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/debug/trace_event.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/numerics/safe_conversions.h"
  15 #include "base/pickle.h"
  16 #include "base/posix/eintr_wrapper.h"
  17 #include "base/posix/unix_domain_socket_linux.h"
  18 #include "base/sys_byteorder.h"
  19 #include "content/common/sandbox_linux/sandbox_linux.h"
  20 #include "content/common/zygote_commands_linux.h"
  21 #include "third_party/WebKit/public/platform/linux/WebFallbackFont.h"
  22 #include "third_party/WebKit/public/platform/linux/WebFontRenderStyle.h"
  23
  24 namespace content {
  25
  26 void GetFallbackFontForCharacter(int32_t character,
  27                                  const char* preferred_locale,
  28                                  blink::WebFallbackFont* fallbackFont) {
  29   TRACE_EVENT0("sandbox_ipc", "GetFontFamilyForCharacter");
  30
  31   Pickle request;
  32   request.WriteInt(LinuxSandbox::METHOD_GET_FALLBACK_FONT_FOR_CHAR);
  33   request.WriteInt(character);
  34   request.WriteString(preferred_locale);
  35
  36   uint8_t buf[512];
  37   const ssize_t n = UnixDomainSocket::SendRecvMsg(GetSandboxFD(), buf,
  38                                                   sizeof(buf), NULL, request);
  39
  40   std::string family_name;
  41   std::string filename;
  42   int fontconfigInterfaceId = 0;
  43   int ttcIndex = 0;
  44   bool isBold = false;
  45   bool isItalic = false;
  46   if (n != -1) {
  47     Pickle reply(reinterpret_cast<char*>(buf), n);
  48     PickleIterator pickle_iter(reply);
  49     if (reply.ReadString(&pickle_iter, &family_name) &&
  50         reply.ReadString(&pickle_iter, &filename) &&
  51         reply.ReadInt(&pickle_iter, &fontconfigInterfaceId) &&
  52         reply.ReadInt(&pickle_iter, &ttcIndex) &&
  53         reply.ReadBool(&pickle_iter, &isBold) &&
  54         reply.ReadBool(&pickle_iter, &isItalic)) {
  55       fallbackFont->name = family_name;
  56       fallbackFont->filename = filename;
  57       fallbackFont->fontconfigInterfaceId = fontconfigInterfaceId;
  58       fallbackFont->ttcIndex = ttcIndex;
  59       fallbackFont->isBold = isBold;
  60       fallbackFont->isItalic = isItalic;
  61     }
  62   }
  63 }
  64
  65 void GetRenderStyleForStrike(const char* family,
  66                              int size_and_style,
  67                              blink::WebFontRenderStyle* out) {
  68   TRACE_EVENT0("sandbox_ipc", "GetRenderStyleForStrike");
  69
  70   out->setDefaults();
  71
  72   if (size_and_style < 0)
  73     return;
  74
  75   const bool bold = size_and_style & 1;
  76   const bool italic = size_and_style & 2;
  77   const int pixel_size = size_and_style >> 2;
  78   if (pixel_size > std::numeric_limits<uint16>::max())
  79     return;
  80
  81   Pickle request;
  82   request.WriteInt(LinuxSandbox::METHOD_GET_STYLE_FOR_STRIKE);
  83   request.WriteString(family);
  84   request.WriteBool(bold);
  85   request.WriteBool(italic);
  86   request.WriteUInt16(pixel_size);
  87
  88   uint8_t buf[512];
  89   const ssize_t n = UnixDomainSocket::SendRecvMsg(GetSandboxFD(), buf,
  90                                                   sizeof(buf), NULL, request);
  91   if (n == -1)
  92     return;
  93
  94   Pickle reply(reinterpret_cast<char*>(buf), n);
  95   PickleIterator pickle_iter(reply);
  96   int use_bitmaps, use_autohint, use_hinting, hint_style, use_antialias;
  97   int use_subpixel_rendering, use_subpixel_positioning;
  98   if (reply.ReadInt(&pickle_iter, &use_bitmaps) &&
  99       reply.ReadInt(&pickle_iter, &use_autohint) &&
 100       reply.ReadInt(&pickle_iter, &use_hinting) &&
 101       reply.ReadInt(&pickle_iter, &hint_style) &&
 102       reply.ReadInt(&pickle_iter, &use_antialias) &&
 103       reply.ReadInt(&pickle_iter, &use_subpixel_rendering) &&
 104       reply.ReadInt(&pickle_iter, &use_subpixel_positioning)) {
 105     out->useBitmaps = use_bitmaps;
 106     out->useAutoHint = use_autohint;
 107     out->useHinting = use_hinting;
 108     out->hintStyle = hint_style;
 109     out->useAntiAlias = use_antialias;
 110     out->useSubpixelRendering = use_subpixel_rendering;
 111     out->useSubpixelPositioning = use_subpixel_positioning;
 112   }
 113 }
 114
 115 int MatchFontWithFallback(const std::string& face,
 116                           bool bold,
 117                           bool italic,
 118                           int charset,
 119                           PP_BrowserFont_Trusted_Family fallback_family) {
 120   TRACE_EVENT0("sandbox_ipc", "MatchFontWithFallback");
 121
 122   Pickle request;
 123   request.WriteInt(LinuxSandbox::METHOD_MATCH_WITH_FALLBACK);
 124   request.WriteString(face);
 125   request.WriteBool(bold);
 126   request.WriteBool(italic);
 127   request.WriteUInt32(charset);
 128   request.WriteUInt32(fallback_family);
 129   uint8_t reply_buf[64];
 130   int fd = -1;
 131   UnixDomainSocket::SendRecvMsg(GetSandboxFD(), reply_buf, sizeof(reply_buf),
 132                                 &fd, request);
 133   return fd;
 134 }
 135
 136 bool GetFontTable(int fd, uint32_t table_tag, off_t offset,
 137                   uint8_t* output, size_t* output_length) {
 138   if (offset < 0)
 139     return false;
 140
 141   size_t data_length = 0;  // the length of the file data.
 142   off_t data_offset = 0;   // the offset of the data in the file.
 143   if (table_tag == 0) {
 144     // Get the entire font file.
 145     struct stat st;
 146     if (fstat(fd, &st) < 0)
 147       return false;
 148     data_length = base::checked_cast<size_t>(st.st_size);
 149   } else {
 150     // Get a font table. Read the header to find its offset in the file.
 151     uint16_t num_tables;
 152     ssize_t n = HANDLE_EINTR(pread(fd, &num_tables, sizeof(num_tables),
 153                              4 /* skip the font type */));
 154     if (n != sizeof(num_tables))
 155       return false;
 156     // Font data is stored in net (big-endian) order.
 157     num_tables = base::NetToHost16(num_tables);
 158
 159     // Read the table directory.
 160     static const size_t kTableEntrySize = 16;
 161     const size_t directory_size = num_tables * kTableEntrySize;
 162     scoped_ptr<uint8_t[]> table_entries(new uint8_t[directory_size]);
 163     n = HANDLE_EINTR(pread(fd, table_entries.get(), directory_size,
 164                            12 /* skip the SFNT header */));
 165     if (n != base::checked_cast<ssize_t>(directory_size))
 166       return false;
 167
 168     for (uint16_t i = 0; i < num_tables; ++i) {
 169       uint8_t* entry = table_entries.get() + i * kTableEntrySize;
 170       uint32_t tag = *reinterpret_cast<uint32_t*>(entry);
 171       if (tag == table_tag) {
 172         // Font data is stored in net (big-endian) order.
 173         data_offset =
 174             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 8));
 175         data_length =
 176             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 12));
 177         break;
 178       }
 179     }
 180   }
 181
 182   if (!data_length)
 183     return false;
 184   // Clamp |offset| inside the allowable range. This allows the read to succeed
 185   // but return 0 bytes.
 186   offset = std::min(offset, base::checked_cast<off_t>(data_length));
 187   // Make sure it's safe to add the data offset and the caller's logical offset.
 188   // Define the maximum positive offset on 32 bit systems.
 189   static const off_t kMaxPositiveOffset32 = 0x7FFFFFFF;  // 2 GB - 1.
 190   if ((offset > kMaxPositiveOffset32 / 2) ||
 191       (data_offset > kMaxPositiveOffset32 / 2))
 192     return false;
 193   data_offset += offset;
 194   data_length -= offset;
 195
 196   if (output) {
 197     // 'output_length' holds the maximum amount of data the caller can accept.
 198     data_length = std::min(data_length, *output_length);
 199     ssize_t n = HANDLE_EINTR(pread(fd, output, data_length, data_offset));
 200     if (n != base::checked_cast<ssize_t>(data_length))
 201       return false;
 202   }
 203   *output_length = data_length;
 204
 205   return true;
 206 }
 207
 208 bool SendZygoteChildPing(int fd) {
 209   return UnixDomainSocket::SendMsg(fd,
 210                                    kZygoteChildPingMessage,
 211                                    sizeof(kZygoteChildPingMessage),
 212                                    std::vector<int>());
 213 }
 214
 215 }  // namespace content