fix: zizmor issue: Resolve template injection vulnerabilities in podvm_mkosi.yaml#3103
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Move all template expressions from inline usage to environment variables to prevent code injection attacks. This fixes 6 template injection vulnerabilities identified by zizmor security scanner. Changes: - Move inputs.registry to REGISTRY environment variable (lines 174, 221) - Move inputs.arch to ARCH environment variable (line 178) - Move inputs.image_tag to IMAGE_TAG environment variable (lines 183, 184) - Add REGISTRY, ARCH, and IMAGE_TAG to env block for proper sanitization All template expressions are now properly sanitized by GitHub Actions through environment variables instead of direct inline usage. Verified with: zizmor .github/workflows/podvm_mkosi.yaml Result: No findings to report Signed-off-by: siddaram-sonnagi <siddaram.sonnagi@ibm.com>
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This PR fixes 6 template injection vulnerabilities identified by zizmor security scanner.
Problem:
The workflow was directly interpolating user-controlled inputs (inputs.registry, inputs.arch, and inputs.image_tag) into shell commands without proper sanitization. This creates a security risk where malicious input containing shell meta characters could potentially be used for command injection attacks.
Vulnerable code locations:
Line 174: image=${{ inputs.registry }}/podvm-generic-fedora - Direct interpolation in shell variable
Line 178: image=${image}-${{ inputs.arch }} - Direct interpolation in shell variable
Line 183: if [ -n "${{ inputs.image_tag }}" ] && [ "${{ inputs.image_tag }}" != "${tag}" ] - Direct interpolation in conditional (2 occurrences)
Line 184: oras push "${image}:${{ inputs.image_tag }}" - Direct interpolation in oras command
Line 221: echo "image=${{ inputs.registry }}/podvm-docker-image-${arch}:${tag}" - Direct interpolation in output variable
Solution
Following GitHub Actions security best practices, all template expressions have been moved to environment variables in the env: block. GitHub Actions automatically escapes environment variable values, preventing injection attacks.
Changes made:
Added env: block to the "Upload the qcow2 with oras" step with:
REGISTRY: ${{ inputs.registry }}
ARCH: ${{ inputs.arch }}
IMAGE_TAG: ${{ inputs.image_tag }}
Replaced all direct template expressions with environment variable references:
${{ inputs.registry }} → ${REGISTRY} (2 occurrences)
${{ inputs.arch }} → ${ARCH} (1 occurrence)
${{ inputs.image_tag }} → ${IMAGE_TAG} (3 occurrences)
Testing:
Workflow syntax is valid
No functional changes to the workflow behavior
Security vulnerabilities are resolved (verified with zizmor: "No findings to report")
References:
Zizmor Documentation: https://docs.zizmor.sh/audits/#template-injection
Reference PR: #2641
Security Impact:
This change eliminates potential command injection vulnerabilities while maintaining the same functionality. The workflow will continue to work exactly as before, but with improved security posture.