Same Dockerfile produces error in Codebuild – Nginx

I have a Dockerfile:

FROM public.ecr.aws/bitnami/node:15 AS stage-01
COPY package.json /app/package.json
COPY package-lock.json /app/package-lock.json
WORKDIR /app
RUN npm ci

FROM stage-01 AS stage-02
COPY src /app/src
COPY public /app/public
COPY tsconfig.json /app/tsconfig.json
WORKDIR /app
RUN PUBLIC_URL=/myapp/web npm run build

FROM public.ecr.aws/bitnami/nginx:1.20

USER 1001

COPY --from=stage-02 /app/build /app/build
COPY nginx.conf /opt/bitnami/nginx/conf/server_blocks/nginx.conf
COPY ./env.sh /app/build
COPY window.env /app/build

EXPOSE 8080
WORKDIR /app/build

CMD ["/bin/sh", "-c", "/app/build/env.sh && nginx -g "daemon off;""]

If I build this image locally it starts normally and does what it has to do.

My local docker version:

Client: Docker Engine - Community
 Version:           20.10.7
 API version:       1.41
 Go version:        go1.13.15
 Git commit:        f0df350
 Built:             Wed Jun  2 11:56:40 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.8
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.16.6
  Git commit:       75249d8
  Built:            Fri Jul 30 19:52:16 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.9
  GitCommit:        e25210fe30a0a703442421b0f60afac609f950a3
 runc:
  Version:          1.0.1
  GitCommit:        v1.0.1-0-g4144b63
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

If I build it in Codebuild it does not starts:

/app/build/env.sh: 4: /app/build/env.sh: cannot create ./env-config.js: Permission denied

This is the image I am using in codebuild: aws/codebuild/amazonlinux2-x86_64-standard:3.0

I have also run the same script in local and still no error.

What could be the cause of this? If you have something in mind please let me know, otherwise I will post more code

This is my env.sh

#!/usr/bin/env sh

# Add assignment
echo "window._env_ = {" > ./env-config.js

# Read each line in .env file
# Each line represents key=value pairs
while read -r line || [ -n "$line" ];
do
  echo "$line"
  # Split env variables by character `=`
  if printf '%sn' "$line" | grep -q -e '='; then
    varname=$(printf '%sn' "$line" | sed -e 's/=.*//')
    varvalue=$(printf '%sn' "$line" | sed -e 's/^[^=]*=//')
  fi

  # Read value of current variable if exists as Environment variable
  eval value="$"$varname""
  # Otherwise use value from .env file
  [ -z "$value" ] && value=${varvalue}

  echo name: "$varname", value: "$value"

  # Append configuration property to JS file
  echo "  $varname: "$value"," >> ./env-config.js
done < window.env

echo "}" >> ./env-config.js

buildspec:

version: 0.2
env:
  git-credential-helper: yes
  secrets-manager:
    GITHUB_TOKEN: "github:GITHUB_TOKEN"

phases:
  install:
    runtime-versions:
      nodejs: 12
    commands:
      - npm install
  build:
    commands:
      - echo Build started on `date`
      - GITHUB_USERNAME=${GITHUB_USERNAME} GITHUB_EMAIL=${GITHUB_EMAIL} GITHUB_TOKEN=${GITHUB_TOKEN} AWS_REGION=${AWS_DEFAULT_REGION} GITHUB_REPOSITORY_URL=${GITHUB_REPOSITORY_URL} ECR_REPOSITORY_URL=${ECR_REPOSITORY_URL} ENV=${ENV} node release.js

My build project terraform configuration:

resource "aws_codebuild_project" "dashboard_image" {
  name = var.project.name
  service_role = var.codebuild_role_arn
  artifacts {
    type = "CODEPIPELINE"
  }
  environment {
    compute_type = "BUILD_GENERAL1_SMALL"
    image = "aws/codebuild/amazonlinux2-x86_64-standard:3.0"
    type = "LINUX_CONTAINER"
    privileged_mode = true

    environment_variable {
      name = "GITHUB_REPOSITORY_URL"
      value = "https://github.com/${var.project.github_organization_name}/${var.project.github_repository_name}.git"
    }

    environment_variable {
      name = "ECR_REPOSITORY_URL"
      value = var.project.ecr_repository_url
    }

    environment_variable {
      name = "ECR_IMAGE_NAME"
      value = var.project.ecr_image_name
    }

    environment_variable {
      name = "ENV"
      value = "prod"
    }
  }
  source {
    type = "CODEPIPELINE"
    buildspec = "buildspec.yml"
  }
}