"X-Amz-User-Agent" causes signature issue with HTTP proxy

[cweiske]

Describe the bug

We've got a MinIO instance running behind a (to me unkown) HTTP proxy, which removes the empty X-Amz-User-Agent header sent by the AWS PHP SDK. This causes a signature error:

There were headers present in the request which were not signed.

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

No signature error.

Current Behavior

Signature error:

There were headers present in the request which were not signed.

This is because SignedHeaders contains x-amz-user-agent, despite it being on the signature blacklist.

Reproduction Steps

1. Send request to HTTP to MinIO S3 server behind a proxy that removes empty HTTP headers

Possible Solution

No response

Additional Information/Context

No response

SDK version used

3.343.8

Environment details (Version of PHP (php -v)? OS name and version, etc.)

PHP 8.2.28

[yenfryherrerafeliz]

Hi @cweiske, sorry to hear about your issues. You could just add a middleware that removes the header in question. For example:

$client = new Aws\S3\S3Client([
    'region' => 'us-east-2',
]);
$client->getHandlerList()->prependSign(\Aws\Middleware::mapRequest(function (RequestInterface $request) {
    return $request->withoutHeader('X-Amz-User-Agent');
}));
$client->listBuckets();

I hope that helps.

Thanks!

[cweiske]

I already provided a patch for this bug; see #3120.

[yenfryherrerafeliz]

Hey @cweiske thanks for providing this PR. However, we already have one open for this here which we have not merged yet due to some backward compatibilities issues we get after doing so. For now we can not prioritize investigating why those issues happen; nonetheless, the workaround I provided you with does the trick in the meantime.

Thanks!

[cweiske]

Where is the list of "backward compatibilities issues" that you are speaking of? All checks in #2882 are green.

[yenfryherrerafeliz]

@cweiske the issues are internal integration tests. I understand your need on having this fixed but for now this can't be prioritized. The workaround I provided you with should be enough to do the trick.

Thank you!