audit: replace magic audit syscall class numbers with macros

Replace audit syscall class magic numbers with macros.

This required putting the macros into new header file
include/linux/audit_arch.h since the syscall macros were
included for both 64 bit and 32 bit in any compat code, causing
redefinition warnings.

Link: https://lore.kernel.org/r/2300b1083a32aade7ae7efb95826e8f3f260b1df.1621363275.git.rgb@redhat.com
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
[PM: renamed header to audit_arch.h after consulting with Richard]
Signed-off-by: Paul Moore <paul@paul-moore.com>

MAINTAINERS

@@ -3113,6 +3113,7 @@ W:	https://github.com/linux-audit
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git
 F:	include/asm-generic/audit_*.h
 F:	include/linux/audit.h
+F:	include/linux/audit_arch.h
 F:	include/uapi/linux/audit.h
 F:	kernel/audit*
 F:	lib/*audit.c

arch/alpha/kernel/audit.c

@@ -37,13 +37,13 @@ int audit_classify_syscall(int abi, unsigned syscall)
 {
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

arch/ia64/kernel/audit.c

@@ -38,13 +38,13 @@ int audit_classify_syscall(int abi, unsigned syscall)
 {
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

arch/parisc/kernel/audit.c

@@ -47,13 +47,13 @@ int audit_classify_syscall(int abi, unsigned syscall)
 #endif
 	switch (syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

arch/parisc/kernel/compat_audit.c

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/audit_arch.h>
 #include <asm/unistd.h>
 
 unsigned int parisc32_dir_class[] = {
@@ -30,12 +31,12 @@ int parisc32_classify_syscall(unsigned syscall)
 {
 	switch (syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 1;
+		return AUDITSC_COMPAT;
 	}
 }

arch/powerpc/kernel/audit.c

@@ -47,15 +47,15 @@ int audit_classify_syscall(int abi, unsigned syscall)
 #endif
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

arch/powerpc/kernel/compat_audit.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #undef __powerpc64__
+#include <linux/audit_arch.h>
 #include <asm/unistd.h>
 
 unsigned ppc32_dir_class[] = {
@@ -31,14 +32,14 @@ int ppc32_classify_syscall(unsigned syscall)
 {
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 1;
+		return AUDITSC_COMPAT;
 	}
 }

arch/s390/kernel/audit.c

@@ -47,15 +47,15 @@ int audit_classify_syscall(int abi, unsigned syscall)
 #endif
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

arch/s390/kernel/compat_audit.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #undef __s390x__
+#include <linux/audit_arch.h>
 #include <asm/unistd.h>
 #include "audit.h"
 
@@ -32,14 +33,14 @@ int s390_classify_syscall(unsigned syscall)
 {
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 1;
+		return AUDITSC_COMPAT;
 	}
 }

arch/sparc/kernel/audit.c

@@ -48,15 +48,15 @@ int audit_classify_syscall(int abi, unsigned int syscall)
 #endif
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

arch/sparc/kernel/compat_audit.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #define __32bit_syscall_numbers__
+#include <linux/audit_arch.h>
 #include <asm/unistd.h>
 #include "kernel.h"
 
@@ -32,14 +33,14 @@ int sparc32_classify_syscall(unsigned int syscall)
 {
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 1;
+		return AUDITSC_COMPAT;
 	}
 }

arch/x86/ia32/audit.c

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/audit_arch.h>
 #include <asm/unistd_32.h>
 #include <asm/audit.h>
 
@@ -31,15 +32,15 @@ int ia32_classify_syscall(unsigned syscall)
 {
 	switch (syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
 	case __NR_execveat:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 1;
+		return AUDITSC_COMPAT;
 	}
 }

arch/x86/kernel/audit_64.c

@@ -47,14 +47,14 @@ int audit_classify_syscall(int abi, unsigned syscall)
 #endif
 	switch(syscall) {
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 	case __NR_execve:
 	case __NR_execveat:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

include/linux/audit.h

@@ -11,6 +11,7 @@
 
 #include <linux/sched.h>
 #include <linux/ptrace.h>
+#include <linux/audit_arch.h>
 #include <uapi/linux/audit.h>
 #include <uapi/linux/netfilter/nf_tables.h>
 

include/linux/audit_arch.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* audit_arch.h -- Arch layer specific support for audit
+ *
+ * Copyright 2021 Red Hat Inc., Durham, North Carolina.
+ * All Rights Reserved.
+ *
+ * Author: Richard Guy Briggs <rgb@redhat.com>
+ */
+#ifndef _LINUX_AUDIT_ARCH_H_
+#define _LINUX_AUDIT_ARCH_H_
+
+enum auditsc_class_t {
+	AUDITSC_NATIVE = 0,
+	AUDITSC_COMPAT,
+	AUDITSC_OPEN,
+	AUDITSC_OPENAT,
+	AUDITSC_SOCKETCALL,
+	AUDITSC_EXECVE,
+
+	AUDITSC_NVALS /* count */
+};
+
+#endif

kernel/auditsc.c

@@ -153,7 +153,7 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
 	n = ctx->major;
 
 	switch (audit_classify_syscall(ctx->arch, n)) {
-	case 0:	/* native */
+	case AUDITSC_NATIVE:
 		if ((mask & AUDIT_PERM_WRITE) &&
 		     audit_match_class(AUDIT_CLASS_WRITE, n))
 			return 1;
@@ -164,7 +164,7 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
 		     audit_match_class(AUDIT_CLASS_CHATTR, n))
 			return 1;
 		return 0;
-	case 1: /* 32bit on biarch */
+	case AUDITSC_COMPAT: /* 32bit on biarch */
 		if ((mask & AUDIT_PERM_WRITE) &&
 		     audit_match_class(AUDIT_CLASS_WRITE_32, n))
 			return 1;
@@ -175,13 +175,13 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
 		     audit_match_class(AUDIT_CLASS_CHATTR_32, n))
 			return 1;
 		return 0;
-	case 2: /* open */
+	case AUDITSC_OPEN:
 		return mask & ACC_MODE(ctx->argv[1]);
-	case 3: /* openat */
+	case AUDITSC_OPENAT:
 		return mask & ACC_MODE(ctx->argv[2]);
-	case 4: /* socketcall */
+	case AUDITSC_SOCKETCALL:
 		return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
-	case 5: /* execve */
+	case AUDITSC_EXECVE:
 		return mask & AUDIT_PERM_EXEC;
 	default:
 		return 0;

lib/audit.c

@@ -45,23 +45,23 @@ int audit_classify_syscall(int abi, unsigned syscall)
 	switch(syscall) {
 #ifdef __NR_open
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 #endif
 #ifdef __NR_openat
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 #endif
 #ifdef __NR_socketcall
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 #endif
 #ifdef __NR_execveat
 	case __NR_execveat:
 #endif
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 0;
+		return AUDITSC_NATIVE;
 	}
 }
 

lib/compat_audit.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/audit_arch.h>
 #include <asm/unistd32.h>
 
 unsigned compat_dir_class[] = {
@@ -33,19 +34,19 @@ int audit_classify_compat_syscall(int abi, unsigned syscall)
 	switch (syscall) {
 #ifdef __NR_open
 	case __NR_open:
-		return 2;
+		return AUDITSC_OPEN;
 #endif
 #ifdef __NR_openat
 	case __NR_openat:
-		return 3;
+		return AUDITSC_OPENAT;
 #endif
 #ifdef __NR_socketcall
 	case __NR_socketcall:
-		return 4;
+		return AUDITSC_SOCKETCALL;
 #endif
 	case __NR_execve:
-		return 5;
+		return AUDITSC_EXECVE;
 	default:
-		return 1;
+		return AUDITSC_COMPAT;
 	}
 }