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