CVE-2021-47482
Global infos:
In the Linux kernel, the following vulnerability has been resolved: net: batman-adv: fix error handling Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was in wrong error handling in batadv_mesh_init(). Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case of any batadv_*_init() calls failure. This approach may work well, when there is some kind of indicator, which can tell which parts of batadv are initialized; but there isn't any. All written above lead to cleaning up uninitialized fields. Even if we hide ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1] To fix these bugs we can unwind batadv_*_init() calls one by one. It is good approach for 2 reasons: 1) It fixes bugs on error handling path 2) It improves the performance, since we won't call unneeded batadv_*_free() functions. So, this patch makes all batadv_*_init() clean up all allocated memory before returning with an error to no call correspoing batadv_*_free() and open-codes batadv_mesh_free() with proper order to avoid touching uninitialized fields.
CVE Status: Awaiting Analysis
References:
Metrics:
| Attribute | Value |
|---|---|
| Attack Complexity | HIGH |
| Attack Vector | NETWORK |
| Availability Impact | HIGH |
| Base Score | 5.3 |
| Base Severity | MEDIUM |
| Confidentiality Impact | NONE |
| Integrity Impact | NONE |
| Privileges Required | LOW |
| Scope | UNCHANGED |
| User Interaction | NONE |
| Vector String | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
| Exploitability Score | 1.6 |
| Impact Score | 3.6 |
| Source | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| Type | Secondary |