Copilot commented on code in PR #3857:
URL: https://github.com/apache/avro/pull/3857#discussion_r3564409018
##########
lang/csharp/src/apache/main/File/Codec.cs:
##########
@@ -29,6 +29,71 @@ namespace Avro.File
/// </summary>
public abstract class Codec
{
+ /// <summary>
+ /// Default upper bound, in bytes, on the size a single data-file
block may
+ /// decompress to. A block with a very high compression ratio (or a
malformed
+ /// block) can otherwise expand to far more memory than its compressed
size.
+ /// Mirrors the Java SDK's decompression limit (AVRO-4247).
Overridable with
+ /// the AVRO_MAX_DECOMPRESS_LENGTH environment variable.
+ /// </summary>
+ public const long DefaultMaxDecompressLength = 200L * 1024 * 1024; //
200 MiB
+
+ /// <summary>
+ /// Name of the environment variable used to override the default
maximum
+ /// decompressed size of a single block.
+ /// </summary>
+ public const string MaxDecompressLengthEnvVar =
"AVRO_MAX_DECOMPRESS_LENGTH";
+
+ /// <summary>
+ /// The maximum number of bytes a single block is allowed to
decompress to.
+ /// </summary>
+ /// <returns>The configured limit, honoring the environment
override.</returns>
+ public static long GetMaxDecompressLength()
+ {
+ var value =
Environment.GetEnvironmentVariable(MaxDecompressLengthEnvVar);
+ if (value != null && long.TryParse(value, out var parsed) &&
parsed > 0)
+ {
+ return parsed;
+ }
+
+ return DefaultMaxDecompressLength;
+ }
+
+ /// <summary>
+ /// Throws if the given decompressed length exceeds the maximum
allowed.
+ /// </summary>
+ /// <param name="length">The number of decompressed bytes.</param>
+ /// <param name="maxLength">The maximum number of decompressed bytes
allowed.</param>
+ public static void CheckDecompressLength(long length, long maxLength)
+ {
+ if (length > maxLength)
+ {
+ throw new AvroRuntimeException(
+ $"Decompressed block size exceeds the maximum allowed of
{maxLength} bytes");
+ }
Review Comment:
The decompression-limit exception message doesn’t include the actual
decompressed size or how to remediate (which env var controls the limit).
Including both the observed length and the override variable makes the error
actionable when surfaced to users.
##########
lang/csharp/src/apache/main/File/Codec.cs:
##########
@@ -29,6 +29,71 @@ namespace Avro.File
/// </summary>
public abstract class Codec
{
+ /// <summary>
+ /// Default upper bound, in bytes, on the size a single data-file
block may
+ /// decompress to. A block with a very high compression ratio (or a
malformed
+ /// block) can otherwise expand to far more memory than its compressed
size.
+ /// Mirrors the Java SDK's decompression limit (AVRO-4247).
Overridable with
+ /// the AVRO_MAX_DECOMPRESS_LENGTH environment variable.
+ /// </summary>
+ public const long DefaultMaxDecompressLength = 200L * 1024 * 1024; //
200 MiB
+
+ /// <summary>
+ /// Name of the environment variable used to override the default
maximum
+ /// decompressed size of a single block.
+ /// </summary>
+ public const string MaxDecompressLengthEnvVar =
"AVRO_MAX_DECOMPRESS_LENGTH";
+
+ /// <summary>
+ /// The maximum number of bytes a single block is allowed to
decompress to.
+ /// </summary>
+ /// <returns>The configured limit, honoring the environment
override.</returns>
+ public static long GetMaxDecompressLength()
+ {
+ var value =
Environment.GetEnvironmentVariable(MaxDecompressLengthEnvVar);
+ if (value != null && long.TryParse(value, out var parsed) &&
parsed > 0)
+ {
+ return parsed;
+ }
+
+ return DefaultMaxDecompressLength;
+ }
+
+ /// <summary>
+ /// Throws if the given decompressed length exceeds the maximum
allowed.
+ /// </summary>
+ /// <param name="length">The number of decompressed bytes.</param>
+ /// <param name="maxLength">The maximum number of decompressed bytes
allowed.</param>
+ public static void CheckDecompressLength(long length, long maxLength)
+ {
+ if (length > maxLength)
+ {
+ throw new AvroRuntimeException(
+ $"Decompressed block size exceeds the maximum allowed of
{maxLength} bytes");
+ }
+ }
+
+ /// <summary>
+ /// Copies a decompression stream to the destination, rejecting the
block as
+ /// soon as its decompressed size would exceed <paramref
name="maxLength"/> so
+ /// an over-large (or malicious) block is not fully materialized in
memory.
+ /// </summary>
+ /// <param name="source">The decompression stream to read from.</param>
+ /// <param name="destination">The stream to write the decompressed
data to.</param>
+ /// <param name="maxLength">The maximum number of decompressed bytes
allowed.</param>
+ public static void CopyBounded(Stream source, Stream destination, long
maxLength)
+ {
+ byte[] buffer = new byte[81920];
+ long total = 0;
+ int read;
+ while ((read = source.Read(buffer, 0, buffer.Length)) > 0)
Review Comment:
CopyBounded is a new public helper but currently throws
NullReferenceException if called with null streams (and behaves unexpectedly
for non-positive maxLength). Since it’s public API, add explicit argument
validation so callers get consistent Argument* exceptions.
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