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Use "read" to fetch misaligned 64bit values from bundle header #63431

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merged 3 commits into from
Jan 7, 2022
Merged

Use "read" to fetch misaligned 64bit values from bundle header #63431

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c48425e
Use "read" to fetch misaligned 64bit values
VSadov Jan 6, 2022
6bcb50e
remove read_direct
VSadov Jan 6, 2022
dddb853
rename read() -> read_byte()
VSadov Jan 6, 2022
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15 changes: 9 additions & 6 deletions src/native/corehost/bundle/file_entry.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,15 +19,18 @@ file_entry_t file_entry_t::read(reader_t &reader, uint32_t bundle_major_version,
// First read the fixed-sized portion of file-entry
file_entry_fixed_t fixed_data;

fixed_data.offset = *(int64_t*)reader.read_direct(sizeof(int64_t));
fixed_data.size = *(int64_t*)reader.read_direct(sizeof(int64_t));
// NB: the file data is potentially unaligned, thus we use "read" to fetch 64bit values
reader.read(&fixed_data.offset, sizeof(int64_t));
reader.read(&fixed_data.size, sizeof(int64_t));

// compressedSize is present only in v6+ headers
fixed_data.compressedSize = bundle_major_version >= 6 ?
*(int64_t*)reader.read_direct(sizeof(int64_t)) :
0;
fixed_data.compressedSize = 0;
if (bundle_major_version >= 6)
{
reader.read(&fixed_data.compressedSize, sizeof(int64_t));
}

fixed_data.type = *(file_type_t*)reader.read_direct(sizeof(file_type_t));
fixed_data.type = (file_type_t)reader.read_byte();

file_entry_t entry(&fixed_data, force_extraction);

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12 changes: 6 additions & 6 deletions src/native/corehost/bundle/header.cpp
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Expand Up @@ -24,23 +24,23 @@ bool header_fixed_t::is_valid() const

header_t header_t::read(reader_t& reader)
{
const header_fixed_t* fixed_header = reinterpret_cast<const header_fixed_t*>(reader.read_direct(sizeof(header_fixed_t)));
header_fixed_t fixed_header;
reader.read(&fixed_header, sizeof(header_fixed_t));

if (!fixed_header->is_valid())
if (!fixed_header.is_valid())
{
trace::error(_X("Failure processing application bundle."));
trace::error(_X("Bundle header version compatibility check failed. Header version: %d.%d"), fixed_header->major_version, fixed_header->minor_version);
trace::error(_X("Bundle header version compatibility check failed. Header version: %d.%d"), fixed_header.major_version, fixed_header.minor_version);

throw StatusCode::BundleExtractionFailure;
}

header_t header(fixed_header->major_version, fixed_header->minor_version, fixed_header->num_embedded_files);
header_t header(fixed_header.major_version, fixed_header.minor_version, fixed_header.num_embedded_files);

// bundle_id is a component of the extraction path
reader.read_path_string(header.m_bundle_id);

const header_fixed_v2_t *v2_header = reinterpret_cast<const header_fixed_v2_t*>(reader.read_direct(sizeof(header_fixed_v2_t)));
header.m_v2_header = *v2_header;
reader.read(&header.m_v2_header, sizeof(header_fixed_v2_t));

return header;
}
4 changes: 2 additions & 2 deletions src/native/corehost/bundle/reader.cpp
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Expand Up @@ -54,7 +54,7 @@ size_t reader_t::read_path_length()
{
size_t length = 0;

int8_t first_byte = read();
int8_t first_byte = read_byte();

// If the high bit is set, it means there are more bytes to read.
if ((first_byte & 0x80) == 0)
Expand All @@ -63,7 +63,7 @@ size_t reader_t::read_path_length()
}
else
{
int8_t second_byte = read();
int8_t second_byte = read_byte();

if (second_byte & 0x80)
{
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12 changes: 1 addition & 11 deletions src/native/corehost/bundle/reader.h
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Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,7 @@ namespace bundle
return m_ptr;
}

int8_t read()
int8_t read_byte()
{
bounds_check();
return *m_ptr++;
Expand All @@ -100,16 +100,6 @@ namespace bundle
m_ptr += len;
}

// Return a pointer to the requested bytes within the memory-mapped file.
// Skip over len bytes.
const char* read_direct(int64_t len)
{
bounds_check(len);
const char *ptr = m_ptr;
m_ptr += len;
return ptr;
}

size_t read_path_length();
size_t read_path_string(pal::string_t &str);

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