From b34b913a38b16b18b3d0313ef224dd1b84853104 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 6 Apr 2022 19:36:51 -0500 Subject: treewide: uapi: Replace zero-length arrays with flexible-array members MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. This code was transformed with the help of Coccinelle: (linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch) @@ identifier S, member, array; type T1, T2; @@ struct S { ... T1 member; T2 array[ - 0 ]; }; -fstrict-flex-arrays=3 is coming and we need to land these changes to prevent issues like these in the short future: ../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0, but the source string has length 2 (including NUL byte) [-Wfortify-source] strcpy(de3->name, "."); ^ Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If this breaks anything, we can use a union with a new member name. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/78 Build-tested-by: kernel test robot Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/ Acked-by: Dan Williams # For ndctl.h Signed-off-by: Gustavo A. R. Silva --- cpukit/libfs/src/jffs2/include/linux/jffs2.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'cpukit/libfs/src/jffs2/include/linux/jffs2.h') diff --git a/cpukit/libfs/src/jffs2/include/linux/jffs2.h b/cpukit/libfs/src/jffs2/include/linux/jffs2.h index 784ba0b969..637ee4a793 100644 --- a/cpukit/libfs/src/jffs2/include/linux/jffs2.h +++ b/cpukit/libfs/src/jffs2/include/linux/jffs2.h @@ -123,7 +123,7 @@ struct jffs2_raw_dirent __u8 unused[2]; jint32_t node_crc; jint32_t name_crc; - __u8 name[0]; + __u8 name[]; }; /* The JFFS2 raw inode structure: Used for storage on physical media. */ @@ -155,7 +155,7 @@ struct jffs2_raw_inode jint16_t flags; /* See JFFS2_INO_FLAG_* */ jint32_t data_crc; /* CRC for the (compressed) data. */ jint32_t node_crc; /* CRC for the raw inode (excluding data) */ - __u8 data[0]; + __u8 data[]; }; struct jffs2_raw_xattr { @@ -170,7 +170,7 @@ struct jffs2_raw_xattr { jint16_t value_len; jint32_t data_crc; jint32_t node_crc; - __u8 data[0]; + __u8 data[]; } __attribute__((packed)); struct jffs2_raw_xref @@ -196,7 +196,7 @@ struct jffs2_raw_summary jint32_t padded; /* sum of the size of padding nodes */ jint32_t sum_crc; /* summary information crc */ jint32_t node_crc; /* node crc */ - jint32_t sum[0]; /* inode summary info */ + jint32_t sum[]; /* inode summary info */ }; union jffs2_node_union -- cgit v1.2.3