[7/8] x86: Enable seccomp constant action bitmaps

Commit Message

Kees Cook June 16, 2020, 7:49 a.m. UTC

Now that CPU-local kernel TLB flushes are available to seccomp, define
the specific architectures seccomp should be expected to reason about,
so that constant action bitmaps can be enabled for x86.

TODO: handle x32 via a "synthetic architecture" check, like done in
syscall entry.

Signed-off-by: Kees Cook <[e-mail]>
---
 arch/x86/Kconfig               | 1 +
 arch/x86/include/asm/syscall.h | 5 +++++
 2 files changed, 6 insertions(+)

Patch

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6a0cc524882d..0f7a0abab88f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -149,6 +149,7 @@  config X86
 	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
 	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_SECCOMP_FILTER
+	select HAVE_ARCH_SECCOMP_BITMAP		if !X86_X32
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
 	select HAVE_ARCH_STACKLEAK
 	select HAVE_ARCH_TRACEHOOK
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index 7cbf733d11af..b89e86f4c061 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -97,6 +97,7 @@  static inline void syscall_set_arguments(struct task_struct *task,
 	memcpy(&regs->bx + i, args, n * sizeof(args[0]));
 }
 
+#define SECCOMP_ARCH		AUDIT_ARCH_I386
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_I386;
@@ -152,6 +153,10 @@  static inline void syscall_set_arguments(struct task_struct *task,
 	}
 }
 
+#define SECCOMP_ARCH		AUDIT_ARCH_X86_64
+#ifdef CONFIG_COMPAT
+#define SECCOMP_ARCH_COMPAT	AUDIT_ARCH_I386
+#endif
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	/* x32 tasks should be considered AUDIT_ARCH_X86_64. */