Root + Impact

Description

• The funding flow is intended to mint msg.value // share_price shares so every wei contributed by a public investor is exchanged for an equivalent stake.

• Contributions smaller than the computed share_price round new_shares down to zero, but the function still increases company_balance and emits SharesIssued, leaving the depositor with no shares.

Risk

Likelihood:

• Share price grows with each profitable cycle, so later investors often face valuations far above 1 wei and are likely to send dust tests or underpriced deposits.

• Wallet UX frequently allows arbitrary amounts, including rounding errors from front-end conversions, making sub-price deposits common.

Impact:

• Investors lose the entire contribution without receiving any shares.

• The protocol accrues unbacked equity entries that damage trust and invite regulatory scrutiny.

Proof of Concept

1. Ensure the share price is greater than the intended deposit (e.g., share_price = 1e15).

2. Call fund_investor with a smaller value (e.g., msg.value = 5e11).

3. new_shares evaluates to zero, the deposit is still credited to company_balance, and the sender's shares balance remains unchanged.

Recommended Mitigation

• Require msg.value >= share_price (or otherwise revert) so users must send at least enough to mint one share.

• Alternatively, track each investor's remainder and only finalize the contribution once the accumulated value crosses the share price.

• Immediately refund msg.value % share_price so callers automatically recover the excess portion of their payment.