Little Aquamarine Jellyfish - Potential Loss of Precision in Swap Amount Conversion

[sherlock-admin4]

Little Aquamarine Jellyfish

High

Potential Loss of Precision in Swap Amount Conversion

Summary

The swap function in swap.rs converts the to_amount from u128 to u64, which could lead to a loss of precision or overflow for large swap amounts.

Relevant links

https://github.com/sherlock-audit/2024-08-woofi-solana-deployment/blob/main/WOOFi_Solana/programs/woofi/src/instructions/swap.rs#L96-L226

Description

In the swap function, the to_amount is calculated as a u128 value but is then cast to u64 when passing it to the transfer_from_vault_to_owner function. This conversion could potentially truncate the value if it exceeds the maximum value of u64 (18,446,744,073,709,551,615).

Impact

This issue could lead to several problems:

1. For very large swap amounts, the truncation could result in a significant loss of funds for the user.

2. It may cause unexpected behavior in the protocol, as the actual transferred amount might be less than what was calculated and expected.

3. It could potentially be exploited by malicious actors to manipulate swap outcomes in their favor.

Code snippet

    transfer_from_vault_to_owner(
    woopool_to,
    token_vault_to,
    token_to_account,
    &ctx.accounts.token_program,
    to_amount as u64,
)?;

Recommendation

Implement a check to ensure that the to_amount does not exceed the maximum value of u64 before the conversion.

Add explicit error handling for cases where the amount exceeds u64 capacity. Example implementation:

    if to_amount > u64::MAX as u128 {
    return Err(ErrorCode::AmountExceedsU64Max.into());
    }

    transfer_from_vault_to_owner(
        woopool_to,
        token_vault_to,
        token_to_account,
        &ctx.accounts.token_program,
        to_amount as u64,
    )?;