From 506ada89629ec7059b96ecfb0dc7d33ece0103ca Mon Sep 17 00:00:00 2001
From: Eduard Zingerman <eddyz87@gmail.com>
Date: Fri, 4 Sep 2026 17:05:56 -0700
Subject: bpf: mark a NULL kfunc argument precise

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 lib/audit.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 lib/audit.c

(limited to 'lib/audit.c')

diff --git a/lib/audit.c b/lib/audit.c
new file mode 100644
index 000000000..bc07fbd3a
--- /dev/null
+++ b/lib/audit.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/audit.h>
+#include <asm/unistd.h>
+
+static unsigned dir_class[] = {
+#include <asm-generic/audit_dir_write.h>
+~0U
+};
+
+static unsigned read_class[] = {
+#include <asm-generic/audit_read.h>
+~0U
+};
+
+static unsigned write_class[] = {
+#include <asm-generic/audit_write.h>
+~0U
+};
+
+static unsigned chattr_class[] = {
+#include <asm-generic/audit_change_attr.h>
+~0U
+};
+
+static unsigned signal_class[] = {
+#include <asm-generic/audit_signal.h>
+~0U
+};
+
+int audit_classify_arch(int arch)
+{
+	if (audit_is_compat(arch))
+		return 1;
+	else
+		return 0;
+}
+
+int audit_classify_syscall(int abi, unsigned syscall)
+{
+	if (audit_is_compat(abi))
+		return audit_classify_compat_syscall(abi, syscall);
+
+	switch (syscall) {
+#ifdef __NR_open
+	case __NR_open:
+		return AUDITSC_OPEN;
+#endif
+#ifdef __NR_openat
+	case __NR_openat:
+		return AUDITSC_OPENAT;
+#endif
+#ifdef __NR_socketcall
+	case __NR_socketcall:
+		return AUDITSC_SOCKETCALL;
+#endif
+#ifdef __NR_execveat
+	case __NR_execveat:
+#endif
+	case __NR_execve:
+		return AUDITSC_EXECVE;
+#ifdef __NR_openat2
+	case __NR_openat2:
+		return AUDITSC_OPENAT2;
+#endif
+	default:
+		return AUDITSC_NATIVE;
+	}
+}
+
+static int __init audit_classes_init(void)
+{
+#ifdef CONFIG_AUDIT_COMPAT_GENERIC
+	audit_register_class(AUDIT_CLASS_WRITE_32, compat_write_class);
+	audit_register_class(AUDIT_CLASS_READ_32, compat_read_class);
+	audit_register_class(AUDIT_CLASS_DIR_WRITE_32, compat_dir_class);
+	audit_register_class(AUDIT_CLASS_CHATTR_32, compat_chattr_class);
+	audit_register_class(AUDIT_CLASS_SIGNAL_32, compat_signal_class);
+#endif
+	audit_register_class(AUDIT_CLASS_WRITE, write_class);
+	audit_register_class(AUDIT_CLASS_READ, read_class);
+	audit_register_class(AUDIT_CLASS_DIR_WRITE, dir_class);
+	audit_register_class(AUDIT_CLASS_CHATTR, chattr_class);
+	audit_register_class(AUDIT_CLASS_SIGNAL, signal_class);
+	return 0;
+}
+
+__initcall(audit_classes_init);
-- 
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