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From: ebiederm@xmission.com (Eric W. Biederman)
To: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org,
	Linux Containers <containers@lists.linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	linux-arch@vger.kernel.org, Dave Martin <Dave.Martin@arm.com>,
	James Morse <james.morse@arm.com>
Subject: [REVIEW][PATCHv2 03/26] signal/arm64: Use force_sig not force_sig_fault for SIGKILL
Date: Thu, 23 May 2019 11:11:19 -0500	[thread overview]
Message-ID: <875zq1gnh4.fsf_-_@xmission.com> (raw)
In-Reply-To: <20190523101702.GG26646@fuggles.cambridge.arm.com> (Will Deacon's message of "Thu, 23 May 2019 11:17:02 +0100")


I don't think this is userspace visible but SIGKILL does not have
any si_codes that use the fault member of the siginfo union.  Correct
this the simple way and call force_sig instead of force_sig_fault when
the signal is SIGKILL.

The two know places where synchronous SIGKILL are generated are
do_bad_area and fpsimd_save.  The call paths to force_sig_fault are:
do_bad_area
  arm64_force_sig_fault
    force_sig_fault
force_signal_inject
  arm64_notify_die
    arm64_force_sig_fault
       force_sig_fault

Which means correcting this in arm64_force_sig_fault is enough
to ensure the arm64 code is not misusing the generic code, which
could lead to maintenance problems later.

Cc: stable@vger.kernel.org
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: af40ff687bc9 ("arm64: signal: Ensure si_code is valid for all fault signals")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---

I have also made the corresponding changes to:
09/26 signal: Remove task parameter from force_sig
21/26 signal: Remove the task parameter from force_sig_fault
But I will leave off reposting those as for now as the changes
are obvious.

arch/arm64/kernel/traps.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index ade32046f3fe..e45d5b440fb1 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -256,7 +256,10 @@ void arm64_force_sig_fault(int signo, int code, void __user *addr,
 			   const char *str)
 {
 	arm64_show_signal(signo, str);
-	force_sig_fault(signo, code, addr, current);
+	if (signo == SIGKILL)
+		force_sig(SIGKILL, current);
+	else
+		force_sig_fault(signo, code, addr, current);
 }
 
 void arm64_force_sig_mceerr(int code, void __user *addr, short lsb,
-- 
2.21.0.dirty


  parent reply	other threads:[~2019-05-23 16:11 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23  0:38 [REVIEW][PATCH 00/26] signal: Remove task argument from force_sig_info Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 01/26] signal: Correct namespace fixups of si_pid and si_uid Eric W. Biederman
     [not found]   ` <20190529131503.F2AC221871@mail.kernel.org>
2019-05-29 15:18     ` Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 02/26] signal/ptrace: Simplify and fix PTRACE_KILL Eric W. Biederman
2019-05-29 14:35   ` Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 03/26] signal/arm64: Use force_sig not force_sig_fault for SIGKILL Eric W. Biederman
2019-05-23 10:17   ` Will Deacon
2019-05-23 14:59     ` Eric W. Biederman
2019-05-23 16:11     ` Eric W. Biederman [this message]
2019-05-23 16:15       ` [REVIEW][PATCHv2 " Will Deacon
2019-05-23 20:59         ` Eric W. Biederman
2019-05-24 10:00           ` Will Deacon
2019-05-24 22:36             ` Eric W. Biederman
2019-05-29 15:12               ` Will Deacon
2019-05-29 15:34                 ` Eric W. Biederman
2019-05-23 10:21   ` [REVIEW][PATCH " Dave Martin
2019-05-23 14:53     ` Eric W. Biederman
2019-05-23 16:12       ` Dave P Martin
2019-05-23 21:00         ` Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 04/26] signal/drbd: Use send_sig not force_sig Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 05/26] signal/bpfilter: Fix bpfilter_kernl to use " Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 06/26] signal/pid_namespace: Fix reboot_pid_ns " Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 07/26] signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sig Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 08/26] signal: Remove task parameter from force_sigsegv Eric W. Biederman
2019-05-23  0:38 ` [REVIEW][PATCH 09/26] signal: Remove task parameter from force_sig Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 10/26] signal: Remove task parameter from force_sig_mceerr Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 11/26] signal/x86: Remove task parameter from send_sigtrap Eric W. Biederman
2019-05-28 18:18   ` Thomas Gleixner
2019-05-23  0:39 ` [REVIEW][PATCH 12/26] signal/um: " Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 13/26] signal/sh: Remove tsk parameter from force_sig_info_fault Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 14/26] signal/riscv: Remove tsk parameter from do_trap Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 15/26] signal/nds32: Remove tsk parameter from send_sigtrap Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 16/26] signal/arm: Remove tsk parameter from ptrace_break Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 17/26] signal/arm: Remove tsk parameter from __do_user_fault Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 18/26] signal/unicore32: " Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 19/26] signal: Explicitly call force_sig_fault on current Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 20/26] signal: Use force_sig_fault_to_task for the two calls that don't deliver to current Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 21/26] signal: Remove the task parameter from force_sig_fault Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 22/26] signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 23/26] signal: Move the computation of force into send_signal and correct it Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 24/26] signal: Generate the siginfo in force_sig Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 25/26] signal: Factor force_sig_info_to_task out of force_sig_info Eric W. Biederman
2019-05-23  0:39 ` [REVIEW][PATCH 26/26] signal: Remove the signal number and task parameters from force_sig_info Eric W. Biederman
2019-05-24 23:35 ` [REVIEW][PATCH 00/26] signal: Remove task argument " Eric W. Biederman
2019-05-29 15:37 ` Eric W. Biederman

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