premature "Nextpart: EOF" on POST /api/v0/add request

Checklist

• This is a bug report, not a question. Ask questions on discuss.ipfs.io.
• I have searched on the issue tracker for my bug.
• I am running the latest go-ipfs version or have an issue updating.

Installation method

built from source

Version

Installation method: nix-env -i ipfs

go-ipfs version: 0.10.0
Repo version: 11
System version: arm64/linux
Golang version: go1.16.9

Config

{
  "API": {
    "HTTPHeaders": {
      "Access-Control-Allow-Methods": [
        "PUT",
        "POST"
      ],
      "Access-Control-Allow-Origin": [
        "http://<censored>:5001"
      ]
    }
  },
  "Addresses": {
    "API": "/ip4/0.0.0.0/tcp/5001",
    "Announce": [],
    "Gateway": "/ip4/127.0.0.1/tcp/8080",
    "NoAnnounce": [],
    "Swarm": [
      "/ip4/0.0.0.0/tcp/4001",
      "/ip6/::/tcp/4001",
      "/ip4/0.0.0.0/udp/4001/quic",
      "/ip6/::/udp/4001/quic"
    ]
  },
  "AutoNAT": {},
  "Bootstrap": [<censored>],
  "DNS": {
    "Resolvers": {}
  },
  "Datastore": {
    "BloomFilterSize": 0,
    "GCPeriod": "1h",
    "HashOnRead": false,
    "Spec": {
      "mounts": [
        {
          "child": {
            "path": "blocks",
            "shardFunc": "/repo/flatfs/shard/v1/next-to-last/2",
            "sync": true,
            "type": "flatfs"
          },
          "mountpoint": "/blocks",
          "prefix": "flatfs.datastore",
          "type": "measure"
        },
        {
          "child": {
            "compression": "none",
            "path": "datastore",
            "type": "levelds"
          },
          "mountpoint": "/",
          "prefix": "leveldb.datastore",
          "type": "measure"
        }
      ],
      "type": "mount"
    },
    "StorageGCWatermark": 90,
    "StorageMax": "10GB"
  },
  "Discovery": {
    "MDNS": {
      "Enabled": true,
      "Interval": 10
    }
  },
  "Experimental": {
    "AcceleratedDHTClient": false,
    "FilestoreEnabled": false,
    "GraphsyncEnabled": false,
    "Libp2pStreamMounting": false,
    "P2pHttpProxy": false,
    "ShardingEnabled": false,
    "StrategicProviding": false,
    "UrlstoreEnabled": false
  },
  "Gateway": {
    "APICommands": [],
    "HTTPHeaders": {
      "Access-Control-Allow-Headers": [
        "X-Requested-With",
        "Range",
        "User-Agent"
      ],
      "Access-Control-Allow-Methods": [
        "GET"
      ],
      "Access-Control-Allow-Origin": [
        "*"
      ]
    },
    "NoDNSLink": false,
    "NoFetch": false,
    "PathPrefixes": [],
    "PublicGateways": null,
    "RootRedirect": "",
    "Writable": false
  },
  "Identity": {
    "PeerID": "<censored>"
  },
  "Internal": {},
  "Ipns": {
    "RecordLifetime": "",
    "RepublishPeriod": "",
    "ResolveCacheSize": 128
  },
  "Migration": {
    "DownloadSources": [],
    "Keep": ""
  },
  "Mounts": {
    "FuseAllowOther": false,
    "IPFS": "/ipfs",
    "IPNS": "/ipns"
  },
  "Peering": {
    "Peers": [<censored>]
  },
  "Pinning": {
    "RemoteServices": {}
  },
  "Plugins": {
    "Plugins": null
  },
  "Provider": {
    "Strategy": ""
  },
  "Pubsub": {
    "DisableSigning": false,
    "Router": ""
  },
  "Reprovider": {
    "Interval": "12h",
    "Strategy": "all"
  },
  "Routing": {
    "Type": "dht"
  },
  "Swarm": {
    "AddrFilters": null,
    "ConnMgr": {
      "GracePeriod": "30s",
      "HighWater": 500,
      "LowWater": 300,
      "Type": "basic"
    },
    "DisableBandwidthMetrics": false,
    "DisableNatPortMap": false,
    "EnableAutoRelay": false,
    "EnableRelayHop": false,
    "Transports": {
      "Multiplexers": {},
      "Network": {},
      "Security": {}
    }
  }
}

Description

POST /api/v0/add will prematurely respond with "Nextpart: EOF" before even the first part has been sent if the HTTP request is split into multiple packets. /ipfs/QmXNuNB13zYS6WDAjkq8YG6mPtdni9xUNrcSzX6xufda8Z/broken.pcap shows a packet dump. note that the HTTP header set comes in two packets, after the second the API responds with the error before the HTTP request even had a chance to send the first part of the multipart request. by comparison /ipfs/QmcNL9Dv9XQ6GBDmHmaHByAhNUe5bNCNPkgpMTaDgqpJrP/works.pcap is the exact same situation except that all HTTP headers come in one packet.

the latter is IPFS command line standard behavior. the former (broken) can e.g. per provoked by inserting an HTTP proxy like tinyproxy in the middle.