forked from AbleOS/holey-bytes
Added runtime bound checking
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0f5d78bb27
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5055626968
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@ -59,14 +59,16 @@ macro_rules! gen_valider {
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let start = program;
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loop {
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use crate::opcode::*;
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extern crate std;
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program = match program {
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// End of program
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[] => return Ok(()),
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// Memory load/store cannot go out-of-bounds register array
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[LD..=ST, reg, _, _, _, _, _, _, _, _, count_0, count_1, ..]
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// B B D1 D2 D3 D4 D5 D6 D7 D8 H1 H2
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[LD..=ST, reg, _, _, _, _, _, _, _, _, _, count_0, count_1, ..]
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if usize::from(*reg) * 8
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+ usize::from(u16::from_le_bytes([*count_1, *count_0]))
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+ usize::from(u16::from_le_bytes([*count_0, *count_1]))
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> 2048 =>
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{
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return Err(Error {
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@ -215,6 +215,8 @@ impl<'a, PfHandler: HandlePageFault, const TIMER_QUOTIENT: usize>
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LD => {
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// Load. If loading more than register size, continue on adjecent registers
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let ParamBBDH(dst, base, off, count) = self.decode();
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ldst_bound_check(dst, count)?;
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let n: usize = match dst {
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0 => 1,
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_ => 0,
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@ -230,6 +232,8 @@ impl<'a, PfHandler: HandlePageFault, const TIMER_QUOTIENT: usize>
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ST => {
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// Store. Same rules apply as to LD
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let ParamBBDH(dst, base, off, count) = self.decode();
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ldst_bound_check(dst, count)?;
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self.memory.store(
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self.read_reg(base).cast::<u64>() + off,
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self.registers.as_ptr().add(usize::from(dst)).cast(),
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@ -250,6 +254,10 @@ impl<'a, PfHandler: HandlePageFault, const TIMER_QUOTIENT: usize>
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BRC => {
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// Block register copy
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let ParamBBB(src, dst, count) = self.decode();
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if src.checked_add(count).is_none() || dst.checked_add(count).is_none() {
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return Err(VmRunError::RegOutOfBounds);
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}
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core::ptr::copy(
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self.registers.get_unchecked(usize::from(src)),
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self.registers.get_unchecked_mut(usize::from(dst)),
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@ -394,6 +402,16 @@ impl<'a, PfHandler: HandlePageFault, const TIMER_QUOTIENT: usize>
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}
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}
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/// Load/Store target/source register range bound checking
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#[inline]
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fn ldst_bound_check(reg: u8, size: u16) -> Result<(), VmRunError> {
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if usize::from(reg) * 8 + usize::from(size) > 2048 {
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Err(VmRunError::RegOutOfBounds)
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} else {
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Ok(())
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}
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}
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/// Virtual machine halt error
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#[derive(Copy, Clone, Debug, PartialEq, Eq)]
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#[repr(u8)]
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@ -407,6 +425,9 @@ pub enum VmRunError {
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/// Unhandled store access exception
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StoreAccessEx(u64),
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/// Register out-of-bounds access
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RegOutOfBounds,
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/// Reached unreachable code
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Unreachable,
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}
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