Vulnerability CVE-2023-52531
Published: 2024-03-02

Description:
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.

 References:
https://git.kernel.org/stable/c/7c8faa31080342aec4903c9acb20caf82fcca1ef
https://git.kernel.org/stable/c/6b3223449c959a8be94a1f042288059e40fcccb0
https://git.kernel.org/stable/c/f06cdd8d4ba5252986f51f80cc30263636397128
https://git.kernel.org/stable/c/8ba438ef3cacc4808a63ed0ce24d4f0942cfe55d
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