[MTE] Cleanup tagged si_addr refs to fix mappings OOB bug.
Currently, all MTE failures end up displaying 'Fault address falls at
0x<addr> after any mapped regions'. Clearly when scanning, we should use
the untagged address to figure out which ranges it's in.
I've taken the liberty of removing all si_addr parsing and moving it
into the common ProcessInfo, as well as making it really explicit
whether you want the (possibly tagged) original si_addr, or whether you
want the untagged variant (for scanning /proc/maps or whatever).
This is not particularly easily testable, as ReadCrashInfo isn't easily
injectable and `dump_all_maps` should already be passed the untagged
pointer to scan for. I've tested this locally on FVP under SYNC MTE with
a simple UaF binary and noted the problem is fixed. Given that this is
making the code more clear, I'm hoping the owners see no need for a
regression test :).
Bug: 135772972
Test: On FVP, run 'adb shell MEMTAG_OPTIONS=sync sanitizer-status' and
check that the use-after-free test ends up with the /proc/maps
desription in the right place.
Change-Id: I220e4200c75a72474a95a67e5bbc36173a438dd2
diff --git a/debuggerd/libdebuggerd/scudo.cpp b/debuggerd/libdebuggerd/scudo.cpp
index f8bfe07..141c3bd 100644
--- a/debuggerd/libdebuggerd/scudo.cpp
+++ b/debuggerd/libdebuggerd/scudo.cpp
@@ -44,7 +44,7 @@
auto region_info = AllocAndReadFully(process_memory, process_info.scudo_region_info,
__scudo_get_region_info_size());
- untagged_fault_addr_ = untag_address(process_info.fault_address);
+ untagged_fault_addr_ = process_info.untagged_fault_address;
uintptr_t fault_page = untagged_fault_addr_ & ~(PAGE_SIZE - 1);
uintptr_t memory_begin = fault_page - PAGE_SIZE * 16;
@@ -67,7 +67,7 @@
memory_tags[(i - memory_begin) / kTagGranuleSize] = process_memory->ReadTag(i);
}
- __scudo_get_error_info(&error_info_, process_info.fault_address, stack_depot.get(),
+ __scudo_get_error_info(&error_info_, process_info.maybe_tagged_fault_address, stack_depot.get(),
region_info.get(), memory.get(), memory_tags.get(), memory_begin,
memory_end - memory_begin);
}