LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H.J. Lu" <hjl.tools@gmail.com>,
	Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Jonathan Corbet <corbet@lwn.net>, Oleg Nesterov <oleg@redhat.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Mike Kravetz <mike.kravetz@oracle.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH 04/10] x86/cet: Handle thread shadow stack
Date: Thu,  7 Jun 2018 07:38:01 -0700	[thread overview]
Message-ID: <20180607143807.3611-5-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20180607143807.3611-1-yu-cheng.yu@intel.com>

When fork() specifies CLONE_VM but not CLONE_VFORK, the child
needs a separate program stack and a separate shadow stack.
This patch handles allocation and freeing of the thread shadow
stack.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
 arch/x86/include/asm/cet.h         |  2 ++
 arch/x86/include/asm/mmu_context.h |  3 +++
 arch/x86/kernel/cet.c              | 34 ++++++++++++++++++++++++++++++++++
 arch/x86/kernel/process.c          |  1 +
 arch/x86/kernel/process_64.c       |  7 +++++++
 5 files changed, 47 insertions(+)

diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h
index 5507469cb803..c8fd87e13859 100644
--- a/arch/x86/include/asm/cet.h
+++ b/arch/x86/include/asm/cet.h
@@ -19,6 +19,7 @@ struct cet_stat {
 unsigned long cet_get_shstk_ptr(void);
 int cet_push_shstk(int ia32, unsigned long ssp, unsigned long val);
 int cet_setup_shstk(void);
+int cet_setup_thread_shstk(struct task_struct *p);
 void cet_disable_shstk(void);
 void cet_disable_free_shstk(struct task_struct *p);
 int cet_restore_signal(unsigned long ssp);
@@ -28,6 +29,7 @@ static inline unsigned long cet_get_shstk_ptr(void) { return 0; }
 static inline int cet_push_shstk(int ia32, unsigned long ssp,
 				 unsigned long val) { return 0; }
 static inline int cet_setup_shstk(void) { return 0; }
+static inline int cet_setup_thread_shstk(struct task_struct *p) { return 0; }
 static inline void cet_disable_shstk(void) {}
 static inline void cet_disable_free_shstk(struct task_struct *p) {}
 static inline int cet_restore_signal(unsigned long ssp) { return 0; }
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index cf9911b5a53c..42395257efc3 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -13,6 +13,7 @@
 #include <asm/tlbflush.h>
 #include <asm/paravirt.h>
 #include <asm/mpx.h>
+#include <asm/cet.h>
 
 extern atomic64_t last_mm_ctx_id;
 
@@ -228,6 +229,8 @@ do {						\
 #else
 #define deactivate_mm(tsk, mm)			\
 do {						\
+	if (!tsk->vfork_done)			\
+		cet_disable_free_shstk(tsk);	\
 	load_gs_index(0);			\
 	loadsegment(fs, 0);			\
 } while (0)
diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index 6f445ce94c83..156f5d88ffd5 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -103,6 +103,40 @@ int cet_setup_shstk(void)
 	return 0;
 }
 
+int cet_setup_thread_shstk(struct task_struct *tsk)
+{
+	unsigned long addr, size;
+	struct cet_user_state *state;
+
+	if (!current->thread.cet.shstk_enabled)
+		return 0;
+
+	state = get_xsave_addr(&tsk->thread.fpu.state.xsave,
+			       XFEATURE_MASK_SHSTK_USER);
+
+	if (!state)
+		return -EINVAL;
+
+	size = tsk->thread.cet.shstk_size;
+	if (size == 0)
+		size = SHSTK_SIZE;
+
+	addr = shstk_mmap(0, size);
+
+	if (addr >= TASK_SIZE) {
+		tsk->thread.cet.shstk_base = 0;
+		tsk->thread.cet.shstk_size = 0;
+		tsk->thread.cet.shstk_enabled = 0;
+		return -ENOMEM;
+	}
+
+	state->user_ssp = (u64)(addr + size - sizeof(u64));
+	tsk->thread.cet.shstk_base = addr;
+	tsk->thread.cet.shstk_size = size;
+	tsk->thread.cet.shstk_enabled = 1;
+	return 0;
+}
+
 void cet_disable_shstk(void)
 {
 	u64 r;
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index b3b0b482983a..ae56caee41f9 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -127,6 +127,7 @@ void exit_thread(struct task_struct *tsk)
 
 	free_vm86(t);
 
+	cet_disable_free_shstk(tsk);
 	fpu__drop(fpu);
 }
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 12bb445fb98d..6e493b0bcedd 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -317,6 +317,13 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
 	if (sp)
 		childregs->sp = sp;
 
+	/* Allocate a new shadow stack for pthread */
+	if ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM) {
+		err = cet_setup_thread_shstk(p);
+		if (err)
+			goto out;
+	}
+
 	err = -ENOMEM;
 	if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
 		p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
-- 
2.15.1

  parent reply	other threads:[~2018-06-07 15:40 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07 14:37 [PATCH 00/10] Control Flow Enforcement - Part (3) Yu-cheng Yu
2018-06-07 14:37 ` [PATCH 01/10] x86/cet: User-mode shadow stack support Yu-cheng Yu
2018-06-07 16:37   ` Andy Lutomirski
2018-06-07 17:46     ` Yu-cheng Yu
2018-06-07 17:55       ` Dave Hansen
2018-06-07 18:23       ` Andy Lutomirski
2018-06-12 11:56   ` Balbir Singh
2018-06-12 15:03     ` Yu-cheng Yu
2018-06-07 14:37 ` [PATCH 02/10] x86/cet: Introduce WRUSS instruction Yu-cheng Yu
2018-06-07 16:40   ` Andy Lutomirski
2018-06-07 16:51     ` Yu-cheng Yu
2018-06-07 18:41     ` Peter Zijlstra
2018-06-07 20:31       ` Yu-cheng Yu
2018-06-11  8:17     ` Peter Zijlstra
2018-06-11 15:02       ` Yu-cheng Yu
2018-06-14  1:30   ` Balbir Singh
2018-06-14 14:43     ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 03/10] x86/cet: Signal handling for shadow stack Yu-cheng Yu
2018-06-07 18:30   ` Andy Lutomirski
2018-06-07 18:58     ` Florian Weimer
2018-06-07 19:51       ` Yu-cheng Yu
2018-06-07 20:07     ` Cyrill Gorcunov
2018-06-07 20:57       ` Andy Lutomirski
2018-06-08 12:07         ` Cyrill Gorcunov
2018-06-07 20:12     ` Yu-cheng Yu
2018-06-07 20:17       ` Dave Hansen
2018-06-07 14:38 ` Yu-cheng Yu [this message]
2018-06-07 18:21   ` [PATCH 04/10] x86/cet: Handle thread " Andy Lutomirski
2018-06-07 19:47     ` Florian Weimer
2018-06-07 20:53       ` Andy Lutomirski
2018-06-08 14:53         ` Florian Weimer
2018-06-08 15:01           ` Andy Lutomirski
2018-06-08 15:50             ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 05/10] x86/cet: ELF header parsing of Control Flow Enforcement Yu-cheng Yu
2018-06-07 18:38   ` Andy Lutomirski
2018-06-07 20:40     ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 06/10] x86/cet: Add arch_prctl functions for shadow stack Yu-cheng Yu
2018-06-07 18:48   ` Andy Lutomirski
2018-06-07 20:30     ` Yu-cheng Yu
2018-06-07 21:01       ` Andy Lutomirski
2018-06-07 22:02         ` H.J. Lu
2018-06-07 23:01           ` Andy Lutomirski
2018-06-08  4:09             ` H.J. Lu
2018-06-08  4:38               ` Andy Lutomirski
2018-06-08 12:24                 ` H.J. Lu
2018-06-08 14:57                   ` Andy Lutomirski
2018-06-08 15:52                     ` Cyrill Gorcunov
2018-06-08  4:22           ` H.J. Lu
2018-06-08  4:35             ` Andy Lutomirski
2018-06-08 12:17               ` H.J. Lu
2018-06-12 10:03           ` Thomas Gleixner
2018-06-12 11:43             ` H.J. Lu
2018-06-12 16:01               ` Andy Lutomirski
2018-06-12 16:05                 ` H.J. Lu
2018-06-12 16:34                   ` Andy Lutomirski
2018-06-12 16:51                     ` H.J. Lu
2018-06-12 18:59                       ` Thomas Gleixner
2018-06-12 19:34                         ` H.J. Lu
2018-06-18 22:03                           ` Andy Lutomirski
2018-06-19  0:52                             ` Kees Cook
2018-06-19  6:40                               ` Florian Weimer
2018-06-19 14:50                               ` Andy Lutomirski
2018-06-19 16:44                                 ` Kees Cook
2018-06-19 16:59                                   ` Yu-cheng Yu
2018-06-19 17:07                                     ` Kees Cook
2018-06-19 17:20                                       ` Andy Lutomirski
2018-06-19 20:12                                         ` Kees Cook
2018-06-19 20:47                                           ` Andy Lutomirski
2018-06-19 22:38                                             ` Yu-cheng Yu
2018-06-20  0:50                                               ` Andy Lutomirski
2018-06-21 23:07                                                 ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 07/10] mm: Prevent mprotect from changing " Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 08/10] mm: Prevent mremap of " Yu-cheng Yu
2018-06-07 18:48   ` Andy Lutomirski
2018-06-07 20:18     ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 09/10] mm: Prevent madvise from changing " Yu-cheng Yu
2018-06-07 20:54   ` Andy Lutomirski
2018-06-07 21:09   ` Nadav Amit
2018-06-07 21:18     ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 10/10] mm: Prevent munmap and remap_file_pages of " Yu-cheng Yu
2018-06-07 18:50   ` Andy Lutomirski
2018-06-07 20:15     ` Yu-cheng Yu
2018-06-12 10:56 ` [PATCH 00/10] Control Flow Enforcement - Part (3) Balbir Singh
2018-06-12 15:03   ` Yu-cheng Yu
2018-06-12 16:00     ` Andy Lutomirski
2018-06-12 16:21       ` Yu-cheng Yu
2018-06-12 16:31         ` Andy Lutomirski
2018-06-12 17:24           ` Yu-cheng Yu
2018-06-12 20:15             ` Yu-cheng Yu
2018-06-14  1:07     ` Balbir Singh
2018-06-14 14:56       ` Yu-cheng Yu
2018-06-17  3:16         ` Balbir Singh
2018-06-18 21:44           ` Andy Lutomirski
2018-06-19  8:52             ` Balbir Singh
2018-06-26  2:46 ` Jann Horn
2018-06-26 14:56   ` Yu-cheng Yu
2018-06-26  5:26 ` Andy Lutomirski
2018-06-26 14:56   ` Yu-cheng Yu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180607143807.3611-5-yu-cheng.yu@intel.com \
    --to=yu-cheng.yu@intel.com \
    --cc=arnd@arndb.de \
    --cc=corbet@lwn.net \
    --cc=dave.hansen@linux.intel.com \
    --cc=hjl.tools@gmail.com \
    --cc=hpa@zytor.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=luto@amacapital.net \
    --cc=mike.kravetz@oracle.com \
    --cc=mingo@redhat.com \
    --cc=oleg@redhat.com \
    --cc=ravi.v.shankar@intel.com \
    --cc=tglx@linutronix.de \
    --cc=vedvyas.shanbhogue@intel.com \
    --cc=x86@kernel.org \
    --subject='Re: [PATCH 04/10] x86/cet: Handle thread shadow stack' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).