Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:3 as permitted sender) client-ip=2620:137:e000::3:3;
Date:   Tue, 24 Oct 2023 06:46:10 -0700
In-Reply-To: <20231024134637.3120277-1-surenb@google.com>
Mime-Version: 1.0
References: <20231024134637.3120277-1-surenb@google.com>
Message-ID: <20231024134637.3120277-14-surenb@google.com>
Subject: [PATCH v2 13/39] lib: code tagging module support
From:   Suren Baghdasaryan <surenb@google.com>
To:     akpm@linux-foundation.org
Cc:     kent.overstreet@linux.dev, mhocko@suse.com, vbabka@suse.cz,
        hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de,
        dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com,
        corbet@lwn.net, void@manifault.com, peterz@infradead.org,
        juri.lelli@redhat.com, ldufour@linux.ibm.com,
        catalin.marinas@arm.com, will@kernel.org, arnd@arndb.de,
        tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com,
        x86@kernel.org, peterx@redhat.com, david@redhat.com,
        axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org,
        nathan@kernel.org, dennis@kernel.org, tj@kernel.org,
        muchun.song@linux.dev, rppt@kernel.org, paulmck@kernel.org,
        pasha.tatashin@soleen.com, yosryahmed@google.com,
        yuzhao@google.com, dhowells@redhat.com, hughd@google.com,
        andreyknvl@gmail.com, keescook@chromium.org,
        ndesaulniers@google.com, vvvvvv@google.com,
        gregkh@linuxfoundation.org, ebiggers@google.com, ytcoode@gmail.com,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
        rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com,
        vschneid@redhat.com, cl@linux.com, penberg@kernel.org,
        iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com, glider@google.com,
        elver@google.com, dvyukov@google.com, shakeelb@google.com,
        songmuchun@bytedance.com, jbaron@akamai.com, rientjes@google.com,
        minchan@google.com, kaleshsingh@google.com, surenb@google.com,
        kernel-team@android.com, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
        linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-modules@vger.kernel.org,
        kasan-dev@googlegroups.com, cgroups@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Add support for code tagging from dynamically loaded modules.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 include/linux/codetag.h | 12 +++++++++
 kernel/module/main.c    |  4 +++
 lib/codetag.c           | 58 +++++++++++++++++++++++++++++++++++++++--
 3 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/include/linux/codetag.h b/include/linux/codetag.h
index a9d7adecc2a5..386733e89b31 100644
--- a/include/linux/codetag.h
+++ b/include/linux/codetag.h
@@ -42,6 +42,10 @@ struct codetag_module {
 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 {
@@ -68,4 +72,12 @@ void codetag_to_text(struct seq_buf *out, struct codetag *ct);
 struct codetag_type *
 codetag_register_type(const struct codetag_type_desc *desc);
 
+#ifdef CONFIG_CODE_TAGGING
+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 */
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 98fedfdb8db5..c0d3f562c7ab 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -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);
 
 	/*
@@ -2975,6 +2977,8 @@ 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);
 
diff --git a/lib/codetag.c b/lib/codetag.c
index 7708f8388e55..4ea57fb37346 100644
--- a/lib/codetag.c
+++ b/lib/codetag.c
@@ -108,15 +108,20 @@ static inline size_t range_size(const struct codetag_type *cttype,
 static void *get_symbol(struct module *mod, const char *prefix, const char *name)
 {
 	char buf[64];
+	void *ret;
 	int res;
 
 	res = snprintf(buf, sizeof(buf), "%s%s", prefix, name);
 	if (WARN_ON(res < 1 || res > sizeof(buf)))
 		return NULL;
 
-	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,
@@ -157,8 +162,11 @@ 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) {
@@ -197,3 +205,49 @@ codetag_register_type(const struct codetag_type_desc *desc)
 
 	return cttype;
 }
+
+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);
+}
-- 
2.42.0.758.gaed0368e0e-goog