Checksum verification fails for composite checkum types #3496
Description
Describe the bug
S3 GetObject fails with a "Response checksums mismatch" error when the target object has a "Composite" checksum type. The only way to successfully retrieve such an object seems to be by setting checksum validation to "WHEN_REQUIRED".
There is a TODO comment in the source where the error is generated that suggests support for these checksums may not be implemented at all: https://github.com/aws/aws-sdk-cpp/blame/5849c282350f3ed1667b8dcd0c34c1259a026928/src/aws-cpp-sdk-core/include/smithy/client/features/ChecksumInterceptor.h#L174
Note that composite checksums end in a dash and number as mentioned in the comment. See also: https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html?icmpid=docs_amazons3_console#ChecksumTypes)
The boto3 API defaults to using mutli-part uploads for files > 8MB, resulting in a Composite checksum by default. However the C++ API does not seems to support these, but defaults to attempting to verify them anyway.
This seems like a problematic situation where PutObject issued via boto3 will succeed, but then a matching GetObject via C++ will fail even though both calls are issued using the default request parameters.
Regression Issue
- Select this option if this issue appears to be a regression.
Expected Behavior
S3 GetObject on an object with a Composite checksum type should succeed
Current Behavior
S3 GetObject on an object with a Composite checksum fails with an error "Response checksums mismatch".
Reproduction Steps
Upload a file to S3 using boto3 python API. File must be > 8MB to trigger use of Composite checksum using default settings.
import boto3
s3 = boto3.client('s3')
s3.upload_file('test.data', 'my-bucket', 'test.data')Now try to dowload the same file with C++ API
#include <aws/core/Aws.h>
#include <aws/s3/S3Client.h>
#include <aws/s3/model/GetObjectRequest.h>
#include <aws/s3/model/GetObjectResult.h>
#include <iostream>
int main(int argc, char const* argv[])
{
Aws::InitAPI({});
Aws::Client::ClientConfiguration config;
// uncomment the below line to make test pass (but should not be needed and is not recommended)
//config.checksumConfig.responseChecksumValidation = Aws::Client::ResponseChecksumValidation::WHEN_REQUIRED;
auto client = Aws::S3::S3Client{config};
auto req = Aws::S3::Model::GetObjectRequest{};
req.SetBucket("my-bucket");
req.SetKey("test.data");
auto res = client.GetObject(req);
if (res.IsSuccess())
std::cout << "Success!\n";
else
std::cerr << "Failure: " << res.GetError().GetMessage() << "\n";
return 0;
}Possible Solution
No response
Additional Information/Context
No response
AWS CPP SDK version used
1.11.613
Compiler and Version used
gcc (GCC) 15.1.1 20250521 (Red Hat 15.1.1-2)
Operating System and version
Fedora release 42 (Adams)