No input size limits: CLI accepts arbitrarily long arguments risking oversized payload RPC DoS

[ALLEN-AYODEJI]

Description

rpc.rs and commands/mod.rs place no length limits on user-supplied strings (agreement_id, proof_uri, addresses). An attacker could provide a 1MB agreement_id string, which would be passed to the stellar CLI and submitted as a contract argument. Large contract arguments increase Soroban resource usage and could cause out-of-gas failures or RPC rejection.

Requirements and context

• Security: Standard security review required for state-mutating changes
• Testing: Full test suite must pass; new tests for changed behavior
• Documentation: Update doc comments and README if user-facing

Suggested execution

Branch: fix/fix/security-input-limits

Implement changes

• Define maximum lengths: agreement_id (64 hex chars max), proof_uri (2048 chars), addresses (56 chars for Stellar keys)
• Add validation in config.rs or a new input.rs module that checks all string inputs against limits
• Return a clear error: 'Input exceeds maximum length of X characters'
• Apply validation in every command before passing to rpc.rs

Test and commit

Test with oversized agreement_id (65+ chars) — verify clear error. Test with oversized proof_uri. Test with valid inputs — no regression. Run cargo test.

Example commit message

fix(security): enforce strict input length limits on all CLI arguments to prevent oversized payload DoS

Guidelines

• Open a PR against master
• Keep PR focused on this single concern
• Run cargo test or npm test before review
• Ensure no lint or typecheck warnings