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authorGustavo A. R. Silva <ocfs2-devel@oss.oracle.com>2022-09-03 00:59:36 +0100
committerAndrew Morton <akpm@linux-foundation.org>2022-10-03 14:21:42 -0700
commit6e4a53ee7989c8a2b9fc3b14cd90f6e2d613ca76 (patch)
treeb07d572511e5a9354a2b99929220c336755071eb
parentb814751175470b00969a317bf3192260750f9455 (diff)
downloadlinux-6e4a53ee7989c8a2b9fc3b14cd90f6e2d613ca76.tar.gz
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>
-rw-r--r--fs/ocfs2/ocfs2_fs.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 638d875eccc7..7aebdbf5cc0a 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -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