[PATCH seccomp 0/8] seccomp: add bitmap cache support on remaining arches and report cache in procfs

From: YiFei Zhu <redacted>

This patch series enables bitmap cache for the remaining arches with
SECCOMP_FILTER, other than MIPS.

I was unable to find any of the arches having subarch-specific NR_syscalls
macros, so generic NR_syscalls is used. SH's syscall_get_arch seems to
only have the 32-bit subarch implementation. I'm not sure if this is
expected.

This series has not been tested; I have not built all the cross compilers
necessary to build test, let alone run the kernel or benchmark the
performance, so help on making sure the bitmap cache works as expected
would be appreciated. The series applies on top of Kees's for-next/seccomp
branch.

YiFei Zhu (8):
  csky: Enable seccomp architecture tracking
  parisc: Enable seccomp architecture tracking
  powerpc: Enable seccomp architecture tracking
  riscv: Enable seccomp architecture tracking
  s390: Enable seccomp architecture tracking
  sh: Enable seccomp architecture tracking
  xtensa: Enable seccomp architecture tracking
  seccomp/cache: Report cache data through /proc/pid/seccomp_cache

 arch/Kconfig                       | 15 ++++++++
 arch/csky/include/asm/Kbuild       |  1 -
 arch/csky/include/asm/seccomp.h    | 11 ++++++
 arch/parisc/include/asm/Kbuild     |  1 -
 arch/parisc/include/asm/seccomp.h  | 22 +++++++++++
 arch/powerpc/include/asm/seccomp.h | 21 +++++++++++
 arch/riscv/include/asm/seccomp.h   | 10 +++++
 arch/s390/include/asm/seccomp.h    |  9 +++++
 arch/sh/include/asm/seccomp.h      | 10 +++++
 arch/xtensa/include/asm/Kbuild     |  1 -
 arch/xtensa/include/asm/seccomp.h  | 11 ++++++
 fs/proc/base.c                     |  6 +++
 include/linux/seccomp.h            |  7 ++++
 kernel/seccomp.c                   | 59 ++++++++++++++++++++++++++++++
 14 files changed, 181 insertions(+), 3 deletions(-)
 create mode 100644 arch/csky/include/asm/seccomp.h
 create mode 100644 arch/parisc/include/asm/seccomp.h
 create mode 100644 arch/xtensa/include/asm/seccomp.h


base-commit: 38c37e8fd3d2590c4234d8cfbc22158362f0eb04
--
2.29.2

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for sh.

Signed-off-by: YiFei Zhu <redacted>
---
 arch/sh/include/asm/seccomp.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/sh/include/asm/seccomp.h b/arch/sh/include/asm/seccomp.h
index 54111e4d32b8..b8d169292a34 100644
--- a/arch/sh/include/asm/seccomp.h
+++ b/arch/sh/include/asm/seccomp.h

@@ -8,4 +8,14 @@
 #define __NR_seccomp_exit __NR_exit
 #define __NR_seccomp_sigreturn __NR_rt_sigreturn
 
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+#define __SECCOMP_ARCH_LE_BIT		__AUDIT_ARCH_LE
+#else
+#define __SECCOMP_ARCH_LE_BIT		0
+#endif
+
+#define SECCOMP_ARCH_NATIVE		(AUDIT_ARCH_SH | __SECCOMP_ARCH_LE)
+#define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+#define SECCOMP_ARCH_NATIVE_NAME	"sh"
+
 #endif /* __ASM_SECCOMP_H */

-- 
2.29.2

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for xtensa.

Signed-off-by: YiFei Zhu <redacted>
---
 arch/xtensa/include/asm/Kbuild    |  1 -
 arch/xtensa/include/asm/seccomp.h | 11 +++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 arch/xtensa/include/asm/seccomp.h

diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild
index c59c42a1221a..9718e9593564 100644
--- a/arch/xtensa/include/asm/Kbuild
+++ b/arch/xtensa/include/asm/Kbuild

@@ -7,5 +7,4 @@ generic-y += mcs_spinlock.h
 generic-y += param.h
 generic-y += qrwlock.h
 generic-y += qspinlock.h
-generic-y += seccomp.h
 generic-y += user.h

diff --git a/arch/xtensa/include/asm/seccomp.h b/arch/xtensa/include/asm/seccomp.h
new file mode 100644
index 000000000000..f1cb6b0a9e1f
--- /dev/null
+++ b/arch/xtensa/include/asm/seccomp.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_SECCOMP_H
+#define _ASM_SECCOMP_H
+
+#include <asm-generic/seccomp.h>
+
+#define SECCOMP_ARCH_NATIVE		AUDIT_ARCH_XTENSA
+#define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+#define SECCOMP_ARCH_NATIVE_NAME	"xtensa"
+
+#endif /* _ASM_SECCOMP_H */

-- 
2.29.2

From: YiFei Zhu <redacted>

Currently the kernel does not provide an infrastructure to translate
architecture numbers to a human-readable name. Translating syscall
numbers to syscall names is possible through FTRACE_SYSCALL
infrastructure but it does not provide support for compat syscalls.

This will create a file for each PID as /proc/pid/seccomp_cache.
The file will be empty when no seccomp filters are loaded, or be
in the format of:
<arch name> <decimal syscall number> <ALLOW | FILTER>
where ALLOW means the cache is guaranteed to allow the syscall,
and filter means the cache will pass the syscall to the BPF filter.

For the docker default profile on x86_64 it looks like:
x86_64 0 ALLOW
x86_64 1 ALLOW
x86_64 2 ALLOW
x86_64 3 ALLOW
[...]
x86_64 132 ALLOW
x86_64 133 ALLOW
x86_64 134 FILTER
x86_64 135 FILTER
x86_64 136 FILTER
x86_64 137 ALLOW
x86_64 138 ALLOW
x86_64 139 FILTER
x86_64 140 ALLOW
x86_64 141 ALLOW
[...]

This file is guarded by CONFIG_SECCOMP_CACHE_DEBUG with a default
of N because I think certain users of seccomp might not want the
application to know which syscalls are definitely usable. For
the same reason, it is also guarded by CAP_SYS_ADMIN.

Suggested-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/lkml/CAG48ez3Ofqp4crXGksLmZY6=fGrF_tWyUCg7PBkAetvbbOPeOA@mail.gmail.com/
Signed-off-by: YiFei Zhu <redacted>
---
 arch/Kconfig            | 15 +++++++++++
 fs/proc/base.c          |  6 +++++
 include/linux/seccomp.h |  7 +++++
 kernel/seccomp.c        | 59 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 87 insertions(+)

diff --git a/arch/Kconfig b/arch/Kconfig
index 56b6ccc0e32d..6e2eb7171da0 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig

@@ -514,6 +514,21 @@ config SECCOMP_FILTER
 
 	  See Documentation/userspace-api/seccomp_filter.rst for details.
 
+config SECCOMP_CACHE_DEBUG
+	bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
+	depends on SECCOMP
+	depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
+	depends on PROC_FS
+	help
+	  This enables the /proc/pid/seccomp_cache interface to monitor
+	  seccomp cache data. The file format is subject to change. Reading
+	  the file requires CAP_SYS_ADMIN.
+
+	  This option is for debugging only. Enabling presents the risk that
+	  an adversary may be able to infer the seccomp filter logic.
+
+	  If unsure, say N.
+
 config HAVE_ARCH_STACKLEAK
 	bool
 	help

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 0f707003dda5..d652f9dbaecc 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c

@@ -3261,6 +3261,9 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_PROC_PID_ARCH_STATUS
 	ONE("arch_status", S_IRUGO, proc_pid_arch_status),
 #endif
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+	ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
+#endif
 };
 
 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)

@@ -3590,6 +3593,9 @@ static const struct pid_entry tid_base_stuff[] = {
 #ifdef CONFIG_PROC_PID_ARCH_STATUS
 	ONE("arch_status", S_IRUGO, proc_pid_arch_status),
 #endif
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+	ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
+#endif
 };
 
 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)

diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index 02aef2844c38..76963ec4641a 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h

@@ -121,4 +121,11 @@ static inline long seccomp_get_metadata(struct task_struct *task,
 	return -EINVAL;
 }
 #endif /* CONFIG_SECCOMP_FILTER && CONFIG_CHECKPOINT_RESTORE */
+
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+struct seq_file;
+
+int proc_pid_seccomp_cache(struct seq_file *m, struct pid_namespace *ns,
+			   struct pid *pid, struct task_struct *task);
+#endif
 #endif /* _LINUX_SECCOMP_H */

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index d8cf468dbe1e..76f524e320b1 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c

@@ -553,6 +553,9 @@ void seccomp_filter_release(struct task_struct *tsk)
 {
 	struct seccomp_filter *orig = tsk->seccomp.filter;
 
+	/* We are effectively holding the siglock by not having any sighand. */
+	WARN_ON(tsk->sighand != NULL);
+
 	/* Detach task from its filter tree. */
 	tsk->seccomp.filter = NULL;
 	__seccomp_filter_release(orig);

@@ -2335,3 +2338,59 @@ static int __init seccomp_sysctl_init(void)
 device_initcall(seccomp_sysctl_init)
 
 #endif /* CONFIG_SYSCTL */
+
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+/* Currently CONFIG_SECCOMP_CACHE_DEBUG implies SECCOMP_ARCH_NATIVE */
+static void proc_pid_seccomp_cache_arch(struct seq_file *m, const char *name,
+					const void *bitmap, size_t bitmap_size)
+{
+	int nr;
+
+	for (nr = 0; nr < bitmap_size; nr++) {
+		bool cached = test_bit(nr, bitmap);
+		char *status = cached ? "ALLOW" : "FILTER";
+
+		seq_printf(m, "%s %d %s\n", name, nr, status);
+	}
+}
+
+int proc_pid_seccomp_cache(struct seq_file *m, struct pid_namespace *ns,
+			   struct pid *pid, struct task_struct *task)
+{
+	struct seccomp_filter *f;
+	unsigned long flags;
+
+	/*
+	 * We don't want some sandboxed process to know what their seccomp
+	 * filters consist of.
+	 */
+	if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (!lock_task_sighand(task, &flags))
+		return -ESRCH;
+
+	f = READ_ONCE(task->seccomp.filter);
+	if (!f) {
+		unlock_task_sighand(task, &flags);
+		return 0;
+	}
+
+	/* prevent filter from being freed while we are printing it */
+	__get_seccomp_filter(f);
+	unlock_task_sighand(task, &flags);
+
+	proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_NATIVE_NAME,
+				    f->cache.allow_native,
+				    SECCOMP_ARCH_NATIVE_NR);
+
+#ifdef SECCOMP_ARCH_COMPAT
+	proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_COMPAT_NAME,
+				    f->cache.allow_compat,
+				    SECCOMP_ARCH_COMPAT_NR);
+#endif /* SECCOMP_ARCH_COMPAT */
+
+	__put_seccomp_filter(f);
+	return 0;
+}
+#endif /* CONFIG_SECCOMP_CACHE_DEBUG */

-- 
2.29.2

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for csky.

Signed-off-by: YiFei Zhu <redacted>
---
 arch/csky/include/asm/Kbuild    |  1 -
 arch/csky/include/asm/seccomp.h | 11 +++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 arch/csky/include/asm/seccomp.h

diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 64876e59e2ef..93372255984d 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild

@@ -4,6 +4,5 @@ generic-y += gpio.h
 generic-y += kvm_para.h
 generic-y += local64.h
 generic-y += qrwlock.h
-generic-y += seccomp.h
 generic-y += user.h
 generic-y += vmlinux.lds.h

diff --git a/arch/csky/include/asm/seccomp.h b/arch/csky/include/asm/seccomp.h
new file mode 100644
index 000000000000..d33e758126fb
--- /dev/null
+++ b/arch/csky/include/asm/seccomp.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_SECCOMP_H
+#define _ASM_SECCOMP_H
+
+#include <asm-generic/seccomp.h>
+
+#define SECCOMP_ARCH_NATIVE		AUDIT_ARCH_CSKY
+#define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+#define SECCOMP_ARCH_NATIVE_NAME	"csky"
+
+#endif /* _ASM_SECCOMP_H */

-- 
2.29.2

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for powerpc.

Signed-off-by: YiFei Zhu <redacted>
---
 arch/powerpc/include/asm/seccomp.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/powerpc/include/asm/seccomp.h b/arch/powerpc/include/asm/seccomp.h
index 51209f6071c5..3efcc83e9cc6 100644
--- a/arch/powerpc/include/asm/seccomp.h
+++ b/arch/powerpc/include/asm/seccomp.h

@@ -8,4 +8,25 @@
 
 #include <asm-generic/seccomp.h>
 
+#ifdef __LITTLE_ENDIAN__
+#define __SECCOMP_ARCH_LE_BIT		__AUDIT_ARCH_LE
+#else
+#define __SECCOMP_ARCH_LE_BIT		0
+#endif
+
+#ifdef CONFIG_PPC64
+# define SECCOMP_ARCH_NATIVE		(AUDIT_ARCH_PPC64 | __SECCOMP_ARCH_LE)
+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"ppc64"
+# ifdef CONFIG_COMPAT
+#  define SECCOMP_ARCH_COMPAT		(AUDIT_ARCH_PPC | __SECCOMP_ARCH_LE)
+#  define SECCOMP_ARCH_COMPAT_NR	NR_syscalls
+#  define SECCOMP_ARCH_COMPAT_NAME	"powerpc"
+# endif
+#else /* !CONFIG_PPC64 */
+# define SECCOMP_ARCH_NATIVE		(AUDIT_ARCH_PPC | __SECCOMP_ARCH_LE)
+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"powerpc"
+#endif
+
 #endif	/* _ASM_POWERPC_SECCOMP_H */

-- 
2.29.2

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for parisc.

Signed-off-by: YiFei Zhu <redacted>
---
 arch/parisc/include/asm/Kbuild    |  1 -
 arch/parisc/include/asm/seccomp.h | 22 ++++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 arch/parisc/include/asm/seccomp.h

diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index e3ee5c0bfe80..f16c4db80116 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild

@@ -5,5 +5,4 @@ generated-y += syscall_table_c32.h
 generic-y += kvm_para.h
 generic-y += local64.h
 generic-y += mcs_spinlock.h
-generic-y += seccomp.h
 generic-y += user.h

diff --git a/arch/parisc/include/asm/seccomp.h b/arch/parisc/include/asm/seccomp.h
new file mode 100644
index 000000000000..b058b2220322
--- /dev/null
+++ b/arch/parisc/include/asm/seccomp.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_SECCOMP_H
+#define _ASM_SECCOMP_H
+
+#include <asm-generic/seccomp.h>
+
+#ifdef CONFIG_64BIT
+# define SECCOMP_ARCH_NATIVE		AUDIT_ARCH_PARISC64
+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"parisc64"
+# ifdef CONFIG_COMPAT
+#  define SECCOMP_ARCH_COMPAT		AUDIT_ARCH_PARISC
+#  define SECCOMP_ARCH_COMPAT_NR	NR_syscalls
+#  define SECCOMP_ARCH_COMPAT_NAME	"parisc"
+# endif
+#else /* !CONFIG_64BIT */
+# define SECCOMP_ARCH_NATIVE		AUDIT_ARCH_PARISC
+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"parisc"
+#endif
+
+#endif /* _ASM_SECCOMP_H */

-- 
2.29.2

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for riscv.

Signed-off-by: YiFei Zhu <redacted>
---
 arch/riscv/include/asm/seccomp.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/riscv/include/asm/seccomp.h b/arch/riscv/include/asm/seccomp.h
index bf7744ee3b3d..c7ee6a3507be 100644
--- a/arch/riscv/include/asm/seccomp.h
+++ b/arch/riscv/include/asm/seccomp.h

@@ -7,4 +7,14 @@
 
 #include <asm-generic/seccomp.h>
 
+#ifdef CONFIG_64BIT
+# define SECCOMP_ARCH_NATIVE		AUDIT_ARCH_RISCV64
+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"riscv64"
+#else /* !CONFIG_64BIT */
+# define SECCOMP_ARCH_NATIVE		AUDIT_ARCH_RISCV32
+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"riscv32"
+#endif
+
 #endif /* _ASM_SECCOMP_H */

-- 
2.29.2

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for s390.

Signed-off-by: YiFei Zhu <redacted>
---
 arch/s390/include/asm/seccomp.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/s390/include/asm/seccomp.h b/arch/s390/include/asm/seccomp.h
index 795bbe0d7ca6..71d46f0ba97b 100644
--- a/arch/s390/include/asm/seccomp.h
+++ b/arch/s390/include/asm/seccomp.h

@@ -16,4 +16,13 @@
 
 #include <asm-generic/seccomp.h>
 
+#define SECCOMP_ARCH_NATIVE		AUDIT_ARCH_S390X
+#define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+#define SECCOMP_ARCH_NATIVE_NAME	"s390x"
+#ifdef CONFIG_COMPAT
+# define SECCOMP_ARCH_COMPAT		AUDIT_ARCH_S390
+# define SECCOMP_ARCH_COMPAT_NR		NR_syscalls
+# define SECCOMP_ARCH_COMPAT_NAME	"s390"
+#endif
+
 #endif	/* _ASM_S390_SECCOMP_H */

-- 
2.29.2

On Tue, Nov 03, 2020 at 07:42:56AM -0600, YiFei Zhu wrote:

From: YiFei Zhu <redacted>

This patch series enables bitmap cache for the remaining arches with
SECCOMP_FILTER, other than MIPS.

I was unable to find any of the arches having subarch-specific NR_syscalls
macros, so generic NR_syscalls is used. SH's syscall_get_arch seems to
only have the 32-bit subarch implementation. I'm not sure if this is
expected.

This series has not been tested; I have not built all the cross compilers
necessary to build test, let alone run the kernel or benchmark the
performance, so help on making sure the bitmap cache works as expected
would be appreciated. The series applies on top of Kees's for-next/seccomp
branch.

Thank you! This looks good. I wonder if the different handling of little
endian is worth solving -- I'm suspicious about powerpc's use of
__LITTLE_ENDIAN__ vs a CONFIG, but I guess the compiler would match the
target endian-ness. Regardless, it captures what the architectures are
doing, and gets things standardized.

YiFei Zhu (8):
  csky: Enable seccomp architecture tracking
  parisc: Enable seccomp architecture tracking

I don't have compilers for these.

  powerpc: Enable seccomp architecture tracking
  riscv: Enable seccomp architecture tracking
  s390: Enable seccomp architecture tracking

These I can build-test immediately.

  sh: Enable seccomp architecture tracking
  xtensa: Enable seccomp architecture tracking

These two are available in Ubuntu's cross compiler set, so I'll get them
added to my cross-builders.

  seccomp/cache: Report cache data through /proc/pid/seccomp_cache

In the meantime, I'll wait a bit to see if we can get some Acks/Reviews
from arch maintainers. :)

-Kees

 arch/Kconfig                       | 15 ++++++++
 arch/csky/include/asm/Kbuild       |  1 -
 arch/csky/include/asm/seccomp.h    | 11 ++++++
 arch/parisc/include/asm/Kbuild     |  1 -
 arch/parisc/include/asm/seccomp.h  | 22 +++++++++++
 arch/powerpc/include/asm/seccomp.h | 21 +++++++++++
 arch/riscv/include/asm/seccomp.h   | 10 +++++
 arch/s390/include/asm/seccomp.h    |  9 +++++
 arch/sh/include/asm/seccomp.h      | 10 +++++
 arch/xtensa/include/asm/Kbuild     |  1 -
 arch/xtensa/include/asm/seccomp.h  | 11 ++++++
 fs/proc/base.c                     |  6 +++
 include/linux/seccomp.h            |  7 ++++
 kernel/seccomp.c                   | 59 ++++++++++++++++++++++++++++++
 14 files changed, 181 insertions(+), 3 deletions(-)
 create mode 100644 arch/csky/include/asm/seccomp.h
 create mode 100644 arch/parisc/include/asm/seccomp.h
 create mode 100644 arch/xtensa/include/asm/seccomp.h


base-commit: 38c37e8fd3d2590c4234d8cfbc22158362f0eb04
--
2.29.2

-- 
Kees Cook

YiFei Zhu [off-list ref] writes:

As Kees mentioned this should (must?!) match the configured endian.

But I think it would still be better to use the CONFIG symbol, which is
CONFIG_CPU_LITTLE_ENDIAN.

+#define __SECCOMP_ARCH_LE_BIT		__AUDIT_ARCH_LE
+#else
+#define __SECCOMP_ARCH_LE_BIT		0
+#endif
+
+#ifdef CONFIG_PPC64
+# define SECCOMP_ARCH_NATIVE		(AUDIT_ARCH_PPC64 | __SECCOMP_ARCH_LE)

You use __SECCOMP_ARCH_LE there, but previously you only defined
__SECCOMP_ARCH_LE_BIT.

Is there some magic somewhere that defines __SECCOMP_ARCH_LE based on
__SECCOMP_ARCH_LE_BIT ?

+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"ppc64"

What's the name used for?

Usually we use "ppc64" for 64-bit big endian and "ppc64le" for 64-bit
little endian.

+# ifdef CONFIG_COMPAT
+#  define SECCOMP_ARCH_COMPAT		(AUDIT_ARCH_PPC | __SECCOMP_ARCH_LE)
+#  define SECCOMP_ARCH_COMPAT_NR	NR_syscalls
+#  define SECCOMP_ARCH_COMPAT_NAME	"powerpc"

And usually we use "ppc" for 32-bit.

+# endif
+#else /* !CONFIG_PPC64 */
+# define SECCOMP_ARCH_NATIVE		(AUDIT_ARCH_PPC | __SECCOMP_ARCH_LE)
+# define SECCOMP_ARCH_NATIVE_NR		NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME	"powerpc"
+#endif
+
 #endif	/* _ASM_POWERPC_SECCOMP_H */
-- 
2.29.2

cheers

On Wed, Nov 4, 2020 at 4:22 AM Michael Ellerman [off-list ref] wrote:

quoted

+#ifdef __LITTLE_ENDIAN__

As Kees mentioned this should (must?!) match the configured endian.

But I think it would still be better to use the CONFIG symbol, which is
CONFIG_CPU_LITTLE_ENDIAN.

My attempt here is to be consistent with asm/syscall.h
syscall_get_arch [1]. Would it make sense to change that to
CONFIG_CPU_LITTLE_ENDIAN then?

[1] https://elixir.bootlin.com/linux/latest/source/arch/powerpc/include/asm/syscall.h#L116

quoted

+# define SECCOMP_ARCH_NATIVE         (AUDIT_ARCH_PPC64 | __SECCOMP_ARCH_LE)

You use __SECCOMP_ARCH_LE there, but previously you only defined
__SECCOMP_ARCH_LE_BIT.

Is there some magic somewhere that defines __SECCOMP_ARCH_LE based on
__SECCOMP_ARCH_LE_BIT ?

Oops, my bad here.

quoted

+# define SECCOMP_ARCH_NATIVE_NR              NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME    "ppc64"

What's the name used for?

This is used in the last patch in this series to report in procfs the
name of each architecture tracked by the bitmap cache.

Usually we use "ppc64" for 64-bit big endian and "ppc64le" for 64-bit
little endian.

And usually we use "ppc" for 32-bit.

Ok.

YiFei Zhu

YiFei Zhu [off-list ref] writes:

On Wed, Nov 4, 2020 at 4:22 AM Michael Ellerman [off-list ref] wrote:

quoted

quoted

+#ifdef __LITTLE_ENDIAN__

As Kees mentioned this should (must?!) match the configured endian.

But I think it would still be better to use the CONFIG symbol, which is
CONFIG_CPU_LITTLE_ENDIAN.

My attempt here is to be consistent with asm/syscall.h
syscall_get_arch [1]. Would it make sense to change that to
CONFIG_CPU_LITTLE_ENDIAN then?

[1] https://elixir.bootlin.com/linux/latest/source/arch/powerpc/include/asm/syscall.h#L116

Looking across the tree with have thousands of usages of
__LITTLE_ENDIAN__, so it's probably not worth converting to
CONFIG_CPU_LITTLE_ENDIAN.

quoted

quoted

+# define SECCOMP_ARCH_NATIVE         (AUDIT_ARCH_PPC64 | __SECCOMP_ARCH_LE)

You use __SECCOMP_ARCH_LE there, but previously you only defined
__SECCOMP_ARCH_LE_BIT.

Is there some magic somewhere that defines __SECCOMP_ARCH_LE based on
__SECCOMP_ARCH_LE_BIT ?

Oops, my bad here.

OK :)

quoted

quoted

+# define SECCOMP_ARCH_NATIVE_NR              NR_syscalls
+# define SECCOMP_ARCH_NATIVE_NAME    "ppc64"

What's the name used for?

This is used in the last patch in this series to report in procfs the
name of each architecture tracked by the bitmap cache.

OK, yeah I think it would be better if the matched the uname -m values.

quoted

Usually we use "ppc64" for 64-bit big endian and "ppc64le" for 64-bit
little endian.

And usually we use "ppc" for 32-bit.

Ok.

cheers

On 11/3/20 2:42 PM, YiFei Zhu wrote:

From: YiFei Zhu <redacted>

To enable seccomp constant action bitmaps, we need to have a static
mapping to the audit architecture and system call table size. Add these
for parisc.

quoted

Signed-off-by: YiFei Zhu <redacted>

I did compile- and boot-tested it, works on 32- and 64-bit parisc kernel.
I don't know how to test it actually, but anyway:

Acked-by: Helge Deller <deller@gmx.de>

Thanks!
Helge

On Tue, Nov 03, 2020 at 07:43:01AM -0600, YiFei Zhu wrote:

Acked-by: Heiko Carstens <hca@linux.ibm.com>