This patch fixes CVE-2023-52531 [1] present in 5.4 and 5.10 stable kernels. The vulnerability concerns flawed pointer arithmetic in iwlwifi driver caused by use of spurious casting to (u8 *). Original upstream commit [3] removed that cast but kept a change to increment a pointer first and only then cast it to (void *) or other type.
However, as older branches did not receive commit 3827cb59b3b8 ("iwlwifi: avoid void pointer arithmetic") [2], the aforementioned kept change is also missing, which should be corrected and applied to other vulnerable versions. This backport ensures that correction and keeps away from dangerous void pointer arithmetic.
[PATCH 5.4/5.10 1/1] wifi: iwlwifi: mvm: Fix a memory corruption issue Change 'channels' pointer before casting it to (void *). Fixes [1].
[1] https://nvd.nist.gov/vuln/detail/cve-2023-52531 [2] https://github.com/torvalds/linux/commit/3827cb59b3b8ce4b1687385d35034dadcd9... [3] https://github.com/torvalds/linux/commit/8ba438ef3cacc4808a63ed0ce24d4f0942c...
From: Christophe JAILLET christophe.jaillet@wanadoo.fr
[ Upstream commit 8ba438ef3cacc4808a63ed0ce24d4f0942cfe55d ]
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@wanadoo.fr Acked-by: Gregory Greenman gregory.greenman@intel.com Link: https://lore.kernel.org/r/23f0ec986ef1529055f4f93dcb3940a6cf8d9a94.169014375... Signed-off-by: Johannes Berg johannes.berg@intel.com [Nikita: no cast to (u8 *) is present in older kernels so just ensure that (void *) cast is used on a modified channels pointer rather than incrementing (void *) pointer after.] Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru --- 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 287f9c551525..c3d7d0e06c87 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; }
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Nikita Zhandarovich