[PATCH] bcachefs: Replace strlcpy() with strscpy()

[Kees Cook]

strlcpy() reads the entire source buffer first. This read may exceed
the destination size limit. This is both inefficient and can lead
to linear read overflows if a source string is not NUL-terminated[1].
Additionally, it returns the size of the source string, not the
resulting size of the destination string. In an effort to remove strlcpy()
completely[2], replace strlcpy() here with strscpy().

Nothing checks the return value here, so a direct replacement with
strspy() is possible.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [1]
Link: https://github.com/KSPP/linux/issues/89 [2]
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Brian Foster <bfoster@xxxxxxxxxx>
Cc: linux-bcachefs@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 fs/bcachefs/super.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index 9dbc35940197..cefe52898e8e 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -1386,8 +1386,8 @@ static int bch2_dev_attach_bdev(struct bch_fs *c, struct bch_sb_handle *sb)
 	prt_bdevname(&name, ca->disk_sb.bdev);
 
 	if (c->sb.nr_devices == 1)
-		strlcpy(c->name, name.buf, sizeof(c->name));
-	strlcpy(ca->name, name.buf, sizeof(ca->name));
+		strscpy(c->name, name.buf, sizeof(c->name));
+	strscpy(ca->name, name.buf, sizeof(ca->name));
 
 	printbuf_exit(&name);
 
-- 
2.34.1