content/common/child_process_sandbox_support_impl_linux.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/common/child_process_sandbox_support_impl_linux.h"
   6
   7 #include <sys/stat.h>
   8
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/pickle.h"
  11 #include "base/posix/eintr_wrapper.h"
  12 #include "base/posix/unix_domain_socket_linux.h"
  13 #include "base/safe_numerics.h"
  14 #include "base/sys_byteorder.h"
  15 #include "content/common/sandbox_linux.h"
  16 #include "third_party/WebKit/public/platform/linux/WebFontFamily.h"
  17 #include "third_party/WebKit/public/web/linux/WebFontRenderStyle.h"
  18
  19 namespace content {
  20
  21 void GetFontFamilyForCharacters(const uint16_t* utf16,
  22                                 size_t num_utf16,
  23                                 const char* preferred_locale,
  24                                 WebKit::WebFontFamily* family) {
  25   Pickle request;
  26   request.WriteInt(LinuxSandbox::METHOD_GET_FONT_FAMILY_FOR_CHARS);
  27   request.WriteInt(num_utf16);
  28   for (size_t i = 0; i < num_utf16; ++i)
  29     request.WriteUInt32(utf16[i]);
  30   request.WriteString(preferred_locale);
  31
  32   uint8_t buf[512];
  33   const ssize_t n = UnixDomainSocket::SendRecvMsg(GetSandboxFD(), buf,
  34                                                   sizeof(buf), NULL, request);
  35
  36   std::string family_name;
  37   bool isBold = false;
  38   bool isItalic = false;
  39   if (n != -1) {
  40     Pickle reply(reinterpret_cast<char*>(buf), n);
  41     PickleIterator pickle_iter(reply);
  42     if (reply.ReadString(&pickle_iter, &family_name) &&
  43         reply.ReadBool(&pickle_iter, &isBold) &&
  44         reply.ReadBool(&pickle_iter, &isItalic)) {
  45       family->name = family_name;
  46       family->isBold = isBold;
  47       family->isItalic = isItalic;
  48     }
  49   }
  50 }
  51
  52 void GetRenderStyleForStrike(const char* family, int sizeAndStyle,
  53                              WebKit::WebFontRenderStyle* out) {
  54   Pickle request;
  55   request.WriteInt(LinuxSandbox::METHOD_GET_STYLE_FOR_STRIKE);
  56   request.WriteString(family);
  57   request.WriteInt(sizeAndStyle);
  58
  59   uint8_t buf[512];
  60   const ssize_t n = UnixDomainSocket::SendRecvMsg(GetSandboxFD(), buf,
  61                                                   sizeof(buf), NULL, request);
  62
  63   out->setDefaults();
  64   if (n == -1) {
  65     return;
  66   }
  67
  68   Pickle reply(reinterpret_cast<char*>(buf), n);
  69   PickleIterator pickle_iter(reply);
  70   int useBitmaps, useAutoHint, useHinting, hintStyle, useAntiAlias;
  71   int useSubpixelRendering, useSubpixelPositioning;
  72   if (reply.ReadInt(&pickle_iter, &useBitmaps) &&
  73       reply.ReadInt(&pickle_iter, &useAutoHint) &&
  74       reply.ReadInt(&pickle_iter, &useHinting) &&
  75       reply.ReadInt(&pickle_iter, &hintStyle) &&
  76       reply.ReadInt(&pickle_iter, &useAntiAlias) &&
  77       reply.ReadInt(&pickle_iter, &useSubpixelRendering) &&
  78       reply.ReadInt(&pickle_iter, &useSubpixelPositioning)) {
  79     out->useBitmaps = useBitmaps;
  80     out->useAutoHint = useAutoHint;
  81     out->useHinting = useHinting;
  82     out->hintStyle = hintStyle;
  83     out->useAntiAlias = useAntiAlias;
  84     out->useSubpixelRendering = useSubpixelRendering;
  85     out->useSubpixelPositioning = useSubpixelPositioning;
  86   }
  87 }
  88
  89 int MatchFontWithFallback(const std::string& face, bool bold,
  90                           bool italic, int charset) {
  91   Pickle request;
  92   request.WriteInt(LinuxSandbox::METHOD_MATCH_WITH_FALLBACK);
  93   request.WriteString(face);
  94   request.WriteBool(bold);
  95   request.WriteBool(italic);
  96   request.WriteUInt32(charset);
  97   uint8_t reply_buf[64];
  98   int fd = -1;
  99   UnixDomainSocket::SendRecvMsg(GetSandboxFD(), reply_buf, sizeof(reply_buf),
 100                                 &fd, request);
 101   return fd;
 102 }
 103
 104 bool GetFontTable(int fd, uint32_t table_tag, off_t offset,
 105                   uint8_t* output, size_t* output_length) {
 106   if (offset < 0)
 107     return false;
 108
 109   size_t data_length = 0;  // the length of the file data.
 110   off_t data_offset = 0;   // the offset of the data in the file.
 111   if (table_tag == 0) {
 112     // Get the entire font file.
 113     struct stat st;
 114     if (fstat(fd, &st) < 0)
 115       return false;
 116     data_length = base::checked_numeric_cast<size_t>(st.st_size);
 117   } else {
 118     // Get a font table. Read the header to find its offset in the file.
 119     uint16_t num_tables;
 120     ssize_t n = HANDLE_EINTR(pread(fd, &num_tables, sizeof(num_tables),
 121                              4 /* skip the font type */));
 122     if (n != sizeof(num_tables))
 123       return false;
 124     // Font data is stored in net (big-endian) order.
 125     num_tables = base::NetToHost16(num_tables);
 126
 127     // Read the table directory.
 128     static const size_t kTableEntrySize = 16;
 129     const size_t directory_size = num_tables * kTableEntrySize;
 130     scoped_ptr<uint8_t[]> table_entries(new uint8_t[directory_size]);
 131     n = HANDLE_EINTR(pread(fd, table_entries.get(), directory_size,
 132                            12 /* skip the SFNT header */));
 133     if (n != base::checked_numeric_cast<ssize_t>(directory_size))
 134       return false;
 135
 136     for (uint16_t i = 0; i < num_tables; ++i) {
 137       uint8_t* entry = table_entries.get() + i * kTableEntrySize;
 138       uint32_t tag = *reinterpret_cast<uint32_t*>(entry);
 139       if (tag == table_tag) {
 140         // Font data is stored in net (big-endian) order.
 141         data_offset =
 142             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 8));
 143         data_length =
 144             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 12));
 145         break;
 146       }
 147     }
 148   }
 149
 150   if (!data_length)
 151     return false;
 152   // Clamp |offset| inside the allowable range. This allows the read to succeed
 153   // but return 0 bytes.
 154   offset = std::min(offset, base::checked_numeric_cast<off_t>(data_length));
 155   // Make sure it's safe to add the data offset and the caller's logical offset.
 156   // Define the maximum positive offset on 32 bit systems.
 157   static const off_t kMaxPositiveOffset32 = 0x7FFFFFFF;  // 2 GB - 1.
 158   if ((offset > kMaxPositiveOffset32 / 2) ||
 159       (data_offset > kMaxPositiveOffset32 / 2))
 160     return false;
 161   data_offset += offset;
 162   data_length -= offset;
 163
 164   if (output) {
 165     // 'output_length' holds the maximum amount of data the caller can accept.
 166     data_length = std::min(data_length, *output_length);
 167     ssize_t n = HANDLE_EINTR(pread(fd, output, data_length, data_offset));
 168     if (n != base::checked_numeric_cast<ssize_t>(data_length))
 169       return false;
 170   }
 171   *output_length = data_length;
 172
 173   return true;
 174 }
 175
 176 }  // namespace content