| 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
| ||
|
Message-Id: <20221203003606.6838-40-rick.p.edgecombe@intel.com>
Date: Fri, 2 Dec 2022 16:36:06 -0800
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
Cc: rick.p.edgecombe@...el.com
Subject: [PATCH v4 39/39] x86/shstk: Add ARCH_SHSTK_STATUS
CRIU and GDB need to get the current shadow stack and WRSS enablement
status. This information is already available via /proc/pid/status, but
this is incovienent for CRIU because it involves parsing the text output
in an area of the code where this is difficult. Provide a status
arch_prctl(), ARCH_SHSTK_STATUS for retrieving the status. Have arg2 be a
userspace address, and make the new arch_prctl simply copy the features
out to userspace.
Tested-by: Pengfei Xu <pengfei.xu@...el.com>
Requested-by: Mike Rapoport <rppt@...nel.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
---
v4:
- New patch
Documentation/x86/shstk.rst | 6 ++++++
arch/x86/include/asm/shstk.h | 4 ++--
arch/x86/include/uapi/asm/prctl.h | 1 +
arch/x86/kernel/process_64.c | 1 +
arch/x86/kernel/shstk.c | 8 +++++++-
5 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/Documentation/x86/shstk.rst b/Documentation/x86/shstk.rst
index 0d7d1ccfff06..b3eb87046c27 100644
--- a/Documentation/x86/shstk.rst
+++ b/Documentation/x86/shstk.rst
@@ -77,6 +77,11 @@ arch_prctl(ARCH_SHSTK_UNLOCK, unsigned long features)
Unlock features. 'features' is a mask of all features to unlock. All
bits set are processed, unset bits are ignored. Only works via ptrace.
+arch_prctl(ARCH_SHSTK_STATUS, unsigned long addr)
+ Copy the currently enabled features to the address passed in addr. The
+ features are described using the bits passed into the others in
+ 'features'.
+
The return values are as following:
On success, return 0. On error, errno can be::
@@ -84,6 +89,7 @@ The return values are as following:
-EOPNOTSUPP if the feature is not supported by the hardware or
disabled by kernel parameter.
-EINVAL arguments (non existing feature, etc)
+ -EFAULT if could not copy information back to userspace
The feature's bits supported are::
diff --git a/arch/x86/include/asm/shstk.h b/arch/x86/include/asm/shstk.h
index c82f22fd5e6d..23bfb63c597d 100644
--- a/arch/x86/include/asm/shstk.h
+++ b/arch/x86/include/asm/shstk.h
@@ -15,7 +15,7 @@ struct thread_shstk {
u64 size;
};
-long shstk_prctl(struct task_struct *task, int option, unsigned long features);
+long shstk_prctl(struct task_struct *task, int option, unsigned long arg2);
void reset_thread_features(void);
int shstk_alloc_thread_stack(struct task_struct *p, unsigned long clone_flags,
unsigned long stack_size,
@@ -31,7 +31,7 @@ static inline bool shstk_enabled(void)
}
#else
static inline long shstk_prctl(struct task_struct *task, int option,
- unsigned long features) { return -EINVAL; }
+ unsigned long arg2) { return -EINVAL; }
static inline void reset_thread_features(void) {}
static inline int shstk_alloc_thread_stack(struct task_struct *p,
unsigned long clone_flags,
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index 0c95688cf58e..abe3fe6db6d2 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -31,6 +31,7 @@
#define ARCH_SHSTK_DISABLE 0x5002
#define ARCH_SHSTK_LOCK 0x5003
#define ARCH_SHSTK_UNLOCK 0x5004
+#define ARCH_SHSTK_STATUS 0x5005
/* ARCH_SHSTK_ features bits */
#define ARCH_SHSTK_SHSTK (1ULL << 0)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 2be6e01fb144..5dcf5426241b 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -922,6 +922,7 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
case ARCH_SHSTK_DISABLE:
case ARCH_SHSTK_LOCK:
case ARCH_SHSTK_UNLOCK:
+ case ARCH_SHSTK_STATUS:
return shstk_prctl(task, option, arg2);
default:
ret = -EINVAL;
diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c
index 95579f7bace3..05f8dcc19dbc 100644
--- a/arch/x86/kernel/shstk.c
+++ b/arch/x86/kernel/shstk.c
@@ -448,8 +448,14 @@ SYSCALL_DEFINE3(map_shadow_stack, unsigned long, addr, unsigned long, size, unsi
return alloc_shstk(addr, aligned_size, size, set_tok);
}
-long shstk_prctl(struct task_struct *task, int option, unsigned long features)
+long shstk_prctl(struct task_struct *task, int option, unsigned long arg2)
{
+ unsigned long features = arg2;
+
+ if (option == ARCH_SHSTK_STATUS) {
+ return put_user(task->thread.features, (unsigned long __user *)arg2);
+ }
+
if (option == ARCH_SHSTK_LOCK) {
task->thread.features_locked |= features;
return 0;
--
2.17.1
Powered by blists - more mailing lists