lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20230319001535.23210-36-rick.p.edgecombe@intel.com>
Date:   Sat, 18 Mar 2023 17:15:30 -0700
From:   Rick Edgecombe <rick.p.edgecombe@...el.com>
To:     x86@...nel.org, "H . Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-mm@...ck.org,
        linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
        Arnd Bergmann <arnd@...db.de>,
        Andy Lutomirski <luto@...nel.org>,
        Balbir Singh <bsingharora@...il.com>,
        Borislav Petkov <bp@...en8.de>,
        Cyrill Gorcunov <gorcunov@...il.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Eugene Syromiatnikov <esyr@...hat.com>,
        Florian Weimer <fweimer@...hat.com>,
        "H . J . Lu" <hjl.tools@...il.com>, Jann Horn <jannh@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        Kees Cook <keescook@...omium.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Nadav Amit <nadav.amit@...il.com>,
        Oleg Nesterov <oleg@...hat.com>, Pavel Machek <pavel@....cz>,
        Peter Zijlstra <peterz@...radead.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Weijiang Yang <weijiang.yang@...el.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        John Allen <john.allen@....com>, kcc@...gle.com,
        eranian@...gle.com, rppt@...nel.org, jamorris@...ux.microsoft.com,
        dethoma@...rosoft.com, akpm@...ux-foundation.org,
        Andrew.Cooper3@...rix.com, christina.schimpe@...el.com,
        david@...hat.com, debug@...osinc.com, szabolcs.nagy@....com
Cc:     rick.p.edgecombe@...el.com
Subject: [PATCH v8 35/40] x86: Expose thread features in /proc/$PID/status

Applications and loaders can have logic to decide whether to enable
shadow stack. They usually don't report whether shadow stack has been
enabled or not, so there is no way to verify whether an application
actually is protected by shadow stack.

Add two lines in /proc/$PID/status to report enabled and locked features.

Since, this involves referring to arch specific defines in asm/prctl.h,
implement an arch breakout to emit the feature lines.

[Switched to CET, added to commit log]

Co-developed-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Reviewed-by: Kees Cook <keescook@...omium.org>
Acked-by: Mike Rapoport (IBM) <rppt@...nel.org>
Tested-by: Pengfei Xu <pengfei.xu@...el.com>
Tested-by: John Allen <john.allen@....com>
Tested-by: Kees Cook <keescook@...omium.org>
---
v4:
 - Remove "CET" references

v3:
 - Move to /proc/pid/status (Kees)

v2:
 - New patch
---
 arch/x86/kernel/cpu/proc.c | 23 +++++++++++++++++++++++
 fs/proc/array.c            |  6 ++++++
 include/linux/proc_fs.h    |  2 ++
 3 files changed, 31 insertions(+)

diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 099b6f0d96bd..31c0e68f6227 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -4,6 +4,8 @@
 #include <linux/string.h>
 #include <linux/seq_file.h>
 #include <linux/cpufreq.h>
+#include <asm/prctl.h>
+#include <linux/proc_fs.h>
 
 #include "cpu.h"
 
@@ -175,3 +177,24 @@ const struct seq_operations cpuinfo_op = {
 	.stop	= c_stop,
 	.show	= show_cpuinfo,
 };
+
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+static void dump_x86_features(struct seq_file *m, unsigned long features)
+{
+	if (features & ARCH_SHSTK_SHSTK)
+		seq_puts(m, "shstk ");
+	if (features & ARCH_SHSTK_WRSS)
+		seq_puts(m, "wrss ");
+}
+
+void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct *task)
+{
+	seq_puts(m, "x86_Thread_features:\t");
+	dump_x86_features(m, task->thread.features);
+	seq_putc(m, '\n');
+
+	seq_puts(m, "x86_Thread_features_locked:\t");
+	dump_x86_features(m, task->thread.features_locked);
+	seq_putc(m, '\n');
+}
+#endif /* CONFIG_X86_USER_SHADOW_STACK */
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 9b0315d34c58..3e1a33dcd0d0 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -423,6 +423,11 @@ static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
 	seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
 }
 
+__weak void arch_proc_pid_thread_features(struct seq_file *m,
+					  struct task_struct *task)
+{
+}
+
 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 			struct pid *pid, struct task_struct *task)
 {
@@ -446,6 +451,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 	task_cpus_allowed(m, task);
 	cpuset_task_status_allowed(m, task);
 	task_context_switch_counts(m, task);
+	arch_proc_pid_thread_features(m, task);
 	return 0;
 }
 
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 0260f5ea98fe..80ff8e533cbd 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -158,6 +158,8 @@ int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns,
 			struct pid *pid, struct task_struct *task);
 #endif /* CONFIG_PROC_PID_ARCH_STATUS */
 
+void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct *task);
+
 #else /* CONFIG_PROC_FS */
 
 static inline void proc_root_init(void)
-- 
2.17.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ