From 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 2 Sep 2026 15:31:14 -0700 Subject: treewide: refresh kmalloc_obj() conversions This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook --- samples/kobject/kobject-example.c | 145 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+) create mode 100644 samples/kobject/kobject-example.c (limited to 'samples/kobject/kobject-example.c') diff --git a/samples/kobject/kobject-example.c b/samples/kobject/kobject-example.c new file mode 100644 index 000000000..36f3fbc47 --- /dev/null +++ b/samples/kobject/kobject-example.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Sample kobject implementation + * + * Copyright (C) 2004-2007 Greg Kroah-Hartman + * Copyright (C) 2007 Novell Inc. + */ +#include +#include +#include +#include +#include + +/* + * This module shows how to create a simple subdirectory in sysfs called + * /sys/kernel/kobject_example In that directory, 3 files are created: + * "foo", "baz", and "bar". If an integer is written to these files, it can be + * later read out of it. + */ + +static int foo; +static int baz; +static int bar; + +/* + * The "foo" file where a static variable is read from and written to. + */ +static ssize_t foo_show(struct kobject *kobj, const struct kobj_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%d\n", foo); +} + +static ssize_t foo_store(struct kobject *kobj, const struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int ret; + + ret = kstrtoint(buf, 10, &foo); + if (ret < 0) + return ret; + + return count; +} + +/* Sysfs attributes cannot be world-writable. */ +static const struct kobj_attribute foo_attribute = + __KOBJ_ATTR(foo, 0664, foo_show, foo_store); + +/* + * More complex function where we determine which variable is being accessed by + * looking at the attribute for the "baz" and "bar" files. + */ +static ssize_t b_show(struct kobject *kobj, const struct kobj_attribute *attr, + char *buf) +{ + int var; + + if (strcmp(attr->attr.name, "baz") == 0) + var = baz; + else + var = bar; + return sysfs_emit(buf, "%d\n", var); +} + +static ssize_t b_store(struct kobject *kobj, const struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int var, ret; + + ret = kstrtoint(buf, 10, &var); + if (ret < 0) + return ret; + + if (strcmp(attr->attr.name, "baz") == 0) + baz = var; + else + bar = var; + return count; +} + +static const struct kobj_attribute baz_attribute = + __KOBJ_ATTR(baz, 0664, b_show, b_store); +static const struct kobj_attribute bar_attribute = + __KOBJ_ATTR(bar, 0664, b_show, b_store); + + +/* + * Create a group of attributes so that we can create and destroy them all + * at once. + */ +static const struct attribute *const attrs[] = { + &foo_attribute.attr, + &baz_attribute.attr, + &bar_attribute.attr, + NULL, /* need to NULL terminate the list of attributes */ +}; + +/* + * An unnamed attribute group will put all of the attributes directly in + * the kobject directory. If we specify a name, a subdirectory will be + * created for the attributes with the directory being the name of the + * attribute group. + */ +static const struct attribute_group attr_group = { + .attrs_const = attrs, +}; + +static struct kobject *example_kobj; + +static int __init example_init(void) +{ + int retval; + + /* + * Create a simple kobject with the name of "kobject_example", + * located under /sys/kernel/ + * + * As this is a simple directory, no uevent will be sent to + * userspace. That is why this function should not be used for + * any type of dynamic kobjects, where the name and number are + * not known ahead of time. + */ + example_kobj = kobject_create_and_add("kobject_example", kernel_kobj); + if (!example_kobj) + return -ENOMEM; + + /* Create the files associated with this kobject */ + retval = sysfs_create_group(example_kobj, &attr_group); + if (retval) + kobject_put(example_kobj); + + return retval; +} + +static void __exit example_exit(void) +{ + kobject_put(example_kobj); +} + +module_init(example_init); +module_exit(example_exit); +MODULE_DESCRIPTION("Sample kobject implementation"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Greg Kroah-Hartman "); -- cgit v1.3.1