Metadata

Id: dockerfile-using-platform-with-from

Platform: Dockerfile

Severity: Low

Category: Best Practices

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Description

FROM instructions in Dockerfiles must not include the --platform flag. Overriding the target platform in the Dockerfile can cause builds to pull different, potentially unvetted or incompatible image variants, undermining image provenance, scanning, and supply-chain controls.

This rule checks FROM instructions and flags any use of the --platform flag. FROM lines should reference the intended image and tag without the --platform option. If a specific architecture is required, configure the build environment or manifest resolution outside the Dockerfile instead of embedding --platform in the instruction.

Secure example:

FROM ubuntu:20.04

Compliant Code Examples

FROM alpine:3.5
RUN apk add --update py2-pip
RUN pip install --upgrade pip
LABEL maintainer="SvenDowideit@home.org.au"
COPY requirements.txt /usr/src/app/
FROM baseimage as baseimage-build

Non-Compliant Code Examples

FROM alpine:3.5
RUN apk add --update py2-pip
RUN pip install --upgrade pip
LABEL maintainer="SvenDowideit@home.org.au"
COPY requirements.txt /usr/src/app/
FROM --platform=arm64 baseimage as baseimage-build