From 5febf6d6ae4d488a5dc388c46d96c17f9556238f Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 24 Feb 2020 10:14:06 -0600 Subject: scsi: Replace zero-length array with flexible-array member 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 found 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") Link: https://lore.kernel.org/r/20200224161406.GA21454@embeddedor Reviewed-by: Lee Duncan Reviewed-by: Satish Kharat Signed-off-by: Gustavo A. R. Silva Signed-off-by: Martin K. Petersen --- include/scsi/iscsi_if.h | 10 +++++----- include/scsi/scsi_bsg_iscsi.h | 2 +- include/scsi/scsi_device.h | 4 ++-- include/scsi/scsi_host.h | 2 +- include/scsi/scsi_ioctl.h | 2 +- include/scsi/srp.h | 8 ++++---- 6 files changed, 14 insertions(+), 14 deletions(-) (limited to 'include/scsi') diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h index 92b11c7e0b4f..b0e240b10bf9 100644 --- a/include/scsi/iscsi_if.h +++ b/include/scsi/iscsi_if.h @@ -311,7 +311,7 @@ enum iscsi_param_type { struct iscsi_param_info { uint32_t len; /* Actual length of the param value */ uint16_t param; /* iscsi param */ - uint8_t value[0]; /* length sized value follows */ + uint8_t value[]; /* length sized value follows */ } __packed; struct iscsi_iface_param_info { @@ -320,7 +320,7 @@ struct iscsi_iface_param_info { uint16_t param; /* iscsi param value */ uint8_t iface_type; /* IPv4 or IPv6 */ uint8_t param_type; /* iscsi_param_type */ - uint8_t value[0]; /* length sized value follows */ + uint8_t value[]; /* length sized value follows */ } __packed; /* @@ -697,7 +697,7 @@ enum iscsi_flashnode_param { struct iscsi_flashnode_param_info { uint32_t len; /* Actual length of the param */ uint16_t param; /* iscsi param value */ - uint8_t value[0]; /* length sized value follows */ + uint8_t value[]; /* length sized value follows */ } __packed; enum iscsi_discovery_parent_type { @@ -815,7 +815,7 @@ struct iscsi_stats { * up to ISCSI_STATS_CUSTOM_MAX */ uint32_t custom_length; - struct iscsi_stats_custom custom[0] + struct iscsi_stats_custom custom[] __attribute__ ((aligned (sizeof(uint64_t)))); }; @@ -946,7 +946,7 @@ struct iscsi_offload_host_stats { * up to ISCSI_HOST_STATS_CUSTOM_MAX */ uint32_t custom_length; - struct iscsi_host_stats_custom custom[0] + struct iscsi_host_stats_custom custom[] __aligned(sizeof(uint64_t)); }; diff --git a/include/scsi/scsi_bsg_iscsi.h b/include/scsi/scsi_bsg_iscsi.h index fa0c820a1663..6b8128005af8 100644 --- a/include/scsi/scsi_bsg_iscsi.h +++ b/include/scsi/scsi_bsg_iscsi.h @@ -52,7 +52,7 @@ struct iscsi_bsg_host_vendor { uint64_t vendor_id; /* start of vendor command area */ - uint32_t vendor_cmd[0]; + uint32_t vendor_cmd[]; }; /* Response: diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index f146a4557787..579e24c92f2f 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -230,7 +230,7 @@ struct scsi_device { struct mutex state_mutex; enum scsi_device_state sdev_state; struct task_struct *quiesced_by; - unsigned long sdev_data[0]; + unsigned long sdev_data[]; } __attribute__((aligned(sizeof(unsigned long)))); #define to_scsi_device(d) \ @@ -314,7 +314,7 @@ struct scsi_target { char scsi_level; enum scsi_target_state state; void *hostdata; /* available to low-level driver */ - unsigned long starget_data[0]; /* for the transport */ + unsigned long starget_data[]; /* for the transport */ /* starget_data must be the last element!!!! */ } __attribute__((aligned(sizeof(unsigned long)))); diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 7464394e7d01..822e8cda8d9b 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -683,7 +683,7 @@ struct Scsi_Host { * and also because some compilers (m68k) don't automatically force * alignment to a long boundary. */ - unsigned long hostdata[0] /* Used for storage of host specific stuff */ + unsigned long hostdata[] /* Used for storage of host specific stuff */ __attribute__ ((aligned (sizeof(unsigned long)))); }; diff --git a/include/scsi/scsi_ioctl.h b/include/scsi/scsi_ioctl.h index 4fe69d863b5d..b465799f4d2d 100644 --- a/include/scsi/scsi_ioctl.h +++ b/include/scsi/scsi_ioctl.h @@ -27,7 +27,7 @@ struct scsi_device; typedef struct scsi_ioctl_command { unsigned int inlen; unsigned int outlen; - unsigned char data[0]; + unsigned char data[]; } Scsi_Ioctl_Command; typedef struct scsi_idlun { diff --git a/include/scsi/srp.h b/include/scsi/srp.h index 9220758d5087..177d8026e96f 100644 --- a/include/scsi/srp.h +++ b/include/scsi/srp.h @@ -109,7 +109,7 @@ struct srp_direct_buf { struct srp_indirect_buf { struct srp_direct_buf table_desc; __be32 len; - struct srp_direct_buf desc_list[0]; + struct srp_direct_buf desc_list[]; } __attribute__((packed)); /* Immediate data buffer descriptor as defined in SRP2. */ @@ -244,7 +244,7 @@ struct srp_cmd { u8 reserved4; u8 add_cdb_len; u8 cdb[16]; - u8 add_data[0]; + u8 add_data[]; }; enum { @@ -274,7 +274,7 @@ struct srp_rsp { __be32 data_in_res_cnt; __be32 sense_data_len; __be32 resp_data_len; - u8 data[0]; + u8 data[]; } __attribute__((packed)); struct srp_cred_req { @@ -306,7 +306,7 @@ struct srp_aer_req { struct scsi_lun lun; __be32 sense_data_len; u32 reserved3; - u8 sense_data[0]; + u8 sense_data[]; } __attribute__((packed)); struct srp_aer_rsp { -- cgit v1.2.3