samples: Replace strlcpy() with strscpy()

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().

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
Link: https://github.com/KSPP/linux/issues/89
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Geliang Tang <geliang.tang@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20231116191510.work.550-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 1c6b843b8c4eeb254e3a67960a5e6129fbcdbff5..23f923ccd529863b3c2b342c06709f35c71a52e7 100644 (file)
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -305,7 +305,7 @@ TRACE_EVENT(foo_bar,
        ),
 
        TP_fast_assign(
-               strlcpy(__entry->foo, foo, 10);
+               strscpy(__entry->foo, foo, 10);
                __entry->bar    = bar;
                memcpy(__get_dynamic_array(list), lst,
                       __length_of(lst) * sizeof(int));

diff --git a/samples/v4l/v4l2-pci-skeleton.c b/samples/v4l/v4l2-pci-skeleton.c
index a61f94db18d9f4434cc027fdae871d0e55326669..69ef788d9e3bc7b4e0fd7cc81fc0417332f3d03e 100644 (file)
--- a/samples/v4l/v4l2-pci-skeleton.c
+++ b/samples/v4l/v4l2-pci-skeleton.c
@@ -291,8 +291,8 @@ static int skeleton_querycap(struct file *file, void *priv,
 {
        struct skeleton *skel = video_drvdata(file);
 
-       strlcpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
-       strlcpy(cap->card, "V4L2 PCI Skeleton", sizeof(cap->card));
+       strscpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
+       strscpy(cap->card, "V4L2 PCI Skeleton", sizeof(cap->card));
        snprintf(cap->bus_info, sizeof(cap->bus_info), "PCI:%s",
                 pci_name(skel->pdev));
        return 0;
@@ -597,11 +597,11 @@ static int skeleton_enum_input(struct file *file, void *priv,
        i->type = V4L2_INPUT_TYPE_CAMERA;
        if (i->index == 0) {
                i->std = SKEL_TVNORMS;
-               strlcpy(i->name, "S-Video", sizeof(i->name));
+               strscpy(i->name, "S-Video", sizeof(i->name));
                i->capabilities = V4L2_IN_CAP_STD;
        } else {
                i->std = 0;
-               strlcpy(i->name, "HDMI", sizeof(i->name));
+               strscpy(i->name, "HDMI", sizeof(i->name));
                i->capabilities = V4L2_IN_CAP_DV_TIMINGS;
        }
        return 0;
@@ -845,7 +845,7 @@ static int skeleton_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
        /* Initialize the video_device structure */
        vdev = &skel->vdev;
-       strlcpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
+       strscpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
        /*
         * There is nothing to clean up, so release is set to an empty release
         * function. The release callback must be non-NULL.