This is a note to let you know that I've just added the patch titled
signal/powerpc: On swapcontext failure force SIGSEGV
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
signal-powerpc-on-swapcontext-failure-force-sigsegv.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.
>From 83a1f27ad773b1d8f0460d3a676114c7651918cc Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebied...@xmission.com>
Date: Wed, 20 Oct 2021 12:43:53 -0500
Subject: signal/powerpc: On swapcontext failure force SIGSEGV
From: Eric W. Biederman <ebied...@xmission.com>
commit 83a1f27ad773b1d8f0460d3a676114c7651918cc upstream.
If the register state may be partial and corrupted instead of calling
do_exit, call force_sigsegv(SIGSEGV). Which properly kills the
process with SIGSEGV and does not let any more userspace code execute,
instead of just killing one thread of the process and potentially
confusing everything.
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Fixes: 756f1ae8a44e ("PPC32: Rework signal code and add a swapcontext system
call.")
Fixes: 04879b04bf50 ("[PATCH] ppc64: VMX (Altivec) support & signal32 rework,
from Ben Herrenschmidt")
Link: https://lkml.kernel.org/r/20211020174406.17889-7-ebied...@xmission.com
Signed-off-by: Eric W. Biederman <ebied...@xmission.com>
Cc: Thomas Backlund <t...@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/powerpc/kernel/signal_32.c | 6 ++++--
arch/powerpc/kernel/signal_64.c | 9 ++++++---
2 files changed, 10 insertions(+), 5 deletions(-)
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -1062,8 +1062,10 @@ SYSCALL_DEFINE3(swapcontext, struct ucon
* or if another thread unmaps the region containing the context.
* We kill the task with a SIGSEGV in this situation.
*/
- if (do_setcontext(new_ctx, regs, 0))
- do_exit(SIGSEGV);
+ if (do_setcontext(new_ctx, regs, 0)) {
+ force_sigsegv(SIGSEGV);
+ return -EFAULT;
+ }
set_thread_flag(TIF_RESTOREALL);
return 0;
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -703,15 +703,18 @@ SYSCALL_DEFINE3(swapcontext, struct ucon
* We kill the task with a SIGSEGV in this situation.
*/
- if (__get_user_sigset(&set, &new_ctx->uc_sigmask))
- do_exit(SIGSEGV);
+ if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) {
+ force_sigsegv(SIGSEGV);
+ return -EFAULT;
+ }
set_current_blocked(&set);
if (!user_read_access_begin(new_ctx, ctx_size))
return -EFAULT;
if (__unsafe_restore_sigcontext(current, NULL, 0,
&new_ctx->uc_mcontext)) {
user_read_access_end();
- do_exit(SIGSEGV);
+ force_sigsegv(SIGSEGV);
+ return -EFAULT;
}
user_read_access_end();
Patches currently in stable-queue which might be from ebied...@xmission.com are
queue-5.15/signal-vm86_32-properly-send-sigsegv-when-the-vm86-state-cannot-be-saved.patch
queue-5.15/signal-don-t-always-set-sa_immutable-for-forced-signals.patch
queue-5.15/signal-x86-in-emulate_vsyscall-force-a-signal-instead-of-calling-do_exit.patch
queue-5.15/ipc-warn-if-trying-to-remove-ipc-object-which-is-absent.patch
queue-5.15/signal-replace-force_sigsegv-sigsegv-with-force_fatal_sig-sigsegv.patch
queue-5.15/signal-powerpc-on-swapcontext-failure-force-sigsegv.patch
queue-5.15/exit-syscall_user_dispatch-send-ordinary-signals-on-failure.patch
queue-5.15/signal-s390-use-force_sigsegv-in-default_trap_handler.patch
queue-5.15/signal-implement-force_fatal_sig.patch
queue-5.15/signal-sparc32-in-setup_rt_frame-and-setup_fram-use-force_fatal_sig.patch
queue-5.15/signal-sparc32-exit-with-a-fatal-signal-when-try_to_clear_window_buffer-fails.patch
queue-5.15/shm-extend-forced-shm-destroy-to-support-objects-from-several-ipc-nses.patch
queue-5.15/signal-replace-force_fatal_sig-with-force_exit_sig-when-in-doubt.patch
