[PATCH v4 0/3] audit: add support for openat2

[PATCH v4 0/3] audit: add support for openat2

[Richard Guy Briggs]

The openat2(2) syscall was added in v5.6.  Add support for openat2 to the
audit syscall classifier and for recording openat2 parameters that cannot
be captured in the syscall parameters of the SYSCALL record.

Supporting userspace code can be found in
https://github.com/rgbriggs/audit-userspace/tree/ghau-openat2

Supporting test case can be found in
https://github.com/linux-audit/audit-testsuite/pull/103

Changelog:
v4:
- change filename include/linux/auditscm.h to auditsc_classmacros.h to avoid socket association

v3:
- re-add commit descriptions that somehow got dropped
- add new file to MAINTAINERS

v2:
- add include/linux/auditscm.h for audit syscall class macros due to syscall redefinition warnings:
        arch/x86/ia32/audit.c:3:
        ./include/linux/audit.h:12,
        ./include/linux/sched.h:22,
        ./include/linux/seccomp.h:21,
        ./arch/x86/include/asm/seccomp.h:5,
        ./arch/x86/include/asm/unistd.h:20,
        ./arch/x86/include/generated/uapi/asm/unistd_64.h:4: warning: "__NR_read" redefined #define __NR_read 0
	...
        ./arch/x86/include/generated/uapi/asm/unistd_64.h:338: warning: "__NR_rseq" redefined #define __NR_rseq 334
    previous:
        arch/x86/ia32/audit.c:2:
        ./arch/x86/include/generated/uapi/asm/unistd_32.h:7: note: this is the location of the previous definition #define __NR_read 3                                                                                                      
	...
        ./arch/x86/include/generated/uapi/asm/unistd_32.h:386: note: this is the location of the previous definition #define __NR_rseq 386

Richard Guy Briggs (3):
  audit: replace magic audit syscall class numbers with macros
  audit: add support for the openat2 syscall
  audit: add OPENAT2 record to list how

 MAINTAINERS                         |  1 +
 arch/alpha/kernel/audit.c           | 10 ++++++----
 arch/ia64/kernel/audit.c            | 10 ++++++----
 arch/parisc/kernel/audit.c          | 10 ++++++----
 arch/parisc/kernel/compat_audit.c   | 11 ++++++----
 arch/powerpc/kernel/audit.c         | 12 ++++++-----
 arch/powerpc/kernel/compat_audit.c  | 13 +++++++-----
 arch/s390/kernel/audit.c            | 12 ++++++-----
 arch/s390/kernel/compat_audit.c     | 13 +++++++-----
 arch/sparc/kernel/audit.c           | 12 ++++++-----
 arch/sparc/kernel/compat_audit.c    | 13 +++++++-----
 arch/x86/ia32/audit.c               | 13 +++++++-----
 arch/x86/kernel/audit_64.c          | 10 ++++++----
 fs/open.c                           |  2 ++
 include/linux/audit.h               | 11 ++++++++++
 include/linux/auditsc_classmacros.h | 24 ++++++++++++++++++++++
 include/uapi/linux/audit.h          |  1 +
 kernel/audit.h                      |  2 ++
 kernel/auditsc.c                    | 31 +++++++++++++++++++++++------
 lib/audit.c                         | 14 ++++++++-----
 lib/compat_audit.c                  | 15 +++++++++-----
 21 files changed, 169 insertions(+), 71 deletions(-)
 create mode 100644 include/linux/auditsc_classmacros.h

-- 
2.27.0

[PATCH v4 1/3] audit: replace magic audit syscall class numbers with macros

[Richard Guy Briggs]

Replace audit syscall class magic numbers with macros.

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

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Link: https://lore.kernel.org/r/2300b1083a32aade7ae7efb95826e8f3f260b1df.1621363275.git.rgb@redhat.com
---
 MAINTAINERS                         |  1 +
 arch/alpha/kernel/audit.c           |  8 ++++----
 arch/ia64/kernel/audit.c            |  8 ++++----
 arch/parisc/kernel/audit.c          |  8 ++++----
 arch/parisc/kernel/compat_audit.c   |  9 +++++----
 arch/powerpc/kernel/audit.c         | 10 +++++-----
 arch/powerpc/kernel/compat_audit.c  | 11 ++++++-----
 arch/s390/kernel/audit.c            | 10 +++++-----
 arch/s390/kernel/compat_audit.c     | 11 ++++++-----
 arch/sparc/kernel/audit.c           | 10 +++++-----
 arch/sparc/kernel/compat_audit.c    | 11 ++++++-----
 arch/x86/ia32/audit.c               | 11 ++++++-----
 arch/x86/kernel/audit_64.c          |  8 ++++----
 include/linux/audit.h               |  1 +
 include/linux/auditsc_classmacros.h | 23 +++++++++++++++++++++++
 kernel/auditsc.c                    | 12 ++++++------
 lib/audit.c                         | 10 +++++-----
 lib/compat_audit.c                  | 11 ++++++-----
 18 files changed, 102 insertions(+), 71 deletions(-)
 create mode 100644 include/linux/auditsc_classmacros.h

diff --git a/MAINTAINERS b/MAINTAINERS
index bd7aff0c120f..3348d12019f9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3036,6 +3036,7 @@ 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/auditsc_classmacros.h
 F:	include/uapi/linux/audit.h
 F:	kernel/audit*
 F:	lib/*audit.c
diff --git a/arch/alpha/kernel/audit.c b/arch/alpha/kernel/audit.c
index 96a9d18ff4c4..81cbd804e375 100644
--- a/arch/alpha/kernel/audit.c
+++ b/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;
 	}
 }
 
diff --git a/arch/ia64/kernel/audit.c b/arch/ia64/kernel/audit.c
index 5192ca899fe6..dba6a74c9ab3 100644
--- a/arch/ia64/kernel/audit.c
+++ b/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;
 	}
 }
 
diff --git a/arch/parisc/kernel/audit.c b/arch/parisc/kernel/audit.c
index 9eb47b2225d2..14244e83db75 100644
--- a/arch/parisc/kernel/audit.c
+++ b/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;
 	}
 }
 
diff --git a/arch/parisc/kernel/compat_audit.c b/arch/parisc/kernel/compat_audit.c
index 20c39c9d86a9..1d6347d37d92 100644
--- a/arch/parisc/kernel/compat_audit.c
+++ b/arch/parisc/kernel/compat_audit.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/auditsc_classmacros.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;
 	}
 }
diff --git a/arch/powerpc/kernel/audit.c b/arch/powerpc/kernel/audit.c
index a2dddd7f3d09..6eb18ef77dff 100644
--- a/arch/powerpc/kernel/audit.c
+++ b/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;
 	}
 }
 
diff --git a/arch/powerpc/kernel/compat_audit.c b/arch/powerpc/kernel/compat_audit.c
index 55c6ccda0a85..b1dc2d1c4bad 100644
--- a/arch/powerpc/kernel/compat_audit.c
+++ b/arch/powerpc/kernel/compat_audit.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #undef __powerpc64__
+#include <linux/auditsc_classmacros.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;
 	}
 }
diff --git a/arch/s390/kernel/audit.c b/arch/s390/kernel/audit.c
index d395c6c9944c..7e331e1831d4 100644
--- a/arch/s390/kernel/audit.c
+++ b/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;
 	}
 }
 
diff --git a/arch/s390/kernel/compat_audit.c b/arch/s390/kernel/compat_audit.c
index 444fb1f66944..fc3d1c7ad21c 100644
--- a/arch/s390/kernel/compat_audit.c
+++ b/arch/s390/kernel/compat_audit.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #undef __s390x__
+#include <linux/auditsc_classmacros.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;
 	}
 }
diff --git a/arch/sparc/kernel/audit.c b/arch/sparc/kernel/audit.c
index a6e91bf34d48..50fab35bdaba 100644
--- a/arch/sparc/kernel/audit.c
+++ b/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;
 	}
 }
 
diff --git a/arch/sparc/kernel/compat_audit.c b/arch/sparc/kernel/compat_audit.c
index 10eeb4f15b20..1c1b6d075421 100644
--- a/arch/sparc/kernel/compat_audit.c
+++ b/arch/sparc/kernel/compat_audit.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #define __32bit_syscall_numbers__
+#include <linux/auditsc_classmacros.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;
 	}
 }
diff --git a/arch/x86/ia32/audit.c b/arch/x86/ia32/audit.c
index 6efe6cb3768a..eedc37a1ee13 100644
--- a/arch/x86/ia32/audit.c
+++ b/arch/x86/ia32/audit.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/auditsc_classmacros.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;
 	}
 }
diff --git a/arch/x86/kernel/audit_64.c b/arch/x86/kernel/audit_64.c
index 83d9cad4e68b..2a6cc9c9c881 100644
--- a/arch/x86/kernel/audit_64.c
+++ b/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;
 	}
 }
 
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 82b7c1116a85..283bc91a6932 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -11,6 +11,7 @@
 
 #include <linux/sched.h>
 #include <linux/ptrace.h>
+#include <linux/auditsc_classmacros.h> /* syscall class macros */
 #include <uapi/linux/audit.h>
 #include <uapi/linux/netfilter/nf_tables.h>
 
diff --git a/include/linux/auditsc_classmacros.h b/include/linux/auditsc_classmacros.h
new file mode 100644
index 000000000000..18757d270961
--- /dev/null
+++ b/include/linux/auditsc_classmacros.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* auditsc_classmacros.h -- Auditing support syscall macros
+ *
+ * Copyright 2021 Red Hat Inc., Durham, North Carolina.
+ * All Rights Reserved.
+ *
+ * Author: Richard Guy Briggs <rgb@redhat.com>
+ */
+#ifndef _LINUX_AUDITSCM_H_
+#define _LINUX_AUDITSCM_H_
+
+enum auditsc_class_t {
+	AUDITSC_NATIVE = 0,
+	AUDITSC_COMPAT,
+	AUDITSC_OPEN,
+	AUDITSC_OPENAT,
+	AUDITSC_SOCKETCALL,
+	AUDITSC_EXECVE,
+
+	AUDITSC_NVALS /* count */
+};
+
+#endif
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 0a9a1569f1ea..d775ea16505b 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -166,7 +166,7 @@ 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;
@@ -177,7 +177,7 @@ 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;
@@ -188,13 +188,13 @@ 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;
diff --git a/lib/audit.c b/lib/audit.c
index 5004bff928a7..3ec1a94d8d64 100644
--- a/lib/audit.c
+++ b/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;
 	}
 }
 
diff --git a/lib/compat_audit.c b/lib/compat_audit.c
index 77eabad69b4a..a38b282d353f 100644
--- a/lib/compat_audit.c
+++ b/lib/compat_audit.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/auditsc_classmacros.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;
 	}
 }
-- 
2.27.0

[PATCH v4 2/3] audit: add support for the openat2 syscall

[Richard Guy Briggs]

The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
("open: introduce openat2(2) syscall")

Add the openat2(2) syscall to the audit syscall classifier.

Link: https://github.com/linux-audit/audit-kernel/issues/67
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
---
 arch/alpha/kernel/audit.c           | 2 ++
 arch/ia64/kernel/audit.c            | 2 ++
 arch/parisc/kernel/audit.c          | 2 ++
 arch/parisc/kernel/compat_audit.c   | 2 ++
 arch/powerpc/kernel/audit.c         | 2 ++
 arch/powerpc/kernel/compat_audit.c  | 2 ++
 arch/s390/kernel/audit.c            | 2 ++
 arch/s390/kernel/compat_audit.c     | 2 ++
 arch/sparc/kernel/audit.c           | 2 ++
 arch/sparc/kernel/compat_audit.c    | 2 ++
 arch/x86/ia32/audit.c               | 2 ++
 arch/x86/kernel/audit_64.c          | 2 ++
 include/linux/auditsc_classmacros.h | 1 +
 kernel/auditsc.c                    | 3 +++
 lib/audit.c                         | 4 ++++
 lib/compat_audit.c                  | 4 ++++
 16 files changed, 36 insertions(+)

diff --git a/arch/alpha/kernel/audit.c b/arch/alpha/kernel/audit.c
index 81cbd804e375..3ab04709784a 100644
--- a/arch/alpha/kernel/audit.c
+++ b/arch/alpha/kernel/audit.c
@@ -42,6 +42,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
 		return AUDITSC_OPENAT;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/arch/ia64/kernel/audit.c b/arch/ia64/kernel/audit.c
index dba6a74c9ab3..ec61f20ca61f 100644
--- a/arch/ia64/kernel/audit.c
+++ b/arch/ia64/kernel/audit.c
@@ -43,6 +43,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
 		return AUDITSC_OPENAT;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/arch/parisc/kernel/audit.c b/arch/parisc/kernel/audit.c
index 14244e83db75..f420b5552140 100644
--- a/arch/parisc/kernel/audit.c
+++ b/arch/parisc/kernel/audit.c
@@ -52,6 +52,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
 		return AUDITSC_OPENAT;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/arch/parisc/kernel/compat_audit.c b/arch/parisc/kernel/compat_audit.c
index 1d6347d37d92..3ec490c28656 100644
--- a/arch/parisc/kernel/compat_audit.c
+++ b/arch/parisc/kernel/compat_audit.c
@@ -36,6 +36,8 @@ int parisc32_classify_syscall(unsigned syscall)
 		return AUDITSC_OPENAT;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_COMPAT;
 	}
diff --git a/arch/powerpc/kernel/audit.c b/arch/powerpc/kernel/audit.c
index 6eb18ef77dff..1bcfca5fdf67 100644
--- a/arch/powerpc/kernel/audit.c
+++ b/arch/powerpc/kernel/audit.c
@@ -54,6 +54,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
 		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/arch/powerpc/kernel/compat_audit.c b/arch/powerpc/kernel/compat_audit.c
index b1dc2d1c4bad..251abf79d536 100644
--- a/arch/powerpc/kernel/compat_audit.c
+++ b/arch/powerpc/kernel/compat_audit.c
@@ -39,6 +39,8 @@ int ppc32_classify_syscall(unsigned syscall)
 		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_COMPAT;
 	}
diff --git a/arch/s390/kernel/audit.c b/arch/s390/kernel/audit.c
index 7e331e1831d4..02051a596b87 100644
--- a/arch/s390/kernel/audit.c
+++ b/arch/s390/kernel/audit.c
@@ -54,6 +54,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
 		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/arch/s390/kernel/compat_audit.c b/arch/s390/kernel/compat_audit.c
index fc3d1c7ad21c..4b3d463e7d97 100644
--- a/arch/s390/kernel/compat_audit.c
+++ b/arch/s390/kernel/compat_audit.c
@@ -40,6 +40,8 @@ int s390_classify_syscall(unsigned syscall)
 		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_COMPAT;
 	}
diff --git a/arch/sparc/kernel/audit.c b/arch/sparc/kernel/audit.c
index 50fab35bdaba..b092274eca79 100644
--- a/arch/sparc/kernel/audit.c
+++ b/arch/sparc/kernel/audit.c
@@ -55,6 +55,8 @@ int audit_classify_syscall(int abi, unsigned int syscall)
 		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/arch/sparc/kernel/compat_audit.c b/arch/sparc/kernel/compat_audit.c
index 1c1b6d075421..2a3f71206fc5 100644
--- a/arch/sparc/kernel/compat_audit.c
+++ b/arch/sparc/kernel/compat_audit.c
@@ -40,6 +40,8 @@ int sparc32_classify_syscall(unsigned int syscall)
 		return AUDITSC_SOCKETCALL;
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_COMPAT;
 	}
diff --git a/arch/x86/ia32/audit.c b/arch/x86/ia32/audit.c
index eedc37a1ee13..efc7d832fefb 100644
--- a/arch/x86/ia32/audit.c
+++ b/arch/x86/ia32/audit.c
@@ -40,6 +40,8 @@ int ia32_classify_syscall(unsigned syscall)
 	case __NR_execve:
 	case __NR_execveat:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_COMPAT;
 	}
diff --git a/arch/x86/kernel/audit_64.c b/arch/x86/kernel/audit_64.c
index 2a6cc9c9c881..44c3601cfdc4 100644
--- a/arch/x86/kernel/audit_64.c
+++ b/arch/x86/kernel/audit_64.c
@@ -53,6 +53,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
 	case __NR_execve:
 	case __NR_execveat:
 		return AUDITSC_EXECVE;
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/include/linux/auditsc_classmacros.h b/include/linux/auditsc_classmacros.h
index 18757d270961..dc8e72536dbd 100644
--- a/include/linux/auditsc_classmacros.h
+++ b/include/linux/auditsc_classmacros.h
@@ -16,6 +16,7 @@ enum auditsc_class_t {
 	AUDITSC_OPENAT,
 	AUDITSC_SOCKETCALL,
 	AUDITSC_EXECVE,
+	AUDITSC_OPENAT2,
 
 	AUDITSC_NVALS /* count */
 };
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d775ea16505b..3f59ab209dfd 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -76,6 +76,7 @@
 #include <linux/fsnotify_backend.h>
 #include <uapi/linux/limits.h>
 #include <uapi/linux/netfilter/nf_tables.h>
+#include <uapi/linux/openat2.h>
 
 #include "audit.h"
 
@@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
 		return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
 	case AUDITSC_EXECVE:
 		return mask & AUDIT_PERM_EXEC;
+	case AUDITSC_OPENAT2:
+		return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
 	default:
 		return 0;
 	}
diff --git a/lib/audit.c b/lib/audit.c
index 3ec1a94d8d64..738bda22dd39 100644
--- a/lib/audit.c
+++ b/lib/audit.c
@@ -60,6 +60,10 @@ int audit_classify_syscall(int abi, unsigned syscall)
 #endif
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+#ifdef __NR_openat2
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
+#endif
 	default:
 		return AUDITSC_NATIVE;
 	}
diff --git a/lib/compat_audit.c b/lib/compat_audit.c
index a38b282d353f..e2a0f914d8b6 100644
--- a/lib/compat_audit.c
+++ b/lib/compat_audit.c
@@ -46,6 +46,10 @@ int audit_classify_compat_syscall(int abi, unsigned syscall)
 #endif
 	case __NR_execve:
 		return AUDITSC_EXECVE;
+#ifdef __NR_openat2
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
+#endif
 	default:
 		return AUDITSC_COMPAT;
 	}
-- 
2.27.0

[PATCH v4 3/3] audit: add OPENAT2 record to list how

[Richard Guy Briggs]

Since the openat2(2) syscall uses a struct open_how pointer to communicate
its parameters they are not usefully recorded by the audit SYSCALL record's
four existing arguments.

Add a new audit record type OPENAT2 that reports the parameters in its
third argument, struct open_how with fields oflag, mode and resolve.

The new record in the context of an event would look like:
time->Wed Mar 17 16:28:53 2021
type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432
type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests"
type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa
type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO"

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com
---
 fs/open.c                  |  2 ++
 include/linux/audit.h      | 10 ++++++++++
 include/uapi/linux/audit.h |  1 +
 kernel/audit.h             |  2 ++
 kernel/auditsc.c           | 18 +++++++++++++++++-
 5 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/fs/open.c b/fs/open.c
index e53af13b5835..2a15bec0cf6d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1235,6 +1235,8 @@ SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename,
 	if (err)
 		return err;
 
+	audit_openat2_how(&tmp);
+
 	/* O_LARGEFILE is only allowed for non-O_PATH. */
 	if (!(tmp.flags & O_PATH) && force_o_largefile())
 		tmp.flags |= O_LARGEFILE;
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 283bc91a6932..580a52caf16f 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -399,6 +399,7 @@ extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
 				  const struct cred *old);
 extern void __audit_log_capset(const struct cred *new, const struct cred *old);
 extern void __audit_mmap_fd(int fd, int flags);
+extern void __audit_openat2_how(struct open_how *how);
 extern void __audit_log_kern_module(char *name);
 extern void __audit_fanotify(unsigned int response);
 extern void __audit_tk_injoffset(struct timespec64 offset);
@@ -495,6 +496,12 @@ static inline void audit_mmap_fd(int fd, int flags)
 		__audit_mmap_fd(fd, flags);
 }
 
+static inline void audit_openat2_how(struct open_how *how)
+{
+	if (unlikely(!audit_dummy_context()))
+		__audit_openat2_how(how);
+}
+
 static inline void audit_log_kern_module(char *name)
 {
 	if (!audit_dummy_context())
@@ -646,6 +653,9 @@ static inline void audit_log_capset(const struct cred *new,
 static inline void audit_mmap_fd(int fd, int flags)
 { }
 
+static inline void audit_openat2_how(struct open_how *how)
+{ }
+
 static inline void audit_log_kern_module(char *name)
 {
 }
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index cd2d8279a5e4..67aea2370c6d 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -118,6 +118,7 @@
 #define AUDIT_TIME_ADJNTPVAL	1333	/* NTP value adjustment */
 #define AUDIT_BPF		1334	/* BPF subsystem */
 #define AUDIT_EVENT_LISTENER	1335	/* Task joined multicast read socket */
+#define AUDIT_OPENAT2		1336	/* Record showing openat2 how args */
 
 #define AUDIT_AVC		1400	/* SE Linux avc denial or grant */
 #define AUDIT_SELINUX_ERR	1401	/* Internal SE Linux Errors */
diff --git a/kernel/audit.h b/kernel/audit.h
index 1522e100fd17..c5af17905976 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -11,6 +11,7 @@
 #include <linux/skbuff.h>
 #include <uapi/linux/mqueue.h>
 #include <linux/tty.h>
+#include <uapi/linux/openat2.h> // struct open_how
 
 /* AUDIT_NAMES is the number of slots we reserve in the audit_context
  * for saving names from getname().  If we get more names we will allocate
@@ -185,6 +186,7 @@ struct audit_context {
 			int			fd;
 			int			flags;
 		} mmap;
+		struct open_how openat2;
 		struct {
 			int			argc;
 		} execve;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 3f59ab209dfd..faf2485323a9 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -76,7 +76,7 @@
 #include <linux/fsnotify_backend.h>
 #include <uapi/linux/limits.h>
 #include <uapi/linux/netfilter/nf_tables.h>
-#include <uapi/linux/openat2.h>
+#include <uapi/linux/openat2.h> // struct open_how
 
 #include "audit.h"
 
@@ -1319,6 +1319,12 @@ static void show_special(struct audit_context *context, int *call_panic)
 		audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
 				 context->mmap.flags);
 		break;
+	case AUDIT_OPENAT2:
+		audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx",
+				 context->openat2.flags,
+				 context->openat2.mode,
+				 context->openat2.resolve);
+		break;
 	case AUDIT_EXECVE:
 		audit_log_execve_info(context, &ab);
 		break;
@@ -2549,6 +2555,16 @@ void __audit_mmap_fd(int fd, int flags)
 	context->type = AUDIT_MMAP;
 }
 
+void __audit_openat2_how(struct open_how *how)
+{
+	struct audit_context *context = audit_context();
+
+	context->openat2.flags = how->flags;
+	context->openat2.mode = how->mode;
+	context->openat2.resolve = how->resolve;
+	context->type = AUDIT_OPENAT2;
+}
+
 void __audit_log_kern_module(char *name)
 {
 	struct audit_context *context = audit_context();
-- 
2.27.0

Re: [PATCH v4 1/3] audit: replace magic audit syscall class numbers with macros

[Christian Brauner]

On Wed, May 19, 2021 at 04:00:20PM -0400, Richard Guy Briggs wrote:
> Replace audit syscall class magic numbers with macros.
> 
> This required putting the macros into new header file
> include/linux/auditsc_classmacros.h since the syscall macros were
> included for both 64 bit and 32 bit in any compat code, causing
> redefinition warnings.
> 
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> Link: https://lore.kernel.org/r/2300b1083a32aade7ae7efb95826e8f3f260b1df.1621363275.git.rgb@redhat.com

Looks good.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

Fwiw, I would explicitly number all enum values in auditsc_class_t not
just the first one.

> ---
>  MAINTAINERS                         |  1 +
>  arch/alpha/kernel/audit.c           |  8 ++++----
>  arch/ia64/kernel/audit.c            |  8 ++++----
>  arch/parisc/kernel/audit.c          |  8 ++++----
>  arch/parisc/kernel/compat_audit.c   |  9 +++++----
>  arch/powerpc/kernel/audit.c         | 10 +++++-----
>  arch/powerpc/kernel/compat_audit.c  | 11 ++++++-----
>  arch/s390/kernel/audit.c            | 10 +++++-----
>  arch/s390/kernel/compat_audit.c     | 11 ++++++-----
>  arch/sparc/kernel/audit.c           | 10 +++++-----
>  arch/sparc/kernel/compat_audit.c    | 11 ++++++-----
>  arch/x86/ia32/audit.c               | 11 ++++++-----
>  arch/x86/kernel/audit_64.c          |  8 ++++----
>  include/linux/audit.h               |  1 +
>  include/linux/auditsc_classmacros.h | 23 +++++++++++++++++++++++
>  kernel/auditsc.c                    | 12 ++++++------
>  lib/audit.c                         | 10 +++++-----
>  lib/compat_audit.c                  | 11 ++++++-----
>  18 files changed, 102 insertions(+), 71 deletions(-)
>  create mode 100644 include/linux/auditsc_classmacros.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index bd7aff0c120f..3348d12019f9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3036,6 +3036,7 @@ 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/auditsc_classmacros.h
>  F:	include/uapi/linux/audit.h
>  F:	kernel/audit*
>  F:	lib/*audit.c
> diff --git a/arch/alpha/kernel/audit.c b/arch/alpha/kernel/audit.c
> index 96a9d18ff4c4..81cbd804e375 100644
> --- a/arch/alpha/kernel/audit.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/arch/ia64/kernel/audit.c b/arch/ia64/kernel/audit.c
> index 5192ca899fe6..dba6a74c9ab3 100644
> --- a/arch/ia64/kernel/audit.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/arch/parisc/kernel/audit.c b/arch/parisc/kernel/audit.c
> index 9eb47b2225d2..14244e83db75 100644
> --- a/arch/parisc/kernel/audit.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/arch/parisc/kernel/compat_audit.c b/arch/parisc/kernel/compat_audit.c
> index 20c39c9d86a9..1d6347d37d92 100644
> --- a/arch/parisc/kernel/compat_audit.c
> +++ b/arch/parisc/kernel/compat_audit.c
> @@ -1,4 +1,5 @@
>  // SPDX-License-Identifier: GPL-2.0
> +#include <linux/auditsc_classmacros.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;
>  	}
>  }
> diff --git a/arch/powerpc/kernel/audit.c b/arch/powerpc/kernel/audit.c
> index a2dddd7f3d09..6eb18ef77dff 100644
> --- a/arch/powerpc/kernel/audit.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/arch/powerpc/kernel/compat_audit.c b/arch/powerpc/kernel/compat_audit.c
> index 55c6ccda0a85..b1dc2d1c4bad 100644
> --- a/arch/powerpc/kernel/compat_audit.c
> +++ b/arch/powerpc/kernel/compat_audit.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #undef __powerpc64__
> +#include <linux/auditsc_classmacros.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;
>  	}
>  }
> diff --git a/arch/s390/kernel/audit.c b/arch/s390/kernel/audit.c
> index d395c6c9944c..7e331e1831d4 100644
> --- a/arch/s390/kernel/audit.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/arch/s390/kernel/compat_audit.c b/arch/s390/kernel/compat_audit.c
> index 444fb1f66944..fc3d1c7ad21c 100644
> --- a/arch/s390/kernel/compat_audit.c
> +++ b/arch/s390/kernel/compat_audit.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #undef __s390x__
> +#include <linux/auditsc_classmacros.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;
>  	}
>  }
> diff --git a/arch/sparc/kernel/audit.c b/arch/sparc/kernel/audit.c
> index a6e91bf34d48..50fab35bdaba 100644
> --- a/arch/sparc/kernel/audit.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/arch/sparc/kernel/compat_audit.c b/arch/sparc/kernel/compat_audit.c
> index 10eeb4f15b20..1c1b6d075421 100644
> --- a/arch/sparc/kernel/compat_audit.c
> +++ b/arch/sparc/kernel/compat_audit.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #define __32bit_syscall_numbers__
> +#include <linux/auditsc_classmacros.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;
>  	}
>  }
> diff --git a/arch/x86/ia32/audit.c b/arch/x86/ia32/audit.c
> index 6efe6cb3768a..eedc37a1ee13 100644
> --- a/arch/x86/ia32/audit.c
> +++ b/arch/x86/ia32/audit.c
> @@ -1,4 +1,5 @@
>  // SPDX-License-Identifier: GPL-2.0
> +#include <linux/auditsc_classmacros.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;
>  	}
>  }
> diff --git a/arch/x86/kernel/audit_64.c b/arch/x86/kernel/audit_64.c
> index 83d9cad4e68b..2a6cc9c9c881 100644
> --- a/arch/x86/kernel/audit_64.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 82b7c1116a85..283bc91a6932 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -11,6 +11,7 @@
>  
>  #include <linux/sched.h>
>  #include <linux/ptrace.h>
> +#include <linux/auditsc_classmacros.h> /* syscall class macros */
>  #include <uapi/linux/audit.h>
>  #include <uapi/linux/netfilter/nf_tables.h>
>  
> diff --git a/include/linux/auditsc_classmacros.h b/include/linux/auditsc_classmacros.h
> new file mode 100644
> index 000000000000..18757d270961
> --- /dev/null
> +++ b/include/linux/auditsc_classmacros.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* auditsc_classmacros.h -- Auditing support syscall macros
> + *
> + * Copyright 2021 Red Hat Inc., Durham, North Carolina.
> + * All Rights Reserved.
> + *
> + * Author: Richard Guy Briggs <rgb@redhat.com>
> + */
> +#ifndef _LINUX_AUDITSCM_H_
> +#define _LINUX_AUDITSCM_H_
> +
> +enum auditsc_class_t {
> +	AUDITSC_NATIVE = 0,
> +	AUDITSC_COMPAT,
> +	AUDITSC_OPEN,
> +	AUDITSC_OPENAT,
> +	AUDITSC_SOCKETCALL,
> +	AUDITSC_EXECVE,
> +
> +	AUDITSC_NVALS /* count */
> +};
> +
> +#endif
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 0a9a1569f1ea..d775ea16505b 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -166,7 +166,7 @@ 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;
> @@ -177,7 +177,7 @@ 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;
> @@ -188,13 +188,13 @@ 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;
> diff --git a/lib/audit.c b/lib/audit.c
> index 5004bff928a7..3ec1a94d8d64 100644
> --- a/lib/audit.c
> +++ b/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;
>  	}
>  }
>  
> diff --git a/lib/compat_audit.c b/lib/compat_audit.c
> index 77eabad69b4a..a38b282d353f 100644
> --- a/lib/compat_audit.c
> +++ b/lib/compat_audit.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #include <linux/init.h>
>  #include <linux/types.h>
> +#include <linux/auditsc_classmacros.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;
>  	}
>  }
> -- 
> 2.27.0
> 

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Christian Brauner]

On Wed, May 19, 2021 at 04:00:21PM -0400, Richard Guy Briggs wrote:
> The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> ("open: introduce openat2(2) syscall")
> 
> Add the openat2(2) syscall to the audit syscall classifier.
> 
> Link: https://github.com/linux-audit/audit-kernel/issues/67
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> ---
>  arch/alpha/kernel/audit.c           | 2 ++
>  arch/ia64/kernel/audit.c            | 2 ++
>  arch/parisc/kernel/audit.c          | 2 ++
>  arch/parisc/kernel/compat_audit.c   | 2 ++
>  arch/powerpc/kernel/audit.c         | 2 ++
>  arch/powerpc/kernel/compat_audit.c  | 2 ++
>  arch/s390/kernel/audit.c            | 2 ++
>  arch/s390/kernel/compat_audit.c     | 2 ++
>  arch/sparc/kernel/audit.c           | 2 ++
>  arch/sparc/kernel/compat_audit.c    | 2 ++
>  arch/x86/ia32/audit.c               | 2 ++
>  arch/x86/kernel/audit_64.c          | 2 ++
>  include/linux/auditsc_classmacros.h | 1 +
>  kernel/auditsc.c                    | 3 +++
>  lib/audit.c                         | 4 ++++
>  lib/compat_audit.c                  | 4 ++++
>  16 files changed, 36 insertions(+)
> 
> diff --git a/arch/alpha/kernel/audit.c b/arch/alpha/kernel/audit.c
> index 81cbd804e375..3ab04709784a 100644
> --- a/arch/alpha/kernel/audit.c
> +++ b/arch/alpha/kernel/audit.c
> @@ -42,6 +42,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
>  		return AUDITSC_OPENAT;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_NATIVE;
>  	}
> diff --git a/arch/ia64/kernel/audit.c b/arch/ia64/kernel/audit.c
> index dba6a74c9ab3..ec61f20ca61f 100644
> --- a/arch/ia64/kernel/audit.c
> +++ b/arch/ia64/kernel/audit.c
> @@ -43,6 +43,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
>  		return AUDITSC_OPENAT;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_NATIVE;
>  	}
> diff --git a/arch/parisc/kernel/audit.c b/arch/parisc/kernel/audit.c
> index 14244e83db75..f420b5552140 100644
> --- a/arch/parisc/kernel/audit.c
> +++ b/arch/parisc/kernel/audit.c
> @@ -52,6 +52,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
>  		return AUDITSC_OPENAT;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_NATIVE;
>  	}
> diff --git a/arch/parisc/kernel/compat_audit.c b/arch/parisc/kernel/compat_audit.c
> index 1d6347d37d92..3ec490c28656 100644
> --- a/arch/parisc/kernel/compat_audit.c
> +++ b/arch/parisc/kernel/compat_audit.c
> @@ -36,6 +36,8 @@ int parisc32_classify_syscall(unsigned syscall)
>  		return AUDITSC_OPENAT;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_COMPAT;
>  	}
> diff --git a/arch/powerpc/kernel/audit.c b/arch/powerpc/kernel/audit.c
> index 6eb18ef77dff..1bcfca5fdf67 100644
> --- a/arch/powerpc/kernel/audit.c
> +++ b/arch/powerpc/kernel/audit.c
> @@ -54,6 +54,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
>  		return AUDITSC_SOCKETCALL;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_NATIVE;
>  	}
> diff --git a/arch/powerpc/kernel/compat_audit.c b/arch/powerpc/kernel/compat_audit.c
> index b1dc2d1c4bad..251abf79d536 100644
> --- a/arch/powerpc/kernel/compat_audit.c
> +++ b/arch/powerpc/kernel/compat_audit.c
> @@ -39,6 +39,8 @@ int ppc32_classify_syscall(unsigned syscall)
>  		return AUDITSC_SOCKETCALL;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_COMPAT;
>  	}
> diff --git a/arch/s390/kernel/audit.c b/arch/s390/kernel/audit.c
> index 7e331e1831d4..02051a596b87 100644
> --- a/arch/s390/kernel/audit.c
> +++ b/arch/s390/kernel/audit.c
> @@ -54,6 +54,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
>  		return AUDITSC_SOCKETCALL;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_NATIVE;
>  	}
> diff --git a/arch/s390/kernel/compat_audit.c b/arch/s390/kernel/compat_audit.c
> index fc3d1c7ad21c..4b3d463e7d97 100644
> --- a/arch/s390/kernel/compat_audit.c
> +++ b/arch/s390/kernel/compat_audit.c
> @@ -40,6 +40,8 @@ int s390_classify_syscall(unsigned syscall)
>  		return AUDITSC_SOCKETCALL;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_COMPAT;
>  	}
> diff --git a/arch/sparc/kernel/audit.c b/arch/sparc/kernel/audit.c
> index 50fab35bdaba..b092274eca79 100644
> --- a/arch/sparc/kernel/audit.c
> +++ b/arch/sparc/kernel/audit.c
> @@ -55,6 +55,8 @@ int audit_classify_syscall(int abi, unsigned int syscall)
>  		return AUDITSC_SOCKETCALL;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_NATIVE;
>  	}
> diff --git a/arch/sparc/kernel/compat_audit.c b/arch/sparc/kernel/compat_audit.c
> index 1c1b6d075421..2a3f71206fc5 100644
> --- a/arch/sparc/kernel/compat_audit.c
> +++ b/arch/sparc/kernel/compat_audit.c
> @@ -40,6 +40,8 @@ int sparc32_classify_syscall(unsigned int syscall)
>  		return AUDITSC_SOCKETCALL;
>  	case __NR_execve:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_COMPAT;
>  	}
> diff --git a/arch/x86/ia32/audit.c b/arch/x86/ia32/audit.c
> index eedc37a1ee13..efc7d832fefb 100644
> --- a/arch/x86/ia32/audit.c
> +++ b/arch/x86/ia32/audit.c
> @@ -40,6 +40,8 @@ int ia32_classify_syscall(unsigned syscall)
>  	case __NR_execve:
>  	case __NR_execveat:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_COMPAT;
>  	}
> diff --git a/arch/x86/kernel/audit_64.c b/arch/x86/kernel/audit_64.c
> index 2a6cc9c9c881..44c3601cfdc4 100644
> --- a/arch/x86/kernel/audit_64.c
> +++ b/arch/x86/kernel/audit_64.c
> @@ -53,6 +53,8 @@ int audit_classify_syscall(int abi, unsigned syscall)
>  	case __NR_execve:
>  	case __NR_execveat:
>  		return AUDITSC_EXECVE;
> +	case __NR_openat2:
> +		return AUDITSC_OPENAT2;
>  	default:
>  		return AUDITSC_NATIVE;
>  	}
> diff --git a/include/linux/auditsc_classmacros.h b/include/linux/auditsc_classmacros.h
> index 18757d270961..dc8e72536dbd 100644
> --- a/include/linux/auditsc_classmacros.h
> +++ b/include/linux/auditsc_classmacros.h
> @@ -16,6 +16,7 @@ enum auditsc_class_t {
>  	AUDITSC_OPENAT,
>  	AUDITSC_SOCKETCALL,
>  	AUDITSC_EXECVE,
> +	AUDITSC_OPENAT2,
>  
>  	AUDITSC_NVALS /* count */
>  };
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index d775ea16505b..3f59ab209dfd 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -76,6 +76,7 @@
>  #include <linux/fsnotify_backend.h>
>  #include <uapi/linux/limits.h>
>  #include <uapi/linux/netfilter/nf_tables.h>
> +#include <uapi/linux/openat2.h>
>  
>  #include "audit.h"
>  
> @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
>  		return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
>  	case AUDITSC_EXECVE:
>  		return mask & AUDIT_PERM_EXEC;
> +	case AUDITSC_OPENAT2:
> +		return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);

That's a lot of dereferncing, casting and masking all at once. Maybe a
small static inline helper would be good for the sake of legibility? Sm
like:

static inline u32 audit_openat2_acc(struct open_how *how, int mask)
{
	u32 flags = how->flags;
	return mask & ACC_MODE(flags);
}

but not sure. Just seems more legible to me.
Otherwise.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

Re: [PATCH v4 3/3] audit: add OPENAT2 record to list how

[Christian Brauner]

On Wed, May 19, 2021 at 04:00:22PM -0400, Richard Guy Briggs wrote:
> Since the openat2(2) syscall uses a struct open_how pointer to communicate
> its parameters they are not usefully recorded by the audit SYSCALL record's
> four existing arguments.
> 
> Add a new audit record type OPENAT2 that reports the parameters in its
> third argument, struct open_how with fields oflag, mode and resolve.
> 
> The new record in the context of an event would look like:
> time->Wed Mar 17 16:28:53 2021
> type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432
> type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests"
> type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa
> type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO"
> 
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com
> ---
>  fs/open.c                  |  2 ++
>  include/linux/audit.h      | 10 ++++++++++
>  include/uapi/linux/audit.h |  1 +
>  kernel/audit.h             |  2 ++
>  kernel/auditsc.c           | 18 +++++++++++++++++-
>  5 files changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/open.c b/fs/open.c
> index e53af13b5835..2a15bec0cf6d 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -1235,6 +1235,8 @@ SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename,
>  	if (err)
>  		return err;
>  
> +	audit_openat2_how(&tmp);
> +
>  	/* O_LARGEFILE is only allowed for non-O_PATH. */
>  	if (!(tmp.flags & O_PATH) && force_o_largefile())
>  		tmp.flags |= O_LARGEFILE;
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 283bc91a6932..580a52caf16f 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -399,6 +399,7 @@ extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
>  				  const struct cred *old);
>  extern void __audit_log_capset(const struct cred *new, const struct cred *old);
>  extern void __audit_mmap_fd(int fd, int flags);
> +extern void __audit_openat2_how(struct open_how *how);
>  extern void __audit_log_kern_module(char *name);
>  extern void __audit_fanotify(unsigned int response);
>  extern void __audit_tk_injoffset(struct timespec64 offset);
> @@ -495,6 +496,12 @@ static inline void audit_mmap_fd(int fd, int flags)
>  		__audit_mmap_fd(fd, flags);
>  }
>  
> +static inline void audit_openat2_how(struct open_how *how)
> +{
> +	if (unlikely(!audit_dummy_context()))
> +		__audit_openat2_how(how);
> +}
> +
>  static inline void audit_log_kern_module(char *name)
>  {
>  	if (!audit_dummy_context())
> @@ -646,6 +653,9 @@ static inline void audit_log_capset(const struct cred *new,
>  static inline void audit_mmap_fd(int fd, int flags)
>  { }
>  
> +static inline void audit_openat2_how(struct open_how *how)
> +{ }
> +
>  static inline void audit_log_kern_module(char *name)
>  {
>  }
> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> index cd2d8279a5e4..67aea2370c6d 100644
> --- a/include/uapi/linux/audit.h
> +++ b/include/uapi/linux/audit.h
> @@ -118,6 +118,7 @@
>  #define AUDIT_TIME_ADJNTPVAL	1333	/* NTP value adjustment */
>  #define AUDIT_BPF		1334	/* BPF subsystem */
>  #define AUDIT_EVENT_LISTENER	1335	/* Task joined multicast read socket */
> +#define AUDIT_OPENAT2		1336	/* Record showing openat2 how args */
>  
>  #define AUDIT_AVC		1400	/* SE Linux avc denial or grant */
>  #define AUDIT_SELINUX_ERR	1401	/* Internal SE Linux Errors */
> diff --git a/kernel/audit.h b/kernel/audit.h
> index 1522e100fd17..c5af17905976 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -11,6 +11,7 @@
>  #include <linux/skbuff.h>
>  #include <uapi/linux/mqueue.h>
>  #include <linux/tty.h>
> +#include <uapi/linux/openat2.h> // struct open_how
>  
>  /* AUDIT_NAMES is the number of slots we reserve in the audit_context
>   * for saving names from getname().  If we get more names we will allocate
> @@ -185,6 +186,7 @@ struct audit_context {
>  			int			fd;
>  			int			flags;
>  		} mmap;
> +		struct open_how openat2;
>  		struct {
>  			int			argc;
>  		} execve;
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 3f59ab209dfd..faf2485323a9 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -76,7 +76,7 @@
>  #include <linux/fsnotify_backend.h>
>  #include <uapi/linux/limits.h>
>  #include <uapi/linux/netfilter/nf_tables.h>
> -#include <uapi/linux/openat2.h>
> +#include <uapi/linux/openat2.h> // struct open_how
>  
>  #include "audit.h"
>  
> @@ -1319,6 +1319,12 @@ static void show_special(struct audit_context *context, int *call_panic)
>  		audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
>  				 context->mmap.flags);
>  		break;
> +	case AUDIT_OPENAT2:
> +		audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx",

Hm, should we maybe follow the struct member names for all entries, i.e.
replace s/oflag/flags? 

Otherwise
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

> +				 context->openat2.flags,
> +				 context->openat2.mode,
> +				 context->openat2.resolve);
> +		break;
>  	case AUDIT_EXECVE:
>  		audit_log_execve_info(context, &ab);
>  		break;
> @@ -2549,6 +2555,16 @@ void __audit_mmap_fd(int fd, int flags)
>  	context->type = AUDIT_MMAP;
>  }
>  
> +void __audit_openat2_how(struct open_how *how)
> +{
> +	struct audit_context *context = audit_context();
> +
> +	context->openat2.flags = how->flags;
> +	context->openat2.mode = how->mode;
> +	context->openat2.resolve = how->resolve;
> +	context->type = AUDIT_OPENAT2;
> +}
> +
>  void __audit_log_kern_module(char *name)
>  {
>  	struct audit_context *context = audit_context();
> -- 
> 2.27.0
> 

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Paul Moore]

On Thu, May 20, 2021 at 3:58 AM Christian Brauner
<christian.brauner@ubuntu.com> wrote:
> On Wed, May 19, 2021 at 04:00:21PM -0400, Richard Guy Briggs wrote:
> > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> > ("open: introduce openat2(2) syscall")
> >
> > Add the openat2(2) syscall to the audit syscall classifier.
> >
> > Link: https://github.com/linux-audit/audit-kernel/issues/67
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> > ---
> >  arch/alpha/kernel/audit.c           | 2 ++
> >  arch/ia64/kernel/audit.c            | 2 ++
> >  arch/parisc/kernel/audit.c          | 2 ++
> >  arch/parisc/kernel/compat_audit.c   | 2 ++
> >  arch/powerpc/kernel/audit.c         | 2 ++
> >  arch/powerpc/kernel/compat_audit.c  | 2 ++
> >  arch/s390/kernel/audit.c            | 2 ++
> >  arch/s390/kernel/compat_audit.c     | 2 ++
> >  arch/sparc/kernel/audit.c           | 2 ++
> >  arch/sparc/kernel/compat_audit.c    | 2 ++
> >  arch/x86/ia32/audit.c               | 2 ++
> >  arch/x86/kernel/audit_64.c          | 2 ++
> >  include/linux/auditsc_classmacros.h | 1 +
> >  kernel/auditsc.c                    | 3 +++
> >  lib/audit.c                         | 4 ++++
> >  lib/compat_audit.c                  | 4 ++++
> >  16 files changed, 36 insertions(+)

...

> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index d775ea16505b..3f59ab209dfd 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -76,6 +76,7 @@
> >  #include <linux/fsnotify_backend.h>
> >  #include <uapi/linux/limits.h>
> >  #include <uapi/linux/netfilter/nf_tables.h>
> > +#include <uapi/linux/openat2.h>
> >
> >  #include "audit.h"
> >
> > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
> >               return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
> >       case AUDITSC_EXECVE:
> >               return mask & AUDIT_PERM_EXEC;
> > +     case AUDITSC_OPENAT2:
> > +             return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
>
> That's a lot of dereferncing, casting and masking all at once. Maybe a
> small static inline helper would be good for the sake of legibility? Sm
> like:
>
> static inline u32 audit_openat2_acc(struct open_how *how, int mask)
> {
>         u32 flags = how->flags;
>         return mask & ACC_MODE(flags);
> }
>
> but not sure. Just seems more legible to me.
> Otherwise.

I'm on the fence about this.  I understand Christian's concern, but I
have a bit of hatred towards single caller functions like this.  Since
this function isn't really high-touch, and I don't expect that to
change in the near future, let's leave the casting mess as-is.

-- 
paul moore
www.paul-moore.com

Re: [PATCH v4 3/3] audit: add OPENAT2 record to list how

[Paul Moore]

On Thu, May 20, 2021 at 4:03 AM Christian Brauner
<christian.brauner@ubuntu.com> wrote:
> On Wed, May 19, 2021 at 04:00:22PM -0400, Richard Guy Briggs wrote:
> > Since the openat2(2) syscall uses a struct open_how pointer to communicate
> > its parameters they are not usefully recorded by the audit SYSCALL record's
> > four existing arguments.
> >
> > Add a new audit record type OPENAT2 that reports the parameters in its
> > third argument, struct open_how with fields oflag, mode and resolve.
> >
> > The new record in the context of an event would look like:
> > time->Wed Mar 17 16:28:53 2021
> > type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432
> > type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> > type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> > type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests"
> > type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa
> > type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO"
> >
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com
> > ---
> >  fs/open.c                  |  2 ++
> >  include/linux/audit.h      | 10 ++++++++++
> >  include/uapi/linux/audit.h |  1 +
> >  kernel/audit.h             |  2 ++
> >  kernel/auditsc.c           | 18 +++++++++++++++++-
> >  5 files changed, 32 insertions(+), 1 deletion(-)

...

> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 3f59ab209dfd..faf2485323a9 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -76,7 +76,7 @@
> >  #include <linux/fsnotify_backend.h>
> >  #include <uapi/linux/limits.h>
> >  #include <uapi/linux/netfilter/nf_tables.h>
> > -#include <uapi/linux/openat2.h>
> > +#include <uapi/linux/openat2.h> // struct open_how
> >
> >  #include "audit.h"
> >
> > @@ -1319,6 +1319,12 @@ static void show_special(struct audit_context *context, int *call_panic)
> >               audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
> >                                context->mmap.flags);
> >               break;
> > +     case AUDIT_OPENAT2:
> > +             audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx",
>
> Hm, should we maybe follow the struct member names for all entries, i.e.
> replace s/oflag/flags?

There is some precedence for using "oflags" to refer to "open" flags,
my guess is Richard is trying to be consistent here.  I agree it's a
little odd, but it looks like the right thing to me from an audit
perspective; the audit perspective is a little odd after all :)

-- 
paul moore
www.paul-moore.com

Re: [PATCH v4 3/3] audit: add OPENAT2 record to list how

[Richard Guy Briggs]

On 2021-05-24 19:08, Paul Moore wrote:
> On Thu, May 20, 2021 at 4:03 AM Christian Brauner
> <christian.brauner@ubuntu.com> wrote:
> > On Wed, May 19, 2021 at 04:00:22PM -0400, Richard Guy Briggs wrote:
> > > Since the openat2(2) syscall uses a struct open_how pointer to communicate
> > > its parameters they are not usefully recorded by the audit SYSCALL record's
> > > four existing arguments.
> > >
> > > Add a new audit record type OPENAT2 that reports the parameters in its
> > > third argument, struct open_how with fields oflag, mode and resolve.
> > >
> > > The new record in the context of an event would look like:
> > > time->Wed Mar 17 16:28:53 2021
> > > type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432
> > > type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> > > type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> > > type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests"
> > > type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa
> > > type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO"
> > >
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com
> > > ---
> > >  fs/open.c                  |  2 ++
> > >  include/linux/audit.h      | 10 ++++++++++
> > >  include/uapi/linux/audit.h |  1 +
> > >  kernel/audit.h             |  2 ++
> > >  kernel/auditsc.c           | 18 +++++++++++++++++-
> > >  5 files changed, 32 insertions(+), 1 deletion(-)
> 
> ...
> 
> > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > index 3f59ab209dfd..faf2485323a9 100644
> > > --- a/kernel/auditsc.c
> > > +++ b/kernel/auditsc.c
> > > @@ -76,7 +76,7 @@
> > >  #include <linux/fsnotify_backend.h>
> > >  #include <uapi/linux/limits.h>
> > >  #include <uapi/linux/netfilter/nf_tables.h>
> > > -#include <uapi/linux/openat2.h>
> > > +#include <uapi/linux/openat2.h> // struct open_how
> > >
> > >  #include "audit.h"
> > >
> > > @@ -1319,6 +1319,12 @@ static void show_special(struct audit_context *context, int *call_panic)
> > >               audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
> > >                                context->mmap.flags);
> > >               break;
> > > +     case AUDIT_OPENAT2:
> > > +             audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx",
> >
> > Hm, should we maybe follow the struct member names for all entries, i.e.
> > replace s/oflag/flags?
> 
> There is some precedence for using "oflags" to refer to "open" flags,
> my guess is Richard is trying to be consistent here.  I agree it's a
> little odd, but it looks like the right thing to me from an audit
> perspective; the audit perspective is a little odd after all :)

Thanks Paul.

I could have sworn I had a conversation with someone about this but I
can't find any of that evidence otherwise I'd paste it here.

With the help of our audit field dictionary we have some guidance of
what these new field names should be:
	https://github.com/linux-audit/audit-documentation/blob/main/specs/fields/field-dictionary.csv

The "flags" field is used for the mmap record (coincidentally in the
context diff), so should not be used here because it will cause issues
in the userspace parser.  The open syscall flags are listed with
"oflag".  Other flag fields are named after their domain.

The value field has a precedence of "val" that is not associated with
any particular domain and is alphanumeric.  Other value fields take the
name of their domain, so that was a possibility.

"resolve" would be a new field for which I have a note to add it to this
document if the patch is accepted.

> paul moore

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH v4 1/3] audit: replace magic audit syscall class numbers with macros

[Paul Moore]

On Wed, May 19, 2021 at 4:01 PM Richard Guy Briggs <rgb@redhat.com> wrote:
>
> Replace audit syscall class magic numbers with macros.
>
> This required putting the macros into new header file
> include/linux/auditsc_classmacros.h since the syscall macros were
> included for both 64 bit and 32 bit in any compat code, causing
> redefinition warnings.
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> Link: https://lore.kernel.org/r/2300b1083a32aade7ae7efb95826e8f3f260b1df.1621363275.git.rgb@redhat.com
> ---
>  MAINTAINERS                         |  1 +
>  arch/alpha/kernel/audit.c           |  8 ++++----
>  arch/ia64/kernel/audit.c            |  8 ++++----
>  arch/parisc/kernel/audit.c          |  8 ++++----
>  arch/parisc/kernel/compat_audit.c   |  9 +++++----
>  arch/powerpc/kernel/audit.c         | 10 +++++-----
>  arch/powerpc/kernel/compat_audit.c  | 11 ++++++-----
>  arch/s390/kernel/audit.c            | 10 +++++-----
>  arch/s390/kernel/compat_audit.c     | 11 ++++++-----
>  arch/sparc/kernel/audit.c           | 10 +++++-----
>  arch/sparc/kernel/compat_audit.c    | 11 ++++++-----
>  arch/x86/ia32/audit.c               | 11 ++++++-----
>  arch/x86/kernel/audit_64.c          |  8 ++++----
>  include/linux/audit.h               |  1 +
>  include/linux/auditsc_classmacros.h | 23 +++++++++++++++++++++++
>  kernel/auditsc.c                    | 12 ++++++------
>  lib/audit.c                         | 10 +++++-----
>  lib/compat_audit.c                  | 11 ++++++-----
>  18 files changed, 102 insertions(+), 71 deletions(-)
>  create mode 100644 include/linux/auditsc_classmacros.h

...

> diff --git a/include/linux/auditsc_classmacros.h b/include/linux/auditsc_classmacros.h
> new file mode 100644
> index 000000000000..18757d270961
> --- /dev/null
> +++ b/include/linux/auditsc_classmacros.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* auditsc_classmacros.h -- Auditing support syscall macros
> + *
> + * Copyright 2021 Red Hat Inc., Durham, North Carolina.
> + * All Rights Reserved.
> + *
> + * Author: Richard Guy Briggs <rgb@redhat.com>
> + */
> +#ifndef _LINUX_AUDITSCM_H_
> +#define _LINUX_AUDITSCM_H_
> +
> +enum auditsc_class_t {
> +       AUDITSC_NATIVE = 0,
> +       AUDITSC_COMPAT,
> +       AUDITSC_OPEN,
> +       AUDITSC_OPENAT,
> +       AUDITSC_SOCKETCALL,
> +       AUDITSC_EXECVE,
> +
> +       AUDITSC_NVALS /* count */
> +};
> +
> +#endif

My apologies Richard, for some reason I had it in my mind that this
series was waiting on you to answer a question and/or respin; however,
now that I'm clearing my patch queues looking for any stragglers I see
that isn't the case.  Looking over the patchset I think it looks okay
to me, my only concern is that "auditsc_classmacros.h" is an awfully
specific header file name and could prove to be annoying if we want to
add to it in the future.  What do you think about something like
"audit_arch.h" instead?

If that change is okay with you I can go ahead and do the rename while
I'm merging the patches, I'll consider it penance for letting this
patchset sit for so long :/

-- 
paul moore
www.paul-moore.com

Re: [PATCH v4 3/3] audit: add OPENAT2 record to list how

[Paul Moore]

On Wed, May 19, 2021 at 4:02 PM Richard Guy Briggs <rgb@redhat.com> wrote:
>
> Since the openat2(2) syscall uses a struct open_how pointer to communicate
> its parameters they are not usefully recorded by the audit SYSCALL record's
> four existing arguments.
>
> Add a new audit record type OPENAT2 that reports the parameters in its
> third argument, struct open_how with fields oflag, mode and resolve.
>
> The new record in the context of an event would look like:
> time->Wed Mar 17 16:28:53 2021
> type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432
> type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests"
> type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa
> type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO"
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com
> ---
>  fs/open.c                  |  2 ++
>  include/linux/audit.h      | 10 ++++++++++
>  include/uapi/linux/audit.h |  1 +
>  kernel/audit.h             |  2 ++
>  kernel/auditsc.c           | 18 +++++++++++++++++-
>  5 files changed, 32 insertions(+), 1 deletion(-)

...

> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> index cd2d8279a5e4..67aea2370c6d 100644
> --- a/include/uapi/linux/audit.h
> +++ b/include/uapi/linux/audit.h
> @@ -118,6 +118,7 @@
>  #define AUDIT_TIME_ADJNTPVAL   1333    /* NTP value adjustment */
>  #define AUDIT_BPF              1334    /* BPF subsystem */
>  #define AUDIT_EVENT_LISTENER   1335    /* Task joined multicast read socket */
> +#define AUDIT_OPENAT2          1336    /* Record showing openat2 how args */

As a heads-up, I had to change the AUDIT_OPENAT2 value to 1337 as the
1336 value is already in use by AUDIT_URINGOP.  It wasn't caught
during my initial build test as the LSM/audit io_uring patches are in
selinux/next and not audit/next, it wasn't until the kernel-secnext
build was merging everything for its test run that the collision
occurred.  I'll be updating the audit/next tree with the new value
shortly.

-- 
paul moore
www.paul-moore.com

Re: [PATCH v4 3/3] audit: add OPENAT2 record to list how

[Richard Guy Briggs]

On 2021-10-04 12:08, Paul Moore wrote:
> On Wed, May 19, 2021 at 4:02 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> >
> > Since the openat2(2) syscall uses a struct open_how pointer to communicate
> > its parameters they are not usefully recorded by the audit SYSCALL record's
> > four existing arguments.
> >
> > Add a new audit record type OPENAT2 that reports the parameters in its
> > third argument, struct open_how with fields oflag, mode and resolve.
> >
> > The new record in the context of an event would look like:
> > time->Wed Mar 17 16:28:53 2021
> > type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432
> > type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> > type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> > type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests"
> > type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa
> > type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO"
> >
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com
> > ---
> >  fs/open.c                  |  2 ++
> >  include/linux/audit.h      | 10 ++++++++++
> >  include/uapi/linux/audit.h |  1 +
> >  kernel/audit.h             |  2 ++
> >  kernel/auditsc.c           | 18 +++++++++++++++++-
> >  5 files changed, 32 insertions(+), 1 deletion(-)
> 
> ...
> 
> > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> > index cd2d8279a5e4..67aea2370c6d 100644
> > --- a/include/uapi/linux/audit.h
> > +++ b/include/uapi/linux/audit.h
> > @@ -118,6 +118,7 @@
> >  #define AUDIT_TIME_ADJNTPVAL   1333    /* NTP value adjustment */
> >  #define AUDIT_BPF              1334    /* BPF subsystem */
> >  #define AUDIT_EVENT_LISTENER   1335    /* Task joined multicast read socket */
> > +#define AUDIT_OPENAT2          1336    /* Record showing openat2 how args */
> 
> As a heads-up, I had to change the AUDIT_OPENAT2 value to 1337 as the
> 1336 value is already in use by AUDIT_URINGOP.  It wasn't caught
> during my initial build test as the LSM/audit io_uring patches are in
> selinux/next and not audit/next, it wasn't until the kernel-secnext
> build was merging everything for its test run that the collision
> occurred.  I'll be updating the audit/next tree with the new value
> shortly.

I was expecting a conflict, so thanks for the heads up, Paul.

Steve: This affects the audit userspace support for this patchset
previously published 2021-05-19 as:
	https://github.com/rgbriggs/audit-userspace/tree/ghau-openat2

The update is here:
	https://github.com/rgbriggs/audit-userspace/tree/ghau-openat2.v2

And a PR has been created:
	https://github.com/linux-audit/audit-userspace/pull/219

> paul moore

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Jeff Mahoney]

Hi Richard -

On 5/19/21 16:00, Richard Guy Briggs wrote:
> The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> ("open: introduce openat2(2) syscall")
> 
> Add the openat2(2) syscall to the audit syscall classifier.
> 
> Link: https://github.com/linux-audit/audit-kernel/issues/67
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> ---

[...]

> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index d775ea16505b..3f59ab209dfd 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -76,6 +76,7 @@
>  #include <linux/fsnotify_backend.h>
>  #include <uapi/linux/limits.h>
>  #include <uapi/linux/netfilter/nf_tables.h>
> +#include <uapi/linux/openat2.h>
>  
>  #include "audit.h"
>  
> @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
>  		return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
>  	case AUDITSC_EXECVE:
>  		return mask & AUDIT_PERM_EXEC;
> +	case AUDITSC_OPENAT2:
> +		return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
>  	default:
>  		return 0;
>  	}

ctx->argv[2] holds a userspace pointer and can't be dereferenced like this.

I'm getting oopses, like so:
BUG: unable to handle page fault for address: 00007fff961bbe70

#PF: supervisor read access in kernel mode

#PF: error_code(0x0001) - permissions violation

PGD 8000000132291067 P4D 8000000132291067 PUD 132174067 PMD 132bb1067
PTE 800000013be02867

Oops: 0001 [#1] PREEMPT SMP PTI

CPU: 1 PID: 4525 Comm: a.out Kdump: loaded Not tainted 5.16.4-1-default
#1 openSUSE Tumbleweed f35df798c13cc3a259a6bf2924380af618948152

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014

RIP: 0010:audit_filter_rules.constprop.0+0x97e/0x1220

Code: 41 21 c5 41 83 7f 18 01 0f 85 5f f7 ff ff e9 65 f9 ff ff 83 f8 05
0f 84 5f 06 00 00 83 f8 06 0f 85 03 02 00 00 49 8b 44 24 40 <48> 8b 00
83 e0 03 0f be 80 c5 5e 45 86 41 21 c5 eb c7 4d 85 e4 0f

RSP: 0018:ffffb096403cbe08 EFLAGS: 00010246

RAX: 00007fff961bbe70 RBX: 0000000000000001 RCX: 000000000000001f

RDX: 0000000000000006 RSI: 00000000000001b5 RDI: 00000000c000003e

RBP: ffff9cb784a85020 R08: ffff9cb78775c380 R09: ffff9cb790ad9eb8

R10: 0000000040000020 R11: ffff9cb783f7b410 R12: ffff9cb78486dc00

R13: 000000000000000f R14: 00000000000001b5 R15: ffff9cb78775c380

FS:  00007ff21fca9740(0000) GS:ffff9cb7ffd00000(0000) knlGS:0000000000000000

CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fff961bbe70 CR3: 0000000121264002 CR4: 0000000000370ee0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000

DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Call Trace:

 <TASK>

 audit_filter_syscall+0xb0/0x100

 ? do_sys_openat2+0x81/0x160

 __audit_syscall_exit+0x69/0xf0

 syscall_exit_to_user_mode_prepare+0x14d/0x180

 syscall_exit_to_user_mode+0x9/0x40

 do_syscall_64+0x69/0x80

 ? syscall_exit_to_user_mode+0x18/0x40

 ? do_syscall_64+0x69/0x80

 entry_SYSCALL_64_after_hwframe+0x44/0xae

RIP: 0033:0x7ff21fdd195d


Where the faulting address matches the open_how address printed with the
following test using a "-w /var/tmp/testfile -k openat2-oops" audit rule.

#include <fcntl.h>

#include <linux/openat2.h>

#include <sys/syscall.h>

#include <unistd.h>

#include <stdio.h>



long openat2(int dirfd, const char *pathname, struct open_how *how,
size_t size)

{

       return  syscall(SYS_openat2, dirfd, pathname, how, size);

}



int

main(void)

{

        struct open_how how = {

                .flags = O_RDONLY|O_DIRECTORY,

        };



        int fd;



        fprintf(stderr, "&how = %p\n", &how);



        fd = openat2(AT_FDCWD, "/var/tmp/testfile", &how, sizeof(struct
open_how));

        perror("openat2");

}


$ mkdir /var/tmp/testfile
$ ./a.out

&how = 0x7fff961bbe70

<crash>

-Jeff

-- 
Jeff Mahoney
Director, SUSE Labs Data & Performance

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Paul Moore]

On Tue, Feb 8, 2022 at 10:44 PM Jeff Mahoney <jeffm@suse.com> wrote:
>
> Hi Richard -
>
> On 5/19/21 16:00, Richard Guy Briggs wrote:
> > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> > ("open: introduce openat2(2) syscall")
> >
> > Add the openat2(2) syscall to the audit syscall classifier.
> >
> > Link: https://github.com/linux-audit/audit-kernel/issues/67
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> > ---
>
> [...]
>
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index d775ea16505b..3f59ab209dfd 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -76,6 +76,7 @@
> >  #include <linux/fsnotify_backend.h>
> >  #include <uapi/linux/limits.h>
> >  #include <uapi/linux/netfilter/nf_tables.h>
> > +#include <uapi/linux/openat2.h>
> >
> >  #include "audit.h"
> >
> > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
> >               return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
> >       case AUDITSC_EXECVE:
> >               return mask & AUDIT_PERM_EXEC;
> > +     case AUDITSC_OPENAT2:
> > +             return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
> >       default:
> >               return 0;
> >       }
>
> ctx->argv[2] holds a userspace pointer and can't be dereferenced like this.
>
> I'm getting oopses, like so:
> BUG: unable to handle page fault for address: 00007fff961bbe70

Thanks Jeff.

Yes, this is obviously the wrong thing to being doing; I remember
checking to make sure we placed the audit_openat2_how() hook after the
open_how was copied from userspace, but I missed the argv dereference
in the syscall exit path when reviewing the code.

Richard, as we are already copying the open_how info into
audit_context::openat2 safely, the obvious fix is to convert
audit_match_perm() to use the previously copied value instead of argv.
If you can't submit a patch for this today please let me know.

-- 
paul-moore.com

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Paul Moore]

On Wed, Feb 9, 2022 at 10:57 AM Paul Moore <paul@paul-moore.com> wrote:
> On Tue, Feb 8, 2022 at 10:44 PM Jeff Mahoney <jeffm@suse.com> wrote:
> >
> > Hi Richard -
> >
> > On 5/19/21 16:00, Richard Guy Briggs wrote:
> > > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> > > ("open: introduce openat2(2) syscall")
> > >
> > > Add the openat2(2) syscall to the audit syscall classifier.
> > >
> > > Link: https://github.com/linux-audit/audit-kernel/issues/67
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> > > ---
> >
> > [...]
> >
> > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > index d775ea16505b..3f59ab209dfd 100644
> > > --- a/kernel/auditsc.c
> > > +++ b/kernel/auditsc.c
> > > @@ -76,6 +76,7 @@
> > >  #include <linux/fsnotify_backend.h>
> > >  #include <uapi/linux/limits.h>
> > >  #include <uapi/linux/netfilter/nf_tables.h>
> > > +#include <uapi/linux/openat2.h>
> > >
> > >  #include "audit.h"
> > >
> > > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
> > >               return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
> > >       case AUDITSC_EXECVE:
> > >               return mask & AUDIT_PERM_EXEC;
> > > +     case AUDITSC_OPENAT2:
> > > +             return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
> > >       default:
> > >               return 0;
> > >       }
> >
> > ctx->argv[2] holds a userspace pointer and can't be dereferenced like this.
> >
> > I'm getting oopses, like so:
> > BUG: unable to handle page fault for address: 00007fff961bbe70
>
> Thanks Jeff.
>
> Yes, this is obviously the wrong thing to being doing; I remember
> checking to make sure we placed the audit_openat2_how() hook after the
> open_how was copied from userspace, but I missed the argv dereference
> in the syscall exit path when reviewing the code.
>
> Richard, as we are already copying the open_how info into
> audit_context::openat2 safely, the obvious fix is to convert
> audit_match_perm() to use the previously copied value instead of argv.
> If you can't submit a patch for this today please let me know.

I haven't heard anything from Richard so I put together a patch which
should fix the problem (link below).  It's currently untested, but
I've got a kernel building now with the patch ...

https://lore.kernel.org/linux-audit/164444111699.153511.15656610495968926251.stgit@olly/T/#u

-- 
paul-moore.com

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Richard Guy Briggs]

On 2022-02-09 10:57, Paul Moore wrote:
> On Tue, Feb 8, 2022 at 10:44 PM Jeff Mahoney <jeffm@suse.com> wrote:
> >
> > Hi Richard -
> >
> > On 5/19/21 16:00, Richard Guy Briggs wrote:
> > > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> > > ("open: introduce openat2(2) syscall")
> > >
> > > Add the openat2(2) syscall to the audit syscall classifier.
> > >
> > > Link: https://github.com/linux-audit/audit-kernel/issues/67
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> > > ---
> >
> > [...]
> >
> > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > index d775ea16505b..3f59ab209dfd 100644
> > > --- a/kernel/auditsc.c
> > > +++ b/kernel/auditsc.c
> > > @@ -76,6 +76,7 @@
> > >  #include <linux/fsnotify_backend.h>
> > >  #include <uapi/linux/limits.h>
> > >  #include <uapi/linux/netfilter/nf_tables.h>
> > > +#include <uapi/linux/openat2.h>
> > >
> > >  #include "audit.h"
> > >
> > > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
> > >               return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
> > >       case AUDITSC_EXECVE:
> > >               return mask & AUDIT_PERM_EXEC;
> > > +     case AUDITSC_OPENAT2:
> > > +             return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
> > >       default:
> > >               return 0;
> > >       }
> >
> > ctx->argv[2] holds a userspace pointer and can't be dereferenced like this.
> >
> > I'm getting oopses, like so:
> > BUG: unable to handle page fault for address: 00007fff961bbe70
> 
> Thanks Jeff.
> 
> Yes, this is obviously the wrong thing to being doing; I remember
> checking to make sure we placed the audit_openat2_how() hook after the
> open_how was copied from userspace, but I missed the argv dereference
> in the syscall exit path when reviewing the code.
> 
> Richard, as we are already copying the open_how info into
> audit_context::openat2 safely, the obvious fix is to convert
> audit_match_perm() to use the previously copied value instead of argv.
> If you can't submit a patch for this today please let me know.

Agreed.  It would have been more awkward with the original order of the
patches.

The syscalls_file test in the audit-testsuite should have caught this.
https://github.com/rgbriggs/audit-testsuite/commit/1c99021ae27ea23eccce2bb1861df4c9c665cd5b
The test provided does essentially the same thing.

I should have a tested patch posted today.

> paul-moore.com

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Richard Guy Briggs]

On 2022-02-09 16:18, Paul Moore wrote:
> On Wed, Feb 9, 2022 at 10:57 AM Paul Moore <paul@paul-moore.com> wrote:
> > On Tue, Feb 8, 2022 at 10:44 PM Jeff Mahoney <jeffm@suse.com> wrote:
> > >
> > > Hi Richard -
> > >
> > > On 5/19/21 16:00, Richard Guy Briggs wrote:
> > > > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> > > > ("open: introduce openat2(2) syscall")
> > > >
> > > > Add the openat2(2) syscall to the audit syscall classifier.
> > > >
> > > > Link: https://github.com/linux-audit/audit-kernel/issues/67
> > > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> > > > ---
> > >
> > > [...]
> > >
> > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > > index d775ea16505b..3f59ab209dfd 100644
> > > > --- a/kernel/auditsc.c
> > > > +++ b/kernel/auditsc.c
> > > > @@ -76,6 +76,7 @@
> > > >  #include <linux/fsnotify_backend.h>
> > > >  #include <uapi/linux/limits.h>
> > > >  #include <uapi/linux/netfilter/nf_tables.h>
> > > > +#include <uapi/linux/openat2.h>
> > > >
> > > >  #include "audit.h"
> > > >
> > > > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
> > > >               return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
> > > >       case AUDITSC_EXECVE:
> > > >               return mask & AUDIT_PERM_EXEC;
> > > > +     case AUDITSC_OPENAT2:
> > > > +             return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
> > > >       default:
> > > >               return 0;
> > > >       }
> > >
> > > ctx->argv[2] holds a userspace pointer and can't be dereferenced like this.
> > >
> > > I'm getting oopses, like so:
> > > BUG: unable to handle page fault for address: 00007fff961bbe70
> >
> > Thanks Jeff.
> >
> > Yes, this is obviously the wrong thing to being doing; I remember
> > checking to make sure we placed the audit_openat2_how() hook after the
> > open_how was copied from userspace, but I missed the argv dereference
> > in the syscall exit path when reviewing the code.
> >
> > Richard, as we are already copying the open_how info into
> > audit_context::openat2 safely, the obvious fix is to convert
> > audit_match_perm() to use the previously copied value instead of argv.
> > If you can't submit a patch for this today please let me know.
> 
> I haven't heard anything from Richard so I put together a patch which
> should fix the problem (link below).  It's currently untested, but
> I've got a kernel building now with the patch ...

Well, the day wasn't over yet...  I've compiled and tested it.

> https://lore.kernel.org/linux-audit/164444111699.153511.15656610495968926251.stgit@olly/T/#u
> 
> -- 
> paul-moore.com
> 

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Paul Moore]

On Wed, Feb 9, 2022 at 4:41 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2022-02-09 10:57, Paul Moore wrote:
> > On Tue, Feb 8, 2022 at 10:44 PM Jeff Mahoney <jeffm@suse.com> wrote:
> > >
> > > Hi Richard -
> > >
> > > On 5/19/21 16:00, Richard Guy Briggs wrote:
> > > > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> > > > ("open: introduce openat2(2) syscall")
> > > >
> > > > Add the openat2(2) syscall to the audit syscall classifier.
> > > >
> > > > Link: https://github.com/linux-audit/audit-kernel/issues/67
> > > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> > > > ---
> > >
> > > [...]
> > >
> > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > > index d775ea16505b..3f59ab209dfd 100644
> > > > --- a/kernel/auditsc.c
> > > > +++ b/kernel/auditsc.c
> > > > @@ -76,6 +76,7 @@
> > > >  #include <linux/fsnotify_backend.h>
> > > >  #include <uapi/linux/limits.h>
> > > >  #include <uapi/linux/netfilter/nf_tables.h>
> > > > +#include <uapi/linux/openat2.h>
> > > >
> > > >  #include "audit.h"
> > > >
> > > > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
> > > >               return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
> > > >       case AUDITSC_EXECVE:
> > > >               return mask & AUDIT_PERM_EXEC;
> > > > +     case AUDITSC_OPENAT2:
> > > > +             return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
> > > >       default:
> > > >               return 0;
> > > >       }
> > >
> > > ctx->argv[2] holds a userspace pointer and can't be dereferenced like this.
> > >
> > > I'm getting oopses, like so:
> > > BUG: unable to handle page fault for address: 00007fff961bbe70
> >
> > Thanks Jeff.
> >
> > Yes, this is obviously the wrong thing to being doing; I remember
> > checking to make sure we placed the audit_openat2_how() hook after the
> > open_how was copied from userspace, but I missed the argv dereference
> > in the syscall exit path when reviewing the code.
> >
> > Richard, as we are already copying the open_how info into
> > audit_context::openat2 safely, the obvious fix is to convert
> > audit_match_perm() to use the previously copied value instead of argv.
> > If you can't submit a patch for this today please let me know.
>
> Agreed.  It would have been more awkward with the original order of the
> patches.
>
> The syscalls_file test in the audit-testsuite should have caught this.
> https://github.com/rgbriggs/audit-testsuite/commit/1c99021ae27ea23eccce2bb1861df4c9c665cd5b
> The test provided does essentially the same thing.

I would have thought so, but I've now run this multiple times on both
affected and patched kernels but I don't see the page fault on my test
system.

Anyway, that test has now been merged with the audit-testsuite as well
as some cleanup on top to test for the new OPENAT2 record when
applicable.

-- 
paul-moore.com

Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

[Paul Moore]

On Wed, Feb 9, 2022 at 5:14 PM Richard Guy Briggs <rgb@redhat.com> wrote:
>
> On 2022-02-09 16:18, Paul Moore wrote:
> > On Wed, Feb 9, 2022 at 10:57 AM Paul Moore <paul@paul-moore.com> wrote:
> > > On Tue, Feb 8, 2022 at 10:44 PM Jeff Mahoney <jeffm@suse.com> wrote:
> > > >
> > > > Hi Richard -
> > > >
> > > > On 5/19/21 16:00, Richard Guy Briggs wrote:
> > > > > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9
> > > > > ("open: introduce openat2(2) syscall")
> > > > >
> > > > > Add the openat2(2) syscall to the audit syscall classifier.
> > > > >
> > > > > Link: https://github.com/linux-audit/audit-kernel/issues/67
> > > > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > > > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
> > > > > ---
> > > >
> > > > [...]
> > > >
> > > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > > > index d775ea16505b..3f59ab209dfd 100644
> > > > > --- a/kernel/auditsc.c
> > > > > +++ b/kernel/auditsc.c
> > > > > @@ -76,6 +76,7 @@
> > > > >  #include <linux/fsnotify_backend.h>
> > > > >  #include <uapi/linux/limits.h>
> > > > >  #include <uapi/linux/netfilter/nf_tables.h>
> > > > > +#include <uapi/linux/openat2.h>
> > > > >
> > > > >  #include "audit.h"
> > > > >
> > > > > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
> > > > >               return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
> > > > >       case AUDITSC_EXECVE:
> > > > >               return mask & AUDIT_PERM_EXEC;
> > > > > +     case AUDITSC_OPENAT2:
> > > > > +             return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags);
> > > > >       default:
> > > > >               return 0;
> > > > >       }
> > > >
> > > > ctx->argv[2] holds a userspace pointer and can't be dereferenced like this.
> > > >
> > > > I'm getting oopses, like so:
> > > > BUG: unable to handle page fault for address: 00007fff961bbe70
> > >
> > > Thanks Jeff.
> > >
> > > Yes, this is obviously the wrong thing to being doing; I remember
> > > checking to make sure we placed the audit_openat2_how() hook after the
> > > open_how was copied from userspace, but I missed the argv dereference
> > > in the syscall exit path when reviewing the code.
> > >
> > > Richard, as we are already copying the open_how info into
> > > audit_context::openat2 safely, the obvious fix is to convert
> > > audit_match_perm() to use the previously copied value instead of argv.
> > > If you can't submit a patch for this today please let me know.
> >
> > I haven't heard anything from Richard so I put together a patch which
> > should fix the problem (link below).  It's currently untested, but
> > I've got a kernel building now with the patch ...
>
> Well, the day wasn't over yet...  I've compiled and tested it.

Yes, I tested my patch too and everything looks good on my end.

For future reference, while I didn't explicitly ask you to acknowledge
this thread and that you were working on a patch (I probably should
have), it would have been nice if you could have sent a quick note to
the list.

-- 
paul-moore.com