bpf: mark a NULL kfunc argument precisegrafted

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>

1 files changed, 36 insertions, 0 deletions

diff --git a/fs/ext2/symlink.c b/fs/ext2/symlink.c
new file mode 100644
index 000000000..948d3a441
--- /dev/null
+++ b/fs/ext2/symlink.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext2/symlink.c
+ *
+ * Only fast symlinks left here - the rest is done by generic code. AV, 1999
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/symlink.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext2 symlink handling code
+ */
+
+#include "ext2.h"
+#include "xattr.h"
+
+const struct inode_operations ext2_symlink_inode_operations = {
+	.get_link	= page_get_link,
+	.getattr	= ext2_getattr,
+	.setattr	= ext2_setattr,
+	.listxattr	= ext2_listxattr,
+};
+ 
+const struct inode_operations ext2_fast_symlink_inode_operations = {
+	.get_link	= simple_get_link,
+	.getattr	= ext2_getattr,
+	.setattr	= ext2_setattr,
+	.listxattr	= ext2_listxattr,
+};