Commit a4735739 authored by Suren Baghdasaryan's avatar Suren Baghdasaryan Committed by Andrew Morton
Browse files

lib: code tagging module support 

Add support for code tagging from dynamically loaded modules.

Link: https://lkml.kernel.org/r/20240321163705.3067592-12-surenb@google.com


Signed-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
Co-developed-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
Tested-by: default avatarKees 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 916cc516

include/linux/codetag.h

+12 −0
Original line number Diff line number Diff line
@@ -33,6 +33,10 @@ union codetag_ref { 
struct codetag_type_desc {

	const char *section;

	size_t tag_size;

	void (*module_load)(struct codetag_type *cttype,

			    struct codetag_module *cmod);

	void (*module_unload)(struct codetag_type *cttype,

			      struct codetag_module *cmod);

};



struct codetag_iterator {
@@ -65,4 +69,12 @@ void codetag_to_text(struct seq_buf *out, struct codetag *ct); 
struct codetag_type *

codetag_register_type(const struct codetag_type_desc *desc);



#if defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES)

void codetag_load_module(struct module *mod);

void codetag_unload_module(struct module *mod);

#else

static inline void codetag_load_module(struct module *mod) {}

static inline void codetag_unload_module(struct module *mod) {}

#endif



#endif /* _LINUX_CODETAG_H */

kernel/module/main.c

+4 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ 
#include <linux/dynamic_debug.h>

#include <linux/audit.h>

#include <linux/cfi.h>

#include <linux/codetag.h>

#include <linux/debugfs.h>

#include <uapi/linux/module.h>

#include "internal.h"
@@ -1242,6 +1243,7 @@ static void free_module(struct module *mod) 
{

	trace_module_free(mod);



	codetag_unload_module(mod);

	mod_sysfs_teardown(mod);



	/*
@@ -2995,6 +2997,8 @@ static int load_module(struct load_info *info, const char __user *uargs, 
	/* Get rid of temporary copy. */

	free_copy(info, flags);



	codetag_load_module(mod);



	/* Done! */

	trace_module_load(mod);

lib/codetag.c

+56 −2
Original line number Diff line number Diff line
@@ -124,15 +124,20 @@ static void *get_symbol(struct module *mod, const char *prefix, const char *name 
{

	DECLARE_SEQ_BUF(sb, KSYM_NAME_LEN);

	const char *buf;

	void *ret;



	seq_buf_printf(&sb, "%s%s", prefix, name);

	if (seq_buf_has_overflowed(&sb))

		return NULL;



	buf = seq_buf_str(&sb);

	return mod ?

	preempt_disable();

	ret = mod ?

		(void *)find_kallsyms_symbol_value(mod, buf) :

		(void *)kallsyms_lookup_name(buf);

	preempt_enable();



	return ret;

}



static struct codetag_range get_section_range(struct module *mod,
@@ -173,8 +178,11 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) 


	down_write(&cttype->mod_lock);

	err = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL);

	if (err >= 0)

	if (err >= 0) {

		cttype->count += range_size(cttype, &range);

		if (cttype->desc.module_load)

			cttype->desc.module_load(cttype, cmod);

	}

	up_write(&cttype->mod_lock);



	if (err < 0) {
@@ -185,6 +193,52 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) 
	return 0;

}



void codetag_load_module(struct module *mod)

{

	struct codetag_type *cttype;



	if (!mod)

		return;



	mutex_lock(&codetag_lock);

	list_for_each_entry(cttype, &codetag_types, link)

		codetag_module_init(cttype, mod);

	mutex_unlock(&codetag_lock);

}



void codetag_unload_module(struct module *mod)

{

	struct codetag_type *cttype;



	if (!mod)

		return;



	mutex_lock(&codetag_lock);

	list_for_each_entry(cttype, &codetag_types, link) {

		struct codetag_module *found = NULL;

		struct codetag_module *cmod;

		unsigned long mod_id, tmp;



		down_write(&cttype->mod_lock);

		idr_for_each_entry_ul(&cttype->mod_idr, cmod, tmp, mod_id) {

			if (cmod->mod && cmod->mod == mod) {

				found = cmod;

				break;

			}

		}

		if (found) {

			if (cttype->desc.module_unload)

				cttype->desc.module_unload(cttype, cmod);



			cttype->count -= range_size(cttype, &cmod->range);

			idr_remove(&cttype->mod_idr, mod_id);

			kfree(cmod);

		}

		up_write(&cttype->mod_lock);

	}

	mutex_unlock(&codetag_lock);

}



#else /* CONFIG_MODULES */

static int codetag_module_init(struct codetag_type *cttype, struct module *mod) { return 0; }

#endif /* CONFIG_MODULES */