From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "x86@kernel.org" <x86@kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"ripatel@wii.dev" <ripatel@wii.dev>,
"tglx@kernel.org" <tglx@kernel.org>,
"bp@alien8.de" <bp@alien8.de>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Cc: "hpa@zytor.com" <hpa@zytor.com>,
"kees@kernel.org" <kees@kernel.org>,
"shuah@kernel.org" <shuah@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-kselftest@vger.kernel.org"
<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH 1/3] x86/shstk: ban ia32 sigreturn when shadow stack is enabled
Date: Thu, 8 Oct 2026 20:59:57 +0000 [thread overview]
Message-ID: <e1a26ac75c39673d043b2860f848827fecbcb843.camel@intel.com> (raw)
In-Reply-To: <20261008201610.1003569-2-ripatel@wii.dev>
On Thu, 2026-10-08 at 20:16 +0000, Richard Patel wrote:
> When returning from a signal via x32 or x64 rt_sigreturn, the
> shadow-stack-restore token is validated, but ia32 (rt_)sigreturn
> do not call restore_signal_shadow_stack().
>
> With IA32_EMULATION, 'int $0x80' allows ia32 sigreturn in 64-bit
> mode, which could defeat sigreturn protection.
>
> Refuse ia32 sigreturn by forcing a SIGSEGV instead.
How can it defeat protection? If doesn't process the shadow stack sigframe at
all, leaving the SSP where ever it was originally. What am I missing?
next prev parent reply other threads:[~2026-10-08 21:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-08 20:16 [PATCH 0/3] x86/shstk: ban ia32 sigreturn Richard Patel
2026-10-08 20:16 ` [PATCH 1/3] x86/shstk: ban ia32 sigreturn when shadow stack is enabled Richard Patel
2026-10-08 20:59 ` Edgecombe, Rick P [this message]
2026-10-08 21:50 ` Richard Patel
2026-10-08 22:34 ` Edgecombe, Rick P
2026-10-08 22:47 ` Richard Patel
2026-10-08 23:11 ` Edgecombe, Rick P
2026-10-08 23:29 ` Richard Patel
2026-10-09 11:36 ` Richard Patel
2026-10-08 20:16 ` [PATCH 2/3] selftests/x86: test shadow stack sigreturn protection Richard Patel
2026-10-08 20:16 ` [PATCH 3/3] selftests/x86: skip shstk tests where perf_event_open() fails Richard Patel
2026-10-08 21:00 ` [PATCH 0/3] x86/shstk: ban ia32 sigreturn Edgecombe, Rick P
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