Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

fix(EVM): Do not check memory boundaries if size is zero #1114

Merged
merged 1 commit into from
Dec 4, 2024
Merged

fix(EVM): Do not check memory boundaries if size is zero #1114

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
84 changes: 54 additions & 30 deletions system-contracts/contracts/EvmEmulator.yul
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -280,10 +280,12 @@ object "EvmEmulator" {
}

function checkMemIsAccessible(relativeOffset, size) {
checkOverflow(relativeOffset, size)
if size {
checkOverflow(relativeOffset, size)

if gt(add(relativeOffset, size), MAX_POSSIBLE_MEM_LEN()) {
panic()
if gt(add(relativeOffset, size), MAX_POSSIBLE_MEM_LEN()) {
panic()
}
}
}

Expand Down Expand Up @@ -2676,14 +2678,17 @@ object "EvmEmulator" {
offset, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)
size, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)

checkMemIsAccessible(offset, size)
if size {
checkMemIsAccessible(offset, size)

evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

returnLen := size

// Don't check overflow here since previous checks are enough to ensure this is safe
returnOffset := add(MEM_OFFSET(), offset)
}

returnLen := size

// Don't check overflow here since previous checks are enough to ensure this is safe
returnOffset := add(MEM_OFFSET(), offset)
break
}
case 0xF4 { // OP_DELEGATECALL
Expand All @@ -2710,12 +2715,19 @@ object "EvmEmulator" {
popStackCheck(sp, 2)
offset, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)
size, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)

checkMemIsAccessible(offset, size)
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

// Don't check overflow here since previous checks are enough to ensure this is safe
offset := add(offset, MEM_OFFSET())

switch iszero(size)
case 0 {
checkMemIsAccessible(offset, size)
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

// Don't check overflow here since previous checks are enough to ensure this is safe
offset := add(offset, MEM_OFFSET())
}
default {
offset := MEM_OFFSET()
}


if eq(isCallerEVM, 1) {
offset := sub(offset, 32)
Expand Down Expand Up @@ -3340,10 +3352,12 @@ object "EvmEmulator" {
}

function checkMemIsAccessible(relativeOffset, size) {
checkOverflow(relativeOffset, size)
if size {
checkOverflow(relativeOffset, size)

if gt(add(relativeOffset, size), MAX_POSSIBLE_MEM_LEN()) {
panic()
if gt(add(relativeOffset, size), MAX_POSSIBLE_MEM_LEN()) {
panic()
}
}
}

Expand Down Expand Up @@ -5736,14 +5750,17 @@ object "EvmEmulator" {
offset, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)
size, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)

checkMemIsAccessible(offset, size)
if size {
checkMemIsAccessible(offset, size)

evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

returnLen := size

// Don't check overflow here since previous checks are enough to ensure this is safe
returnOffset := add(MEM_OFFSET(), offset)
}

returnLen := size

// Don't check overflow here since previous checks are enough to ensure this is safe
returnOffset := add(MEM_OFFSET(), offset)
break
}
case 0xF4 { // OP_DELEGATECALL
Expand All @@ -5770,12 +5787,19 @@ object "EvmEmulator" {
popStackCheck(sp, 2)
offset, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)
size, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)

checkMemIsAccessible(offset, size)
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

// Don't check overflow here since previous checks are enough to ensure this is safe
offset := add(offset, MEM_OFFSET())

switch iszero(size)
case 0 {
checkMemIsAccessible(offset, size)
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

// Don't check overflow here since previous checks are enough to ensure this is safe
offset := add(offset, MEM_OFFSET())
}
default {
offset := MEM_OFFSET()
}


if eq(isCallerEVM, 1) {
offset := sub(offset, 32)
Expand Down
8 changes: 5 additions & 3 deletions system-contracts/evm-emulator/EvmEmulatorFunctions.template.yul
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -218,10 +218,12 @@ function expandMemory2(retOffset, retSize, argsOffset, argsSize) -> maxExpand {
}

function checkMemIsAccessible(relativeOffset, size) {
checkOverflow(relativeOffset, size)
if size {
checkOverflow(relativeOffset, size)

if gt(add(relativeOffset, size), MAX_POSSIBLE_MEM_LEN()) {
panic()
if gt(add(relativeOffset, size), MAX_POSSIBLE_MEM_LEN()) {
panic()
}
}
}

Expand Down
34 changes: 22 additions & 12 deletions system-contracts/evm-emulator/EvmEmulatorLoop.template.yul
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1454,14 +1454,17 @@ for { } true { } {
offset, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)
size, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)

checkMemIsAccessible(offset, size)
if size {
checkMemIsAccessible(offset, size)

evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

returnLen := size

// Don't check overflow here since previous checks are enough to ensure this is safe
returnOffset := add(MEM_OFFSET(), offset)
}

returnLen := size

// Don't check overflow here since previous checks are enough to ensure this is safe
returnOffset := add(MEM_OFFSET(), offset)
break
}
case 0xF4 { // OP_DELEGATECALL
Expand All @@ -1488,12 +1491,19 @@ for { } true { } {
popStackCheck(sp, 2)
offset, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)
size, sp, stackHead := popStackItemWithoutCheck(sp, stackHead)

checkMemIsAccessible(offset, size)
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

// Don't check overflow here since previous checks are enough to ensure this is safe
offset := add(offset, MEM_OFFSET())

switch iszero(size)
case 0 {
checkMemIsAccessible(offset, size)
evmGasLeft := chargeGas(evmGasLeft, expandMemory(offset, size))

// Don't check overflow here since previous checks are enough to ensure this is safe
offset := add(offset, MEM_OFFSET())
}
default {
offset := MEM_OFFSET()
}


if eq(isCallerEVM, 1) {
offset := sub(offset, 32)
Expand Down
Loading