[PULL,02/15] loader: Check access size when calling rom_ptr() to avoid crashes

diff --git a/hw/core/loader.c b/hw/core/loader.c
index 06bdbca537..bbb6e65bb5 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -191,7 +191,7 @@  void pstrcpy_targphys(const char *name, hwaddr dest, int buf_size,
         rom_add_blob_fixed(name, source, (nulp - source) + 1, dest);
     } else {
         rom_add_blob_fixed(name, source, buf_size, dest);
-        ptr = rom_ptr(dest + buf_size - 1);
+        ptr = rom_ptr(dest + buf_size - 1, sizeof(*ptr));
         *ptr = 0;
     }
 }
@@ -1165,7 +1165,7 @@  void rom_reset_order_override(void)
     fw_cfg_reset_order_override(fw_cfg);
 }
 
-static Rom *find_rom(hwaddr addr)
+static Rom *find_rom(hwaddr addr, size_t size)
 {
     Rom *rom;
 
@@ -1179,7 +1179,7 @@  static Rom *find_rom(hwaddr addr)
         if (rom->addr > addr) {
             continue;
         }
-        if (rom->addr + rom->romsize < addr) {
+        if (rom->addr + rom->romsize < addr + size) {
             continue;
         }
         return rom;
@@ -1249,11 +1249,11 @@  int rom_copy(uint8_t *dest, hwaddr addr, size_t size)
     return (d + l) - dest;
 }
 
-void *rom_ptr(hwaddr addr)
+void *rom_ptr(hwaddr addr, size_t size)
 {
     Rom *rom;
 
-    rom = find_rom(addr);
+    rom = find_rom(addr, size);
     if (!rom || !rom->data)
         return NULL;
     return rom->data + (addr - rom->addr);
diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
index b9d92bf47e..1b4e32e58e 100644
--- a/hw/mips/mips_malta.c
+++ b/hw/mips/mips_malta.c
@@ -1133,11 +1133,13 @@  void mips_malta_init(MachineState *machine)
            a neat trick which allows bi-endian firmware. */
 #ifndef TARGET_WORDS_BIGENDIAN
         {
-            uint32_t *end, *addr = rom_ptr(FLASH_ADDRESS);
+            uint32_t *end, *addr;
+            const size_t swapsize = MIN(bios_size, 0x3e0000);
+            addr = rom_ptr(FLASH_ADDRESS, swapsize);
             if (!addr) {
                 addr = memory_region_get_ram_ptr(bios);
             }
-            end = (void *)addr + MIN(bios_size, 0x3e0000);
+            end = (void *)addr + swapsize;
             while (addr < end) {
                 bswap32s(addr);
                 addr++;
diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index f278036fa7..21f64ad26a 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -33,7 +33,6 @@ 
 #define KERN_PARM_AREA                  0x010480UL
 #define INITRD_START                    0x800000UL
 #define INITRD_PARM_START               0x010408UL
-#define INITRD_PARM_SIZE                0x010410UL
 #define PARMFILE_START                  0x001000UL
 #define ZIPL_IMAGE_START                0x009000UL
 #define IPL_PSW_MASK                    (PSW_MASK_32 | PSW_MASK_64)
@@ -165,12 +164,12 @@  static void s390_ipl_realize(DeviceState *dev, Error **errp)
                 goto error;
             }
             /* if this is Linux use KERN_IMAGE_START */
-            magic = rom_ptr(LINUX_MAGIC_ADDR);
+            magic = rom_ptr(LINUX_MAGIC_ADDR, 6);
             if (magic && !memcmp(magic, "S390EP", 6)) {
                 pentry = KERN_IMAGE_START;
             } else {
                 /* if not Linux load the address of the (short) IPL PSW */
-                ipl_psw = rom_ptr(4);
+                ipl_psw = rom_ptr(4, 4);
                 if (ipl_psw) {
                     pentry = be32_to_cpu(*ipl_psw) & 0x7fffffffUL;
                 } else {
@@ -186,9 +185,12 @@  static void s390_ipl_realize(DeviceState *dev, Error **errp)
          * loader) and it won't work. For this case we force it to 0x10000, too.
          */
         if (pentry == KERN_IMAGE_START || pentry == 0x800) {
+            char *parm_area = rom_ptr(KERN_PARM_AREA, strlen(ipl->cmdline) + 1);
             ipl->start_addr = KERN_IMAGE_START;
             /* Overwrite parameters in the kernel image, which are "rom" */
-            strcpy(rom_ptr(KERN_PARM_AREA), ipl->cmdline);
+            if (parm_area) {
+                strcpy(parm_area, ipl->cmdline);
+            }
         } else {
             ipl->start_addr = pentry;
         }
@@ -196,6 +198,7 @@  static void s390_ipl_realize(DeviceState *dev, Error **errp)
         if (ipl->initrd) {
             ram_addr_t initrd_offset;
             int initrd_size;
+            uint64_t *romptr;
 
             initrd_offset = INITRD_START;
             while (kernel_size + 0x100000 > initrd_offset) {
@@ -212,8 +215,11 @@  static void s390_ipl_realize(DeviceState *dev, Error **errp)
              * we have to overwrite values in the kernel image,
              * which are "rom"
              */
-            stq_p(rom_ptr(INITRD_PARM_START), initrd_offset);
-            stq_p(rom_ptr(INITRD_PARM_SIZE), initrd_size);
+            romptr = rom_ptr(INITRD_PARM_START, 16);
+            if (romptr) {
+                stq_p(romptr, initrd_offset);
+                stq_p(romptr + 1, initrd_size);
+            }
         }
     }
     /*
diff --git a/hw/sparc/sun4m.c b/hw/sparc/sun4m.c
index b984d2da0e..21078cc121 100644
--- a/hw/sparc/sun4m.c
+++ b/hw/sparc/sun4m.c
@@ -272,8 +272,8 @@  static unsigned long sun4m_load_kernel(const char *kernel_filename,
         }
         if (initrd_size > 0) {
             for (i = 0; i < 64 * TARGET_PAGE_SIZE; i += TARGET_PAGE_SIZE) {
-                ptr = rom_ptr(KERNEL_LOAD_ADDR + i);
-                if (ldl_p(ptr) == 0x48647253) { // HdrS
+                ptr = rom_ptr(KERNEL_LOAD_ADDR + i, 24);
+                if (ptr && ldl_p(ptr) == 0x48647253) { /* HdrS */
                     stl_p(ptr + 16, INITRD_LOAD_ADDR);
                     stl_p(ptr + 20, initrd_size);
                     break;
diff --git a/hw/sparc64/sun4u.c b/hw/sparc64/sun4u.c
index 3975a7b65a..334dd7008e 100644
--- a/hw/sparc64/sun4u.c
+++ b/hw/sparc64/sun4u.c
@@ -186,8 +186,8 @@  static uint64_t sun4u_load_kernel(const char *kernel_filename,
         }
         if (*initrd_size > 0) {
             for (i = 0; i < 64 * TARGET_PAGE_SIZE; i += TARGET_PAGE_SIZE) {
-                ptr = rom_ptr(*kernel_addr + i);
-                if (ldl_p(ptr + 8) == 0x48647253) { /* HdrS */
+                ptr = rom_ptr(*kernel_addr + i, 32);
+                if (ptr && ldl_p(ptr + 8) == 0x48647253) { /* HdrS */
                     stl_p(ptr + 24, *initrd_addr + *kernel_addr);
                     stl_p(ptr + 28, *initrd_size);
                     break;
diff --git a/include/hw/loader.h b/include/hw/loader.h
index 5ed3fd8ae6..e98b84b8f9 100644
--- a/include/hw/loader.h
+++ b/include/hw/loader.h
@@ -226,7 +226,7 @@  void rom_set_fw(FWCfgState *f);
 void rom_set_order_override(int order);
 void rom_reset_order_override(void);
 int rom_copy(uint8_t *dest, hwaddr addr, size_t size);
-void *rom_ptr(hwaddr addr);
+void *rom_ptr(hwaddr addr, size_t size);
 void hmp_info_roms(Monitor *mon, const QDict *qdict);
 
 #define rom_add_file_fixed(_f, _a, _i)          \
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 82ff450f9a..64a8005a4b 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -239,7 +239,7 @@  static void arm_cpu_reset(CPUState *s)
 
         /* Load the initial SP and PC from offset 0 and 4 in the vector table */
         vecbase = env->v7m.vecbase[env->v7m.secure];
-        rom = rom_ptr(vecbase);
+        rom = rom_ptr(vecbase, 8);
         if (rom) {
             /* Address zero is covered by ROM which hasn't yet been
              * copied into physical memory.