On Mon, Mar 23, 2026 at 10:22:09AM -0700, Kees Cook wrote: > Replace the deprecated[1] strncpy() with strscpy_pad() in the > xfile_create and xmbuf_create tracepoints. > > Both tracepoints use file_path() to resolve a pathname into > __entry->pathname (a char[MAXNAMELEN] trace ring buffer field). On > failure, the error path overwrites the buffer with the string literal > "(unknown)" via strncpy(). The original strncpy() zero-pads the > remaining 246 bytes (MAXNAMELEN is 256, "(unknown)" is 10 bytes > including NUL). > > strscpy_pad() preserves this zero-padding, which matters because the > destination is a trace ring buffer entry: ring buffer slots are not > zeroed on allocation, and the raw buffer is readable by userspace via > tracefs. The zero-padding ensures no stale data remains in the > buffer after the error path overwrites it. > > The source is a 10-byte string literal into a 256-byte destination, > so there is no behavioral change. > > Link: https://github.com/KSPP/linux/issues/90 [1] > Signed-off-by: Kees Cook <[email protected]>
Seems fine to me, Reviewed-by: "Darrick J. Wong" <[email protected]> --D > --- > fs/xfs/scrub/trace.h | 3 +-- > fs/xfs/xfs_trace.h | 3 +-- > 2 files changed, 2 insertions(+), 4 deletions(-) > > diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h > index 39ea651cbb75..46c420f51129 100644 > --- a/fs/xfs/scrub/trace.h > +++ b/fs/xfs/scrub/trace.h > @@ -980,8 +980,7 @@ TRACE_EVENT(xfile_create, > __entry->ino = file_inode(xf->file)->i_ino; > path = file_path(xf->file, __entry->pathname, MAXNAMELEN); > if (IS_ERR(path)) > - strncpy(__entry->pathname, "(unknown)", > - sizeof(__entry->pathname)); > + strscpy_pad(__entry->pathname, "(unknown)"); > ), > TP_printk("xfino 0x%lx path '%s'", > __entry->ino, > diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h > index 813e5a9f57eb..9f9fb86097ed 100644 > --- a/fs/xfs/xfs_trace.h > +++ b/fs/xfs/xfs_trace.h > @@ -5101,8 +5101,7 @@ TRACE_EVENT(xmbuf_create, > __entry->ino = file_inode(file)->i_ino; > path = file_path(file, __entry->pathname, MAXNAMELEN); > if (IS_ERR(path)) > - strncpy(__entry->pathname, "(unknown)", > - sizeof(__entry->pathname)); > + strscpy_pad(__entry->pathname, "(unknown)"); > ), > TP_printk("dev %d:%d xmino 0x%lx path '%s'", > MAJOR(__entry->dev), MINOR(__entry->dev), > -- > 2.34.1 > >
