fix(awsutil): only set AssumeRole ExternalID when provided#186
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nomeelnoj wants to merge 1 commit into
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fix(awsutil): only set AssumeRole ExternalID when provided#186nomeelnoj wants to merge 1 commit into
nomeelnoj wants to merge 1 commit into
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The non-web-identity AssumeRole path set options.ExternalID unconditionally
via aws.String(c.RoleExternalId). When no external ID was configured this
produced a non-nil pointer to an empty string, which the SDK serializes as
ExternalId="" on the STS AssumeRole call. STS then rejects the request with
a ValidationError ("Member must have length greater than or equal to 2"),
breaking role assumption for any caller that does not use an external ID.
Guard the assignment so ExternalID is only set when a non-empty value is
provided, matching the existing empty-value handling for this field. Adds a
regression test covering AssumeRole without an external ID.
Signed-off-by: nomeelnoj <4316746+nomeelnoj@users.noreply.github.com>
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Summary
The non-web-identity AssumeRole path in
awsutil/generate_credentials.gosetoptions.ExternalIDunconditionally:When no external ID is configured,
aws.String("")is a non-nil pointer to an empty string, which the SDK serializes asExternalId=""on thests:AssumeRolecall. STS rejects it with:This breaks role assumption for any caller that does not use an external ID.
Fix
Only assign
ExternalIDwhen a non-empty value was provided. This matches the existing empty-value handling forRoleExternalIdelsewhere in the file (line 149) and leavesAssumeRoleOptions.ExternalIDasnilwhen unset, so noExternalIdparameter is sent to STS.Only the plain (non-web-identity) AssumeRole path is affected; the web-identity branches never set
ExternalID.Fixes: #185
Context
Surfaced downstream in
terraform-provider-vault(hashicorp/terraform-provider-vault#2922, fix in hashicorp/terraform-provider-vault#2923). The provider change stops routing non-web-identity assumption throughWithRoleArn, which incidentally avoids this code path; this PR fixes the underlying library defect so other consumers are protected.Notes for maintainers
awsutilmodule has noCHANGELOGfile, so no changelog entry was added. Happy to add one if you keep release notes elsewhere.CONTRIBUTING, flagging that this touches credential/AssumeRole behavior used across multiple products; reviewers from affected teams welcome. The change is intentionally minimal and behavior-preserving when an external ID is provided.PCI review checklist
If applicable, I've documented a plan to revert these changes if they require more than reverting the pull request.
If applicable, I've worked with GRC to document the impact of any changes to security controls.
Examples of changes to controls include access controls, encryption, logging, etc.
If applicable, I've worked with GRC to ensure compliance due to a significant change to the in-scope PCI environment.
Examples include changes to operating systems, ports, protocols, services, cryptography-related components, PII processing code, etc.