From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@kernel.org>,
Balbir Singh <bsingharora@gmail.com>,
Borislav Petkov <bp@alien8.de>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
Dave Martin <Dave.Martin@arm.com>,
Weijiang Yang <weijiang.yang@intel.com>,
Pengfei Xu <pengfei.xu@intel.com>,
Haitao Huang <haitao.huang@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v23 3/9] x86/cet/ibt: Handle signals for Indirect Branch Tracking
Date: Tue, 16 Mar 2021 08:13:13 -0700 [thread overview]
Message-ID: <20210316151320.6123-4-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20210316151320.6123-1-yu-cheng.yu@intel.com>
When an indirect CALL/JMP instruction is executed and before it reaches
the target, it is in 'WAIT_ENDBR' status, which can be read from
MSR_IA32_U_CET. The status is part of a task's status before a signal is
raised and preserved in the signal frame. It is restored for sigreturn.
IBT state machine is described in Intel SDM Vol. 1, Sec. 18.3.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
arch/x86/kernel/cet.c | 26 ++++++++++++++++++++++++--
arch/x86/kernel/fpu/signal.c | 8 +++++---
2 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index 3361706ba950..34a26eb7f259 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -300,6 +300,13 @@ void cet_restore_signal(struct sc_ext *sc_ext)
msr_val |= CET_SHSTK_EN;
}
+ if (cet->ibt_enabled) {
+ msr_val |= (CET_ENDBR_EN | CET_NO_TRACK_EN);
+
+ if (sc_ext->wait_endbr)
+ msr_val |= CET_WAIT_ENDBR;
+ }
+
if (test_thread_flag(TIF_NEED_FPU_LOAD))
cet_user_state->user_cet = msr_val;
else
@@ -340,9 +347,24 @@ int cet_setup_signal(bool ia32, unsigned long rstor_addr, struct sc_ext *sc_ext)
sc_ext->ssp = new_ssp;
}
- if (ssp) {
+ if (ssp || cet->ibt_enabled) {
start_update_msrs();
- wrmsrl(MSR_IA32_PL3_SSP, ssp);
+
+ if (ssp)
+ wrmsrl(MSR_IA32_PL3_SSP, ssp);
+
+ if (cet->ibt_enabled) {
+ u64 r;
+
+ rdmsrl(MSR_IA32_U_CET, r);
+
+ if (r & CET_WAIT_ENDBR) {
+ sc_ext->wait_endbr = 1;
+ r &= ~CET_WAIT_ENDBR;
+ wrmsrl(MSR_IA32_U_CET, r);
+ }
+ }
+
end_update_msrs();
}
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 270e4649f435..b914d74c8ba6 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -57,7 +57,8 @@ int save_cet_to_sigframe(int ia32, void __user *fp, unsigned long restorer)
{
int err = 0;
- if (!current->thread.cet.shstk_size)
+ if (!current->thread.cet.shstk_size &&
+ !current->thread.cet.ibt_enabled)
return 0;
if (fp) {
@@ -89,7 +90,8 @@ static int get_cet_from_sigframe(int ia32, void __user *fp, struct sc_ext *ext)
memset(ext, 0, sizeof(*ext));
- if (!current->thread.cet.shstk_size)
+ if (!current->thread.cet.shstk_size &&
+ !current->thread.cet.ibt_enabled)
return 0;
if (fp) {
@@ -577,7 +579,7 @@ static unsigned long fpu__alloc_sigcontext_ext(unsigned long sp)
* sigcontext_ext is at: fpu + fpu_user_xstate_size +
* FP_XSTATE_MAGIC2_SIZE, then aligned to 8.
*/
- if (cet->shstk_size)
+ if (cet->shstk_size || cet->ibt_enabled)
sp -= (sizeof(struct sc_ext) + 8);
return sp;
--
2.21.0
next prev parent reply other threads:[~2021-03-16 15:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 15:13 [PATCH v23 0/9] Control-flow Enforcement: Indirect Branch Tracking Yu-cheng Yu
2021-03-16 15:13 ` [PATCH v23 1/9] x86/cet/ibt: Update Kconfig for user-mode " Yu-cheng Yu
2021-03-16 15:13 ` [PATCH v23 2/9] x86/cet/ibt: User-mode Indirect Branch Tracking support Yu-cheng Yu
2021-03-16 15:13 ` Yu-cheng Yu [this message]
2021-03-16 15:13 ` [PATCH v23 4/9] x86/cet/ibt: Update ELF header parsing for Indirect Branch Tracking Yu-cheng Yu
2021-03-16 15:13 ` [PATCH v23 5/9] x86/cet/ibt: Update arch_prctl functions " Yu-cheng Yu
2021-03-16 15:13 ` [PATCH v23 6/9] x86/entry: Introduce ENDBR macro Yu-cheng Yu
2021-03-16 15:49 ` Dave Hansen
2021-03-16 17:12 ` Yu, Yu-cheng
2021-03-16 17:28 ` Dave Hansen
2021-03-16 17:44 ` Yu, Yu-cheng
2021-03-16 17:46 ` Dave Hansen
2021-03-16 17:30 ` Borislav Petkov
2021-03-16 17:42 ` Yu, Yu-cheng
2021-03-16 19:57 ` Peter Zijlstra
2021-03-16 20:05 ` Yu, Yu-cheng
2021-03-16 20:15 ` Peter Zijlstra
2021-03-16 20:26 ` Yu, Yu-cheng
2021-03-16 21:01 ` Yu, Yu-cheng
2021-03-16 21:01 ` Peter Zijlstra
2021-03-16 15:13 ` [PATCH v23 7/9] x86/vdso/32: Add ENDBR to __kernel_vsyscall entry point Yu-cheng Yu
2021-03-16 15:13 ` [PATCH v23 8/9] x86/vdso: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2021-03-16 15:13 ` [PATCH v23 9/9] x86/vdso: Add ENDBR to __vdso_sgx_enter_enclave Yu-cheng Yu
2021-03-16 19:22 ` Jarkko Sakkinen
2021-03-16 19:27 ` Yu, Yu-cheng
2021-03-17 1:42 ` Jarkko Sakkinen
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