CVE-2022-29156 (published 2022-04-13T07:15Z)

drivers/infiniband/ulp/rtrs/rtrs-clt.c in the Linux kernel before 5.16.12 has a double free related to rtrs_clt_dev_release.

Severity: HIGH
CVSS v2 base score: 7.2 (AV:L/AC:L/Au:N/C:C/I:C/A:C)
CVSS v3 base score: 7.8, HIGH (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)

Weakness information:
cwe_id: CWE-415
cwe_name: Double Free
description: The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations.
extended_description: When a program calls free() twice with the same argument, the program's memory management data structures become corrupted. This corruption can cause the program to crash or, in some circumstances, cause two later calls to malloc() to return the same pointer. If malloc() returns the same value twice and the program later gives the attacker control over the data that is written into this doubly-allocated memory, the program becomes vulnerable to a buffer overflow attack.
         

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Md Haris Iqbal
author_date: 2022-02-17 04:09:28+01:00
msg: RDMA/rtrs-clt: Fix possible double free in error case

Callback function rtrs_clt_dev_release() for put_device() calls kfree(clt)
to free memory. We shouldn't call kfree(clt) again, and we can't use the
clt after kfree too.

Replace device_register() with device_initialize() and device_add() so that
dev_set_name can() be used appropriately.

Move mutex_destroy() to the release function so it can be called in
the alloc_clt err path.

Fixes: eab098246625 ("RDMA/rtrs-clt: Refactor the failure cases in alloc_clt")
Link: https://lore.kernel.org/r/20220217030929.323849-1-haris.iqbal@ionos.com
Reported-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: rtrs-clt.c
change_type: ModificationType.MODIFY
diff: @@ -2682,6 +2682,8 @@ static void rtrs_clt_dev_release(struct device *dev)
 	struct rtrs_clt_sess *clt = container_of(dev, struct rtrs_clt_sess,
 						 dev);
 
+	mutex_destroy(&clt->paths_ev_mutex);
+	mutex_destroy(&clt->paths_mutex);
 	kfree(clt);
 }
 
@@ -2711,6 +2713,8 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
 		return ERR_PTR(-ENOMEM);
 	}
 
+	clt->dev.class = rtrs_clt_dev_class;
+	clt->dev.release = rtrs_clt_dev_release;
 	uuid_gen(&clt->paths_uuid);
 	INIT_LIST_HEAD_RCU(&clt->paths_list);
 	clt->paths_num = paths_num;
@@ -2727,43 +2731,41 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num,
 	init_waitqueue_head(&clt->permits_wait);
 	mutex_init(&clt->paths_ev_mutex);
 	mutex_init(&clt->paths_mutex);
+	device_initialize(&clt->dev);
 
-	clt->dev.class = rtrs_clt_dev_class;
-	clt->dev.release = rtrs_clt_dev_release;
 	err = dev_set_name(&clt->dev, "%s", sessname);
 	if (err)
-		goto err;
+		goto err_put;
+
 	/*
 	 * Suppress user space notification until
 	 * sysfs files are created
 	 */
 	dev_set_uevent_suppress(&clt->dev, true);
-	err = device_register(&clt->dev);
-	if (err) {
-		put_device(&clt->dev);
-		goto err;
-	}
+	err = device_add(&clt->dev);
+	if (err)
+		goto err_put;
 
 	clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj);
 	if (!clt->kobj_paths) {
 		err = -ENOMEM;
-		goto err_dev;
+		goto err_del;
 	}
 	err = rtrs_clt_create_sysfs_root_files(clt);
 	if (err) {
 		kobject_del(clt->kobj_paths);
 		kobject_put(clt->kobj_paths);
-		goto err_dev;
+		goto err_del;
 	}
 	dev_set_uevent_suppress(&clt->dev, false);
 	kobject_uevent(&clt->dev.kobj, KOBJ_ADD);
 
 	return clt;
-err_dev:
-	device_unregister(&clt->dev);
-err:
+err_del:
+	device_del(&clt->dev);
+err_put:
 	free_percpu(clt->pcpu_path);
-	kfree(clt);
+	put_device(&clt->dev);
 	return ERR_PTR(err);
 }
 
@@ -2771,9 +2773,10 @@ static void free_clt(struct rtrs_clt_sess *clt)
 {
 	free_permits(clt);
 	free_percpu(clt->pcpu_path);
-	mutex_destroy(&clt->paths_ev_mutex);
-	mutex_destroy(&clt->paths_mutex);
-	/* release callback will free clt in last put */
+
+	/*
+	 * release callback will free clt and destroy mutexes in last put
+	 */
 	device_unregister(&clt->dev);
 }
 

programming_language: C