lib: code tagging framework
Add basic infrastructure to support code tagging which stores tag common information consisting of the module name, function, file name and line number. Provide functions to register a new code tag type and navigate between code tags. Link: https://lkml.kernel.org/r/20240321163705.3067592-11-surenb@google.com Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Tested-by: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alex Gaynor <alex.gaynor@gmail.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andreas Hindborg <a.hindborg@samsung.com> Cc: Benno Lossin <benno.lossin@proton.me> Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Gary Guo <gary@garyguo.net> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Suren Baghdasaryan
Andrew Morton
parent
53ce720359
commit
916cc5167c
|
|
@ -0,0 +1,68 @@
|
|||
/* SPDX-License-Identifier: GPL-2.0 */
|
||||
/*
|
||||
* code tagging framework
|
||||
*/
|
||||
#ifndef _LINUX_CODETAG_H
|
||||
#define _LINUX_CODETAG_H
|
||||
|
||||
#include <linux/types.h>
|
||||
|
||||
struct codetag_iterator;
|
||||
struct codetag_type;
|
||||
struct codetag_module;
|
||||
struct seq_buf;
|
||||
struct module;
|
||||
|
||||
/*
|
||||
* An instance of this structure is created in a special ELF section at every
|
||||
* code location being tagged. At runtime, the special section is treated as
|
||||
* an array of these.
|
||||
*/
|
||||
struct codetag {
|
||||
unsigned int flags; /* used in later patches */
|
||||
unsigned int lineno;
|
||||
const char *modname;
|
||||
const char *function;
|
||||
const char *filename;
|
||||
} __aligned(8);
|
||||
|
||||
union codetag_ref {
|
||||
struct codetag *ct;
|
||||
};
|
||||
|
||||
struct codetag_type_desc {
|
||||
const char *section;
|
||||
size_t tag_size;
|
||||
};
|
||||
|
||||
struct codetag_iterator {
|
||||
struct codetag_type *cttype;
|
||||
struct codetag_module *cmod;
|
||||
unsigned long mod_id;
|
||||
struct codetag *ct;
|
||||
};
|
||||
|
||||
#ifdef MODULE
|
||||
#define CT_MODULE_NAME KBUILD_MODNAME
|
||||
#else
|
||||
#define CT_MODULE_NAME NULL
|
||||
#endif
|
||||
|
||||
#define CODE_TAG_INIT { \
|
||||
.modname = CT_MODULE_NAME, \
|
||||
.function = __func__, \
|
||||
.filename = __FILE__, \
|
||||
.lineno = __LINE__, \
|
||||
.flags = 0, \
|
||||
}
|
||||
|
||||
void codetag_lock_module_list(struct codetag_type *cttype, bool lock);
|
||||
struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype);
|
||||
struct codetag *codetag_next_ct(struct codetag_iterator *iter);
|
||||
|
||||
void codetag_to_text(struct seq_buf *out, struct codetag *ct);
|
||||
|
||||
struct codetag_type *
|
||||
codetag_register_type(const struct codetag_type_desc *desc);
|
||||
|
||||
#endif /* _LINUX_CODETAG_H */
|
||||
|
|
@ -968,6 +968,10 @@ config DEBUG_STACKOVERFLOW
|
|||
|
||||
If in doubt, say "N".
|
||||
|
||||
config CODE_TAGGING
|
||||
bool
|
||||
select KALLSYMS
|
||||
|
||||
source "lib/Kconfig.kasan"
|
||||
source "lib/Kconfig.kfence"
|
||||
source "lib/Kconfig.kmsan"
|
||||
|
|
|
|||
|
|
@ -233,6 +233,7 @@ obj-$(CONFIG_OF_RECONFIG_NOTIFIER_ERROR_INJECT) += \
|
|||
of-reconfig-notifier-error-inject.o
|
||||
obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
|
||||
|
||||
obj-$(CONFIG_CODE_TAGGING) += codetag.o
|
||||
lib-$(CONFIG_GENERIC_BUG) += bug.o
|
||||
|
||||
obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,219 @@
|
|||
// SPDX-License-Identifier: GPL-2.0-only
|
||||
#include <linux/codetag.h>
|
||||
#include <linux/idr.h>
|
||||
#include <linux/kallsyms.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/seq_buf.h>
|
||||
#include <linux/slab.h>
|
||||
|
||||
struct codetag_type {
|
||||
struct list_head link;
|
||||
unsigned int count;
|
||||
struct idr mod_idr;
|
||||
struct rw_semaphore mod_lock; /* protects mod_idr */
|
||||
struct codetag_type_desc desc;
|
||||
};
|
||||
|
||||
struct codetag_range {
|
||||
struct codetag *start;
|
||||
struct codetag *stop;
|
||||
};
|
||||
|
||||
struct codetag_module {
|
||||
struct module *mod;
|
||||
struct codetag_range range;
|
||||
};
|
||||
|
||||
static DEFINE_MUTEX(codetag_lock);
|
||||
static LIST_HEAD(codetag_types);
|
||||
|
||||
void codetag_lock_module_list(struct codetag_type *cttype, bool lock)
|
||||
{
|
||||
if (lock)
|
||||
down_read(&cttype->mod_lock);
|
||||
else
|
||||
up_read(&cttype->mod_lock);
|
||||
}
|
||||
|
||||
struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype)
|
||||
{
|
||||
struct codetag_iterator iter = {
|
||||
.cttype = cttype,
|
||||
.cmod = NULL,
|
||||
.mod_id = 0,
|
||||
.ct = NULL,
|
||||
};
|
||||
|
||||
return iter;
|
||||
}
|
||||
|
||||
static inline struct codetag *get_first_module_ct(struct codetag_module *cmod)
|
||||
{
|
||||
return cmod->range.start < cmod->range.stop ? cmod->range.start : NULL;
|
||||
}
|
||||
|
||||
static inline
|
||||
struct codetag *get_next_module_ct(struct codetag_iterator *iter)
|
||||
{
|
||||
struct codetag *res = (struct codetag *)
|
||||
((char *)iter->ct + iter->cttype->desc.tag_size);
|
||||
|
||||
return res < iter->cmod->range.stop ? res : NULL;
|
||||
}
|
||||
|
||||
struct codetag *codetag_next_ct(struct codetag_iterator *iter)
|
||||
{
|
||||
struct codetag_type *cttype = iter->cttype;
|
||||
struct codetag_module *cmod;
|
||||
struct codetag *ct;
|
||||
|
||||
lockdep_assert_held(&cttype->mod_lock);
|
||||
|
||||
if (unlikely(idr_is_empty(&cttype->mod_idr)))
|
||||
return NULL;
|
||||
|
||||
ct = NULL;
|
||||
while (true) {
|
||||
cmod = idr_find(&cttype->mod_idr, iter->mod_id);
|
||||
|
||||
/* If module was removed move to the next one */
|
||||
if (!cmod)
|
||||
cmod = idr_get_next_ul(&cttype->mod_idr,
|
||||
&iter->mod_id);
|
||||
|
||||
/* Exit if no more modules */
|
||||
if (!cmod)
|
||||
break;
|
||||
|
||||
if (cmod != iter->cmod) {
|
||||
iter->cmod = cmod;
|
||||
ct = get_first_module_ct(cmod);
|
||||
} else
|
||||
ct = get_next_module_ct(iter);
|
||||
|
||||
if (ct)
|
||||
break;
|
||||
|
||||
iter->mod_id++;
|
||||
}
|
||||
|
||||
iter->ct = ct;
|
||||
return ct;
|
||||
}
|
||||
|
||||
void codetag_to_text(struct seq_buf *out, struct codetag *ct)
|
||||
{
|
||||
if (ct->modname)
|
||||
seq_buf_printf(out, "%s:%u [%s] func:%s",
|
||||
ct->filename, ct->lineno,
|
||||
ct->modname, ct->function);
|
||||
else
|
||||
seq_buf_printf(out, "%s:%u func:%s",
|
||||
ct->filename, ct->lineno, ct->function);
|
||||
}
|
||||
|
||||
static inline size_t range_size(const struct codetag_type *cttype,
|
||||
const struct codetag_range *range)
|
||||
{
|
||||
return ((char *)range->stop - (char *)range->start) /
|
||||
cttype->desc.tag_size;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_MODULES
|
||||
static void *get_symbol(struct module *mod, const char *prefix, const char *name)
|
||||
{
|
||||
DECLARE_SEQ_BUF(sb, KSYM_NAME_LEN);
|
||||
const char *buf;
|
||||
|
||||
seq_buf_printf(&sb, "%s%s", prefix, name);
|
||||
if (seq_buf_has_overflowed(&sb))
|
||||
return NULL;
|
||||
|
||||
buf = seq_buf_str(&sb);
|
||||
return mod ?
|
||||
(void *)find_kallsyms_symbol_value(mod, buf) :
|
||||
(void *)kallsyms_lookup_name(buf);
|
||||
}
|
||||
|
||||
static struct codetag_range get_section_range(struct module *mod,
|
||||
const char *section)
|
||||
{
|
||||
return (struct codetag_range) {
|
||||
get_symbol(mod, "__start_", section),
|
||||
get_symbol(mod, "__stop_", section),
|
||||
};
|
||||
}
|
||||
|
||||
static int codetag_module_init(struct codetag_type *cttype, struct module *mod)
|
||||
{
|
||||
struct codetag_range range;
|
||||
struct codetag_module *cmod;
|
||||
int err;
|
||||
|
||||
range = get_section_range(mod, cttype->desc.section);
|
||||
if (!range.start || !range.stop) {
|
||||
pr_warn("Failed to load code tags of type %s from the module %s\n",
|
||||
cttype->desc.section,
|
||||
mod ? mod->name : "(built-in)");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
/* Ignore empty ranges */
|
||||
if (range.start == range.stop)
|
||||
return 0;
|
||||
|
||||
BUG_ON(range.start > range.stop);
|
||||
|
||||
cmod = kmalloc(sizeof(*cmod), GFP_KERNEL);
|
||||
if (unlikely(!cmod))
|
||||
return -ENOMEM;
|
||||
|
||||
cmod->mod = mod;
|
||||
cmod->range = range;
|
||||
|
||||
down_write(&cttype->mod_lock);
|
||||
err = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL);
|
||||
if (err >= 0)
|
||||
cttype->count += range_size(cttype, &range);
|
||||
up_write(&cttype->mod_lock);
|
||||
|
||||
if (err < 0) {
|
||||
kfree(cmod);
|
||||
return err;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#else /* CONFIG_MODULES */
|
||||
static int codetag_module_init(struct codetag_type *cttype, struct module *mod) { return 0; }
|
||||
#endif /* CONFIG_MODULES */
|
||||
|
||||
struct codetag_type *
|
||||
codetag_register_type(const struct codetag_type_desc *desc)
|
||||
{
|
||||
struct codetag_type *cttype;
|
||||
int err;
|
||||
|
||||
BUG_ON(desc->tag_size <= 0);
|
||||
|
||||
cttype = kzalloc(sizeof(*cttype), GFP_KERNEL);
|
||||
if (unlikely(!cttype))
|
||||
return ERR_PTR(-ENOMEM);
|
||||
|
||||
cttype->desc = *desc;
|
||||
idr_init(&cttype->mod_idr);
|
||||
init_rwsem(&cttype->mod_lock);
|
||||
|
||||
err = codetag_module_init(cttype, NULL);
|
||||
if (unlikely(err)) {
|
||||
kfree(cttype);
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
mutex_lock(&codetag_lock);
|
||||
list_add_tail(&cttype->link, &codetag_types);
|
||||
mutex_unlock(&codetag_lock);
|
||||
|
||||
return cttype;
|
||||
}
|
||||
Loading…
Reference in New Issue