diff mbox

[RFC,v2,1/1] audit: Add generic compat syscall support

Message ID 1384854235-6567-1-git-send-email-takahiro.akashi@linaro.org
State New
Headers show

Commit Message

AKASHI Takahiro Nov. 19, 2013, 9:43 a.m. UTC 
(v1 was created mistakenly. Please igore it.)

lib/audit.c provides a generic definition for auditing system calls.
lib/compat_audit.c similarly adds compat syscall support for
bi-architectures (32/64-bit).

Each architecture must define audit_is_compat() in asm/audit.h.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 include/linux/audit.h |    9 +++++++++
 lib/Makefile          |    3 +++
 lib/audit.c           |   17 +++++++++++++++++
 lib/compat_audit.c    |   51 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 80 insertions(+)
 create mode 100644 lib/compat_audit.c

Comments

Will Deacon Nov. 25, 2013, 7:01 p.m. UTC | #1 
On Tue, Nov 19, 2013 at 09:43:55AM +0000, AKASHI Takahiro wrote:
> (v1 was created mistakenly. Please igore it.)
> 
> lib/audit.c provides a generic definition for auditing system calls.
> lib/compat_audit.c similarly adds compat syscall support for
> bi-architectures (32/64-bit).
> 
> Each architecture must define audit_is_compat() in asm/audit.h.
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
>  include/linux/audit.h |    9 +++++++++
>  lib/Makefile          |    3 +++
>  lib/audit.c           |   17 +++++++++++++++++
>  lib/compat_audit.c    |   51 +++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 80 insertions(+)
>  create mode 100644 lib/compat_audit.c
> 
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 729a4d1..c49a312 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -76,6 +76,15 @@ struct audit_field {
>  extern int __init audit_register_class(int class, unsigned *list);
>  extern int audit_classify_syscall(int abi, unsigned syscall);
>  extern int audit_classify_arch(int arch);
> +#if defined(CONFIG_AUDIT_GENERIC) && defined(CONFIG_COMPAT)
> +extern unsigned compat_write_class[];
> +extern unsigned compat_read_class[];
> +extern unsigned compat_dir_class[];
> +extern unsigned compat_chattr_class[];
> +extern unsigned compat_signal_class[];
> +
> +extern int audit_classify_compat_syscall(int abi, unsigned syscall);
> +#endif
>  
>  /* audit_names->type values */
>  #define	AUDIT_TYPE_UNKNOWN	0	/* we don't know yet */
> diff --git a/lib/Makefile b/lib/Makefile
> index f3bb2cb..5bb185a 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -96,6 +96,9 @@ obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o
>  obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
>  obj-$(CONFIG_SMP) += percpu_counter.o
>  obj-$(CONFIG_AUDIT_GENERIC) += audit.o
> +ifeq ($(CONFIG_COMPAT),y)
> +obj-$(CONFIG_AUDIT_GENERIC) += compat_audit.o
> +endif
>  
>  obj-$(CONFIG_SWIOTLB) += swiotlb.o
>  obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
> diff --git a/lib/audit.c b/lib/audit.c
> index 76bbed4..3bf3858 100644
> --- a/lib/audit.c
> +++ b/lib/audit.c
> @@ -1,6 +1,7 @@
>  #include <linux/init.h>
>  #include <linux/types.h>
>  #include <linux/audit.h>
> +#include <asm/audit.h>
>  #include <asm/unistd.h>
>  
>  static unsigned dir_class[] = {
> @@ -30,11 +31,20 @@ static unsigned signal_class[] = {
>  
>  int audit_classify_arch(int arch)
>  {
> +#ifdef CONFIG_COMPAT
> +	if (audit_is_compat(arch))
> +		return 1;
> +#endif
>  	return 0;
>  }
>  
>  int audit_classify_syscall(int abi, unsigned syscall)
>  {
> +#ifdef CONFIG_COMPAT
> +	if (audit_is_compat(abi))
> +		return audit_classify_compat_syscall(abi, syscall);
> +#endif

Hmm, I'm not sure this is the right way to solve this problem. Whether
something is compat or not depends on the task to which it is associated. If
this is always the current task for the audit cases, then you can just use
something like is_compat_task. Otherwise, I think we need to get a handle on
the task_struct here. An arch-callback feels like the wrong approach to me.

Will
AKASHI Takahiro Nov. 27, 2013, 1:34 a.m. UTC | #2 
Will, I always thank you for your comments:

On 11/26/2013 04:01 AM, Will Deacon wrote:
> On Tue, Nov 19, 2013 at 09:43:55AM +0000, AKASHI Takahiro wrote:
>> (v1 was created mistakenly. Please igore it.)
>>
>> lib/audit.c provides a generic definition for auditing system calls.
>> lib/compat_audit.c similarly adds compat syscall support for
>> bi-architectures (32/64-bit).
>>
>> Each architecture must define audit_is_compat() in asm/audit.h.
>>
>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
>> ---
>>   include/linux/audit.h |    9 +++++++++
>>   lib/Makefile          |    3 +++
>>   lib/audit.c           |   17 +++++++++++++++++
>>   lib/compat_audit.c    |   51 +++++++++++++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 80 insertions(+)
>>   create mode 100644 lib/compat_audit.c
>>
>> diff --git a/include/linux/audit.h b/include/linux/audit.h
>> index 729a4d1..c49a312 100644
>> --- a/include/linux/audit.h
>> +++ b/include/linux/audit.h
>> @@ -76,6 +76,15 @@ struct audit_field {
>>   extern int __init audit_register_class(int class, unsigned *list);
>>   extern int audit_classify_syscall(int abi, unsigned syscall);
>>   extern int audit_classify_arch(int arch);
>> +#if defined(CONFIG_AUDIT_GENERIC) && defined(CONFIG_COMPAT)
>> +extern unsigned compat_write_class[];
>> +extern unsigned compat_read_class[];
>> +extern unsigned compat_dir_class[];
>> +extern unsigned compat_chattr_class[];
>> +extern unsigned compat_signal_class[];
>> +
>> +extern int audit_classify_compat_syscall(int abi, unsigned syscall);
>> +#endif
>>
>>   /* audit_names->type values */
>>   #define	AUDIT_TYPE_UNKNOWN	0	/* we don't know yet */
>> diff --git a/lib/Makefile b/lib/Makefile
>> index f3bb2cb..5bb185a 100644
>> --- a/lib/Makefile
>> +++ b/lib/Makefile
>> @@ -96,6 +96,9 @@ obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o
>>   obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
>>   obj-$(CONFIG_SMP) += percpu_counter.o
>>   obj-$(CONFIG_AUDIT_GENERIC) += audit.o
>> +ifeq ($(CONFIG_COMPAT),y)
>> +obj-$(CONFIG_AUDIT_GENERIC) += compat_audit.o
>> +endif
>>
>>   obj-$(CONFIG_SWIOTLB) += swiotlb.o
>>   obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
>> diff --git a/lib/audit.c b/lib/audit.c
>> index 76bbed4..3bf3858 100644
>> --- a/lib/audit.c
>> +++ b/lib/audit.c
>> @@ -1,6 +1,7 @@
>>   #include <linux/init.h>
>>   #include <linux/types.h>
>>   #include <linux/audit.h>
>> +#include <asm/audit.h>
>>   #include <asm/unistd.h>
>>
>>   static unsigned dir_class[] = {
>> @@ -30,11 +31,20 @@ static unsigned signal_class[] = {
>>
>>   int audit_classify_arch(int arch)
>>   {
>> +#ifdef CONFIG_COMPAT
>> +	if (audit_is_compat(arch))
>> +		return 1;
>> +#endif
>>   	return 0;
>>   }
>>
>>   int audit_classify_syscall(int abi, unsigned syscall)
>>   {
>> +#ifdef CONFIG_COMPAT
>> +	if (audit_is_compat(abi))
>> +		return audit_classify_compat_syscall(abi, syscall);
>> +#endif
>
> Hmm, I'm not sure this is the right way to solve this problem. Whether
> something is compat or not depends on the task to which it is associated. If
> this is always the current task for the audit cases, then you can just use
> something like is_compat_task. Otherwise, I think we need to get a handle on
> the task_struct here. An arch-callback feels like the wrong approach to me.

You are completely right. In my current (v3 prototype) implementation,
"abi" argument, which can be AUDIT_ARCH_ARM(EB) or AUDIT_ARCH_AARCH64(EB),
passed to audit_classify_syscall() is determined per-task using is_compat_thread()
when audit_syscall_entry() is executed in syscall_trace().
(Obviously audit_is_compat() is true only in case of AUDIT_ARCH_ARM.)

V3 based on this patch is working for 32-bit and 64-bit userland.
I can submit v3 patch if you want.

Thanks,
-Takahiro AKASHI

> Will
>
diff mbox

Patch

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 729a4d1..c49a312 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -76,6 +76,15 @@  struct audit_field {
 extern int __init audit_register_class(int class, unsigned *list);
 extern int audit_classify_syscall(int abi, unsigned syscall);
 extern int audit_classify_arch(int arch);
+#if defined(CONFIG_AUDIT_GENERIC) && defined(CONFIG_COMPAT)
+extern unsigned compat_write_class[];
+extern unsigned compat_read_class[];
+extern unsigned compat_dir_class[];
+extern unsigned compat_chattr_class[];
+extern unsigned compat_signal_class[];
+
+extern int audit_classify_compat_syscall(int abi, unsigned syscall);
+#endif
 
 /* audit_names->type values */
 #define	AUDIT_TYPE_UNKNOWN	0	/* we don't know yet */
diff --git a/lib/Makefile b/lib/Makefile
index f3bb2cb..5bb185a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -96,6 +96,9 @@  obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o
 obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
 obj-$(CONFIG_SMP) += percpu_counter.o
 obj-$(CONFIG_AUDIT_GENERIC) += audit.o
+ifeq ($(CONFIG_COMPAT),y)
+obj-$(CONFIG_AUDIT_GENERIC) += compat_audit.o
+endif
 
 obj-$(CONFIG_SWIOTLB) += swiotlb.o
 obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
diff --git a/lib/audit.c b/lib/audit.c
index 76bbed4..3bf3858 100644
--- a/lib/audit.c
+++ b/lib/audit.c
@@ -1,6 +1,7 @@ 
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/audit.h>
+#include <asm/audit.h>
 #include <asm/unistd.h>
 
 static unsigned dir_class[] = {
@@ -30,11 +31,20 @@  static unsigned signal_class[] = {
 
 int audit_classify_arch(int arch)
 {
+#ifdef CONFIG_COMPAT
+	if (audit_is_compat(arch))
+		return 1;
+#endif
 	return 0;
 }
 
 int audit_classify_syscall(int abi, unsigned syscall)
 {
+#ifdef CONFIG_COMPAT
+	if (audit_is_compat(abi))
+		return audit_classify_compat_syscall(abi, syscall);
+#endif
+
 	switch(syscall) {
 #ifdef __NR_open
 	case __NR_open:
@@ -57,6 +67,13 @@  int audit_classify_syscall(int abi, unsigned syscall)
 
 static int __init audit_classes_init(void)
 {
+#ifdef CONFIG_COMPAT
+	audit_register_class(AUDIT_CLASS_WRITE, compat_write_class);
+	audit_register_class(AUDIT_CLASS_READ, compat_read_class);
+	audit_register_class(AUDIT_CLASS_DIR_WRITE, compat_dir_class);
+	audit_register_class(AUDIT_CLASS_CHATTR, compat_chattr_class);
+	audit_register_class(AUDIT_CLASS_SIGNAL, compat_signal_class);
+#endif
 	audit_register_class(AUDIT_CLASS_WRITE, write_class);
 	audit_register_class(AUDIT_CLASS_READ, read_class);
 	audit_register_class(AUDIT_CLASS_DIR_WRITE, dir_class);
diff --git a/lib/compat_audit.c b/lib/compat_audit.c
new file mode 100644
index 0000000..94f6480
--- /dev/null
+++ b/lib/compat_audit.c
@@ -0,0 +1,51 @@ 
+#include <linux/init.h>
+#include <linux/types.h>
+/* FIXME: this might be architecture dependent */
+#include <asm/unistd_32.h>
+
+unsigned compat_dir_class[] = {
+#include <asm-generic/audit_dir_write.h>
+~0U
+};
+
+unsigned compat_read_class[] = {
+#include <asm-generic/audit_read.h>
+~0U
+};
+
+unsigned compat_write_class[] = {
+#include <asm-generic/audit_write.h>
+~0U
+};
+
+unsigned compat_chattr_class[] = {
+#include <asm-generic/audit_change_attr.h>
+~0U
+};
+
+unsigned compat_signal_class[] = {
+#include <asm-generic/audit_signal.h>
+~0U
+};
+
+int audit_classify_compat_syscall(int abi, unsigned syscall)
+{
+	switch (syscall) {
+#ifdef __NR_open
+	case __NR_open:
+		return 2;
+#endif
+#ifdef __NR_openat
+	case __NR_openat:
+		return 3;
+#endif
+#ifdef __NR_socketcall
+	case __NR_socketcall:
+		return 4;
+#endif
+	case __NR_execve:
+		return 5;
+	default:
+		return 1;
+	}
+}