EDAC/mc_sysfs: Replace deprecated strncpy() with memcpy()

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

We've already calculated bounds, possible truncation with '\0' or '\n'
and manually NUL-terminated. The situation is now just a literal byte
copy from one buffer to another, let's treat it as such and use a less
ambiguous interface in memcpy.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230918-strncpy-drivers-edac-edac_mc_sysfs-c-v4-1-38a23d2fcdd8@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index 15f6345..5116873 100644 (file)
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -229,7 +229,7 @@ static ssize_t channel_dimm_label_store(struct device *dev,
        if (copy_count == 0 || copy_count >= sizeof(rank->dimm->label))
                return -EINVAL;
 
-       strncpy(rank->dimm->label, data, copy_count);
+       memcpy(rank->dimm->label, data, copy_count);
        rank->dimm->label[copy_count] = '\0';
 
        return count;
@@ -535,7 +535,7 @@ static ssize_t dimmdev_label_store(struct device *dev,
        if (copy_count == 0 || copy_count >= sizeof(dimm->label))
                return -EINVAL;
 
-       strncpy(dimm->label, data, copy_count);
+       memcpy(dimm->label, data, copy_count);
        dimm->label[copy_count] = '\0';
 
        return count;