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fixed: Thread safety in AssemblyStoreReader #4814

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9f176f7
fixed: Thread safety in AssemblyStoreReader
jamescrosswell Dec 16, 2025
c6ec0d3
Added unit tests
jamescrosswell Dec 17, 2025
cc772dc
Format code
getsentry-bot Dec 17, 2025
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48 changes: 26 additions & 22 deletions src/Sentry.Android.AssemblyReader/V2/AssemblyStoreReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ internal abstract class AssemblyStoreReader

private static readonly UTF8Encoding ReaderEncoding = new UTF8Encoding(false);

internal object StreamLock { get; } = new();
protected Stream StoreStream { get; }

public abstract string Description { get; }
Expand Down Expand Up @@ -44,34 +45,37 @@ protected AssemblyStoreReader(Stream store, string path, DebugLogger? logger)

protected BinaryReader CreateReader() => new BinaryReader(StoreStream, ReaderEncoding, leaveOpen: true);

protected abstract bool IsSupported();
protected internal abstract bool IsSupported();
protected abstract void Prepare();
protected abstract ulong GetStoreStartDataOffset();

public MemoryStream ReadEntryImageData(AssemblyStoreItem entry, bool uncompressIfNeeded = false)
{
ulong startOffset = GetStoreStartDataOffset();
StoreStream.Seek((uint)startOffset + entry.DataOffset, SeekOrigin.Begin);
var stream = new MemoryStream();

if (uncompressIfNeeded)
{
throw new NotImplementedException();
}

const long BufferSize = 65535;
byte[] buffer = Utils.BytePool.Rent((int)BufferSize);
long remainingToRead = entry.DataSize;

while (remainingToRead > 0)
lock (StreamLock)
{
int nread = StoreStream.Read(buffer, 0, (int)Math.Min(BufferSize, remainingToRead));
stream.Write(buffer, 0, nread);
remainingToRead -= (long)nread;
ulong startOffset = GetStoreStartDataOffset();
StoreStream.Seek((uint)startOffset + entry.DataOffset, SeekOrigin.Begin);
var stream = new MemoryStream();

if (uncompressIfNeeded)
{
throw new NotImplementedException();
}

const long BufferSize = 65535;
byte[] buffer = Utils.BytePool.Rent((int)BufferSize);
long remainingToRead = entry.DataSize;

while (remainingToRead > 0)
{
int nread = StoreStream.Read(buffer, 0, (int)Math.Min(BufferSize, remainingToRead));
stream.Write(buffer, 0, nread);
remainingToRead -= (long)nread;
}
stream.Flush();
stream.Seek(0, SeekOrigin.Begin);

return stream;
}
stream.Flush();
stream.Seek(0, SeekOrigin.Begin);

return stream;
}
}
6 changes: 3 additions & 3 deletions src/Sentry.Android.AssemblyReader/V2/StoreReader.Classes.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ public Header(uint magic, uint version, uint entry_count, uint index_entry_count
}
}

private sealed class IndexEntry
internal sealed class IndexEntry
{
public readonly ulong name_hash;
public readonly uint descriptor_index;
Expand All @@ -45,7 +45,7 @@ public IndexEntry(ulong name_hash, uint descriptor_index, bool ignore)
}
}

private sealed class EntryDescriptor
internal sealed class EntryDescriptor
{
public uint mapping_index;

Expand All @@ -59,7 +59,7 @@ private sealed class EntryDescriptor
public uint config_data_size;
}

private sealed class StoreItemV2 : AssemblyStoreItem
internal sealed class StoreItemV2 : AssemblyStoreItem
{
public StoreItemV2(AndroidTargetArch targetArch, string name, bool is64Bit, List<IndexEntry> indexEntries,
EntryDescriptor descriptor, bool ignore)
Expand Down
246 changes: 123 additions & 123 deletions src/Sentry.Android.AssemblyReader/V2/StoreReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -91,163 +91,163 @@ public StoreReader(Stream store, string path, DebugLogger? logger)

protected override ulong GetStoreStartDataOffset() => elfOffset;

protected override bool IsSupported()
protected internal override bool IsSupported()
{
StoreStream.Seek(0, SeekOrigin.Begin);
using var reader = CreateReader();

uint magic = reader.ReadUInt32();
if (magic == Utils.ELFMagic)
lock (StreamLock)
{
ELFPayloadError error;
(elfOffset, _, error) = Utils.FindELFPayloadSectionOffsetAndSize(StoreStream);
StoreStream.Seek(0, SeekOrigin.Begin);
using var reader = CreateReader();

if (error != ELFPayloadError.None)
var magic = reader.ReadUInt32();
if (magic == Utils.ELFMagic)
{
string message = error switch
(elfOffset, _, var error) = Utils.FindELFPayloadSectionOffsetAndSize(StoreStream);

if (error != ELFPayloadError.None)
{
ELFPayloadError.NotELF => $"Store '{StorePath}' is not a valid ELF binary",
ELFPayloadError.LoadFailed => $"Store '{StorePath}' could not be loaded",
ELFPayloadError.NotSharedLibrary => $"Store '{StorePath}' is not a shared ELF library",
ELFPayloadError.NotLittleEndian => $"Store '{StorePath}' is not a little-endian ELF image",
ELFPayloadError.NoPayloadSection => $"Store '{StorePath}' does not contain the 'payload' section",
_ => $"Unknown ELF payload section error for store '{StorePath}': {error}"
};
Logger?.Invoke(DebugLoggerLevel.Debug, message);
// Was originally:
// ```
// } else if (elfOffset >= 0) {
// ```
// However since elfOffset is an ulong, it will never be less than 0
var message = error switch
{
ELFPayloadError.NotELF => $"Store '{StorePath}' is not a valid ELF binary",
ELFPayloadError.LoadFailed => $"Store '{StorePath}' could not be loaded",
ELFPayloadError.NotSharedLibrary => $"Store '{StorePath}' is not a shared ELF library",
ELFPayloadError.NotLittleEndian => $"Store '{StorePath}' is not a little-endian ELF image",
ELFPayloadError.NoPayloadSection => $"Store '{StorePath}' does not contain the 'payload' section",
_ => $"Unknown ELF payload section error for store '{StorePath}': {error}"
};
Logger?.Invoke(DebugLoggerLevel.Debug, message);
}
else
{
StoreStream.Seek((long)elfOffset, SeekOrigin.Begin);
magic = reader.ReadUInt32();
}
}
else

if (magic != Utils.AssemblyStoreMagic)
{
StoreStream.Seek((long)elfOffset, SeekOrigin.Begin);
magic = reader.ReadUInt32();
Logger?.Invoke(DebugLoggerLevel.Debug, "Store '{0}' has invalid header magic number.", StorePath);
return false;
}
}

if (magic != Utils.AssemblyStoreMagic)
{
Logger?.Invoke(DebugLoggerLevel.Debug, "Store '{0}' has invalid header magic number.", StorePath);
return false;
}

uint version = reader.ReadUInt32();
if (!supportedVersions.Contains(version))
{
Logger?.Invoke(DebugLoggerLevel.Debug, "Store '{0}' has unsupported version 0x{1:x}", StorePath, version);
return false;
}
var version = reader.ReadUInt32();
if (!supportedVersions.Contains(version))
{
Logger?.Invoke(DebugLoggerLevel.Debug, "Store '{0}' has unsupported version 0x{1:x}", StorePath, version);
return false;
}

uint entry_count = reader.ReadUInt32();
uint index_entry_count = reader.ReadUInt32();
uint index_size = reader.ReadUInt32();
var entry_count = reader.ReadUInt32();
var index_entry_count = reader.ReadUInt32();
var index_size = reader.ReadUInt32();

header = new Header(magic, version, entry_count, index_entry_count, index_size);
return true;
header = new Header(magic, version, entry_count, index_entry_count, index_size);
return true;
}
}

protected override void Prepare()
{
if (header == null)
lock (StreamLock)
{
throw new InvalidOperationException("Internal error: header not set, was IsSupported() called?");
}
if (header == null)
{
throw new InvalidOperationException("Internal error: header not set, was IsSupported() called?");
}

TargetArch = (header.version & ASSEMBLY_STORE_ABI_MASK) switch
{
ASSEMBLY_STORE_ABI_AARCH64 => AndroidTargetArch.Arm64,
ASSEMBLY_STORE_ABI_ARM => AndroidTargetArch.Arm,
ASSEMBLY_STORE_ABI_X64 => AndroidTargetArch.X86_64,
ASSEMBLY_STORE_ABI_X86 => AndroidTargetArch.X86,
_ => throw new NotSupportedException($"Unsupported ABI in store version: 0x{header.version:x}")
};
TargetArch = (header.version & ASSEMBLY_STORE_ABI_MASK) switch
{
ASSEMBLY_STORE_ABI_AARCH64 => AndroidTargetArch.Arm64,
ASSEMBLY_STORE_ABI_ARM => AndroidTargetArch.Arm,
ASSEMBLY_STORE_ABI_X64 => AndroidTargetArch.X86_64,
ASSEMBLY_STORE_ABI_X86 => AndroidTargetArch.X86,
_ => throw new NotSupportedException($"Unsupported ABI in store version: 0x{header.version:x}")
};

Is64Bit = (header.version & ASSEMBLY_STORE_FORMAT_VERSION_MASK) != 0;
AssemblyCount = header.entry_count;
IndexEntryCount = header.index_entry_count;
Is64Bit = (header.version & ASSEMBLY_STORE_FORMAT_VERSION_MASK) != 0;
AssemblyCount = header.entry_count;
IndexEntryCount = header.index_entry_count;

StoreStream.Seek((long)elfOffset + Header.NativeSize, SeekOrigin.Begin);
using var reader = CreateReader();
StoreStream.Seek((long)elfOffset + Header.NativeSize, SeekOrigin.Begin);
using var reader = CreateReader();

var index = new List<IndexEntry>();
for (uint i = 0; i < header.index_entry_count; i++)
{
ulong name_hash;
if (Is64Bit)
{
name_hash = reader.ReadUInt64();
}
else
var index = new List<IndexEntry>();
for (uint i = 0; i < header.index_entry_count; i++)
{
name_hash = (ulong)reader.ReadUInt32();
}
ulong name_hash;
if (Is64Bit)
{
name_hash = reader.ReadUInt64();
}
else
{
name_hash = (ulong)reader.ReadUInt32();
}

uint descriptor_index = reader.ReadUInt32();
uint descriptor_index = reader.ReadUInt32();
#if NET10_0_OR_GREATER
bool ignore = reader.ReadByte () != 0;
#else
bool ignore = false;
bool ignore = false;
#endif
index.Add(new IndexEntry(name_hash, descriptor_index, ignore));
}
index.Add(new IndexEntry(name_hash, descriptor_index, ignore));
}

var descriptors = new List<EntryDescriptor>();
for (uint i = 0; i < header.entry_count; i++)
{
uint mapping_index = reader.ReadUInt32();
uint data_offset = reader.ReadUInt32();
uint data_size = reader.ReadUInt32();
uint debug_data_offset = reader.ReadUInt32();
uint debug_data_size = reader.ReadUInt32();
uint config_data_offset = reader.ReadUInt32();
uint config_data_size = reader.ReadUInt32();

var desc = new EntryDescriptor
var descriptors = new List<EntryDescriptor>();
for (uint i = 0; i < header.entry_count; i++)
{
mapping_index = mapping_index,
data_offset = data_offset,
data_size = data_size,
debug_data_offset = debug_data_offset,
debug_data_size = debug_data_size,
config_data_offset = config_data_offset,
config_data_size = config_data_size,
};
descriptors.Add(desc);
}
uint mapping_index = reader.ReadUInt32();
uint data_offset = reader.ReadUInt32();
uint data_size = reader.ReadUInt32();
uint debug_data_offset = reader.ReadUInt32();
uint debug_data_size = reader.ReadUInt32();
uint config_data_offset = reader.ReadUInt32();
uint config_data_size = reader.ReadUInt32();

var desc = new EntryDescriptor
{
mapping_index = mapping_index,
data_offset = data_offset,
data_size = data_size,
debug_data_offset = debug_data_offset,
debug_data_size = debug_data_size,
config_data_offset = config_data_offset,
config_data_size = config_data_size,
};
descriptors.Add(desc);
}

var names = new List<string>();
for (uint i = 0; i < header.entry_count; i++)
{
uint name_length = reader.ReadUInt32();
byte[] name_bytes = reader.ReadBytes((int)name_length);
names.Add(Encoding.UTF8.GetString(name_bytes));
}
var names = new List<string>();
for (uint i = 0; i < header.entry_count; i++)
{
uint name_length = reader.ReadUInt32();
byte[] name_bytes = reader.ReadBytes((int)name_length);
names.Add(Encoding.UTF8.GetString(name_bytes));
}

var tempItems = new Dictionary<uint, TemporaryItem>();
foreach (IndexEntry ie in index)
{
if (!tempItems.TryGetValue(ie.descriptor_index, out TemporaryItem? item))
var tempItems = new Dictionary<uint, TemporaryItem>();
foreach (IndexEntry ie in index)
{
item = new TemporaryItem(names[(int)ie.descriptor_index], descriptors[(int)ie.descriptor_index], ie.ignore);
tempItems.Add(ie.descriptor_index, item);
if (!tempItems.TryGetValue(ie.descriptor_index, out TemporaryItem? item))
{
item = new TemporaryItem(names[(int)ie.descriptor_index], descriptors[(int)ie.descriptor_index], ie.ignore);
tempItems.Add(ie.descriptor_index, item);
}
item.IndexEntries.Add(ie);
}
item.IndexEntries.Add(ie);
}

if (tempItems.Count != descriptors.Count)
{
throw new InvalidOperationException($"Assembly store '{StorePath}' index is corrupted.");
}
if (tempItems.Count != descriptors.Count)
{
throw new InvalidOperationException($"Assembly store '{StorePath}' index is corrupted.");
}

var storeItems = new List<AssemblyStoreItem>();
foreach (var kvp in tempItems)
{
TemporaryItem ti = kvp.Value;
var item = new StoreItemV2(TargetArch, ti.Name, Is64Bit, ti.IndexEntries, ti.Descriptor, ti.Ignored);
storeItems.Add(item);
var storeItems = new List<AssemblyStoreItem>();
foreach (var kvp in tempItems)
{
TemporaryItem ti = kvp.Value;
var item = new StoreItemV2(TargetArch, ti.Name, Is64Bit, ti.IndexEntries, ti.Descriptor, ti.Ignored);
storeItems.Add(item);
}
Assemblies = storeItems.AsReadOnly();
}
Assemblies = storeItems.AsReadOnly();
}
}
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