CVE-2026-74368: wifi: ath12k: fix memory leak in ath12k_wifi7_dp_rx_h_verify_tkip_mic()

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

wifi: ath12k: fix memory leak in ath12kwifi7dprxhverifytkipmic()

In ath12kwifi7dprxhverifytkipmic(), the call to ath12kdprxchecknwifihdrlenvalid() may return false when the NWIFI header length is invalid, causing the function to abort early with -EINVAL.

When this happens, the error propagates to ath12kwifi7dprxhdefrag(), which clears firstfrag by setting it to NULL. As a result, the corresponding MSDU is no longer referenced by the defragmentation path and is never freed.

This leads to a memory leak for the affected MSDU on this error path. Proper cleanup is required to ensure the MSDU is released when header validation fails during TKIP MIC verification.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPLV1.0V2.0SILICONZ-1.115823.3