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      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
    216