fix(api): sign S3 report download URLs with Signature Version 4 - #12746
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pujitha24 wants to merge 2 commits into
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fix(api): sign S3 report download URLs with Signature Version 4#12746pujitha24 wants to merge 2 commits into
pujitha24 wants to merge 2 commits into
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Motivation: get_s3_client() in api/src/backend/tasks/jobs/export.py
builds its boto3 S3 client without an explicit signature_version.
boto3/botocore's presigned-URL query signer for S3 falls back to
Signature Version 2 unless Config(signature_version="s3v4") is passed
explicitly, even though the resolved client config otherwise reports
"s3v4". AWS S3 rejects SigV2 presigned requests against objects
encrypted with default SSE-KMS ("Requests specifying Server Side
Encryption with AWS KMS managed keys require AWS Signature Version
4."), so report downloads fail whenever the output bucket has default
SSE-KMS encryption enabled, despite valid credentials and an
accessible object.
Approach: pin config=Config(signature_version="s3v4") on both
boto3.client("s3", ...) calls in get_s3_client() (the primary
credentialed path and the credential-less fallback), so
generate_presigned_url always emits a proper SigV4 URL. Adds
test_get_s3_client_generates_sigv4_presigned_url to
api/src/backend/tasks/tests/test_export.py, which exercises a real
(unmocked) boto3 client through get_s3_client() -- only stubbing the
network-dependent list_buckets() credential check -- and asserts the
real generate_presigned_url() output contains
X-Amz-Algorithm=AWS4-HMAC-SHA256. Adds a changelog fragment at
api/changelog.d/s3-report-download-sigv4.fixed.md.
Validation: independently reproduced the exact defect and fix using
the dependency versions this repo pins (botocore==1.40.61,
boto3==1.40.61, matching the issue reporter's environment) in an
isolated Python environment, calling the same boto3.client(...)
construction get_s3_client() uses. Without
config=Config(signature_version="s3v4"), generate_presigned_url
produced a SigV2 URL (AWSAccessKeyId=...&Signature=...&Expires=...);
with it added, the same call produced a SigV4 URL
(X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=...) -- the exact
fail-before/pass-after behavior the new test asserts. Could not run
this repo's own pytest/Django test suite (including the new test)
because it requires a live PostgreSQL 16 instance normally started
via docker compose, and this sandbox has neither docker nor enough
free disk space to provision one; ruff, pylint, and uv sync could not
be run here for the same reason. The new test was traced by hand
against the reproduction above and believed correct, but was not
executed through pytest in this environment.
Report: prowler-cloud#12734
Signed-off-by: Pujitha Paladugu <10557236+pujitha24@users.noreply.github.com>
Assisted-by: claude-sonnet-5 (via Claude Code)
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✅ No Conflicts No conflict markers, and the branch merges cleanly into its base. |
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No actionable comments were generated in the recent review. 🎉 ℹ️ Recent review info⚙️ Run configurationConfiguration used: Organization UI Review profile: ASSERTIVE Plan: Team Run ID: 📒 Files selected for processing (1)
Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review. 📝 WalkthroughWalkthroughThe export job configures credentialed and fallback S3 clients to use AWS Signature Version 4. Tests verify generated GetObject presigned URLs. The changelog documents the SSE-KMS report download fix. ChangesS3 SigV4 report downloads
Estimated code review effort: 2 (Simple) | ~10 minutes Merge Risk: ⚪ Minimal · up to Report-download URLs now consistently use SigV4, allowing downloads from SSE-KMS-encrypted S3 buckets while retaining the existing credentialed and task-role fallback flows. No current merge-blocking risk is identified. Suggested reviewers: 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
✨ Finishing Touches🧪 Generate unit tests (beta)
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Inline comments:
In `@api/src/backend/tasks/tests/test_export.py`:
- Line 64: Update the test’s client setup around create_client so it uses an
unpatched boto3 client factory, avoiding the patched
tasks.jobs.export.boto3.client mock and its recursive invocation while
preserving the existing URL-generation assertions.
- Line 70: Update test_get_s3_client_generates_sigv4_presigned_url to use an
unpatched boto3 client factory within the mock side effect, avoiding recursive
calls while preserving URL generation. Strengthen test_get_s3_client_fallback to
assert the generated URL contains X-Amz-Algorithm=AWS4-HMAC-SHA256, ensuring the
fallback still uses the SigV4 configuration.
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Review profile: ASSERTIVE
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Run ID: aa3a815a-8463-4f42-a490-d765c46ed273
📒 Files selected for processing (3)
api/changelog.d/s3-report-download-sigv4.fixed.mdapi/src/backend/tasks/jobs/export.pyapi/src/backend/tasks/tests/test_export.py
Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.
… export tests test_get_s3_client_generates_sigv4_presigned_url called boto3.client() from within its own side_effect while boto3.client itself was patched, causing infinite recursion. Build the real client via boto3.Session().client() instead. Also strengthen test_get_s3_client_fallback to assert the credential-less fallback path still produces a SigV4 presigned URL, rather than only checking the client is not None. Signed-off-by: Pujitha Paladugu <10557236+pujitha24@users.noreply.github.com>
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Context
Prowler App report downloads redirect the browser to a presigned S3
GetObjectURL generated byget_s3_client()inapi/src/backend/tasks/jobs/export.py. That function builds itsboto3S3 client without an explicitsignature_version. Even though the resolved client config reportssignature_version="s3v4", boto3/botocore's presigned-URL query signer for S3 still falls back to Signature Version 2 (AWSAccessKeyId=...&Signature=...&Expires=...) unlessConfig(signature_version="s3v4")is passed explicitly — this is a long-standing boto3/botocore quirk specific togenerate_presigned_url, separate from normal request signing.AWS S3 rejects SigV2 presigned requests for objects encrypted with SSE-KMS:
InvalidArgument: Requests specifying Server Side Encryption with AWS KMS managed keys require AWS Signature Version 4.So report downloads fail whenever the output bucket uses default SSE-KMS encryption, even though the object itself is accessible and the credentials are valid.
Description
Explicitly pins
config=Config(signature_version="s3v4")on bothboto3.client("s3", ...)calls inget_s3_client()(the primary credentialed path and the credential-less fallback), sogenerate_presigned_urlalways emits a proper SigV4 (X-Amz-Algorithm=AWS4-HMAC-SHA256...) URL. No settings, defaults, or public API change; only the client construction insideget_s3_client()is touched.Adds
test_get_s3_client_generates_sigv4_presigned_urltoapi/src/backend/tasks/tests/test_export.py, which builds a real (unmocked) S3 client throughget_s3_client()— only stubbing out the network-dependentlist_buckets()credential check — and asserts the realgenerate_presigned_url()output containsX-Amz-Algorithm=AWS4-HMAC-SHA256.Adds a changelog fragment at
api/changelog.d/s3-report-download-sigv4.fixed.md.Validation
botocore==1.40.61,boto3==1.40.61, matching the issue reporter's environment) in an isolated Python environment, calling the sameboto3.client(...)constructionget_s3_client()uses:config=Config(signature_version="s3v4"):generate_presigned_url("get_object", ...)producedhttps://.../report.zip?AWSAccessKeyId=...&Signature=...&Expires=...(SigV2 — reproduces the reported defect).config=Config(signature_version="s3v4")added: it producedhttps://.../report.zip?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=...(SigV4 — confirms the fix). This is the exact fail-before/pass-after behavior the new test asserts.pytest/Django test suite (including the new test), because it requires a live PostgreSQL 16 instance (normally started withdocker compose up postgres valkey) and this sandbox has neitherdockernor enough free disk space to install/run one. For the same reason,uv sync,ruff, andpylintcould not be run here either. The new test was traced by hand against the reproduction above and is believed correct, but it was not executed through pytest in this environment.Steps to review
boto3.client("s3").generate_presigned_url(...)defaults to SigV2 for S3 unlessConfig(signature_version="s3v4")is passed explicitly, and AWS S3 requires SigV4 for presigned requests against SSE-KMS objects.get_s3_client()inapi/src/backend/tasks/jobs/export.py— both the try and except branches now pass the sames3_config.api/src/backend/tasks/tests/test_export.py; it uses a real (unmocked)boto3client so the signing behavior it asserts on is genuine, not mocked away.uv run pytest src/backend/tasks/tests/test_export.py -vfromapi/against a live PostgreSQL instance to confirm the new test passes; I was unable to do this locally (see Validation).Checklist
Community Checklist
SDK/CLI
UI
API
GET /api/v1/scans/{id}/report; the response shape and status codes are unchanged.MCP Server
License
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
Fixes #12734
Summary by CodeRabbit
InvalidArgumenterrors.