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[ASan]Fix logic bugs that break RestrictMemoryToMaxAddress (#124712) #9991

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Merged
merged 1 commit into from
Feb 11, 2025
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[ASan]Fix logic bugs that break RestrictMemoryToMaxAddress (#124712) #9991

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16 changes: 11 additions & 5 deletions compiler-rt/lib/sanitizer_common/sanitizer_mac.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1195,13 +1195,14 @@ uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
const uptr left_padding =
Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);

uptr space_size = shadow_size_bytes + left_padding;
uptr space_size = shadow_size_bytes;

uptr largest_gap_found = 0;
uptr max_occupied_addr = 0;

VReport(2, "FindDynamicShadowStart, space_size = %p\n", (void *)space_size);
uptr shadow_start =
FindAvailableMemoryRange(space_size, alignment, granularity,
FindAvailableMemoryRange(space_size, alignment, left_padding,
&largest_gap_found, &max_occupied_addr);
// If the shadow doesn't fit, restrict the address space to make it fit.
if (shadow_start == 0) {
Expand All @@ -1221,9 +1222,9 @@ uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
}
RestrictMemoryToMaxAddress(new_max_vm);
high_mem_end = new_max_vm - 1;
space_size = (high_mem_end >> shadow_scale) + left_padding;
space_size = (high_mem_end >> shadow_scale);
VReport(2, "FindDynamicShadowStart, space_size = %p\n", (void *)space_size);
shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
shadow_start = FindAvailableMemoryRange(space_size, alignment, left_padding,
nullptr, nullptr);
if (shadow_start == 0) {
Report("Unable to find a memory range after restricting VM.\n");
Expand Down Expand Up @@ -1264,10 +1265,15 @@ uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
mach_msg_type_number_t count = kRegionInfoSize;
kr = mach_vm_region_recurse(mach_task_self(), &address, &vmsize, &depth,
(vm_region_info_t)&vminfo, &count);
if (kr == KERN_INVALID_ADDRESS) {

// There are cases where going beyond the processes' max vm does
// not return KERN_INVALID_ADDRESS so we check for going beyond that
// max address as well.
if (kr == KERN_INVALID_ADDRESS || address > max_vm_address) {
// No more regions beyond "address", consider the gap at the end of VM.
address = max_vm_address;
vmsize = 0;
kr = -1; // break after this iteration.
} else {
if (max_occupied_addr) *max_occupied_addr = address + vmsize;
}
Expand Down