audit: Add generic compat syscall support

lib/audit.c provides a generic function for auditing system calls.
This patch extends it for compat syscall support on bi-architectures
(32/64-bit) by adding lib/compat_audit.c.
What is required to support this feature are:
 * add asm/unistd32.h for compat system call names
 * select CONFIG_AUDIT_ARCH_COMPAT_GENERIC

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

diff --git a/include/linux/audit.h b/include/linux/audit.h
index ec1464df4c60930a7fde38f1bc6f35a35b7f79d3..4b2983e25ce0cc07c929ad81f4de187f78ffe1a3 100644 (file)
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -79,6 +79,14 @@ extern int is_audit_feature_set(int which);
 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);
+/* only for compat system calls */
+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 __weak audit_classify_compat_syscall(int abi, unsigned syscall);
 
 /* audit_names->type values */
 #define        AUDIT_TYPE_UNKNOWN      0       /* we don't know yet */

diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 4315ee99b967f33661a2000b8988bceb029c798f..9af01d77dc44bd3d4fd9b4800e114496990c1a37 100644 (file)
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -362,6 +362,12 @@ enum {
 #define AUDIT_ARCH_SPARC64     (EM_SPARCV9|__AUDIT_ARCH_64BIT)
 #define AUDIT_ARCH_X86_64      (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
 
+#ifdef CONFIG_COMPAT
+#define audit_is_compat(arch)  (!((arch) & __AUDIT_ARCH_64BIT))
+#else
+#define audit_is_compat(arch)  false
+#endif
+
 #define AUDIT_PERM_EXEC                1
 #define AUDIT_PERM_WRITE       2
 #define AUDIT_PERM_READ                4

diff --git a/lib/Kconfig b/lib/Kconfig
index 991c98bc4a3f51e9e7f377274084bec909483ea9..1e80cb3c77a9cab901ac31dad4b1126c80d09cde 100644 (file)
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -182,6 +182,15 @@ config AUDIT_GENERIC
        depends on AUDIT && !AUDIT_ARCH
        default y
 
+config AUDIT_ARCH_COMPAT_GENERIC
+       bool
+       default n
+
+config AUDIT_COMPAT_GENERIC
+       bool
+       depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
+       default y
+
 config RANDOM32_SELFTEST
        bool "PRNG perform self test on init"
        default n

diff --git a/lib/Makefile b/lib/Makefile
index a459c31e8c6bb0286237b27bcb65d776bccad1b7..972552b39cf512aaa30f5d9448882e8fddb0e126 100644 (file)
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -93,6 +93,7 @@ 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
+obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o
 
 obj-$(CONFIG_SWIOTLB) += swiotlb.o
 obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o

diff --git a/lib/audit.c b/lib/audit.c
index 76bbed4a20e55d85ebdfc32881d436ee98592f4f..1d726a22565bdc41a36a19b1a5c26a441549f9b3 100644 (file)
--- a/lib/audit.c
+++ b/lib/audit.c
@@ -30,11 +30,17 @@ static unsigned signal_class[] = {
 
 int audit_classify_arch(int arch)
 {
-       return 0;
+       if (audit_is_compat(arch))
+               return 1;
+       else
+               return 0;
 }
 
 int audit_classify_syscall(int abi, unsigned syscall)
 {
+       if (audit_is_compat(abi))
+               return audit_classify_compat_syscall(abi, syscall);
+
        switch(syscall) {
 #ifdef __NR_open
        case __NR_open:
@@ -57,6 +63,13 @@ int audit_classify_syscall(int abi, unsigned syscall)
 
 static int __init audit_classes_init(void)
 {
+#ifdef CONFIG_AUDIT_COMPAT_GENERIC
+       audit_register_class(AUDIT_CLASS_WRITE_32, compat_write_class);
+       audit_register_class(AUDIT_CLASS_READ_32, compat_read_class);
+       audit_register_class(AUDIT_CLASS_DIR_WRITE_32, compat_dir_class);
+       audit_register_class(AUDIT_CLASS_CHATTR_32, compat_chattr_class);
+       audit_register_class(AUDIT_CLASS_SIGNAL_32, 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 (file)
index 0000000..873f75b
--- /dev/null
+++ b/lib/compat_audit.c
@@ -0,0 +1,50 @@
+#include <linux/init.h>
+#include <linux/types.h>
+#include <asm/unistd32.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;
+       }
+}