cmd: pxe_utils: sysboot: fix crash if either board or soc are not set.

If the environment does not have "soc" or "board" set, and fdtdir
option is specified in extlinux.conf, the bootloader will crash whilst
dereferencing a null pointer. Add a guard against null soc or
board. Fixes a crash of qemu-riscv64_smode configuration, which does
not have CONFIG_SYS_SOC defined.

Signed-off-by: Dimitri John Ledkov <xnox@ubuntu.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

diff --git a/cmd/pxe_utils.c b/cmd/pxe_utils.c
index 71c5af4c25d8cb1e9306ffe3398a6017cfbf7529..9a30629e26e1ac9f39ae832cb3087d23bec30704 100644 (file)
--- a/cmd/pxe_utils.c
+++ b/cmd/pxe_utils.c
@@ -587,6 +587,14 @@ static int label_boot(struct cmd_tbl *cmdtp, struct pxe_label *label)
                                f2 = "-";
                                f3 = env_get("board");
                                f4 = ".dtb";
+                               if (!f1) {
+                                       f1 = "";
+                                       f2 = "";
+                               }
+                               if (!f3) {
+                                       f2 = "";
+                                       f3 = "";
+                               }
                        }
 
                        len = strlen(label->fdtdir);