cmd: fdt: Check argc before accessing argv in fdt bootcpu

On case 'fdt bootcpu' is invoked without parameters, argv[2] is not
valid and this command would SEGFAULT in sandbox environment. Add
missing argc test to avoid the crash and rather print usage help
message.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/cmd/fdt.c b/cmd/fdt.c
index 29d7488..734c9b3 100644 (file)
--- a/cmd/fdt.c
+++ b/cmd/fdt.c
@@ -597,7 +597,12 @@ static int do_fdt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
         * Set boot cpu id
         */
        } else if (strncmp(argv[1], "boo", 3) == 0) {
-               unsigned long tmp = hextoul(argv[2], NULL);
+               unsigned long tmp;
+
+               if (argc != 3)
+                       return CMD_RET_USAGE;
+
+               tmp = hextoul(argv[2], NULL);
                fdt_set_boot_cpuid_phys(working_fdt, tmp);
 
        /*