rpmsg: core: Replace deprecated strncpy with strscpy

JIRA: https://issues.redhat.com/browse/RHEL-78824

commit a9580b9
Author: Justin Stitt <justinstitt@google.com>
Date:   Fri Oct 20 19:56:59 2023 +0000

    rpmsg: core: Replace deprecated strncpy with strscpy

    strncpy() is deprecated for use on NUL-terminated destination strings
    [1] and as such we should prefer more robust and less ambiguous string
    interfaces.

    We expect chinfo.name to be NUL-terminated based on its usage with
    strncmp():

    rpmsg_core.c:
    389: if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))

    Moreover, NUL-padding is not required as chinfo has stack default
    initialized all fields to zero:

    rpmsg_core.c:
    539: struct rpmsg_channel_info chinfo = {};

    Considering the above, a suitable replacement is `strscpy` [2] due to
    the fact that it guarantees NUL-termination on the destination buffer
    without unnecessarily NUL-padding.

    Also, favor the more idiomatic strscpy() usage of:
    (dest, src, sizeof(dest)).

    Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
    Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
    Link: KSPP/linux#90
    Cc: linux-hardening@vger.kernel.org
    Signed-off-by: Justin Stitt <justinstitt@google.com>
    Link: https://lore.kernel.org/r/20231020-strncpy-drivers-rpmsg-rpmsg_core-c-v1-1-a86b7930c1cf@google.com
    Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Signed-off-by: Jared Kangas <jkangas@redhat.com>

Author: rh-jkangas

drivers/rpmsg/rpmsg_core.c

@@ -526,7 +526,7 @@ static int rpmsg_dev_probe(struct device *dev)
 		goto out;
 
 	if (rpdrv->callback) {
-		strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+		strscpy(chinfo.name, rpdev->id.name, sizeof(chinfo.name));
 		chinfo.src = rpdev->src;
 		chinfo.dst = RPMSG_ADDR_ANY;