From fa226f1d81e2d3798d30eaa14550d7f35c35e6f3 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Fri, 21 Feb 2020 09:06:12 -0600 Subject: [PATCH] s390: 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://lkml.kernel.org/r/20200221150612.GA9717@embeddedor Signed-off-by: Gustavo A. R. Silva Signed-off-by: Vasily Gorbik --- arch/s390/appldata/appldata_os.c | 2 +- drivers/s390/block/dasd_diag.c | 2 +- drivers/s390/block/dasd_eckd.h | 2 +- drivers/s390/char/raw3270.h | 2 +- drivers/s390/char/sclp_pci.c | 2 +- drivers/s390/cio/idset.c | 2 +- drivers/s390/crypto/pkey_api.c | 2 +- drivers/s390/crypto/zcrypt_ccamisc.h | 2 +- drivers/s390/crypto/zcrypt_msgtype6.c | 2 +- 9 files changed, 9 insertions(+), 9 deletions(-) diff --git a/arch/s390/appldata/appldata_os.c b/arch/s390/appldata/appldata_os.c index 54f375627532..8bf46d705957 100644 --- a/arch/s390/appldata/appldata_os.c +++ b/arch/s390/appldata/appldata_os.c @@ -75,7 +75,7 @@ struct appldata_os_data { (waiting for I/O) */ /* per cpu data */ - struct appldata_os_per_cpu os_cpu[0]; + struct appldata_os_per_cpu os_cpu[]; } __attribute__((packed)); static struct appldata_os_data *appldata_os_data; diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c index 8d4971645cf1..facb588d09e4 100644 --- a/drivers/s390/block/dasd_diag.c +++ b/drivers/s390/block/dasd_diag.c @@ -58,7 +58,7 @@ struct dasd_diag_private { struct dasd_diag_req { unsigned int block_count; - struct dasd_diag_bio bio[0]; + struct dasd_diag_bio bio[]; }; static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */ diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h index 6943508d0f1d..ca24a78a256e 100644 --- a/drivers/s390/block/dasd_eckd.h +++ b/drivers/s390/block/dasd_eckd.h @@ -220,7 +220,7 @@ struct LRE_eckd_data { __u8 imbedded_count; __u8 extended_operation; __u16 extended_parameter_length; - __u8 extended_parameter[0]; + __u8 extended_parameter[]; } __attribute__ ((packed)); /* Prefix data for format 0x00 and 0x01 */ diff --git a/drivers/s390/char/raw3270.h b/drivers/s390/char/raw3270.h index 3afaa35f7351..08f36e973b43 100644 --- a/drivers/s390/char/raw3270.h +++ b/drivers/s390/char/raw3270.h @@ -211,7 +211,7 @@ struct string struct list_head update; unsigned long size; unsigned long len; - char string[0]; + char string[]; } __attribute__ ((aligned(8))); static inline struct string * diff --git a/drivers/s390/char/sclp_pci.c b/drivers/s390/char/sclp_pci.c index 995e9196852e..a3e5a5fb0c1e 100644 --- a/drivers/s390/char/sclp_pci.c +++ b/drivers/s390/char/sclp_pci.c @@ -39,7 +39,7 @@ struct err_notify_evbuf { u8 atype; u32 fh; u32 fid; - u8 data[0]; + u8 data[]; } __packed; struct err_notify_sccb { diff --git a/drivers/s390/cio/idset.c b/drivers/s390/cio/idset.c index 835de44dbbcc..77d0ea7b381b 100644 --- a/drivers/s390/cio/idset.c +++ b/drivers/s390/cio/idset.c @@ -13,7 +13,7 @@ struct idset { int num_ssid; int num_id; - unsigned long bitmap[0]; + unsigned long bitmap[]; }; static inline unsigned long bitmap_size(int num_ssid, int num_id) diff --git a/drivers/s390/crypto/pkey_api.c b/drivers/s390/crypto/pkey_api.c index 2f33c5fcf676..74e63ec49068 100644 --- a/drivers/s390/crypto/pkey_api.c +++ b/drivers/s390/crypto/pkey_api.c @@ -80,7 +80,7 @@ struct clearaeskeytoken { u8 res1[3]; u32 keytype; /* key type, one of the PKEY_KEYTYPE values */ u32 len; /* bytes actually stored in clearkey[] */ - u8 clearkey[0]; /* clear key value */ + u8 clearkey[]; /* clear key value */ } __packed; /* diff --git a/drivers/s390/crypto/zcrypt_ccamisc.h b/drivers/s390/crypto/zcrypt_ccamisc.h index 3a9876d5ab0e..8b7a641671c9 100644 --- a/drivers/s390/crypto/zcrypt_ccamisc.h +++ b/drivers/s390/crypto/zcrypt_ccamisc.h @@ -90,7 +90,7 @@ struct cipherkeytoken { u16 kmf1; /* key management field 1 */ u16 kmf2; /* key management field 2 */ u16 kmf3; /* key management field 3 */ - u8 vdata[0]; /* variable part data follows */ + u8 vdata[]; /* variable part data follows */ } __packed; /* Some defines for the CCA AES cipherkeytoken kmf1 field */ diff --git a/drivers/s390/crypto/zcrypt_msgtype6.c b/drivers/s390/crypto/zcrypt_msgtype6.c index a36251d138fb..eadd3a438a4b 100644 --- a/drivers/s390/crypto/zcrypt_msgtype6.c +++ b/drivers/s390/crypto/zcrypt_msgtype6.c @@ -590,7 +590,7 @@ struct type86x_reply { struct CPRBX cprbx; unsigned char pad[4]; /* 4 byte function code/rules block ? */ unsigned short length; - char text[0]; + char text[]; } __packed; struct type86_ep11_reply {