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/debug/trace_event.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/pickle.h"
  12 #include "base/posix/eintr_wrapper.h"
  13 #include "base/posix/unix_domain_socket_linux.h"
  14 #include "base/safe_numerics.h"
  15 #include "base/sys_byteorder.h"
  16 #include "content/common/sandbox_linux.h"
  17 #include "third_party/WebKit/public/platform/linux/WebFontFamily.h"
  18 #include "third_party/WebKit/public/platform/linux/WebFontRenderStyle.h"
  19
  20 namespace content {
  21
  22 void GetFontFamilyForCharacter(int32_t character,
  23                                const char* preferred_locale,
  24                                WebKit::WebFontFamily* family) {
  25   TRACE_EVENT0("sandbox_ipc", "GetFontFamilyForCharacter");
  26
  27   Pickle request;
  28   request.WriteInt(LinuxSandbox::METHOD_GET_FONT_FAMILY_FOR_CHAR);
  29   request.WriteInt(character);
  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   TRACE_EVENT0("sandbox_ipc", "GetRenderStyleForStrike");
  55
  56   Pickle request;
  57   request.WriteInt(LinuxSandbox::METHOD_GET_STYLE_FOR_STRIKE);
  58   request.WriteString(family);
  59   request.WriteInt(sizeAndStyle);
  60
  61   uint8_t buf[512];
  62   const ssize_t n = UnixDomainSocket::SendRecvMsg(GetSandboxFD(), buf,
  63                                                   sizeof(buf), NULL, request);
  64
  65   out->setDefaults();
  66   if (n == -1) {
  67     return;
  68   }
  69
  70   Pickle reply(reinterpret_cast<char*>(buf), n);
  71   PickleIterator pickle_iter(reply);
  72   int useBitmaps, useAutoHint, useHinting, hintStyle, useAntiAlias;
  73   int useSubpixelRendering, useSubpixelPositioning;
  74   if (reply.ReadInt(&pickle_iter, &useBitmaps) &&
  75       reply.ReadInt(&pickle_iter, &useAutoHint) &&
  76       reply.ReadInt(&pickle_iter, &useHinting) &&
  77       reply.ReadInt(&pickle_iter, &hintStyle) &&
  78       reply.ReadInt(&pickle_iter, &useAntiAlias) &&
  79       reply.ReadInt(&pickle_iter, &useSubpixelRendering) &&
  80       reply.ReadInt(&pickle_iter, &useSubpixelPositioning)) {
  81     out->useBitmaps = useBitmaps;
  82     out->useAutoHint = useAutoHint;
  83     out->useHinting = useHinting;
  84     out->hintStyle = hintStyle;
  85     out->useAntiAlias = useAntiAlias;
  86     out->useSubpixelRendering = useSubpixelRendering;
  87     out->useSubpixelPositioning = useSubpixelPositioning;
  88   }
  89 }
  90
  91 int MatchFontWithFallback(const std::string& face, bool bold,
  92                           bool italic, int charset) {
  93   TRACE_EVENT0("sandbox_ipc", "MatchFontWithFallback");
  94
  95   Pickle request;
  96   request.WriteInt(LinuxSandbox::METHOD_MATCH_WITH_FALLBACK);
  97   request.WriteString(face);
  98   request.WriteBool(bold);
  99   request.WriteBool(italic);
 100   request.WriteUInt32(charset);
 101   uint8_t reply_buf[64];
 102   int fd = -1;
 103   UnixDomainSocket::SendRecvMsg(GetSandboxFD(), reply_buf, sizeof(reply_buf),
 104                                 &fd, request);
 105   return fd;
 106 }
 107
 108 bool GetFontTable(int fd, uint32_t table_tag, off_t offset,
 109                   uint8_t* output, size_t* output_length) {
 110   if (offset < 0)
 111     return false;
 112
 113   size_t data_length = 0;  // the length of the file data.
 114   off_t data_offset = 0;   // the offset of the data in the file.
 115   if (table_tag == 0) {
 116     // Get the entire font file.
 117     struct stat st;
 118     if (fstat(fd, &st) < 0)
 119       return false;
 120     data_length = base::checked_numeric_cast<size_t>(st.st_size);
 121   } else {
 122     // Get a font table. Read the header to find its offset in the file.
 123     uint16_t num_tables;
 124     ssize_t n = HANDLE_EINTR(pread(fd, &num_tables, sizeof(num_tables),
 125                              4 /* skip the font type */));
 126     if (n != sizeof(num_tables))
 127       return false;
 128     // Font data is stored in net (big-endian) order.
 129     num_tables = base::NetToHost16(num_tables);
 130
 131     // Read the table directory.
 132     static const size_t kTableEntrySize = 16;
 133     const size_t directory_size = num_tables * kTableEntrySize;
 134     scoped_ptr<uint8_t[]> table_entries(new uint8_t[directory_size]);
 135     n = HANDLE_EINTR(pread(fd, table_entries.get(), directory_size,
 136                            12 /* skip the SFNT header */));
 137     if (n != base::checked_numeric_cast<ssize_t>(directory_size))
 138       return false;
 139
 140     for (uint16_t i = 0; i < num_tables; ++i) {
 141       uint8_t* entry = table_entries.get() + i * kTableEntrySize;
 142       uint32_t tag = *reinterpret_cast<uint32_t*>(entry);
 143       if (tag == table_tag) {
 144         // Font data is stored in net (big-endian) order.
 145         data_offset =
 146             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 8));
 147         data_length =
 148             base::NetToHost32(*reinterpret_cast<uint32_t*>(entry + 12));
 149         break;
 150       }
 151     }
 152   }
 153
 154   if (!data_length)
 155     return false;
 156   // Clamp |offset| inside the allowable range. This allows the read to succeed
 157   // but return 0 bytes.
 158   offset = std::min(offset, base::checked_numeric_cast<off_t>(data_length));
 159   // Make sure it's safe to add the data offset and the caller's logical offset.
 160   // Define the maximum positive offset on 32 bit systems.
 161   static const off_t kMaxPositiveOffset32 = 0x7FFFFFFF;  // 2 GB - 1.
 162   if ((offset > kMaxPositiveOffset32 / 2) ||
 163       (data_offset > kMaxPositiveOffset32 / 2))
 164     return false;
 165   data_offset += offset;
 166   data_length -= offset;
 167
 168   if (output) {
 169     // 'output_length' holds the maximum amount of data the caller can accept.
 170     data_length = std::min(data_length, *output_length);
 171     ssize_t n = HANDLE_EINTR(pread(fd, output, data_length, data_offset));
 172     if (n != base::checked_numeric_cast<ssize_t>(data_length))
 173       return false;
 174   }
 175   *output_length = data_length;
 176
 177   return true;
 178 }
 179
 180 }  // namespace content