misc: mic: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20200311074916.8783-1-tiwai@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mic/host/mic_x100.c b/drivers/misc/mic/host/mic_x100.c
index a774331..d18cda9 100644 (file)
--- a/drivers/misc/mic/host/mic_x100.c
+++ b/drivers/misc/mic/host/mic_x100.c
@@ -350,10 +350,10 @@ mic_x100_load_command_line(struct mic_device *mdev, const struct firmware *fw)
        if (!buf)
                return -ENOMEM;
 
-       len += snprintf(buf, CMDLINE_SIZE - len,
+       len += scnprintf(buf, CMDLINE_SIZE - len,
                " mem=%dM", boot_mem);
        if (mdev->cosm_dev->cmdline)
-               snprintf(buf + len, CMDLINE_SIZE - len, " %s",
+               scnprintf(buf + len, CMDLINE_SIZE - len, " %s",
                         mdev->cosm_dev->cmdline);
        memcpy_toio(cmd_line_va, buf, strlen(buf) + 1);
        kfree(buf);