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Nice stack smashing postmortem message
Wire everything that relies on stack smashing detection to call __stack_chk_fail()
(aka what libssp / ssp / stack-protector uses) Expose it in our debugging header
Rename overflow -> smashing, as these are different things we are trying to detect (meaning, that we check for things writing there, not some kind of alloca
issue or the way -fstack-check
would have worked) ref. #8666
-fstack-protector
continues to work as it always did CONT replaces abort()
, also moves its check to the loop wrapper to avoid dumping otherwise useless SYS context memory StackThunk replaces a similar abort()
call
btw, something to reproduce failures
#include <Arduino.h>
#include <StackThunk.h>
#include <umm_malloc/umm_malloc.h>
#include <cont.h>
#include <user_interface.h>
#include <array>
// reproduce crash for all three methods, in sequence
constexpr uintptr_t RtcMem { 0x60001200 + 128 };
auto* count = reinterpret_cast<volatile uint32_t*>(RtcMem);
extern "C" rst_info resetInfo;
// there is only a single thunk in the app
extern "C" void thunk_failme();
extern "C" void failme() {
printf("will ravage %p\n", stack_thunk_ptr);
*stack_thunk_ptr = 0xfafafafa;
}
make_stack_thunk(failme)
// needs -fstack-protector to work
void ssp_failme() __attribute__((stack_protect));
void ssp_failme() {
char buf[4];
strcpy(buf, "ABCDE");
puts(buf);
}
void setup() {
Serial.begin(115200);
switch (resetInfo.reason) {
case REASON_DEFAULT_RST:
case REASON_EXT_SYS_RST:
*count = 0;
break;
}
}
void loop() {
const auto last = *count;
*count = ((last + 1) % 3);
puts("");
printf("%u - wait for it...\n", last);
delay(3000);
switch (last) {
case 0:
g_pcont->stack_guard1 = 0xfafafafa;
g_pcont->stack_guard2 = 0xfafafafa;
break;
case 1:
stack_thunk_add_ref();
thunk_failme();
break;
case 2:
ssp_failme();
break;
}
}