CVE-2021-47194

In the Linux kernel, the following vulnerability has been resolved:

cfg80211: call cfg80211_stop_ap when switch from P2P_GO type

If the userspace tools switch from NL80211_IFTYPE_P2P_GO to NL80211_IFTYPE_ADHOC via send_msg(NL80211_CMD_SET_INTERFACE), it does not call the cleanup cfg80211_stop_ap(), this leads to the initialization of in-use data. For example, this path re-init the sdata->assigned_chanctx_list while it is still an element of assigned_vifs list, and makes that linked list corrupt.

Weakness

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable’s type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• https://git.kernel.org/stable/c/0738cdb636c21ab552eaecf905efa4a6070e3ebc
• https://git.kernel.org/stable/c/4e458abbb4a523f1413bfe15c079cf4e24c15b21
• https://git.kernel.org/stable/c/52affc201fc22a1ab9a59ef0ed641a9adfcb8d13
• https://git.kernel.org/stable/c/563fbefed46ae4c1f70cffb8eb54c02df480b2c2
• https://git.kernel.org/stable/c/5a9b671c8d74a3e1b999e7a0c7f366079bcc93dd
• https://git.kernel.org/stable/c/7b97b5776daa0b39dbdadfea176f9cc0646d4a66
• https://git.kernel.org/stable/c/8f06bb8c216bcd172394f61e557727e691b4cb24
• https://git.kernel.org/stable/c/b8a045e2a9b234cfbc06cf36923886164358ddec