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Commit bf2d6dd7 authored by Mitch Phillips's avatar Mitch Phillips
Browse files

Update debuggerd for stack MTE. 

Two things need changing for debuggerd_test to pass.

 1. The seccomp policy needs to allow for PROT_MTE (0x20) in both
    mprotect() and mmap(). Stack MTE processes do a mprotect()/mmap() of
    the stack when launching a process.
 2. The fault address and stack pointer need to be untagged when trying
    to figure out the stack overflow cause.

Bug: 320448268
Bug: 292478827
Test: atest debuggerd_test --iterations=10
Change-Id: I56471c32ca40edffbb61b7547bdf2b85a6eb1ff7
parent 749e2e8e

debuggerd/libdebuggerd/tombstone_proto.cpp

+5 −0
Original line number Diff line number Diff line
@@ -94,6 +94,11 @@ static Architecture get_arch() { 


static std::optional<std::string> get_stack_overflow_cause(uint64_t fault_addr, uint64_t sp,

                                                           unwindstack::Maps* maps) {

  // Under stack MTE the stack pointer and/or the fault address can be tagged.

  // In order to calculate deltas between them, strip off the tags off both

  // addresses.

  fault_addr = untag_address(fault_addr);

  sp = untag_address(sp);

  static constexpr uint64_t kMaxDifferenceBytes = 256;

  uint64_t difference;

  if (sp >= fault_addr) {

debuggerd/seccomp_policy/crash_dump.arm64.policy

+2 −2
Original line number Diff line number Diff line
@@ -28,11 +28,11 @@ rt_sigaction: 1 
rt_tgsigqueueinfo: 1

prctl: arg0 == PR_GET_NO_NEW_PRIVS || arg0 == 0x53564d41 || arg0 == PR_PAC_RESET_KEYS || arg0 == 56 || arg0 == 61

madvise: 1

mprotect: arg2 in 0x1|0x2

mprotect: arg2 in 0x1|0x2|0x20

munmap: 1

getuid: 1

fstat: 1

mmap: arg2 in 0x1|0x2

mmap: arg2 in 0x1|0x2|0x20

geteuid: 1

getgid: 1

getegid: 1