- std::string host = url.host();
- if (host.empty()) {
- // URL contains no host, the path is the filename. In this case, the path
- // will probably be preceded with a slash, as in "/C:/foo.txt", so we
- // trim out that here.
- path = url.path();
- size_t first_non_slash = path.find_first_not_of("/\\");
- if (first_non_slash != std::string::npos && first_non_slash > 0)
- path.erase(0, first_non_slash);
- } else {
- // URL contains a host: this means it's UNC. We keep the preceding slash
- // on the path.
- path = "\\\\";
- path.append(host);
- path.append(url.path());
- }
- std::replace(path.begin(), path.end(), '/', '\\');
- #else // BUILDFLAG(IS_WIN)
- // On POSIX, there's no obvious interpretation of file:// URLs with a host.
- // Usually, remote mounts are still mounted onto the local filesystem.
- // Therefore, we discard all URLs that are not obviously local to prevent
- // spoofing attacks using file:// URLs. See crbug.com/881675.
- if (!url.host().empty() && !net::IsLocalhost(url)) {
- return false;
- }
- std::string path = url.path();
- #endif // !BUILDFLAG(IS_WIN)
- if (path.empty())
- return false;
- // "%2F" ('/') results in failure, because it represents a literal '/'
- // character in a path segment (not a path separator). If this were decoded,
- // it would be interpreted as a path separator on both POSIX and Windows (note
- // that Firefox *does* decode this, but it was decided on
- // https://crbug.com/585422 that this represents a potential security risk).
- // It isn't correct to keep it as "%2F", so this just fails. This is fine,
- // because '/' is not a valid filename character on either POSIX or Windows.
- std::set<unsigned char> illegal_encoded_bytes{'/'};
- #if BUILDFLAG(IS_WIN)
- // "%5C" ('\\') on Windows results in failure, for the same reason as '/'
- // above. On POSIX, "%5C" simply decodes as '\\', a valid filename character.
- illegal_encoded_bytes.insert('\\');
- #endif
- if (base::ContainsEncodedBytes(path, illegal_encoded_bytes))
- return false;
- // Unescape all percent-encoded sequences, including blocked-for-display
- // characters, control characters and invalid UTF-8 byte sequences.
- // Percent-encoded bytes are not meaningful in a file system.
- path = base::UnescapeBinaryURLComponent(path);
- #if BUILDFLAG(IS_WIN)
- if (base::IsStringUTF8(path)) {
- file_path_str.assign(base::UTF8ToWide(path));
- // We used to try too hard and see if |path| made up entirely of
- // the 1st 256 characters in the Unicode was a zero-extended UTF-16.
- // If so, we converted it to 'Latin-1' and checked if the result was UTF-8.
- // If the check passed, we converted the result to UTF-8.
- // Otherwise, we treated the result as the native OS encoding.
- // However, that led to http://crbug.com/4619 and http://crbug.com/14153
- } else {
- // Not UTF-8, assume encoding is native codepage and we're done. We know we
- // are giving the conversion function a nonempty string, and it may fail if
- // the given string is not in the current encoding and give us an empty
- // string back. We detect this and report failure.
- file_path_str = base::SysNativeMBToWide(path);
- }
- #else // BUILDFLAG(IS_WIN)
- // Collapse multiple path slashes into a single path slash.
- std::string new_path;
- do {
- new_path = path;
- base::ReplaceSubstringsAfterOffset(&new_path, 0, "//", "/");
- path.swap(new_path);
- } while (new_path != path);
- file_path_str.assign(path);
- #endif // !BUILDFLAG(IS_WIN)
- return !file_path_str.empty();
- }
- void GenerateSafeFileName(const std::string& mime_type,
- bool ignore_extension,
- base::FilePath* file_path) {
- // Make sure we get the right file extension
- EnsureSafeExtension(mime_type, ignore_extension, file_path);
- #if BUILDFLAG(IS_WIN)
- // Prepend "_" to the file name if it's a reserved name
- base::FilePath::StringType leaf_name = file_path->BaseName().value();
- DCHECK(!leaf_name.empty());
- if (IsReservedNameOnWindows(leaf_name)) {
- leaf_name = base::FilePath::StringType(FILE_PATH_LITERAL("_")) + leaf_name;
- *file_path = file_path->DirName();
- if (file_path->value() == base::FilePath::kCurrentDirectory) {
- *file_path = base::FilePath(leaf_name);
- } else {
- *file_path = file_path->Append(leaf_name);
- }
- }
- #endif
- }
- bool IsReservedNameOnWindows(const base::FilePath::StringType& filename) {
- // This list is taken from the MSDN article "Naming a file"
- // http://msdn2.microsoft.com/en-us/library/aa365247(VS.85).aspx
- // I also added clock$ because GetSaveFileName seems to consider it as a
- // reserved name too.
- static const char* const known_devices[] = {
- "con", "prn", "aux", "nul", "com1", "com2", "com3", "com4",
- "com5", "com6", "com7", "com8", "com9", "lpt1", "lpt2", "lpt3",
- "lpt4", "lpt5", "lpt6", "lpt7", "lpt8", "lpt9", "clock$"};
- #if BUILDFLAG(IS_WIN)
- std::string filename_lower = base::ToLowerASCII(base::WideToUTF8(filename));
- #elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
- std::string filename_lower = base::ToLowerASCII(filename);
- #endif
- for (const char* const device : known_devices) {
- // Exact match.
- if (filename_lower == device)
- return true;
- // Starts with "DEVICE.".
- if (base::StartsWith(filename_lower, std::string(device) + ".",
- base::CompareCase::SENSITIVE)) {
- return true;
- }
- }
- static const char* const magic_names[] = {
- // These file names are used by the "Customize folder" feature of the
- // shell.
- "desktop.ini",
- "thumbs.db",
- };
- for (const char* const magic_name : magic_names) {
- if (filename_lower == magic_name)
- return true;
- }
- return false;
- }
- } // namespace net
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