All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Stanislav Yakovlev <stas.yakovlev@gmail.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	Stanislaw Gruszka <stf_xl@wp.pl>,
	Johannes Berg <johannes.berg@intel.com>,
	Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
	Luca Coelho <luciano.coelho@intel.com>,
	Intel Linux Wireless <linuxwifi@intel.com>
Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH][next] wireless: intel: Replace zero-length array with flexible-array member
Date: Mon, 24 Feb 2020 11:09:07 -0600	[thread overview]
Message-ID: <20200224170907.GA9948@embeddedor> (raw)

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was detected with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/net/wireless/intel/ipw2x00/ipw2200.c  |  2 +-
 drivers/net/wireless/intel/ipw2x00/ipw2200.h  | 10 +++----
 drivers/net/wireless/intel/ipw2x00/libipw.h   | 28 +++++++++----------
 .../wireless/intel/iwlegacy/iwl-spectrum.h    |  4 +--
 .../wireless/intel/iwlwifi/fw/api/dbg-tlv.h   |  2 +-
 .../net/wireless/intel/iwlwifi/fw/api/debug.h |  4 +--
 .../wireless/intel/iwlwifi/fw/api/filter.h    |  2 +-
 .../wireless/intel/iwlwifi/fw/api/nvm-reg.h   |  4 +--
 .../net/wireless/intel/iwlwifi/fw/api/sta.h   |  2 +-
 .../net/wireless/intel/iwlwifi/fw/api/tdls.h  |  2 +-
 .../net/wireless/intel/iwlwifi/fw/debugfs.c   |  2 +-
 .../wireless/intel/iwlwifi/fw/error-dump.h    |  2 +-
 drivers/net/wireless/intel/iwlwifi/fw/file.h  | 12 ++++----
 .../net/wireless/intel/iwlwifi/iwl-op-mode.h  |  2 +-
 .../net/wireless/intel/iwlwifi/iwl-trans.h    |  2 +-
 15 files changed, 40 insertions(+), 40 deletions(-)

diff --git a/drivers/net/wireless/intel/ipw2x00/ipw2200.c b/drivers/net/wireless/intel/ipw2x00/ipw2200.c
index 5ef6f87a48ac..f7c7b2cb73b8 100644
--- a/drivers/net/wireless/intel/ipw2x00/ipw2200.c
+++ b/drivers/net/wireless/intel/ipw2x00/ipw2200.c
@@ -3386,7 +3386,7 @@ struct ipw_fw {
 	__le32 boot_size;
 	__le32 ucode_size;
 	__le32 fw_size;
-	u8 data[0];
+	u8 data[];
 };
 
 static int ipw_get_fw(struct ipw_priv *priv,
diff --git a/drivers/net/wireless/intel/ipw2x00/ipw2200.h b/drivers/net/wireless/intel/ipw2x00/ipw2200.h
index 4346520545c4..09fa7f19050f 100644
--- a/drivers/net/wireless/intel/ipw2x00/ipw2200.h
+++ b/drivers/net/wireless/intel/ipw2x00/ipw2200.h
@@ -448,7 +448,7 @@ struct tfd_command {
 	u8 index;
 	u8 length;
 	__le16 reserved;
-	u8 payload[0];
+	u8 payload[];
 } __packed;
 
 struct tfd_data {
@@ -675,7 +675,7 @@ struct ipw_rx_frame {
 	// is identical)
 	u8 rtscts_seen;		// 0x1 RTS seen ; 0x2 CTS seen
 	__le16 length;
-	u8 data[0];
+	u8 data[];
 } __packed;
 
 struct ipw_rx_header {
@@ -1002,7 +1002,7 @@ struct ipw_cmd {	 /* XXX */
    * Incoming parameters listed 1-st, followed by outcoming params.
    * nParams=(len+3)/4+status_len
    */
-	u32 param[0];
+	u32 param[];
 } __packed;
 
 #define STATUS_HCMD_ACTIVE      (1<<0)	/**< host command in progress */
@@ -1108,7 +1108,7 @@ struct ipw_fw_error {	 /* XXX */
 	u32 log_len;
 	struct ipw_error_elem *elem;
 	struct ipw_event *log;
-	u8 payload[0];
+	u8 payload[];
 } __packed;
 
 #ifdef CONFIG_IPW2200_PROMISCUOUS
@@ -1153,7 +1153,7 @@ struct ipw_rt_hdr {
 	s8 rt_dbmsignal;	/* signal in dbM, kluged to signed */
 	s8 rt_dbmnoise;
 	u8 rt_antenna;	/* antenna number */
-	u8 payload[0];  /* payload... */
+	u8 payload[];  /* payload... */
 } __packed;
 #endif
 
diff --git a/drivers/net/wireless/intel/ipw2x00/libipw.h b/drivers/net/wireless/intel/ipw2x00/libipw.h
index e4a6ab4e8391..e87538a8b88b 100644
--- a/drivers/net/wireless/intel/ipw2x00/libipw.h
+++ b/drivers/net/wireless/intel/ipw2x00/libipw.h
@@ -334,7 +334,7 @@ struct libipw_hdr_1addr {
 	__le16 frame_ctl;
 	__le16 duration_id;
 	u8 addr1[ETH_ALEN];
-	u8 payload[0];
+	u8 payload[];
 } __packed;
 
 struct libipw_hdr_2addr {
@@ -342,7 +342,7 @@ struct libipw_hdr_2addr {
 	__le16 duration_id;
 	u8 addr1[ETH_ALEN];
 	u8 addr2[ETH_ALEN];
-	u8 payload[0];
+	u8 payload[];
 } __packed;
 
 struct libipw_hdr_3addr {
@@ -352,7 +352,7 @@ struct libipw_hdr_3addr {
 	u8 addr2[ETH_ALEN];
 	u8 addr3[ETH_ALEN];
 	__le16 seq_ctl;
-	u8 payload[0];
+	u8 payload[];
 } __packed;
 
 struct libipw_hdr_4addr {
@@ -363,7 +363,7 @@ struct libipw_hdr_4addr {
 	u8 addr3[ETH_ALEN];
 	__le16 seq_ctl;
 	u8 addr4[ETH_ALEN];
-	u8 payload[0];
+	u8 payload[];
 } __packed;
 
 struct libipw_hdr_3addrqos {
@@ -380,7 +380,7 @@ struct libipw_hdr_3addrqos {
 struct libipw_info_element {
 	u8 id;
 	u8 len;
-	u8 data[0];
+	u8 data[];
 } __packed;
 
 /*
@@ -406,7 +406,7 @@ struct libipw_auth {
 	__le16 transaction;
 	__le16 status;
 	/* challenge */
-	struct libipw_info_element info_element[0];
+	struct libipw_info_element info_element[];
 } __packed;
 
 struct libipw_channel_switch {
@@ -442,7 +442,7 @@ struct libipw_disassoc {
 struct libipw_probe_request {
 	struct libipw_hdr_3addr header;
 	/* SSID, supported rates */
-	struct libipw_info_element info_element[0];
+	struct libipw_info_element info_element[];
 } __packed;
 
 struct libipw_probe_response {
@@ -452,7 +452,7 @@ struct libipw_probe_response {
 	__le16 capability;
 	/* SSID, supported rates, FH params, DS params,
 	 * CF params, IBSS params, TIM (if beacon), RSN */
-	struct libipw_info_element info_element[0];
+	struct libipw_info_element info_element[];
 } __packed;
 
 /* Alias beacon for probe_response */
@@ -463,7 +463,7 @@ struct libipw_assoc_request {
 	__le16 capability;
 	__le16 listen_interval;
 	/* SSID, supported rates, RSN */
-	struct libipw_info_element info_element[0];
+	struct libipw_info_element info_element[];
 } __packed;
 
 struct libipw_reassoc_request {
@@ -471,7 +471,7 @@ struct libipw_reassoc_request {
 	__le16 capability;
 	__le16 listen_interval;
 	u8 current_ap[ETH_ALEN];
-	struct libipw_info_element info_element[0];
+	struct libipw_info_element info_element[];
 } __packed;
 
 struct libipw_assoc_response {
@@ -480,7 +480,7 @@ struct libipw_assoc_response {
 	__le16 status;
 	__le16 aid;
 	/* supported rates */
-	struct libipw_info_element info_element[0];
+	struct libipw_info_element info_element[];
 } __packed;
 
 struct libipw_txb {
@@ -490,7 +490,7 @@ struct libipw_txb {
 	u8 reserved;
 	u16 frag_size;
 	u16 payload_size;
-	struct sk_buff *fragments[0];
+	struct sk_buff *fragments[];
 };
 
 /* SWEEP TABLE ENTRIES NUMBER */
@@ -594,7 +594,7 @@ struct libipw_ibss_dfs {
 	struct libipw_info_element ie;
 	u8 owner[ETH_ALEN];
 	u8 recovery_interval;
-	struct libipw_channel_map channel_map[0];
+	struct libipw_channel_map channel_map[];
 };
 
 struct libipw_csa {
@@ -830,7 +830,7 @@ struct libipw_device {
 
 	/* This must be the last item so that it points to the data
 	 * allocated beyond this structure by alloc_libipw */
-	u8 priv[0];
+	u8 priv[];
 };
 
 #define IEEE_A            (1<<0)
diff --git a/drivers/net/wireless/intel/iwlegacy/iwl-spectrum.h b/drivers/net/wireless/intel/iwlegacy/iwl-spectrum.h
index a3b490501a70..1e8ab704dbfb 100644
--- a/drivers/net/wireless/intel/iwlegacy/iwl-spectrum.h
+++ b/drivers/net/wireless/intel/iwlegacy/iwl-spectrum.h
@@ -53,7 +53,7 @@ struct ieee80211_measurement_params {
 struct ieee80211_info_element {
 	u8 id;
 	u8 len;
-	u8 data[0];
+	u8 data[];
 } __packed;
 
 struct ieee80211_measurement_request {
@@ -61,7 +61,7 @@ struct ieee80211_measurement_request {
 	u8 token;
 	u8 mode;
 	u8 type;
-	struct ieee80211_measurement_params params[0];
+	struct ieee80211_measurement_params params[];
 } __packed;
 
 struct ieee80211_measurement_report {
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/dbg-tlv.h b/drivers/net/wireless/intel/iwlwifi/fw/api/dbg-tlv.h
index b9d7ed93311c..da84dc69dbd0 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/api/dbg-tlv.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/api/dbg-tlv.h
@@ -77,7 +77,7 @@ struct iwl_fw_ini_hcmd {
 	u8 id;
 	u8 group;
 	__le16 reserved;
-	u8 data[0];
+	u8 data[];
 } __packed; /* FW_DEBUG_TLV_HCMD_DATA_API_S_VER_1 */
 
 /**
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/debug.h b/drivers/net/wireless/intel/iwlwifi/fw/api/debug.h
index 98e957ecbeed..d3791f73b67f 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/api/debug.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/api/debug.h
@@ -266,7 +266,7 @@ struct iwl_mfu_assert_dump_notif {
 	__le16   index_num;
 	__le16   parts_num;
 	__le32   data_size;
-	__le32   data[0];
+	__le32   data[];
 } __packed; /* MFU_DUMP_ASSERT_API_S_VER_1 */
 
 /**
@@ -302,7 +302,7 @@ struct iwl_mvm_marker {
 	u8 marker_id;
 	__le16 reserved;
 	__le64 timestamp;
-	__le32 metadata[0];
+	__le32 metadata[];
 } __packed; /* MARKER_API_S_VER_1 */
 
 /**
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/filter.h b/drivers/net/wireless/intel/iwlwifi/fw/api/filter.h
index befc3b126041..a4064a6fb4d1 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/api/filter.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/api/filter.h
@@ -89,7 +89,7 @@ struct iwl_mcast_filter_cmd {
 	u8 pass_all;
 	u8 bssid[6];
 	u8 reserved[2];
-	u8 addr_list[0];
+	u8 addr_list[];
 } __packed; /* MCAST_FILTERING_CMD_API_S_VER_1 */
 
 #define MAX_BCAST_FILTERS 8
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h b/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h
index 97b49843e318..397ac89a04c2 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h
@@ -351,7 +351,7 @@ struct iwl_mcc_update_resp_v3 {
 	__le16 time;
 	__le16 geo_info;
 	__le32 n_channels;
-	__le32 channels[0];
+	__le32 channels[];
 } __packed; /* LAR_UPDATE_MCC_CMD_RESP_S_VER_3 */
 
 /**
@@ -380,7 +380,7 @@ struct iwl_mcc_update_resp {
 	u8 source_id;
 	u8 reserved[3];
 	__le32 n_channels;
-	__le32 channels[0];
+	__le32 channels[];
 } __packed; /* LAR_UPDATE_MCC_CMD_RESP_S_VER_4 */
 
 /**
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/sta.h b/drivers/net/wireless/intel/iwlwifi/fw/api/sta.h
index 970e9e508ad0..8f9ef474f3b1 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/api/sta.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/api/sta.h
@@ -552,7 +552,7 @@ struct iwl_mvm_wep_key_cmd {
 	u8 decryption_type;
 	u8 flags;
 	u8 reserved;
-	struct iwl_mvm_wep_key wep_key[0];
+	struct iwl_mvm_wep_key wep_key[];
 } __packed; /* SEC_CURR_WEP_KEY_CMD_API_S_VER_2 */
 
 /**
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/tdls.h b/drivers/net/wireless/intel/iwlwifi/fw/api/tdls.h
index b089285ac466..ec2a00d6c684 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/api/tdls.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/api/tdls.h
@@ -190,7 +190,7 @@ struct iwl_tdls_config_cmd {
 
 	__le32 pti_req_data_offset;
 	struct iwl_tx_cmd pti_req_tx_cmd;
-	u8 pti_req_template[0];
+	u8 pti_req_template[];
 } __packed; /* TDLS_CONFIG_CMD_API_S_VER_1 */
 
 /**
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c b/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c
index 89f74116569d..cc1d93606d9b 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c
@@ -261,7 +261,7 @@ struct hcmd_write_data {
 	__be32 cmd_id;
 	__be32 flags;
 	__be16 length;
-	u8 data[0];
+	u8 data[];
 } __packed;
 
 static ssize_t iwl_dbgfs_send_hcmd_write(struct iwl_fw_runtime *fwrt, char *buf,
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/error-dump.h b/drivers/net/wireless/intel/iwlwifi/fw/error-dump.h
index f008e1bbfdf4..f331a16fd940 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/error-dump.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/error-dump.h
@@ -141,7 +141,7 @@ struct iwl_fw_error_dump_data {
 struct iwl_fw_error_dump_file {
 	__le32 barker;
 	__le32 file_len;
-	u8 data[0];
+	u8 data[];
 } __packed;
 
 /**
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/file.h b/drivers/net/wireless/intel/iwlwifi/fw/file.h
index 1554f5fdd483..92910af88666 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/file.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/file.h
@@ -165,7 +165,7 @@ enum iwl_ucode_tlv_type {
 struct iwl_ucode_tlv {
 	__le32 type;		/* see above */
 	__le32 length;		/* not including type/length fields */
-	u8 data[0];
+	u8 data[];
 };
 
 #define IWL_TLV_UCODE_MAGIC		0x0a4c5749
@@ -191,7 +191,7 @@ struct iwl_tlv_ucode_header {
 	 * Note that each TLV is padded to a length
 	 * that is a multiple of 4 for alignment.
 	 */
-	u8 data[0];
+	u8 data[];
 };
 
 /*
@@ -652,7 +652,7 @@ struct iwl_fw_dbg_dest_tlv_v1 {
 	__le32 wrap_count;
 	u8 base_shift;
 	u8 end_shift;
-	struct iwl_fw_dbg_reg_op reg_ops[0];
+	struct iwl_fw_dbg_reg_op reg_ops[];
 } __packed;
 
 /* Mask of the register for defining the LDBG MAC2SMEM buffer SMEM size */
@@ -672,14 +672,14 @@ struct iwl_fw_dbg_dest_tlv {
 	__le32 wrap_count;
 	u8 base_shift;
 	u8 size_shift;
-	struct iwl_fw_dbg_reg_op reg_ops[0];
+	struct iwl_fw_dbg_reg_op reg_ops[];
 } __packed;
 
 struct iwl_fw_dbg_conf_hcmd {
 	u8 id;
 	u8 reserved;
 	__le16 len;
-	u8 data[0];
+	u8 data[];
 } __packed;
 
 /**
@@ -754,7 +754,7 @@ struct iwl_fw_dbg_trigger_tlv {
 	u8 flags;
 	u8 reserved[5];
 
-	u8 data[0];
+	u8 data[];
 } __packed;
 
 #define FW_DBG_START_FROM_ALIVE	0
diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h b/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h
index 3008a5246be8..b35b8920941b 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h
@@ -175,7 +175,7 @@ void iwl_opmode_deregister(const char *name);
 struct iwl_op_mode {
 	const struct iwl_op_mode_ops *ops;
 
-	char op_mode_specific[0] __aligned(sizeof(void *));
+	char op_mode_specific[] __aligned(sizeof(void *));
 };
 
 static inline void iwl_op_mode_stop(struct iwl_op_mode *op_mode)
diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-trans.h b/drivers/net/wireless/intel/iwlwifi/iwl-trans.h
index 7b3b1f4c99b4..a3fdaa9f2654 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-trans.h
@@ -875,7 +875,7 @@ struct iwl_trans {
 
 	/* pointer to trans specific struct */
 	/*Ensure that this pointer will always be aligned to sizeof pointer */
-	char trans_specific[0] __aligned(sizeof(void *));
+	char trans_specific[] __aligned(sizeof(void *));
 };
 
 const char *iwl_get_cmd_string(struct iwl_trans *trans, u32 id);
-- 
2.25.0


             reply	other threads:[~2020-02-24 17:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24 17:09 Gustavo A. R. Silva [this message]
2020-03-23 16:51 ` [PATCH][next] wireless: intel: Replace zero-length array with flexible-array member Kalle Valo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200224170907.GA9948@embeddedor \
    --to=gustavo@embeddedor.com \
    --cc=davem@davemloft.net \
    --cc=emmanuel.grumbach@intel.com \
    --cc=johannes.berg@intel.com \
    --cc=kvalo@codeaurora.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linuxwifi@intel.com \
    --cc=luciano.coelho@intel.com \
    --cc=netdev@vger.kernel.org \
    --cc=stas.yakovlev@gmail.com \
    --cc=stf_xl@wp.pl \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.