From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org, alyssa.milburn@linux.intel.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
samitolvanen@google.com, keescook@chromium.org,
jpoimboe@kernel.org, joao@overdrivepizza.com,
tim.c.chen@linux.intel.com
Subject: [PATCH 0/2] x86/cfi: Fix FineIBT
Date: Thu, 15 Jun 2023 21:35:46 +0200 [thread overview]
Message-ID: <20230615193546.949657149@infradead.org> (raw)
Hi!
Alyssa reported a FineIBT issue; these patches sort that.
Basically the morale of the story is that CALL_NOSPEC and JMP_NOSPEC are
suspect and likely not what you want. The remaining users are:
arch/x86/crypto/crc32c-pcl-intel-asm_64.S: JMP_NOSPEC bufp
This is broken on anything IBT afaict.
arch/x86/include/asm/mshyperv.h: CALL_NOSPEC
arch/x86/include/asm/mshyperv.h: __asm__ __volatile__(CALL_NOSPEC
arch/x86/include/asm/mshyperv.h: __asm__ __volatile__(CALL_NOSPEC
arch/x86/include/asm/mshyperv.h: __asm__ __volatile__ (CALL_NOSPEC
arch/x86/include/asm/mshyperv.h: CALL_NOSPEC
arch/x86/include/asm/mshyperv.h: __asm__ __volatile__ (CALL_NOSPEC
arch/x86/include/asm/xen/hypercall.h: asm volatile(CALL_NOSPEC
These are hypercalls and supposedly the targets are having ENDBR on.
arch/x86/kernel/ftrace_64.S: CALL_NOSPEC r8
The thing is !DYNAMIC_FTRACE only, which we can fix with a Kconfig
dependency I suppose.
arch/x86/kvm/emulate.c: asm("push %[flags]; popf; " CALL_NOSPEC
arch/x86/kvm/emulate.c: asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n"
calls into the magic fastop stuff and should be ok, those have explicit
ENDBR + IBT_NOSEAL() annotations.
arch/x86/kvm/vmx/vmenter.S: VMX_DO_EVENT_IRQOFF CALL_NOSPEC _ASM_ARG1
calls the IDT vectors manually, so should be ok (gross, but not broken
from this pov).
arch/x86/platform/efi/efi_stub_64.S: CALL_NOSPEC rdi
effectively a nocfi call, so should be ok.
next reply other threads:[~2023-06-15 19:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-15 19:35 Peter Zijlstra [this message]
2023-06-15 19:35 ` [PATCH 1/2] x86/cfi: Fix ret_from_fork indirect calls Peter Zijlstra
2023-06-20 21:56 ` Kees Cook
2023-06-21 8:52 ` Peter Zijlstra
2023-06-21 9:27 ` Peter Zijlstra
2023-06-21 18:08 ` Kees Cook
2023-06-21 18:16 ` Peter Zijlstra
2023-06-21 18:33 ` Peter Zijlstra
2023-06-21 20:13 ` Peter Zijlstra
2023-06-21 21:07 ` Brian Gerst
2023-06-15 19:35 ` [PATCH 2/2] x86/fineibt: Poison ENDBR at +0 Peter Zijlstra
2023-06-20 21:55 ` Kees Cook
2023-06-21 0:04 ` Sami Tolvanen
2023-06-21 8:51 ` Peter Zijlstra
2023-06-21 8:18 ` Peter Zijlstra
2023-06-21 8:48 ` Peter Zijlstra
2023-06-21 18:07 ` Kees Cook
2023-07-10 8:13 ` [tip: x86/urgent] " tip-bot2 for Peter Zijlstra
2023-06-16 23:24 ` [PATCH 0/2] x86/cfi: Fix FineIBT Sami Tolvanen
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