u-boot/boot/bootmeth_efi.c
Simon Glass 741d1e9d3f bootstd: Avoid freeing a non-allocated buffer
EFI applications can be very large and thus used to cause boot failures
when malloc() space was exhausted.

A recent changed fixed this by using the kernel_addr_r environment var
as the address of the buffer. However, it still frees the buffer when
the bootflow is discarded.

Fix this by introducing a flag to indicate whether the buffer was
allocated, or not.

Note that kernel_addr_r is not the last word here. It might be better
to use lmb to place images. But there is a lot of refactoring to do
before we can remove the environment variables. The distro scripts rely
on them so it is safe for bootstd to do so too.

Fixes: 6a8c2f9781 bootstd: Avoid allocating memory for the EFI file

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported by: Simon Glass <sjg@chromium.org>
Reported by: Shantur Rathore <i@shantur.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Tested-by: Shantur Rathore <i@shantur.com>
2023-11-17 11:58:26 -05:00

484 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Bootmethod for distro boot via EFI
*
* Copyright 2021 Google LLC
* Written by Simon Glass <sjg@chromium.org>
*/
#define LOG_CATEGORY UCLASS_BOOTSTD
#include <common.h>
#include <bootdev.h>
#include <bootflow.h>
#include <bootmeth.h>
#include <command.h>
#include <dm.h>
#include <efi_loader.h>
#include <fs.h>
#include <malloc.h>
#include <mapmem.h>
#include <mmc.h>
#include <net.h>
#include <pxe_utils.h>
#include <linux/sizes.h>
#define EFI_DIRNAME "efi/boot/"
/**
* get_efi_leafname() - Get the leaf name for the EFI file we expect
*
* @str: Place to put leaf name for this architecture, e.g. "bootaa64.efi".
* Must have at least 16 bytes of space
* @max_len: Length of @str, must be >=16
*/
static int get_efi_leafname(char *str, int max_len)
{
const char *base;
if (max_len < 16)
return log_msg_ret("spc", -ENOSPC);
if (IS_ENABLED(CONFIG_ARM64))
base = "bootaa64";
else if (IS_ENABLED(CONFIG_ARM))
base = "bootarm";
else if (IS_ENABLED(CONFIG_X86_RUN_32BIT))
base = "bootia32";
else if (IS_ENABLED(CONFIG_X86_RUN_64BIT))
base = "bootx64";
else if (IS_ENABLED(CONFIG_ARCH_RV32I))
base = "bootriscv32";
else if (IS_ENABLED(CONFIG_ARCH_RV64I))
base = "bootriscv64";
else if (IS_ENABLED(CONFIG_SANDBOX))
base = "bootsbox";
else
return -EINVAL;
strcpy(str, base);
strcat(str, ".efi");
return 0;
}
static int get_efi_pxe_arch(void)
{
/* http://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xml */
if (IS_ENABLED(CONFIG_ARM64))
return 0xb;
else if (IS_ENABLED(CONFIG_ARM))
return 0xa;
else if (IS_ENABLED(CONFIG_X86_64))
return 0x6;
else if (IS_ENABLED(CONFIG_X86))
return 0x7;
else if (IS_ENABLED(CONFIG_ARCH_RV32I))
return 0x19;
else if (IS_ENABLED(CONFIG_ARCH_RV64I))
return 0x1b;
else if (IS_ENABLED(CONFIG_SANDBOX))
return 0; /* not used */
return -EINVAL;
}
static int get_efi_pxe_vci(char *str, int max_len)
{
int ret;
ret = get_efi_pxe_arch();
if (ret < 0)
return ret;
snprintf(str, max_len, "PXEClient:Arch:%05x:UNDI:003000", ret);
return 0;
}
/**
* bootmeth_uses_network() - check if the media device is Ethernet
*
* @bflow: Bootflow to check
* Returns: true if the media device is Ethernet, else false
*/
static bool bootmeth_uses_network(struct bootflow *bflow)
{
const struct udevice *media = dev_get_parent(bflow->dev);
return IS_ENABLED(CONFIG_CMD_DHCP) &&
device_get_uclass_id(media) == UCLASS_ETH;
}
static void set_efi_bootdev(struct blk_desc *desc, struct bootflow *bflow)
{
const struct udevice *media_dev;
int size = bflow->size;
const char *dev_name;
char devnum_str[9];
char dirname[200];
char *last_slash;
/*
* This is a horrible hack to tell EFI about this boot device. Once we
* unify EFI with the rest of U-Boot we can clean this up. The same hack
* exists in multiple places, e.g. in the fs, tftp and load commands.
*
* Once we can clean up the EFI code to make proper use of driver model,
* this can go away.
*/
media_dev = dev_get_parent(bflow->dev);
snprintf(devnum_str, sizeof(devnum_str), "%x:%x",
desc ? desc->devnum : dev_seq(media_dev),
bflow->part);
strlcpy(dirname, bflow->fname, sizeof(dirname));
last_slash = strrchr(dirname, '/');
if (last_slash)
*last_slash = '\0';
log_debug("setting bootdev %s, %s, %s, %p, %x\n",
dev_get_uclass_name(media_dev), devnum_str, bflow->fname,
bflow->buf, size);
dev_name = device_get_uclass_id(media_dev) == UCLASS_MASS_STORAGE ?
"usb" : dev_get_uclass_name(media_dev);
efi_set_bootdev(dev_name, devnum_str, bflow->fname, bflow->buf, size);
}
static int efiload_read_file(struct bootflow *bflow, ulong addr)
{
struct blk_desc *desc = NULL;
loff_t bytes_read;
int ret;
if (bflow->blk)
desc = dev_get_uclass_plat(bflow->blk);
ret = bootmeth_setup_fs(bflow, desc);
if (ret)
return log_msg_ret("set", ret);
ret = fs_read(bflow->fname, addr, 0, bflow->size, &bytes_read);
if (ret)
return log_msg_ret("read", ret);
bflow->buf = map_sysmem(addr, bflow->size);
bflow->flags |= BOOTFLOWF_STATIC_BUF;
set_efi_bootdev(desc, bflow);
return 0;
}
static int distro_efi_check(struct udevice *dev, struct bootflow_iter *iter)
{
/* This only works on block and network devices */
if (bootflow_iter_check_blk(iter) && bootflow_iter_check_net(iter))
return log_msg_ret("blk", -ENOTSUPP);
/* This works on block devices and network devices */
if (iter->method_flags & BOOTFLOW_METHF_PXE_ONLY)
return log_msg_ret("pxe", -ENOTSUPP);
return 0;
}
/**
* distro_efi_get_fdt_name() - Get the filename for reading the .dtb file
*
* @fname: Place to put filename
* @size: Max size of filename
* @seq: Sequence number, to cycle through options (0=first)
* Returns: 0 on success, -ENOENT if the "fdtfile" env var does not exist,
* -EINVAL if there are no more options, -EALREADY if the control FDT should be
* used
*/
static int distro_efi_get_fdt_name(char *fname, int size, int seq)
{
const char *fdt_fname;
const char *prefix;
/* select the prefix */
switch (seq) {
case 0:
/* this is the default */
prefix = "/dtb";
break;
case 1:
prefix = "";
break;
case 2:
prefix = "/dtb/current";
break;
default:
return log_msg_ret("pref", -EINVAL);
}
fdt_fname = env_get("fdtfile");
if (fdt_fname) {
snprintf(fname, size, "%s/%s", prefix, fdt_fname);
log_debug("Using device tree: %s\n", fname);
} else if (IS_ENABLED(CONFIG_OF_HAS_PRIOR_STAGE)) {
strcpy(fname, "<prior>");
return log_msg_ret("pref", -EALREADY);
/* Use this fallback only for 32-bit ARM */
} else if (IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_ARM64)) {
const char *soc = env_get("soc");
const char *board = env_get("board");
const char *boardver = env_get("boardver");
/* cf the code in label_boot() which seems very complex */
snprintf(fname, size, "%s/%s%s%s%s.dtb", prefix,
soc ? soc : "", soc ? "-" : "", board ? board : "",
boardver ? boardver : "");
log_debug("Using default device tree: %s\n", fname);
} else {
return log_msg_ret("env", -ENOENT);
}
return 0;
}
/*
* distro_efi_try_bootflow_files() - Check that files are present
*
* This reads any FDT file and checks whether the bootflow file is present, for
* later reading. We avoid reading the bootflow now, since it is likely large,
* it may take a long time and we want to avoid needing to allocate memory for
* it
*
* @dev: bootmeth device to use
* @bflow: bootflow to update
*/
static int distro_efi_try_bootflow_files(struct udevice *dev,
struct bootflow *bflow)
{
struct blk_desc *desc = NULL;
ulong fdt_addr, size;
char fname[256];
int ret, seq;
/* We require a partition table */
if (!bflow->part)
return -ENOENT;
strcpy(fname, EFI_DIRNAME);
ret = get_efi_leafname(fname + strlen(fname),
sizeof(fname) - strlen(fname));
if (ret)
return log_msg_ret("leaf", ret);
if (bflow->blk)
desc = dev_get_uclass_plat(bflow->blk);
ret = bootmeth_try_file(bflow, desc, NULL, fname);
if (ret)
return log_msg_ret("try", ret);
/* Since we can access the file, let's call it ready */
bflow->state = BOOTFLOWST_READY;
fdt_addr = env_get_hex("fdt_addr_r", 0);
/* try the various available names */
ret = -ENOENT;
*fname = '\0';
for (seq = 0; ret == -ENOENT; seq++) {
ret = distro_efi_get_fdt_name(fname, sizeof(fname), seq);
if (ret == -EALREADY)
bflow->flags = BOOTFLOWF_USE_PRIOR_FDT;
if (!ret) {
/* Limit FDT files to 4MB */
size = SZ_4M;
ret = bootmeth_common_read_file(dev, bflow, fname,
fdt_addr, &size);
}
}
if (*fname) {
bflow->fdt_fname = strdup(fname);
if (!bflow->fdt_fname)
return log_msg_ret("fil", -ENOMEM);
}
if (!ret) {
bflow->fdt_size = size;
bflow->fdt_addr = fdt_addr;
/*
* TODO: Apply extension overlay
*
* Here we need to load and apply the extension overlay. This is
* not implemented. See do_extension_apply(). The extension
* stuff needs an implementation in boot/extension.c so it is
* separate from the command code. Really the extension stuff
* should use the device tree and a uclass / driver interface
* rather than implementing its own list
*/
} else {
log_debug("No device tree available\n");
}
return 0;
}
static int distro_efi_read_bootflow_net(struct bootflow *bflow)
{
char file_addr[17], fname[256];
char *tftp_argv[] = {"tftp", file_addr, fname, NULL};
struct cmd_tbl cmdtp = {}; /* dummy */
const char *addr_str, *fdt_addr_str;
int ret, arch, size;
ulong addr, fdt_addr;
char str[36];
ret = get_efi_pxe_vci(str, sizeof(str));
if (ret)
return log_msg_ret("vci", ret);
ret = get_efi_pxe_arch();
if (ret < 0)
return log_msg_ret("arc", ret);
arch = ret;
ret = env_set("bootp_vci", str);
if (ret)
return log_msg_ret("vcs", ret);
ret = env_set_ulong("bootp_arch", arch);
if (ret)
return log_msg_ret("ars", ret);
/* figure out the load address */
addr_str = env_get("kernel_addr_r");
addr = addr_str ? hextoul(addr_str, NULL) : image_load_addr;
/* clear any previous bootfile */
env_set("bootfile", NULL);
/* read the kernel */
ret = dhcp_run(addr, NULL, true);
if (ret)
return log_msg_ret("dhc", ret);
size = env_get_hex("filesize", -1);
if (size <= 0)
return log_msg_ret("sz", -EINVAL);
bflow->size = size;
/* do the hideous EFI hack */
efi_set_bootdev("Net", "", bflow->fname, map_sysmem(addr, 0),
bflow->size);
/* read the DT file also */
fdt_addr_str = env_get("fdt_addr_r");
if (!fdt_addr_str)
return log_msg_ret("fdt", -EINVAL);
fdt_addr = hextoul(fdt_addr_str, NULL);
sprintf(file_addr, "%lx", fdt_addr);
/* We only allow the first prefix with PXE */
ret = distro_efi_get_fdt_name(fname, sizeof(fname), 0);
if (ret)
return log_msg_ret("nam", ret);
bflow->fdt_fname = strdup(fname);
if (!bflow->fdt_fname)
return log_msg_ret("fil", -ENOMEM);
if (!do_tftpb(&cmdtp, 0, 3, tftp_argv)) {
bflow->fdt_size = env_get_hex("filesize", 0);
bflow->fdt_addr = fdt_addr;
} else {
log_debug("No device tree available\n");
}
bflow->state = BOOTFLOWST_READY;
return 0;
}
static int distro_efi_read_bootflow(struct udevice *dev, struct bootflow *bflow)
{
int ret;
if (bootmeth_uses_network(bflow)) {
/* we only support reading from one device, so ignore 'dev' */
ret = distro_efi_read_bootflow_net(bflow);
if (ret)
return log_msg_ret("net", ret);
} else {
ret = distro_efi_try_bootflow_files(dev, bflow);
if (ret)
return log_msg_ret("blk", ret);
}
return 0;
}
static int distro_efi_boot(struct udevice *dev, struct bootflow *bflow)
{
ulong kernel, fdt;
char cmd[50];
int ret;
kernel = env_get_hex("kernel_addr_r", 0);
if (!bootmeth_uses_network(bflow)) {
ret = efiload_read_file(bflow, kernel);
if (ret)
return log_msg_ret("read", ret);
/*
* use the provided device tree if available, else fall back to
* the control FDT
*/
if (bflow->fdt_fname)
fdt = bflow->fdt_addr;
else
fdt = (ulong)map_to_sysmem(gd->fdt_blob);
} else {
/*
* This doesn't actually work for network devices:
*
* do_bootefi_image() No UEFI binary known at 0x02080000
*
* But this is the same behaviour for distro boot, so it can be
* fixed here.
*/
fdt = env_get_hex("fdt_addr_r", 0);
}
/*
* At some point we can add a real interface to bootefi so we can call
* this directly. For now, go through the CLI, like distro boot.
*/
snprintf(cmd, sizeof(cmd), "bootefi %lx %lx", kernel, fdt);
if (run_command(cmd, 0))
return log_msg_ret("run", -EINVAL);
return 0;
}
static int distro_bootmeth_efi_bind(struct udevice *dev)
{
struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
plat->desc = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
"EFI boot from an .efi file" : "EFI";
return 0;
}
static struct bootmeth_ops distro_efi_bootmeth_ops = {
.check = distro_efi_check,
.read_bootflow = distro_efi_read_bootflow,
.read_file = bootmeth_common_read_file,
.boot = distro_efi_boot,
};
static const struct udevice_id distro_efi_bootmeth_ids[] = {
{ .compatible = "u-boot,distro-efi" },
{ }
};
U_BOOT_DRIVER(bootmeth_efi) = {
.name = "bootmeth_efi",
.id = UCLASS_BOOTMETH,
.of_match = distro_efi_bootmeth_ids,
.ops = &distro_efi_bootmeth_ops,
.bind = distro_bootmeth_efi_bind,
};