[SRU][F][PATCH 1/1] wifi: iwlwifi: mvm: Fix a memory corruption issue

[Koichiro Den]

From: Christophe JAILLET <christophe.jaillet at wanadoo.fr>

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.

Fixes: 8ca151b568b6 ("iwlwifi: add the MVM driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
Acked-by: Gregory Greenman <gregory.greenman at intel.com>
Link: https://lore.kernel.org/r/23f0ec986ef1529055f4f93dcb3940a6cf8d9a94.1690143750.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
(backported from commit 8ba438ef3cacc4808a63ed0ce24d4f0942cfe55d)
[koichiroden: Adjusted context due to missing commit 3827cb59b3b8
 ("iwlwifi: avoid void pointer arithmetic") and its dependencies]
CVE-2023-52531
Signed-off-by: Koichiro Den <koichiro.den at canonical.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/fw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
index 27bd9ed48bec..5806dc5a2f24 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -653,7 +653,7 @@ int iwl_run_init_mvm_ucode(struct iwl_mvm *mvm, bool read_nvm)
 		mvm->nvm_data->bands[0].n_channels = 1;
 		mvm->nvm_data->bands[0].n_bitrates = 1;
 		mvm->nvm_data->bands[0].bitrates =
-			(void *)mvm->nvm_data->channels + 1;
+			(void *)(mvm->nvm_data->channels + 1);
 		mvm->nvm_data->bands[0].bitrates->hw_value = 10;
 	}
 
-- 
2.43.0