From: ebiederm@xmission.com (Eric W. Biederman)
To: <linux-kernel@vger.kernel.org>
Cc: Kyle Huey <me@kylehuey.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrea Righi <andrea.righi@canonical.com>,
Shuah Khan <shuah@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Will Drewry <wad@chromium.org>,
"open list\:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
linux-hardening@vger.kernel.org,
Robert O'Callahan <rocallahan@gmail.com>,
Kees Cook <keescook@chromium.org>,
Oliver Sang <oliver.sang@intel.com>,
lkp@lists.01.org, lkp@intel.com
Subject: [PATCH 0/2] SA_IMMUTABLE fixes
Date: Thu, 18 Nov 2021 15:58:02 -0600 [thread overview]
Message-ID: <87h7c9qg7p.fsf_-_@email.froward.int.ebiederm.org> (raw)
In-Reply-To: <202111171728.D85A4E2571@keescook> (Kees Cook's message of "Wed, 17 Nov 2021 17:32:20 -0800")
SA_IMMUTABLE fixed issues with force_sig_seccomp and the introduction
for force_sig_fatal where the exit previously could not be interrupted
but now it can. Unfortunately it added that behavior to all force_sig
functions under the right conditions which debuggers usage of SIG_TRAP
and debuggers handling of SIGSEGV.
Solve that by limiting SA_IMMUTABLE to just the cases that historically
debuggers have not been able to intercept.
The first patch changes force_sig_info_to_task to take a flag
that requests which behavior is desired.
The second patch adds force_exit_sig which replaces force_fatal_sig
in the cases where historically userspace would only find out about
the ``signal'' after the process has exited.
The first one with the hunk changing force_fatal_sig removed should be
suitable for backporting to v5.15. v5.15 does not implement
force_fatal_sig.
This should be enough to fix the regressions.
Kyle if you can double check me that I have properly fixed these issues
that would be appreciated.
Any other review or suggestions to improve the names would be
appreciated. I think I have named things reasonably well but I am very
close to the code so it is easy for me to miss things.
Eric W. Biederman (2):
signal: Don't always set SA_IMMUTABLE for forced signals
signal: Replace force_fatal_sig with force_exit_sig when in doubt
arch/m68k/kernel/traps.c | 2 +-
arch/powerpc/kernel/signal_32.c | 2 +-
arch/powerpc/kernel/signal_64.c | 4 ++--
arch/s390/kernel/traps.c | 2 +-
arch/sparc/kernel/signal_32.c | 4 ++--
arch/sparc/kernel/windows.c | 2 +-
arch/x86/entry/vsyscall/vsyscall_64.c | 2 +-
arch/x86/kernel/vm86_32.c | 2 +-
include/linux/sched/signal.h | 1 +
kernel/entry/syscall_user_dispatch.c | 4 ++--
kernel/signal.c | 36 ++++++++++++++++++++++++++++-------
11 files changed, 42 insertions(+), 19 deletions(-)
Eric
next prev parent reply other threads:[~2021-11-18 21:58 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 18:47 [REGRESSION] 5.16rc1: SA_IMMUTABLE breaks debuggers Kyle Huey
2021-11-17 18:51 ` Kees Cook
2021-11-17 19:05 ` Kyle Huey
2021-11-17 19:09 ` Kyle Huey
2021-11-17 21:04 ` Eric W. Biederman
2021-11-17 21:54 ` Kees Cook
2021-11-17 23:24 ` Linus Torvalds
2021-11-18 0:05 ` Kees Cook
2021-11-18 0:15 ` Linus Torvalds
2021-11-18 0:37 ` Kyle Huey
2021-11-18 1:11 ` Linus Torvalds
2021-11-18 1:20 ` Kyle Huey
2021-11-18 1:32 ` Kees Cook
2021-11-18 16:10 ` Eric W. Biederman
2021-11-19 16:07 ` Kyle Huey
2021-11-19 16:35 ` Kees Cook
2021-11-19 16:58 ` Kyle Huey
2021-11-18 21:58 ` Eric W. Biederman [this message]
2021-11-18 22:04 ` [PATCH 1/2] signal: Don't always set SA_IMMUTABLE for forced signals Eric W. Biederman
2021-11-18 23:52 ` Kees Cook
2021-11-18 23:54 ` Kees Cook
2021-11-19 15:08 ` Eric W. Biederman
2021-11-19 1:13 ` Kyle Huey
2021-11-19 15:03 ` Eric W. Biederman
2021-11-18 22:05 ` [PATCH 2/2] signal: Replace force_fatal_sig with force_exit_sig when in doubt Eric W. Biederman
2021-11-18 23:53 ` Kees Cook
2021-11-19 1:12 ` [PATCH 0/2] SA_IMMUTABLE fixes Kyle Huey
2021-11-19 15:41 ` [GIT PULL] SA_IMMUTABLE fixes for v5.16-rc2 Eric W. Biederman
2021-11-19 19:46 ` pr-tracker-bot
2021-11-17 22:29 ` [REGRESSION] 5.16rc1: SA_IMMUTABLE breaks debuggers Kyle Huey
2021-11-18 5:43 ` Thorsten Leemhuis
2021-11-20 6:13 ` Thorsten Leemhuis
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