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qemu/hw/s390x/ipl.c
Thomas Huth 0f0f8b611e loader: Check access size when calling rom_ptr() to avoid crashes 
The rom_ptr() function allows direct access to the ROM blobs that we
load during startup. However, there are currently no checks for the
size of the accesses, so it's currently possible to crash QEMU for
example with:

$ echo "Insane in the mainframe" > /tmp/test.txt
$ s390x-softmmu/qemu-system-s390x -kernel /tmp/test.txt -append xyz
Segmentation fault (core dumped)
$ s390x-softmmu/qemu-system-s390x -kernel /tmp/test.txt -initrd /tmp/test.txt
Segmentation fault (core dumped)
$ echo -n HdrS > /tmp/hdr.txt
$ sparc64-softmmu/qemu-system-sparc64 -kernel /tmp/hdr.txt -initrd /tmp/hdr.txt
Segmentation fault (core dumped)

We need a possibility to check the size of the ROM area that we want
to access, thus let's add a size parameter to the rom_ptr() function
to avoid these problems.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1530005740-25254-1-git-send-email-thuth@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2018-07-02 10:37:38 +02:00

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/*
* bootloader support
*
* Copyright IBM, Corp. 2012
*
* Authors:
* Christian Borntraeger <borntraeger@de.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at your
* option) any later version. See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "sysemu/sysemu.h"
#include "cpu.h"
#include "elf.h"
#include "hw/loader.h"
#include "hw/boards.h"
#include "hw/s390x/virtio-ccw.h"
#include "hw/s390x/css.h"
#include "hw/s390x/ebcdic.h"
#include "ipl.h"
#include "qemu/error-report.h"
#include "qemu/config-file.h"
#include "qemu/cutils.h"
#include "qemu/option.h"
#include "exec/exec-all.h"
#define KERN_IMAGE_START 0x010000UL
#define LINUX_MAGIC_ADDR 0x010008UL
#define KERN_PARM_AREA 0x010480UL
#define INITRD_START 0x800000UL
#define INITRD_PARM_START 0x010408UL
#define PARMFILE_START 0x001000UL
#define ZIPL_IMAGE_START 0x009000UL
#define IPL_PSW_MASK (PSW_MASK_32 | PSW_MASK_64)
static bool iplb_extended_needed(void *opaque)
{
S390IPLState *ipl = S390_IPL(object_resolve_path(TYPE_S390_IPL, NULL));
return ipl->iplbext_migration;
}
static const VMStateDescription vmstate_iplb_extended = {
.name = "ipl/iplb_extended",
.version_id = 0,
.minimum_version_id = 0,
.needed = iplb_extended_needed,
.fields = (VMStateField[]) {
VMSTATE_UINT8_ARRAY(reserved_ext, IplParameterBlock, 4096 - 200),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription vmstate_iplb = {
.name = "ipl/iplb",
.version_id = 0,
.minimum_version_id = 0,
.fields = (VMStateField[]) {
VMSTATE_UINT8_ARRAY(reserved1, IplParameterBlock, 110),
VMSTATE_UINT16(devno, IplParameterBlock),
VMSTATE_UINT8_ARRAY(reserved2, IplParameterBlock, 88),
VMSTATE_END_OF_LIST()
},
.subsections = (const VMStateDescription*[]) {
&vmstate_iplb_extended,
NULL
}
};
static const VMStateDescription vmstate_ipl = {
.name = "ipl",
.version_id = 0,
.minimum_version_id = 0,
.fields = (VMStateField[]) {
VMSTATE_UINT64(compat_start_addr, S390IPLState),
VMSTATE_UINT64(compat_bios_start_addr, S390IPLState),
VMSTATE_STRUCT(iplb, S390IPLState, 0, vmstate_iplb, IplParameterBlock),
VMSTATE_BOOL(iplb_valid, S390IPLState),
VMSTATE_UINT8(cssid, S390IPLState),
VMSTATE_UINT8(ssid, S390IPLState),
VMSTATE_UINT16(devno, S390IPLState),
VMSTATE_END_OF_LIST()
}
};
static S390IPLState *get_ipl_device(void)
{
return S390_IPL(object_resolve_path_type("", TYPE_S390_IPL, NULL));
}
static uint64_t bios_translate_addr(void *opaque, uint64_t srcaddr)
{
uint64_t dstaddr = *(uint64_t *) opaque;
/*
* Assuming that our s390-ccw.img was linked for starting at address 0,
* we can simply add the destination address for the final location
*/
return srcaddr + dstaddr;
}
static void s390_ipl_realize(DeviceState *dev, Error **errp)
{
S390IPLState *ipl = S390_IPL(dev);
uint32_t *ipl_psw;
uint64_t pentry;
char *magic;
int kernel_size;
Error *err = NULL;
int bios_size;
char *bios_filename;
/*
* Always load the bios if it was enforced,
* even if an external kernel has been defined.
*/
if (!ipl->kernel || ipl->enforce_bios) {
uint64_t fwbase = (MIN(ram_size, 0x80000000U) - 0x200000) & ~0xffffUL;
if (bios_name == NULL) {
bios_name = ipl->firmware;
}
bios_filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
if (bios_filename == NULL) {
error_setg(&err, "could not find stage1 bootloader");
goto error;
}
bios_size = load_elf(bios_filename, bios_translate_addr, &fwbase,
&ipl->bios_start_addr, NULL, NULL, 1,
EM_S390, 0, 0);
if (bios_size > 0) {
/* Adjust ELF start address to final location */
ipl->bios_start_addr += fwbase;
} else {
/* Try to load non-ELF file */
bios_size = load_image_targphys(bios_filename, ZIPL_IMAGE_START,
4096);
ipl->bios_start_addr = ZIPL_IMAGE_START;
}
g_free(bios_filename);
if (bios_size == -1) {
error_setg(&err, "could not load bootloader '%s'", bios_name);
goto error;
}
/* default boot target is the bios */
ipl->start_addr = ipl->bios_start_addr;
}
if (ipl->kernel) {
kernel_size = load_elf(ipl->kernel, NULL, NULL, &pentry, NULL,
NULL, 1, EM_S390, 0, 0);
if (kernel_size < 0) {
kernel_size = load_image_targphys(ipl->kernel, 0, ram_size);
if (kernel_size < 0) {
error_setg(&err, "could not load kernel '%s'", ipl->kernel);
goto error;
}
/* if this is Linux use KERN_IMAGE_START */
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, 4);
if (ipl_psw) {
pentry = be32_to_cpu(*ipl_psw) & 0x7fffffffUL;
} else {
error_setg(&err, "Could not get IPL PSW");
goto error;
}
}
}
/*
* Is it a Linux kernel (starting at 0x10000)? If yes, we fill in the
* kernel parameters here as well. Note: For old kernels (up to 3.2)
* we can not rely on the ELF entry point - it was 0x800 (the SALIPL
* 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" */
if (parm_area) {
strcpy(parm_area, ipl->cmdline);
}
} else {
ipl->start_addr = pentry;
}
if (ipl->initrd) {
ram_addr_t initrd_offset;
int initrd_size;
uint64_t *romptr;
initrd_offset = INITRD_START;
while (kernel_size + 0x100000 > initrd_offset) {
initrd_offset += 0x100000;
}
initrd_size = load_image_targphys(ipl->initrd, initrd_offset,
ram_size - initrd_offset);
if (initrd_size == -1) {
error_setg(&err, "could not load initrd '%s'", ipl->initrd);
goto error;
}
/*
* we have to overwrite values in the kernel image,
* which are "rom"
*/
romptr = rom_ptr(INITRD_PARM_START, 16);
if (romptr) {
stq_p(romptr, initrd_offset);
stq_p(romptr + 1, initrd_size);
}
}
}
/*
* Don't ever use the migrated values, they could come from a different
* BIOS and therefore don't work. But still migrate the values, so
* QEMUs relying on it don't break.
*/
ipl->compat_start_addr = ipl->start_addr;
ipl->compat_bios_start_addr = ipl->bios_start_addr;
qemu_register_reset(qdev_reset_all_fn, dev);
error:
error_propagate(errp, err);
}
static Property s390_ipl_properties[] = {
DEFINE_PROP_STRING("kernel", S390IPLState, kernel),
DEFINE_PROP_STRING("initrd", S390IPLState, initrd),
DEFINE_PROP_STRING("cmdline", S390IPLState, cmdline),
DEFINE_PROP_STRING("firmware", S390IPLState, firmware),
DEFINE_PROP_STRING("netboot_fw", S390IPLState, netboot_fw),
DEFINE_PROP_BOOL("enforce_bios", S390IPLState, enforce_bios, false),
DEFINE_PROP_BOOL("iplbext_migration", S390IPLState, iplbext_migration,
true),
DEFINE_PROP_END_OF_LIST(),
};
static void s390_ipl_set_boot_menu(S390IPLState *ipl)
{
QemuOptsList *plist = qemu_find_opts("boot-opts");
QemuOpts *opts = QTAILQ_FIRST(&plist->head);
uint8_t *flags = &ipl->qipl.qipl_flags;
uint32_t *timeout = &ipl->qipl.boot_menu_timeout;
const char *tmp;
unsigned long splash_time = 0;
if (!get_boot_device(0)) {
if (boot_menu) {
error_report("boot menu requires a bootindex to be specified for "
"the IPL device");
}
return;
}
switch (ipl->iplb.pbt) {
case S390_IPL_TYPE_CCW:
/* In the absence of -boot menu, use zipl parameters */
if (!qemu_opt_get(opts, "menu")) {
*flags |= QIPL_FLAG_BM_OPTS_ZIPL;
return;
}
break;
case S390_IPL_TYPE_QEMU_SCSI:
break;
default:
if (boot_menu) {
error_report("boot menu is not supported for this device type");
}
return;
}
if (!boot_menu) {
return;
}
*flags |= QIPL_FLAG_BM_OPTS_CMD;
tmp = qemu_opt_get(opts, "splash-time");
if (tmp && qemu_strtoul(tmp, NULL, 10, &splash_time)) {
error_report("splash-time is invalid, forcing it to 0");
*timeout = 0;
return;
}
if (splash_time > 0xffffffff) {
error_report("splash-time is too large, forcing it to max value");
*timeout = 0xffffffff;
return;
}
*timeout = cpu_to_be32(splash_time);
}
static CcwDevice *s390_get_ccw_device(DeviceState *dev_st)
{
CcwDevice *ccw_dev = NULL;
if (dev_st) {
VirtioCcwDevice *virtio_ccw_dev = (VirtioCcwDevice *)
object_dynamic_cast(OBJECT(qdev_get_parent_bus(dev_st)->parent),
TYPE_VIRTIO_CCW_DEVICE);
if (virtio_ccw_dev) {
ccw_dev = CCW_DEVICE(virtio_ccw_dev);
} else {
SCSIDevice *sd = (SCSIDevice *)
object_dynamic_cast(OBJECT(dev_st),
TYPE_SCSI_DEVICE);
if (sd) {
SCSIBus *bus = scsi_bus_from_device(sd);
VirtIOSCSI *vdev = container_of(bus, VirtIOSCSI, bus);
VirtIOSCSICcw *scsi_ccw = container_of(vdev, VirtIOSCSICcw,
vdev);
ccw_dev = (CcwDevice *)object_dynamic_cast(OBJECT(scsi_ccw),
TYPE_CCW_DEVICE);
}
}
}
return ccw_dev;
}
static bool s390_gen_initial_iplb(S390IPLState *ipl)
{
DeviceState *dev_st;
CcwDevice *ccw_dev = NULL;
dev_st = get_boot_device(0);
if (dev_st) {
ccw_dev = s390_get_ccw_device(dev_st);
}
/*
* Currently allow IPL only from CCW devices.
*/
if (ccw_dev) {
SCSIDevice *sd = (SCSIDevice *) object_dynamic_cast(OBJECT(dev_st),
TYPE_SCSI_DEVICE);
if (sd) {
ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN);
ipl->iplb.blk0_len =
cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN - S390_IPLB_HEADER_LEN);
ipl->iplb.pbt = S390_IPL_TYPE_QEMU_SCSI;
ipl->iplb.scsi.lun = cpu_to_be32(sd->lun);
ipl->iplb.scsi.target = cpu_to_be16(sd->id);
ipl->iplb.scsi.channel = cpu_to_be16(sd->channel);
ipl->iplb.scsi.devno = cpu_to_be16(ccw_dev->sch->devno);
ipl->iplb.scsi.ssid = ccw_dev->sch->ssid & 3;
} else {
VirtIONet *vn = (VirtIONet *) object_dynamic_cast(OBJECT(dev_st),
TYPE_VIRTIO_NET);
ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
ipl->iplb.blk0_len =
cpu_to_be32(S390_IPLB_MIN_CCW_LEN - S390_IPLB_HEADER_LEN);
ipl->iplb.pbt = S390_IPL_TYPE_CCW;
ipl->iplb.ccw.devno = cpu_to_be16(ccw_dev->sch->devno);
ipl->iplb.ccw.ssid = ccw_dev->sch->ssid & 3;
if (vn) {
ipl->netboot = true;
}
}
if (!s390_ipl_set_loadparm(ipl->iplb.loadparm)) {
ipl->iplb.flags |= DIAG308_FLAGS_LP_VALID;
}
return true;
}
return false;
}
int s390_ipl_set_loadparm(uint8_t *loadparm)
{
MachineState *machine = MACHINE(qdev_get_machine());
char *lp = object_property_get_str(OBJECT(machine), "loadparm", NULL);
if (lp) {
int i;
/* lp is an uppercase string without leading/embedded spaces */
for (i = 0; i < 8 && lp[i]; i++) {
loadparm[i] = ascii2ebcdic[(uint8_t) lp[i]];
}
if (i < 8) {
memset(loadparm + i, 0x40, 8 - i); /* fill with EBCDIC spaces */
}
g_free(lp);
return 0;
}
return -1;
}
static int load_netboot_image(Error **errp)
{
S390IPLState *ipl = get_ipl_device();
char *netboot_filename;
MemoryRegion *sysmem = get_system_memory();
MemoryRegion *mr = NULL;
void *ram_ptr = NULL;
int img_size = -1;
mr = memory_region_find(sysmem, 0, 1).mr;
if (!mr) {
error_setg(errp, "Failed to find memory region at address 0");
return -1;
}
ram_ptr = memory_region_get_ram_ptr(mr);
if (!ram_ptr) {
error_setg(errp, "No RAM found");
goto unref_mr;
}
netboot_filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, ipl->netboot_fw);
if (netboot_filename == NULL) {
error_setg(errp, "Could not find network bootloader '%s'",
ipl->netboot_fw);
goto unref_mr;
}
img_size = load_elf_ram(netboot_filename, NULL, NULL, &ipl->start_addr,
NULL, NULL, 1, EM_S390, 0, 0, NULL, false);
if (img_size < 0) {
img_size = load_image_size(netboot_filename, ram_ptr, ram_size);
ipl->start_addr = KERN_IMAGE_START;
}
if (img_size < 0) {
error_setg(errp, "Failed to load network bootloader");
}
g_free(netboot_filename);
unref_mr:
memory_region_unref(mr);
return img_size;
}
static bool is_virtio_ccw_device_of_type(IplParameterBlock *iplb,
int virtio_id)
{
uint8_t cssid;
uint8_t ssid;
uint16_t devno;
uint16_t schid;
SubchDev *sch = NULL;
if (iplb->pbt != S390_IPL_TYPE_CCW) {
return false;
}
devno = be16_to_cpu(iplb->ccw.devno);
ssid = iplb->ccw.ssid & 3;
for (schid = 0; schid < MAX_SCHID; schid++) {
for (cssid = 0; cssid < MAX_CSSID; cssid++) {
sch = css_find_subch(1, cssid, ssid, schid);
if (sch && sch->devno == devno) {
return sch->id.cu_model == virtio_id;
}
}
}
return false;
}
static bool is_virtio_net_device(IplParameterBlock *iplb)
{
return is_virtio_ccw_device_of_type(iplb, VIRTIO_ID_NET);
}
static bool is_virtio_scsi_device(IplParameterBlock *iplb)
{
return is_virtio_ccw_device_of_type(iplb, VIRTIO_ID_SCSI);
}
void s390_ipl_update_diag308(IplParameterBlock *iplb)
{
S390IPLState *ipl = get_ipl_device();
ipl->iplb = *iplb;
ipl->iplb_valid = true;
ipl->netboot = is_virtio_net_device(iplb);
}
IplParameterBlock *s390_ipl_get_iplb(void)
{
S390IPLState *ipl = get_ipl_device();
if (!ipl->iplb_valid) {
return NULL;
}
return &ipl->iplb;
}
void s390_ipl_reset_request(CPUState *cs, enum s390_reset reset_type)
{
S390IPLState *ipl = get_ipl_device();
if (reset_type == S390_RESET_EXTERNAL || reset_type == S390_RESET_REIPL) {
/* use CPU 0 for full resets */
ipl->reset_cpu_index = 0;
} else {
ipl->reset_cpu_index = cs->cpu_index;
}
ipl->reset_type = reset_type;
if (reset_type == S390_RESET_REIPL &&
ipl->iplb_valid &&
!ipl->netboot &&
ipl->iplb.pbt == S390_IPL_TYPE_CCW &&
is_virtio_scsi_device(&ipl->iplb)) {
CcwDevice *ccw_dev = s390_get_ccw_device(get_boot_device(0));
if (ccw_dev &&
cpu_to_be16(ccw_dev->sch->devno) == ipl->iplb.ccw.devno &&
(ccw_dev->sch->ssid & 3) == ipl->iplb.ccw.ssid) {
/*
* this is the original boot device's SCSI
* so restore IPL parameter info from it
*/
ipl->iplb_valid = s390_gen_initial_iplb(ipl);
}
}
if (reset_type == S390_RESET_MODIFIED_CLEAR ||
reset_type == S390_RESET_LOAD_NORMAL) {
/* ignore -no-reboot, send no event */
qemu_system_reset_request(SHUTDOWN_CAUSE_SUBSYSTEM_RESET);
} else {
qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
}
/* as this is triggered by a CPU, make sure to exit the loop */
if (tcg_enabled()) {
cpu_loop_exit(cs);
}
}
void s390_ipl_get_reset_request(CPUState **cs, enum s390_reset *reset_type)
{
S390IPLState *ipl = get_ipl_device();
*cs = qemu_get_cpu(ipl->reset_cpu_index);
if (!*cs) {
/* use any CPU */
*cs = first_cpu;
}
*reset_type = ipl->reset_type;
}
void s390_ipl_clear_reset_request(void)
{
S390IPLState *ipl = get_ipl_device();
ipl->reset_type = S390_RESET_EXTERNAL;
/* use CPU 0 for full resets */
ipl->reset_cpu_index = 0;
}
static void s390_ipl_prepare_qipl(S390CPU *cpu)
{
S390IPLState *ipl = get_ipl_device();
uint8_t *addr;
uint64_t len = 4096;
addr = cpu_physical_memory_map(cpu->env.psa, &len, 1);
if (!addr || len < QIPL_ADDRESS + sizeof(QemuIplParameters)) {
error_report("Cannot set QEMU IPL parameters");
return;
}
memcpy(addr + QIPL_ADDRESS, &ipl->qipl, sizeof(QemuIplParameters));
cpu_physical_memory_unmap(addr, len, 1, len);
}
void s390_ipl_prepare_cpu(S390CPU *cpu)
{
S390IPLState *ipl = get_ipl_device();
Error *err = NULL;
cpu->env.psw.addr = ipl->start_addr;
cpu->env.psw.mask = IPL_PSW_MASK;
if (!ipl->kernel || ipl->iplb_valid) {
cpu->env.psw.addr = ipl->bios_start_addr;
if (!ipl->iplb_valid) {
ipl->iplb_valid = s390_gen_initial_iplb(ipl);
}
}
if (ipl->netboot) {
if (load_netboot_image(&err) < 0) {
error_report_err(err);
exit(1);
}
ipl->qipl.netboot_start_addr = cpu_to_be64(ipl->start_addr);
}
s390_ipl_set_boot_menu(ipl);
s390_ipl_prepare_qipl(cpu);
}
static void s390_ipl_reset(DeviceState *dev)
{
S390IPLState *ipl = S390_IPL(dev);
if (ipl->reset_type != S390_RESET_REIPL) {
ipl->iplb_valid = false;
memset(&ipl->iplb, 0, sizeof(IplParameterBlock));
}
}
static void s390_ipl_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = s390_ipl_realize;
dc->props = s390_ipl_properties;
dc->reset = s390_ipl_reset;
dc->vmsd = &vmstate_ipl;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
/* Reason: Loads the ROMs and thus can only be used one time - internally */
dc->user_creatable = false;
}
static const TypeInfo s390_ipl_info = {
.class_init = s390_ipl_class_init,
.parent = TYPE_DEVICE,
.name = TYPE_S390_IPL,
.instance_size = sizeof(S390IPLState),
};
static void s390_ipl_register_types(void)
{
type_register_static(&s390_ipl_info);
}
type_init(s390_ipl_register_types)
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