LiquidityManager.sol

120:   struct AddLiquidityParams {
121:     address token0;
122:     address token1;
123:     uint256 token0Exp;
124:     uint256 token1Exp;
125:     uint256 upperBound;
126:     uint256 liquidity;
127:     uint256 amount0Min;
128:     uint256 amount1Min;
129:     uint256 sizeMin;
130:     address recipient;
131:     uint256 deadline;
132:   }
133:
134:   /// @notice Add liquidity to a liquidity position
135:   function addLiquidity(AddLiquidityParams calldata params) external payable checkDeadline(params.deadline) {
136:     address lendgine = LendgineAddress.computeAddress(
137:       factory, params.token0, params.token1, params.token0Exp, params.token1Exp, params.upperBound
138:     );
139:
140:     uint256 r0 = ILendgine(lendgine).reserve0();
141:     uint256 r1 = ILendgine(lendgine).reserve1();
142:     uint256 totalLiquidity = ILendgine(lendgine).totalLiquidity();
143:
144:     uint256 amount0;
145:     uint256 amount1;
146:
147:     if (totalLiquidity == 0) {
148:       amount0 = params.amount0Min;//@audit-info caller specifies the actual reserve amount
149:       amount1 = params.amount1Min;//@audit-info
150:     } else {
151:       amount0 = FullMath.mulDivRoundingUp(params.liquidity, r0, totalLiquidity);
152:       amount1 = FullMath.mulDivRoundingUp(params.liquidity, r1, totalLiquidity);
153:     }
154:
155:     if (amount0 < params.amount0Min || amount1 < params.amount1Min) revert AmountError();
156:
157:     uint256 size = ILendgine(lendgine).deposit(
158:       address(this),
159:       params.liquidity,
160:       abi.encode(
161:         PairMintCallbackData({
162:           token0: params.token0,
163:           token1: params.token1,
164:           token0Exp: params.token0Exp,
165:           token1Exp: params.token1Exp,
166:           upperBound: params.upperBound,
167:           amount0: amount0,
168:           amount1: amount1,
169:           payer: msg.sender
170:         })
171:       )
172:     );
173:     if (size < params.sizeMin) revert AmountError();
174:
175:     Position memory position = positions[params.recipient][lendgine]; // SLOAD
176:
177:     (, uint256 rewardPerPositionPaid,) = ILendgine(lendgine).positions(address(this));
178:     position.tokensOwed += FullMath.mulDiv(position.size, rewardPerPositionPaid - position.rewardPerPositionPaid, 1e18);
179:     position.rewardPerPositionPaid = rewardPerPositionPaid;
180:     position.size += size;
181:
182:     positions[params.recipient][lendgine] = position; // SSTORE
183:
184:     emit AddLiquidity(msg.sender, lendgine, params.liquidity, size, amount0, amount1, params.recipient);
185:   }
Pair.sol
52:   /// @inheritdoc IPair
53:   function invariant(uint256 amount0, uint256 amount1, uint256 liquidity) public view override returns (bool) {
54:     if (liquidity == 0) return (amount0 == 0 && amount1 == 0);
55:
56:     uint256 scale0 = FullMath.mulDiv(amount0, 1e18, liquidity) * token0Scale;
57:     uint256 scale1 = FullMath.mulDiv(amount1, 1e18, liquidity) * token1Scale;
58:
59:     if (scale1 > 2 * upperBound) revert InvariantError();
60:
61:     uint256 a = scale0 * 1e18;
62:     uint256 b = scale1 * upperBound;
63:     uint256 c = (scale1 * scale1) / 4;
64:     uint256 d = upperBound * upperBound;
65:
66:     return a + b >= c + d;//@audit-info if strict inequality holds, anyone can pull token0 using swap()
67:   }
