linux-kernel - [PATCH AUTOSEL 4.19 29/29] kernel/module: Fix mem leak in module_add_modinfo

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Message-Id: <20190829105009.2265-29-sashal@kernel.org>
Date:   Thu, 29 Aug 2019 06:50:09 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     YueHaibing <yuehaibing@...wei.com>,
        Miroslav Benes <mbenes@...e.cz>, Jessica Yu <jeyu@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.19 29/29] kernel/module: Fix mem leak in module_add_modinfo_attrs

From: YueHaibing <yuehaibing@...wei.com>

[ Upstream commit bc6f2a757d525e001268c3658bd88822e768f8db ]

In module_add_modinfo_attrs if sysfs_create_file
fails, we forget to free allocated modinfo_attrs
and roll back the sysfs files.

Fixes: 03e88ae1b13d ("[PATCH] fix module sysfs files reference counting")
Reviewed-by: Miroslav Benes <mbenes@...e.cz>
Signed-off-by: YueHaibing <yuehaibing@...wei.com>
Signed-off-by: Jessica Yu <jeyu@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/module.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 2dec3d4a9b627..0d86fc73d63d1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1694,6 +1694,8 @@ static int add_usage_links(struct module *mod)
 	return ret;
 }
 
+static void module_remove_modinfo_attrs(struct module *mod, int end);
+
 static int module_add_modinfo_attrs(struct module *mod)
 {
 	struct module_attribute *attr;
@@ -1708,24 +1710,34 @@ static int module_add_modinfo_attrs(struct module *mod)
 		return -ENOMEM;
 
 	temp_attr = mod->modinfo_attrs;
-	for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
+	for (i = 0; (attr = modinfo_attrs[i]); i++) {
 		if (!attr->test || attr->test(mod)) {
 			memcpy(temp_attr, attr, sizeof(*temp_attr));
 			sysfs_attr_init(&temp_attr->attr);
 			error = sysfs_create_file(&mod->mkobj.kobj,
 					&temp_attr->attr);
+			if (error)
+				goto error_out;
 			++temp_attr;
 		}
 	}
+
+	return 0;
+
+error_out:
+	if (i > 0)
+		module_remove_modinfo_attrs(mod, --i);
 	return error;
 }
 
-static void module_remove_modinfo_attrs(struct module *mod)
+static void module_remove_modinfo_attrs(struct module *mod, int end)
 {
 	struct module_attribute *attr;
 	int i;
 
 	for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
+		if (end >= 0 && i > end)
+			break;
 		/* pick a field to test for end of list */
 		if (!attr->attr.name)
 			break;
@@ -1813,7 +1825,7 @@ static int mod_sysfs_setup(struct module *mod,
 	return 0;
 
 out_unreg_modinfo_attrs:
-	module_remove_modinfo_attrs(mod);
+	module_remove_modinfo_attrs(mod, -1);
 out_unreg_param:
 	module_param_sysfs_remove(mod);
 out_unreg_holders:
@@ -1849,7 +1861,7 @@ static void mod_sysfs_fini(struct module *mod)
 {
 }
 
-static void module_remove_modinfo_attrs(struct module *mod)
+static void module_remove_modinfo_attrs(struct module *mod, int end)
 {
 }
 
@@ -1865,7 +1877,7 @@ static void init_param_lock(struct module *mod)
 static void mod_sysfs_teardown(struct module *mod)
 {
 	del_usage_links(mod);
-	module_remove_modinfo_attrs(mod);
+	module_remove_modinfo_attrs(mod, -1);
 	module_param_sysfs_remove(mod);
 	kobject_put(mod->mkobj.drivers_dir);
 	kobject_put(mod->holders_dir);
-- 
2.20.1