Re: [PATCH 3/4] arm64: audit: Add AArch32 support
On 11/08/2013 11:55 PM, Will Deacon wrote:
On Wed, Nov 06, 2013 at 10:25:45AM +0000, AKASHI Takahiro wrote:
> ---
> arch/arm64/include/asm/audit32.h | 12 ++
> arch/arm64/include/asm/unistd32.h | 387 +++++++++++++++++++++++++++++++++++++
> arch/arm64/kernel/Makefile | 3 +
> arch/arm64/kernel/audit.c | 18 ++
> arch/arm64/kernel/audit32.c | 46 +++++
> 5 files changed, 466 insertions(+)
> create mode 100644 arch/arm64/include/asm/audit32.h
> create mode 100644 arch/arm64/kernel/audit32.c
>
> diff --git a/arch/arm64/include/asm/audit32.h b/arch/arm64/include/asm/audit32.h
> new file mode 100644
> index 0000000..debfe57
> --- /dev/null
> +++ b/arch/arm64/include/asm/audit32.h
> @@ -0,0 +1,12 @@
> +#ifndef __ASM_AUDIT32_H
> +#define __ASM_AUDIT32_H
> +
> +extern unsigned aarch32_dir_class[];
> +extern unsigned aarch32_read_class[];
> +extern unsigned aarch32_write_class[];
> +extern unsigned aarch32_chattr_class[];
> +extern unsigned aarch32_signal_class[];
> +
> +extern int aarch32_classify_syscall(unsigned);
> +
> +#endif /* __ASM_AUDIT32_H */
> diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
> index 58125bf..fdf5e56 100644
> --- a/arch/arm64/include/asm/unistd32.h
> +++ b/arch/arm64/include/asm/unistd32.h
> @@ -21,6 +21,393 @@
> #define __SYSCALL(x, y)
> #endif
>
> +#ifdef __AARCH32_AUDITSYSCALL
> +/*
> + * FIXME: Currenty only audit uses (part of) these definitions.
> + * See audit32.c
> + */
> +#define __NR_restart_syscall 0
> +#define __NR_exit 1
> +#define __NR_fork 2
> +#define __NR_read 3
Don't bother with this file. It's a needless replication of data already in
the file and you don't even need it all.
Unfortunately, I need them not only for aarch32_classify_syscall(), but
also in asm-generic/audit_*.h. Actually 47 of __NR_xxx are referred to
in those files.
The problem is that aarch64 and aarch32 have different system call
numbers, but that there are no __NR_xxx definitions for aarch32 in
asm/unistd32.h.
> diff --git a/arch/arm64/kernel/audit32.c
b/arch/arm64/kernel/audit32.c
> new file mode 100644
> index 0000000..2aa4d7d
> --- /dev/null
> +++ b/arch/arm64/kernel/audit32.c
> @@ -0,0 +1,46 @@
> +#define __AARCH32_AUDITSYSCALL
> +#include <asm/unistd32.h>
> +
> +unsigned aarch32_dir_class[] = {
> +#include <asm-generic/audit_dir_write.h>
> +~0U
> +};
> +
> +unsigned aarch32_read_class[] = {
> +#include <asm-generic/audit_read.h>
> +~0U
> +};
> +
> +unsigned aarch32_write_class[] = {
> +#include <asm-generic/audit_write.h>
> +~0U
> +};
> +
> +unsigned aarch32_chattr_class[] = {
> +#include <asm-generic/audit_change_attr.h>
> +~0U
> +};
> +
> +unsigned aarch32_signal_class[] = {
> +#include <asm-generic/audit_signal.h>
> +~0U
> +};
> +
> +int aarch32_classify_syscall(unsigned syscall)
> +{
> + switch(syscall) {
> + case __NR_open:
> + return 2;
> + case __NR_openat:
> + return 3;
> + /*
> + * obsolute in EABI
> + * case __NR_socketcall:
> + * return 4;
> + */
> + case __NR_execve:
> + return 5;
> + default:
> + return 1; /* 32-bit on biarch */
> + }
Instead, just add __NR_compat_{open,openat,execve}, like we have done for
the signal-related syscalls.
As far as xxx_classify_syscall is concerned, it is possible to change
the code to use __NR_compat_..., but it is difficult to remove __NR_...
from unistd32.h because, as I mentioned above, asm-generic/audit_xxx.h
use __NR_...
Also, can't the generic lib/audit.c be reworked to work with
compat too?
I hope so, but don't think re-work is practical unless we have
generic solution against this issue.
(In addition, other architectures already have their own
implementation.)
-Takahiro AKASHI
Will