ibmvmc: 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.

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

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
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/20230927-strncpy-drivers-misc-ibmvmc-c-v1-1-29f56cd3a269@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/ibmvmc.c b/drivers/misc/ibmvmc.c
index 2101eb12bcba0540bcd4ec6e4dd304b2fbf953f3..6d9ed9325f9f1f0e04f5f681c8d0f94552492cd6 100644 (file)
--- a/drivers/misc/ibmvmc.c
+++ b/drivers/misc/ibmvmc.c
@@ -1249,9 +1249,7 @@ static long ibmvmc_ioctl_sethmcid(struct ibmvmc_file_session *session,
                return -EIO;
        }
 
-       /* Make sure buffer is NULL terminated before trying to print it */
-       memset(print_buffer, 0, HMC_ID_LEN + 1);
-       strncpy(print_buffer, hmc->hmc_id, HMC_ID_LEN);
+       strscpy(print_buffer, hmc->hmc_id, sizeof(print_buffer));
        pr_info("ibmvmc: sethmcid: Set HMC ID: \"%s\"\n", print_buffer);
 
        memcpy(buffer->real_addr_local, hmc->hmc_id, HMC_ID_LEN);