treewide: Replace open-coded flex arrays in unions

In support of enabling -Warray-bounds and -Wzero-length-bounds and
correctly handling run-time memcpy() bounds checking, replace all
open-coded flexible arrays (i.e. 0-element arrays) in unions with the
DECLARE_FLEX_ARRAY() helper macro.

This fixes warnings such as:

fs/hpfs/anode.c: In function 'hpfs_add_sector_to_btree':
fs/hpfs/anode.c:209:27: warning: array subscript 0 is outside the bounds of an interior zero-length array 'struct bplus_internal_node[0]' [-Wzero-length-bounds]
  209 |    anode->btree.u.internal[0].down = cpu_to_le32(a);
      |    ~~~~~~~~~~~~~~~~~~~~~~~^~~
In file included from fs/hpfs/hpfs_fn.h:26,
                 from fs/hpfs/anode.c:10:
fs/hpfs/hpfs.h:412:32: note: while referencing 'internal'
  412 |     struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
      |                                ^~~~~~~~

drivers/net/can/usb/etas_es58x/es58x_fd.c: In function 'es58x_fd_tx_can_msg':
drivers/net/can/usb/etas_es58x/es58x_fd.c:360:35: warning: array subscript 65535 is outside the bounds of an interior zero-length array 'u8[0]' {aka 'unsigned char[]'} [-Wzero-length-bounds]
  360 |  tx_can_msg = (typeof(tx_can_msg))&es58x_fd_urb_cmd->raw_msg[msg_len];
      |                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from drivers/net/can/usb/etas_es58x/es58x_core.h:22,
                 from drivers/net/can/usb/etas_es58x/es58x_fd.c:17:
drivers/net/can/usb/etas_es58x/es58x_fd.h:231:6: note: while referencing 'raw_msg'
  231 |   u8 raw_msg[0];
      |      ^~~~~~~

Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ayush Sawal <ayush.sawal@chelsio.com>
Cc: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Cc: Rohit Maheshwari <rohitm@chelsio.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Stanislaw Gruszka <stf_xl@wp.pl>
Cc: Luca Coelho <luciano.coelho@intel.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Mordechay Goodstein <mordechay.goodstein@intel.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: linux-crypto@vger.kernel.org
Cc: ath10k@lists.infradead.org
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: linux-can@vger.kernel.org
Cc: bpf@vger.kernel.org
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> # drivers/net/can/usb/etas_es58x/*
Signed-off-by: Kees Cook <keescook@chromium.org>

8 files changed, 36 insertions, 19 deletions

diff --git a/drivers/crypto/chelsio/chcr_crypto.h b/drivers/crypto/chelsio/chcr_crypto.h
index e89f9e0094b4..c7816c83e324 100644
--- a/drivers/crypto/chelsio/chcr_crypto.h
+++ b/drivers/crypto/chelsio/chcr_crypto.h
@@ -222,8 +222,10 @@ struct chcr_authenc_ctx {
 };
 
 struct __aead_ctx {
-	struct chcr_gcm_ctx gcm[0];
-	struct chcr_authenc_ctx authenc[];
+	union {
+		DECLARE_FLEX_ARRAY(struct chcr_gcm_ctx, gcm);
+		DECLARE_FLEX_ARRAY(struct chcr_authenc_ctx, authenc);
+	};
 };
 
 struct chcr_aead_ctx {
@@ -245,9 +247,11 @@ struct hmac_ctx {
 };
 
 struct __crypto_ctx {
-	struct hmac_ctx hmacctx[0];
-	struct ablk_ctx ablkctx[0];
-	struct chcr_aead_ctx aeadctx[];
+	union {
+		DECLARE_FLEX_ARRAY(struct hmac_ctx, hmacctx);
+		DECLARE_FLEX_ARRAY(struct ablk_ctx, ablkctx);
+		DECLARE_FLEX_ARRAY(struct chcr_aead_ctx, aeadctx);
+	};
 };
 
 struct chcr_context {
diff --git a/drivers/net/can/usb/etas_es58x/es581_4.h b/drivers/net/can/usb/etas_es58x/es581_4.h
index 4bc60a6df697..667ecb77168c 100644
--- a/drivers/net/can/usb/etas_es58x/es581_4.h
+++ b/drivers/net/can/usb/etas_es58x/es581_4.h
@@ -192,7 +192,7 @@ struct es581_4_urb_cmd {
 		struct es581_4_rx_cmd_ret rx_cmd_ret;
 		__le64 timestamp;
 		u8 rx_cmd_ret_u8;
-		u8 raw_msg[0];
+		DECLARE_FLEX_ARRAY(u8, raw_msg);
 	} __packed;
 
 	__le16 reserved_for_crc16_do_not_use;
diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.h b/drivers/net/can/usb/etas_es58x/es58x_fd.h
index a191891b8777..c4b19a6a33ae 100644
--- a/drivers/net/can/usb/etas_es58x/es58x_fd.h
+++ b/drivers/net/can/usb/etas_es58x/es58x_fd.h
@@ -219,7 +219,7 @@ struct es58x_fd_urb_cmd {
 		struct es58x_fd_tx_ack_msg tx_ack_msg;
 		__le64 timestamp;
 		__le32 rx_cmd_ret_le32;
-		u8 raw_msg[0];
+		DECLARE_FLEX_ARRAY(u8, raw_msg);
 	} __packed;
 
 	__le16 reserved_for_crc16_do_not_use;
diff --git a/drivers/net/wireless/ath/ath10k/htt.h b/drivers/net/wireless/ath/ath10k/htt.h
index ec689e3ce48a..a6de08d3bf4a 100644
--- a/drivers/net/wireless/ath/ath10k/htt.h
+++ b/drivers/net/wireless/ath/ath10k/htt.h
@@ -1674,8 +1674,11 @@ struct htt_tx_fetch_ind {
 	__le32 token;
 	__le16 num_resp_ids;
 	__le16 num_records;
-	__le32 resp_ids[0]; /* ath10k_htt_get_tx_fetch_ind_resp_ids() */
-	struct htt_tx_fetch_record records[];
+	union {
+		/* ath10k_htt_get_tx_fetch_ind_resp_ids() */
+		DECLARE_FLEX_ARRAY(__le32, resp_ids);
+		DECLARE_FLEX_ARRAY(struct htt_tx_fetch_record, records);
+	};
 } __packed;
 
 static inline void *
diff --git a/drivers/net/wireless/intel/iwlegacy/commands.h b/drivers/net/wireless/intel/iwlegacy/commands.h
index 89c6671b32bc..4a97310f8fee 100644
--- a/drivers/net/wireless/intel/iwlegacy/commands.h
+++ b/drivers/net/wireless/intel/iwlegacy/commands.h
@@ -1408,8 +1408,10 @@ struct il3945_tx_cmd {
 	 * MAC header goes here, followed by 2 bytes padding if MAC header
 	 * length is 26 or 30 bytes, followed by payload data
 	 */
-	u8 payload[0];
-	struct ieee80211_hdr hdr[];
+	union {
+		DECLARE_FLEX_ARRAY(u8, payload);
+		DECLARE_FLEX_ARRAY(struct ieee80211_hdr, hdr);
+	};
 } __packed;
 
 /*
diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
index 235c7a2e3483..75a4b8e26232 100644
--- a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
@@ -1251,8 +1251,10 @@ struct iwl_tx_cmd {
 	 * MAC header goes here, followed by 2 bytes padding if MAC header
 	 * length is 26 or 30 bytes, followed by payload data
 	 */
-	u8 payload[0];
-	struct ieee80211_hdr hdr[];
+	union {
+		DECLARE_FLEX_ARRAY(u8, payload);
+		DECLARE_FLEX_ARRAY(struct ieee80211_hdr, hdr);
+	};
 } __packed;
 
 /*
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/tx.h b/drivers/net/wireless/intel/iwlwifi/fw/api/tx.h
index 24e4a82a55da..5fddfd391941 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/api/tx.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/api/tx.h
@@ -239,8 +239,10 @@ struct iwl_tx_cmd {
 	u8 tid_tspec;
 	__le16 pm_frame_timeout;
 	__le16 reserved4;
-	u8 payload[0];
-	struct ieee80211_hdr hdr[0];
+	union {
+		DECLARE_FLEX_ARRAY(u8, payload);
+		DECLARE_FLEX_ARRAY(struct ieee80211_hdr, hdr);
+	};
 } __packed; /* TX_CMD_API_S_VER_6 */
 
 struct iwl_dram_sec_info {
@@ -713,8 +715,10 @@ struct iwl_mvm_compressed_ba_notif {
 	__le32 tx_rate;
 	__le16 tfd_cnt;
 	__le16 ra_tid_cnt;
-	struct iwl_mvm_compressed_ba_ratid ra_tid[0];
-	struct iwl_mvm_compressed_ba_tfd tfd[];
+	union {
+		DECLARE_FLEX_ARRAY(struct iwl_mvm_compressed_ba_ratid, ra_tid);
+		DECLARE_FLEX_ARRAY(struct iwl_mvm_compressed_ba_tfd, tfd);
+	};
 } __packed; /* COMPRESSED_BA_RES_API_S_VER_4 */
 
 /**
diff --git a/drivers/scsi/aic94xx/aic94xx_sds.c b/drivers/scsi/aic94xx/aic94xx_sds.c
index 46815e65f7a4..5def83c88f13 100644
--- a/drivers/scsi/aic94xx/aic94xx_sds.c
+++ b/drivers/scsi/aic94xx/aic94xx_sds.c
@@ -517,8 +517,10 @@ struct asd_ms_conn_map {
 	u8    num_nodes;
 	u8    usage_model_id;
 	u32   _resvd;
-	struct asd_ms_conn_desc conn_desc[0];
-	struct asd_ms_node_desc node_desc[];
+	union {
+		DECLARE_FLEX_ARRAY(struct asd_ms_conn_desc, conn_desc);
+		DECLARE_FLEX_ARRAY(struct asd_ms_node_desc, node_desc);
+	};
 } __attribute__ ((packed));
 
 struct asd_ctrla_phy_entry {