[PATCH -tip] x86: headers - fix export private data to userspace

Cyrill Gorcunov
2009-01-13T18:35:37Z

Impact: cleanup

'make headers_check' warn us about leaking of kernel private
(mostly compile time vars) data to userspace in headers. Fix it.

More detailed report for easier reviewing:

1) boot.h - neither BOOT_HEAP_SIZE, BOOT_STACK_SIZE refs
was found by searching thru net (ie in user-space area).

2) prctl.h - sys_arch_prctl is completely removed from
header since frankly I don't even understand why we
describe it here. It is described like
__SYSCALL(__NR_arch_prctl, sys_arch_prctl) in unistd_64.h
and implemented in process_64.c. User-mode linux involved?
So this one in fact is suspicious.

3) ptrace-abi.h - ptrace_bts_config struct is wrapped
by __KERNEL__ -- not sure if it was ever proposed for
userland.

4) setup.h - COMMAND_LINE_SIZE saved for userspace, bootloaders
could use it.

5) sigcontext32.h - we really need linux/types.h here
since we use __u... types.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---

I should probably write "Impact: break the kernel" :)

It requires _STRONG_ review, randconfig and so on. It's
really fragile -- having NAK on response will be fine.

arch/x86/include/asm/boot.h | 10 +++++++---
arch/x86/include/asm/prctl.h | 4 ----
arch/x86/include/asm/ptrace-abi.h | 4 +++-
arch/x86/include/asm/setup.h | 4 ++--
arch/x86/include/asm/sigcontext32.h | 2 ++
5 files changed, 14 insertions(+), 10 deletions(-)

Index: linux-2.6.git/arch/x86/include/asm/boot.h
===================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/boot.h
+++ linux-2.6.git/arch/x86/include/asm/boot.h
@@ -10,14 +10,16 @@
#define EXTENDED_VGA 0xfffe /* 80x50 mode */
#define ASK_VGA 0xfffd /* ask for it at bootup */

+#ifdef __KERNEL__
+
/* Physical address where kernel should be loaded. */
#define LOAD_PHYSICAL_ADDR ((CONFIG_PHYSICAL_START \
+ (CONFIG_PHYSICAL_ALIGN - 1)) \
& ~(CONFIG_PHYSICAL_ALIGN - 1))

-#if (defined CONFIG_KERNEL_BZIP2)
+#ifdef CONFIG_KERNEL_BZIP2
#define BOOT_HEAP_SIZE 0x400000
-#else
+#else /* !CONFIG_KERNEL_BZIP2 */

#ifdef CONFIG_X86_64
#define BOOT_HEAP_SIZE 0x7000
@@ -25,7 +27,7 @@
#define BOOT_HEAP_SIZE 0x4000
#endif

-#endif
+#endif /* !CONFIG_KERNEL_BZIP2 */

#ifdef CONFIG_X86_64
#define BOOT_STACK_SIZE 0x4000
@@ -33,4 +35,6 @@
#define BOOT_STACK_SIZE 0x1000
#endif

+#endif /* __KERNEL__ */
+
#endif /* _ASM_X86_BOOT_H */
Index: linux-2.6.git/arch/x86/include/asm/prctl.h
===================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/prctl.h
+++ linux-2.6.git/arch/x86/include/asm/prctl.h
@@ -6,8 +6,4 @@
#define ARCH_GET_FS 0x1003
#define ARCH_GET_GS 0x1004

-#ifdef CONFIG_X86_64
-extern long sys_arch_prctl(int, unsigned long);
-#endif /* CONFIG_X86_64 */
-
#endif /* _ASM_X86_PRCTL_H */
Index: linux-2.6.git/arch/x86/include/asm/ptrace-abi.h
===================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/ptrace-abi.h
+++ linux-2.6.git/arch/x86/include/asm/ptrace-abi.h
@@ -50,7 +50,7 @@
#define RSP 152
#define SS 160
#define ARGOFFSET R11
-#endif /* __ASSEMBLY__ */
+#endif /* __ASSEMBLY__ || __FRAME_OFFSETS */

/* top of stack page */
#define FRAME_SIZE 168
@@ -80,6 +80,7 @@

#define PTRACE_SINGLEBLOCK 33 /* resume execution until next branch */

+#ifdef __KERNEL__
#ifdef CONFIG_X86_PTRACE_BTS

#ifndef __ASSEMBLY__
@@ -141,5 +142,6 @@ struct ptrace_bts_config {
Returns number of BTS records drained.
*/
#endif /* CONFIG_X86_PTRACE_BTS */
+#endif /* __KERNEL__ */

#endif /* _ASM_X86_PTRACE_ABI_H */
Index: linux-2.6.git/arch/x86/include/asm/setup.h
===================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/setup.h
+++ linux-2.6.git/arch/x86/include/asm/setup.h
@@ -3,6 +3,8 @@

#define COMMAND_LINE_SIZE 2048

+#ifdef __KERNEL__
+
#ifndef __ASSEMBLY__

/* Interrupt control for vSMPowered x86_64 systems */
@@ -56,8 +58,6 @@ extern unsigned long saved_video_mode;
#endif
#endif /* __ASSEMBLY__ */

-#ifdef __KERNEL__
-
#ifdef __i386__

#include <linux/pfn.h>
Index: linux-2.6.git/arch/x86/include/asm/sigcontext32.h
===================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/sigcontext32.h
+++ linux-2.6.git/arch/x86/include/asm/sigcontext32.h
@@ -1,6 +1,8 @@
#ifndef _ASM_X86_SIGCONTEXT32_H
#define _ASM_X86_SIGCONTEXT32_H

+#include <linux/types.h>
+
/* signal context for 32bit programs. */

#define X86_FXSR_MAGIC 0x0000