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ocfs2: replace zero-length arrays with DECLARE_FLEX_ARRAY() helper 

Zero-length arrays are deprecated and we are moving towards adopting C99
flexible-array members, instead.  So, replace zero-length array
declarations in a couple of structures and unions with the new
DECLARE_FLEX_ARRAY() helper macro.

This helper allows for a flexible-array member in a union and as only
member in a structure.

Also, this addresses multiple warnings reported when building with
Clang-15 and -Wzero-length-array.

Lastly, this will also help memcpy (in a coming hardening update) execute
proper bounds-checking on variable length object i_symlink at
fs/ocfs2/namei.c:1973:

fs/ocfs2/namei.c:
1973                 memcpy((char *) fe->id2.i_symlink, symname, l);

Link: https://github.com/KSPP/linux/issues/21
Link: https://github.com/KSPP/linux/issues/193
Link: https://github.com/KSPP/linux/issues/197
Link: https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
Link: https://lkml.kernel.org/r/YxKY6O2hmdwNh8r8@work
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Gustavo A. R. Silva 2022-09-03 00:59:36 +01:00 committed by Andrew Morton
parent b814751175
commit 6e4a53ee79
1 changed files with 4 additions and 4 deletions
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8
fs/ocfs2/ocfs2_fs.h
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@ -527,7 +527,7 @@ struct ocfs2_extent_block
* value -1 (0xFFFF) is OCFS2_INVALID_SLOT. This marks a slot empty.
*/
struct ocfs2_slot_map {
/*00*/ __le16 sm_slots[0];
/*00*/ DECLARE_FLEX_ARRAY(__le16, sm_slots);
/*
* Actual on-disk size is one block. OCFS2_MAX_SLOTS is 255,
* 255 * sizeof(__le16) == 512B, within the 512B block minimum blocksize.
@ -548,7 +548,7 @@ struct ocfs2_extended_slot {
* i_size.
*/
struct ocfs2_slot_map_extended {
/*00*/ struct ocfs2_extended_slot se_slots[0];
/*00*/ DECLARE_FLEX_ARRAY(struct ocfs2_extended_slot, se_slots);
/*
* Actual size is i_size of the slot_map system file. It should
* match s_max_slots * sizeof(struct ocfs2_extended_slot)
@ -727,7 +727,7 @@ struct ocfs2_dinode {
struct ocfs2_extent_list i_list;
struct ocfs2_truncate_log i_dealloc;
struct ocfs2_inline_data i_data;
__u8 i_symlink[0];
DECLARE_FLEX_ARRAY(__u8, i_symlink);
} id2;
/* Actual on-disk size is one block */
};
@ -892,7 +892,7 @@ struct ocfs2_group_desc
/*30*/ struct ocfs2_block_check bg_check; /* Error checking */
__le64 bg_reserved2;
/*40*/ union {
__u8 bg_bitmap[0];
DECLARE_FLEX_ARRAY(__u8, bg_bitmap);
struct {
/*
* Block groups may be discontiguous when