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 <limits>
  10
  11 #include "base/basictypes.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/numerics/safe_conversions.h"
  14 #include "base/pickle.h"
  15 #include "base/posix/eintr_wrapper.h"
  16 #include "base/posix/unix_domain_socket_linux.h"
  17 #include "base/sys_byteorder.h"
  18 #include "base/trace_event/trace_event.h"
  19 #include "content/common/sandbox_linux/sandbox_linux.h"
  20 #include "third_party/WebKit/public/platform/linux/WebFallbackFont.h"
  21 #include "third_party/WebKit/public/platform/linux/WebFontRenderStyle.h"
  22
  23 namespace content {
  24
  25 void GetFallbackFontForCharacter(int32_t character,
  26                                  const char* preferred_locale,
  27                                  blink::WebFallbackFont* fallbackFont) {
  28   TRACE_EVENT0("sandbox_ipc", "GetFontFamilyForCharacter");
  29
  30   Pickle request;
  31   request.WriteInt(LinuxSandbox::METHOD_GET_FALLBACK_FONT_FOR_CHAR);
  32   request.WriteInt(character);
  33   request.WriteString(preferred_locale);
  34
  35   uint8_t buf[512];
  36   const ssize_t n = UnixDomainSocket::SendRecvMsg(GetSandboxFD(), buf,
  37                                                   sizeof(buf), NULL, request);
  38
  39   std::string family_name;
  40   std::string filename;
  41   int fontconfigInterfaceId = 0;
  42   int ttcIndex = 0;
  43   bool isBold = false;
  44   bool isItalic = false;
  45   if (n != -1) {
  46     Pickle reply(reinterpret_cast<char*>(buf), n);
  47     PickleIterator pickle_iter(reply);
  48     if (pickle_iter.ReadString(&family_name) &&
  49         pickle_iter.ReadString(&filename) &&
  50         pickle_iter.ReadInt(&fontconfigInterfaceId) &&
  51         pickle_iter.ReadInt(&ttcIndex) &&
  52         pickle_iter.ReadBool(&isBold) &&
  53         pickle_iter.ReadBool(&isItalic)) {
  54       fallbackFont->name = family_name;
  55       fallbackFont->filename = filename;
  56       fallbackFont->fontconfigInterfaceId = fontconfigInterfaceId;
  57       fallbackFont->ttcIndex = ttcIndex;
  58       fallbackFont->isBold = isBold;
  59       fallbackFont->isItalic = isItalic;
  60     }
  61   }
  62 }
  63
  64 void GetRenderStyleForStrike(const char* family,
  65                              int size_and_style,
  66                              blink::WebFontRenderStyle* out) {
  67   TRACE_EVENT0("sandbox_ipc", "GetRenderStyleForStrike");
  68
  69   out->setDefaults();
  70
  71   if (size_and_style < 0)
  72     return;
  73
  74   const bool bold = size_and_style & 1;
  75   const bool italic = size_and_style & 2;
  76   const int pixel_size = size_and_style >> 2;
  77   if (pixel_size > std::numeric_limits<uint16>::max())
  78     return;
  79
  80   Pickle request;
  81   request.WriteInt(LinuxSandbox::METHOD_GET_STYLE_FOR_STRIKE);
  82   request.WriteString(family);
  83   request.WriteBool(bold);
  84   request.WriteBool(italic);
  85   request.WriteUInt16(pixel_size);
  86
  87   uint8_t buf[512];
  88   const ssize_t n = UnixDomainSocket::SendRecvMsg(GetSandboxFD(), buf,
  89                                                   sizeof(buf), NULL, request);
  90   if (n == -1)
  91     return;
  92
  93   Pickle reply(reinterpret_cast<char*>(buf), n);
  94   PickleIterator pickle_iter(reply);
  95   int use_bitmaps, use_autohint, use_hinting, hint_style, use_antialias;
  96   int use_subpixel_rendering, use_subpixel_positioning;
  97   if (pickle_iter.ReadInt(&use_bitmaps) &&
  98       pickle_iter.ReadInt(&use_autohint) &&
  99       pickle_iter.ReadInt(&use_hinting) &&
 100       pickle_iter.ReadInt(&hint_style) &&
 101       pickle_iter.ReadInt(&use_antialias) &&
 102       pickle_iter.ReadInt(&use_subpixel_rendering) &&
 103       pickle_iter.ReadInt(&use_subpixel_positioning)) {
 104     out->useBitmaps = use_bitmaps;
 105     out->useAutoHint = use_autohint;
 106     out->useHinting = use_hinting;
 107     out->hintStyle = hint_style;
 108     out->useAntiAlias = use_antialias;
 109     out->useSubpixelRendering = use_subpixel_rendering;
 110     out->useSubpixelPositioning = use_subpixel_positioning;
 111   }
 112 }
 113
 114 int MatchFontWithFallback(const std::string& face,
 115                           bool bold,
 116                           bool italic,
 117                           int charset,
 118                           PP_BrowserFont_Trusted_Family fallback_family) {
 119   TRACE_EVENT0("sandbox_ipc", "MatchFontWithFallback");
 120
 121   Pickle request;
 122   request.WriteInt(LinuxSandbox::METHOD_MATCH_WITH_FALLBACK);
 123   request.WriteString(face);
 124   request.WriteBool(bold);
 125   request.WriteBool(italic);
 126   request.WriteUInt32(charset);
 127   request.WriteUInt32(fallback_family);
 128   uint8_t reply_buf[64];
 129   int fd = -1;
 130   UnixDomainSocket::SendRecvMsg(GetSandboxFD(), reply_buf, sizeof(reply_buf),
 131                                 &fd, request);
 132   return fd;
 133 }
 134
 135 bool GetFontTable(int fd, uint32_t table_tag, off_t offset,
 136                   uint8_t* output, size_t* output_length) {
 137   if (offset < 0)
 138     return false;
 139
 140   size_t data_length = 0;  // the length of the file data.
 141   off_t data_offset = 0;   // the offset of the data in the file.
 142   if (table_tag == 0) {
 143     // Get the entire font file.
 144     struct stat st;
 145     if (fstat(fd, &st) < 0)
 146       return false;
 147     data_length = base::checked_cast<size_t>(st.st_size);
 148   } else {
 149     // Get a font table. Read the header to find its offset in the file.
 150     uint16_t num_tables;
 151     ssize_t n = HANDLE_EINTR(pread(fd, &num_tables, sizeof(num_tables),
 152                              4 /* skip the font type */));
 153     if (n != sizeof(num_tables))
 154       return false;
 155     // Font data is stored in net (big-endian) order.
 156     num_tables = base::NetToHost16(num_tables);
 157
 158     // Read the table directory.
 159     static const size_t kTableEntrySize = 16;
 160     const size_t directory_size = num_tables * kTableEntrySize;
 161     scoped_ptr<uint8_t[]> table_entries(new uint8_t[directory_size]);
 162     n = HANDLE_EINTR(pread(fd, table_entries.get(), directory_size,
 163                            12 /* skip the SFNT header */));
 164     if (n != base::checked_cast<ssize_t>(directory_size))
 165       return false;
 166
 167     for (uint16_t i = 0; i < num_tables; ++i) {
 168       uint8_t* entry = table_entries.get() + i * kTableEntrySize;
 169       uint32_t tag = *reinterpret_cast<uint32_t*>(entry);
 170       if (tag == table_tag) {
 171         // Font data is stored in net (big-endian) order.
 172         data_offset =
 173             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 8));
 174         data_length =
 175             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 12));
 176         break;
 177       }
 178     }
 179   }
 180
 181   if (!data_length)
 182     return false;
 183   // Clamp |offset| inside the allowable range. This allows the read to succeed
 184   // but return 0 bytes.
 185   offset = std::min(offset, base::checked_cast<off_t>(data_length));
 186   // Make sure it's safe to add the data offset and the caller's logical offset.
 187   // Define the maximum positive offset on 32 bit systems.
 188   static const off_t kMaxPositiveOffset32 = 0x7FFFFFFF;  // 2 GB - 1.
 189   if ((offset > kMaxPositiveOffset32 / 2) ||
 190       (data_offset > kMaxPositiveOffset32 / 2))
 191     return false;
 192   data_offset += offset;
 193   data_length -= offset;
 194
 195   if (output) {
 196     // 'output_length' holds the maximum amount of data the caller can accept.
 197     data_length = std::min(data_length, *output_length);
 198     ssize_t n = HANDLE_EINTR(pread(fd, output, data_length, data_offset));
 199     if (n != base::checked_cast<ssize_t>(data_length))
 200       return false;
 201   }
 202   *output_length = data_length;
 203
 204   return true;
 205 }
 206
 207 }  // namespace content