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[NFC][asan] Simplify __sanitizer_annotate_contiguous_container

This commit is contained in:
Vitaly Buka 2022-11-18 00:54:21 -08:00
parent bfa3551dd3
commit d13dd10da0
1 changed files with 25 additions and 24 deletions
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49
compiler-rt/lib/asan/asan_poisoning.cpp
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@ -398,49 +398,48 @@ void __sanitizer_annotate_contiguous_container(const void *beg_p,
if (UNLIKELY(!AddrIsAlignedByGranularity(end))) {
uptr end_down = RoundDownTo(end, granularity);
// Either new or old mid must be in the granule to affect it.
if (new_mid > end_down) {
if (new_mid > end_down || old_mid > end_down) {
// Do nothing if the byte after the container is unpoisoned. Asan can't
// poison only the begining of the granule.
if (AddressIsPoisoned(end)) {
*(u8 *)MemToShadow(end_down) = static_cast<u8>(new_mid - end_down);
} else {
// Something after the container - don't touch.
}
} else if (old_mid > end_down) {
if (AddressIsPoisoned(end)) {
*(u8 *)MemToShadow(end_down) = kAsanContiguousContainerOOBMagic;
} else {
// Something after the container - don't touch.
*(u8 *)MemToShadow(end_down) = new_mid > end_down
? static_cast<u8>(new_mid - end_down)
: kAsanContiguousContainerOOBMagic;
}
old_mid = Min(end_down, old_mid);
new_mid = Min(end_down, new_mid);
if (old_mid == new_mid)
return;
}
if (beg >= end_down)
return; // Same granule.
old_mid = Min(end_down, old_mid);
new_mid = Min(end_down, new_mid);
end = end_down;
}
// Handle misaligned begin and cut it off.
if (UNLIKELY(!AddrIsAlignedByGranularity(beg))) {
uptr beg_up = RoundUpTo(beg, granularity);
uptr beg_down = RoundDownTo(beg, granularity);
// As soon as we add first byte into container we will not be able to
// determine the state of the byte before the container. So we assume it's
// always unpoison.
// Either new or old mid must be in the granule to affect it.
if (new_mid < beg_up) {
*(u8 *)MemToShadow(beg_down) = static_cast<u8>(new_mid - beg_down);
} else if (old_mid < beg_up) {
*(u8 *)MemToShadow(beg_down) = 0;
if (new_mid < beg_up || old_mid < beg_up) {
uptr beg_down = RoundDownTo(beg, granularity);
*(u8 *)MemToShadow(beg_down) =
new_mid < beg_up ? static_cast<u8>(new_mid - beg_down) : 0;
old_mid = Max(beg_up, old_mid);
new_mid = Max(beg_up, new_mid);
if (old_mid == new_mid)
return;
}
old_mid = Max(beg_up, old_mid);
new_mid = Max(beg_up, new_mid);
beg = beg_up;
}
if (old_mid == new_mid)
return;
uptr a = RoundDownTo(Min(old_mid, new_mid), granularity);
uptr c = RoundUpTo(Max(old_mid, new_mid), granularity);
uptr d1 = RoundDownTo(old_mid, granularity);
@ -463,8 +462,10 @@ void __sanitizer_annotate_contiguous_container(const void *beg_p,
uptr b2 = RoundUpTo(new_mid, granularity);
// New state:
// [a, b1) is good, [b2, c) is bad, [b1, b2) is partially good.
PoisonShadow(a, b1 - a, 0);
PoisonShadow(b2, c - b2, kAsanContiguousContainerOOBMagic);
if (b1 > a)
PoisonShadow(a, b1 - a, 0);
else if (c > b2)
PoisonShadow(b2, c - b2, kAsanContiguousContainerOOBMagic);
if (b1 != b2) {
CHECK_EQ(b2 - b1, granularity);
*(u8 *)MemToShadow(b1) = static_cast<u8>(new_mid - b1);