CVE-2021-47482: net: batman-adv: fix error handling

First published: Wed May 22 2024(Updated: )

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.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

• agent/title
• agent/references
• agent/description
• agent/type
• agent/first-publish-date
• agent/author
• collector/nvd-api
• source/NVD
• agent/severity
• agent/weakness
• agent/event
• collector/mitre-cve
• source/MITRE
• agent/last-modified-date
• agent/source
• agent/softwarecombine
• agent/tags
• agent/guess-ai
• agent/software-canonical-lookup
• agent/software-canonical-lookup-request
• vendor/linux foundation
• canonical/linux kernel