CVE-2023-52531: Out-of-bounds Write

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

wifi: iwlwifi: mvm: Fix a memory corruption issue

A few lines above, space is kzalloc()'ed for: sizeof(struct iwl_nvm_data) + sizeof(struct ieee80211_channel) + sizeof(struct ieee80211_rate)

'mvm->nvm_data' is a 'struct iwl_nvm_data', so it is fine.

At the end of this structure, there is the 'channels' flex array. Each element is of type 'struct ieee80211_channel'. So only 1 element is allocated in this array.

When doing: mvm->nvm_data->bands[0].channels = mvm->nvm_data->channels; We point at the first element of the 'channels' flex array. So this is fine.

However, when doing: mvm->nvm_data->bands[0].bitrates = (void *)((u8 *)mvm->nvm_data->channels + 1); because of the "(u8 *)" cast, we add only 1 to the address of the beginning of the flex array.

It is likely that we want point at the 'struct ieee80211_rate' allocated just after.

Remove the spurious casting so that the pointer arithmetic works as expected.