ocfs2: replace deprecated strcpy with strscpy

strcpy() has been deprecated [1] because it performs no bounds checking on
the destination buffer, which can lead to buffer overflows. Replace it
with the safer strscpy(), and copy directly into '->rf_signature' instead
of using the start of the struct as the destination buffer.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy [1]
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Thorsten Blum <[e-mail]>
Reviewed-by: Joseph Qi <[e-mail]>
Cc: Joel Becker <[e-mail]>
Cc: Mark Fasheh <[e-mail]>
Cc: Junxiao Bi <[e-mail]>
Cc: Changwei Ge <[e-mail]>
Cc: Jun Piao <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

fs/ocfs2/refcounttree.c

···
 #include <linux/pagevec.h>
 #include <linux/swap.h>
 #include <linux/security.h>
+#include <linux/string.h>
 #include <linux/fsnotify.h>
 #include <linux/quotaops.h>
 #include <linux/namei.h>
···
 	/* Initialize ocfs2_refcount_block. */
 	rb = (struct ocfs2_refcount_block *)new_bh->b_data;
 	memset(rb, 0, inode->i_sb->s_blocksize);
-	strcpy((void *)rb, OCFS2_REFCOUNT_BLOCK_SIGNATURE);
+	strscpy(rb->rf_signature, OCFS2_REFCOUNT_BLOCK_SIGNATURE);
 	rb->rf_suballoc_slot = cpu_to_le16(meta_ac->ac_alloc_slot);
 	rb->rf_suballoc_loc = cpu_to_le64(suballoc_loc);
 	rb->rf_suballoc_bit = cpu_to_le16(suballoc_bit_start);
···
 	/* Initialize ocfs2_refcount_block. */
 	new_rb = (struct ocfs2_refcount_block *)new_bh->b_data;
 	memset(new_rb, 0, sb->s_blocksize);
-	strcpy((void *)new_rb, OCFS2_REFCOUNT_BLOCK_SIGNATURE);
+	strscpy(new_rb->rf_signature, OCFS2_REFCOUNT_BLOCK_SIGNATURE);
 	new_rb->rf_suballoc_slot = cpu_to_le16(meta_ac->ac_alloc_slot);
 	new_rb->rf_suballoc_loc = cpu_to_le64(suballoc_loc);
 	new_rb->rf_suballoc_bit = cpu_to_le16(suballoc_bit_start);