diff options
author | H.J. Lu <hjl.tools@gmail.com> | 2020-02-10 07:58:45 -0800 |
---|---|---|
committer | H.J. Lu <hjl.tools@gmail.com> | 2020-02-10 07:59:10 -0800 |
commit | bf6465d0461234ccd45ae34d5e2375a0bee0081d (patch) | |
tree | 71a56036daba549bcf0290f3780a4b27a1304c37 /gcc/fortran/array.c | |
parent | 1cad5e89a9e1b4ffa47bc6e3551643b342f6cfe8 (diff) | |
download | gcc-bf6465d0461234ccd45ae34d5e2375a0bee0081d.zip gcc-bf6465d0461234ccd45ae34d5e2375a0bee0081d.tar.gz gcc-bf6465d0461234ccd45ae34d5e2375a0bee0081d.tar.bz2 |
i386: Properly pop restore token in signal frame
Linux CET kernel places a restore token on shadow stack for signal
handler to enhance security. The restore token is 8 byte and aligned
to 8 bytes. It is usually transparent to user programs since kernel
will pop the restore token when signal handler returns. But when an
exception is thrown from a signal handler, now we need to pop the
restore token from shadow stack. For x86-64, we just need to treat
the signal frame as normal frame. For i386, we need to search for
the restore token to check if the original shadow stack is 8 byte
aligned. If the original shadow stack is 8 byte aligned, we just
need to pop 2 slots, one restore token, from shadow stack. Otherwise,
we need to pop 3 slots, one restore token + 4 byte padding, from
shadow stack.
This patch also includes 2 tests, one has a restore token with 4 byte
padding and one without.
Tested on Linux/x86-64 CET machine with and without -m32.
libgcc/
PR libgcc/85334
* config/i386/shadow-stack-unwind.h (_Unwind_Frames_Increment):
New.
gcc/testsuite/
PR libgcc/85334
* g++.target/i386/pr85334-1.C: New test.
* g++.target/i386/pr85334-2.C: Likewise.
Diffstat (limited to 'gcc/fortran/array.c')
0 files changed, 0 insertions, 0 deletions