Security: Fix 3 critical AMM vulnerabilities (LP inflation attack, swap logic bugs) - #1
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…c bugs Three critical vulnerabilities found and fixed in the AMM program: 1. CRITICAL: First-depositor LP inflation attack (fund loss) - No minimum liquidity lock on first deposit - Attacker can steal all subsequent depositors' funds - Fix: Lock MINIMUM_LIQUIDITY (1000) on first deposit (Uniswap V2 pattern) 2. CRITICAL: Swap formula uses inverted reserves - from_reserve and to_reserve swapped in calculation - Results in incorrect swap amounts (users get wrong output) - Fix: Use output_reserve in numerator, input_reserve in denominator 3. CRITICAL: Swap token routing sends to wrong reserves - User's input tokens sent to output reserve (mint mismatch = always reverts) - Output tokens sent from input reserve (mint mismatch = always reverts) - Fix: Route input tokens to input_reserve, output from output_reserve
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Security Audit: Critical AMM Vulnerabilities
Summary
An audit of the AMM program revealed 3 critical vulnerabilities that can lead to loss of user funds and broken swap functionality.
Vulnerability 1: First-Depositor LP Inflation Attack (CRITICAL - Fund Loss)
Location:
amm/programs/amm/src/instructions/deposit.rsDescription: The first liquidity provider receives LP tokens equal to
sqrt(quantity_a * quantity_b)with no minimum liquidity lock. This enables a classic inflation attack:Attack Scenario:
9999/10001 * 1 = 0(integer division rounds down)Impact: Complete loss of funds for any depositor after the attacker.
Fix: Lock
MINIMUM_LIQUIDITY = 1000LP tokens permanently on first deposit (Uniswap V2 pattern).Vulnerability 2: Swap Formula Uses Inverted Reserves (CRITICAL)
Location:
amm/programs/amm/src/instructions/swap.rsDescription: The constant product formula has
from_reserveandto_reserveswapped, producing incorrect output amounts.Fix: Use
output_reserve * amountIn / (input_reserve + amountIn).Vulnerability 3: Swap Token Routing Sends to Wrong Reserves (CRITICAL - DoS)
Location:
amm/programs/amm/src/instructions/swap.rsDescription: Swap transfers input tokens to the output reserve (mint mismatch), causing all swaps to always revert.
Fix: Route input tokens to input_reserve, output tokens from output_reserve.