On 7/14/2022 3:55 PM, H.J. Lu via Gcc-patches wrote:
Check stack canary for noreturn function to catch stack corruption
before calling noreturn function. For C++, check stack canary when
throwing exception or resuming stack unwind to avoid corrupted stack.
gcc/
PR middle-end/58245
* calls.cc (expand_call): Check stack canary for noreturn
function.
gcc/testsuite/
PR middle-end/58245
* c-c++-common/pr58245-1.c: New test.
* g++.dg/pr58245-1.C: Likewise.
* g++.dg/fstack-protector-strong.C: Adjusted.
But is this really something we want? I'd actually lean towards
eliminating the useless load -- I don't necessarily think we should be
treating non-returning paths specially here.
The whole point of the stack protector is to prevent the *return* path
from going to an attacker controlled location. I'm not sure checking
the protector at this point actually does anything particularly useful.
jeff
