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Fix Heki patch index/offset calculation bugs #732

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Merged
sangho2 merged 1 commit into from
Mar 17, 2026
Merged

Fix Heki patch index/offset calculation bugs #732

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35 changes: 20 additions & 15 deletions litebox_platform_lvbs/src/mshv/vsm.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -889,13 +889,12 @@ fn apply_vtl0_text_patch(heki_patch: HekiPatch) -> Result<(), VsmError> {
return Err(VsmError::Vtl0CopyFailed);
}
} else {
let (patch_first, patch_second) = heki_patch.code.split_at(bytes_in_first_page);
let (patch_first, patch_second) =
heki_patch.code[..usize::from(heki_patch.size)].split_at(bytes_in_first_page);

unsafe {
if !crate::platform_low().copy_slice_to_vtl0_phys(
heki_patch_pa_0 + patch_target_page_offset as u64,
patch_first,
) || !crate::platform_low().copy_slice_to_vtl0_phys(heki_patch_pa_1, patch_second)
if !crate::platform_low().copy_slice_to_vtl0_phys(heki_patch_pa_0, patch_first)
|| !crate::platform_low().copy_slice_to_vtl0_phys(heki_patch_pa_1, patch_second)
{
return Err(VsmError::Vtl0CopyFailed);
}
Expand Down Expand Up @@ -1683,24 +1682,30 @@ impl PatchDataMap {

// the buffer looks like below:
// [`HekiPatchInfo`, [`HekiPatch`, ...], `HekiPatchInfo`, [`HekiPatch`, ...], ...]
// each `HekiPatchInfo` contains the number of `HekiPatch` structures (`patch_index`) that follow it.
// Each `HekiPatchInfo`'s `patch_index` field specifies the number of `HekiPatch` entries that follow it.
// The buffer may have trailing bytes (from page-aligned VTL0 ranges) that don't form a valid record.
let mut index: usize = 0;
while index <= patch_info_buf.len() - core::mem::size_of::<HekiPatchInfo>() {
let patch_info = HekiPatchInfo::try_from_bytes(
while index + core::mem::size_of::<HekiPatchInfo>() <= patch_info_buf.len() {
let Some(patch_info) = HekiPatchInfo::try_from_bytes(
&patch_info_buf[index..index + core::mem::size_of::<HekiPatchInfo>()],
)
.ok_or(PatchDataMapError::InvalidHekiPatchInfo)?;
) else {
// Remaining bytes don't form a valid header. End of meaningful patch data.
break;
};

let patch_index: usize = patch_info.patch_index.truncate();
let total_patch_size = core::mem::size_of::<HekiPatch>()
.checked_mul(patch_index)
.ok_or(PatchDataMapError::InvalidHekiPatchInfo)?;
index = index
.checked_add(core::mem::size_of::<HekiPatchInfo>() + total_patch_size)
.filter(|&x| x <= patch_info_buf.len())
let patches_start = index
.checked_add(core::mem::size_of::<HekiPatchInfo>())
.ok_or(PatchDataMapError::InvalidHekiPatchInfo)?;
let patches_end = patches_start
.checked_add(total_patch_size)
.filter(|&end| end <= patch_info_buf.len())
.ok_or(PatchDataMapError::InvalidHekiPatchInfo)?;

for patch in patch_info_buf[index - total_patch_size..index]
for patch in patch_info_buf[patches_start..patches_end]
.chunks(core::mem::size_of::<HekiPatch>())
.map(HekiPatch::try_from_bytes)
{
Expand Down Expand Up @@ -1745,7 +1750,7 @@ impl PatchDataMap {
}
}
}
index += total_patch_size;
index = patches_end;
}

Ok(())
Expand Down
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