prepare process: add magic header in program_load_desc

Check we mapped the correct region with a magic header in the struct

Original commit: d246b93a3bced92d0ac2a4a337118091b010658a

Fujitsu: POSTK_DEBUG_TEMP_FIX_76
Change-Id: If848be64af5d76844ba65b48493021637c8114f4

kernel/host.c

@@ -441,6 +441,13 @@ static int process_msg_prepare_process(unsigned long rphys)
 		return -ENOMEM;
 	}
 
+	if (p->magic != PLD_MAGIC) {
+		kprintf("%s: broken mcexec program_load_desc\n", __func__);
+		ihk_mc_unmap_virtual(p, npages);
+		ihk_mc_unmap_memory(NULL, phys, sz);
+		return -EFAULT;
+	}
+
 	n = p->num_sections;
 	if (n > 16 || 0 >= n) {
 		kprintf("%s: ERROR: ELF sections other than 1 to 16 ??\n",

kernel/include/syscall.h

@@ -174,7 +174,10 @@ typedef unsigned long __cpu_set_unit;
 #define MPOL_NO_BSS               0x04
 #define MPOL_SHM_PREMAP           0x08
 
+#define PLD_MAGIC 0xcafecafe44332211UL
+
 struct program_load_desc {
+	unsigned long magic;
 	int num_sections;
 	int cpu;
 	int pid;