A maliciously crafted archive may produce a large amount of data on decompression that may lead to a denial-of-service (DoS) attack on the application.

It is recommended to use io.CopyN instead of io.Copy and io.CopyBuffer to control the number of bytes copied from the decompression reader.

Bad practice

package main

import (
    "bytes"
    "compress/zlib"
    "io"
    "os"
)

func foo(b io.Reader) {
    r, err := zlib.NewReader(b)
    if err != nil {
        panic(err)
    }

    _, err = io.Copy(os.Stdout, r)
    if err != nil {
        panic(err)
    }

    r.Close()
}

Recommended

package main

import (
    "bytes"
    "compress/zlib"
    "io"
    "os"
)

func foo(b io.Reader) {
    r, err := zlib.NewReader(b)
    if err != nil {
        panic(err)
    }

    _, err = io.CopyN(os.Stdout, r, 1024) // "n" may change depending on the application
    if err != nil {
        panic(err)
    }

    r.Close()
}

References

CWE-409

convox / convox

No ignore rules found