From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gustavo A. R. Silva" Subject: [PATCH] iwlwifi: d3: use struct_size() in kzalloc() Date: Thu, 23 Aug 2018 20:15:40 -0500 Message-ID: <20180824011540.GA25716@embeddedor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Kees Cook , "Gustavo A. R. Silva" To: Johannes Berg , Emmanuel Grumbach , Luca Coelho , Intel Linux Wireless , Kalle Valo , "David S. Miller" Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); This issue was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- drivers/net/wireless/intel/iwlwifi/mvm/d3.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c index 79bdae9..6960318 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c @@ -1769,8 +1769,7 @@ static void iwl_mvm_query_netdetect_reasons(struct iwl_mvm *mvm, n_matches = 0; } - net_detect = kzalloc(sizeof(*net_detect) + - (n_matches * sizeof(net_detect->matches[0])), + net_detect = kzalloc(struct_size(net_detect, matches, n_matches), GFP_KERNEL); if (!net_detect || !n_matches) goto out_report_nd; @@ -1785,8 +1784,7 @@ static void iwl_mvm_query_netdetect_reasons(struct iwl_mvm *mvm, for (j = 0; j < SCAN_OFFLOAD_MATCHING_CHANNELS_LEN; j++) n_channels += hweight8(fw_match->matching_channels[j]); - match = kzalloc(sizeof(*match) + - (n_channels * sizeof(*match->channels)), + match = kzalloc(struct_size(match, channels, n_channels), GFP_KERNEL); if (!match) goto out_report_nd; -- 2.7.4