boot/vbe_simple.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Verified Boot for Embedded (VBE) 'simple' method
   4  *
   5  * Copyright 2022 Google LLC
   6  * Written by Simon Glass <[email protected]>
   7  */
   8
   9 #define LOG_CATEGORY LOGC_BOOT
  10
  11 #include <bootdev.h>
  12 #include <bootflow.h>
  13 #include <bootmeth.h>
  14 #include <dm.h>
  15 #include <log.h>
  16 #include <memalign.h>
  17 #include <mmc.h>
  18 #include <vbe.h>
  19 #include <dm/device-internal.h>
  20 #include <dm/ofnode.h>
  21 #include <u-boot/crc.h>
  22 #include "vbe_simple.h"
  23
  24 /** struct simple_nvdata - storage format for non-volatile data */
  25 struct simple_nvdata {
  26         u8 crc8;
  27         u8 hdr;
  28         u16 spare1;
  29         u32 fw_vernum;
  30         u8 spare2[0x38];
  31 };
  32
  33 static int simple_read_version(struct udevice *dev, struct blk_desc *desc,
  34                                u8 *buf, struct simple_state *state)
  35 {
  36         struct simple_priv *priv = dev_get_priv(dev);
  37         int start;
  38
  39         if (priv->version_size > MMC_MAX_BLOCK_LEN)
  40                 return log_msg_ret("ver", -E2BIG);
  41
  42         start = priv->area_start + priv->version_offset;
  43         if (start & (MMC_MAX_BLOCK_LEN - 1))
  44                 return log_msg_ret("get", -EBADF);
  45         start /= MMC_MAX_BLOCK_LEN;
  46
  47         if (blk_dread(desc, start, 1, buf) != 1)
  48                 return log_msg_ret("read", -EIO);
  49         strlcpy(state->fw_version, buf, MAX_VERSION_LEN);
  50         log_debug("version=%s\n", state->fw_version);
  51
  52         return 0;
  53 }
  54
  55 static int simple_read_nvdata(struct udevice *dev, struct blk_desc *desc,
  56                               u8 *buf, struct simple_state *state)
  57 {
  58         struct simple_priv *priv = dev_get_priv(dev);
  59         uint hdr_ver, hdr_size, size, crc;
  60         const struct simple_nvdata *nvd;
  61         int start;
  62
  63         if (priv->state_size > MMC_MAX_BLOCK_LEN)
  64                 return log_msg_ret("state", -E2BIG);
  65
  66         start = priv->area_start + priv->state_offset;
  67         if (start & (MMC_MAX_BLOCK_LEN - 1))
  68                 return log_msg_ret("get", -EBADF);
  69         start /= MMC_MAX_BLOCK_LEN;
  70
  71         if (blk_dread(desc, start, 1, buf) != 1)
  72                 return log_msg_ret("read", -EIO);
  73         nvd = (struct simple_nvdata *)buf;
  74         hdr_ver = (nvd->hdr & NVD_HDR_VER_MASK) >> NVD_HDR_VER_SHIFT;
  75         hdr_size = (nvd->hdr & NVD_HDR_SIZE_MASK) >> NVD_HDR_SIZE_SHIFT;
  76         if (hdr_ver != NVD_HDR_VER_CUR)
  77                 return log_msg_ret("hdr", -EPERM);
  78         size = 1 << hdr_size;
  79         if (size > sizeof(*nvd))
  80                 return log_msg_ret("sz", -ENOEXEC);
  81
  82         crc = crc8(0, buf + 1, size - 1);
  83         if (crc != nvd->crc8)
  84                 return log_msg_ret("crc", -EPERM);
  85         state->fw_vernum = nvd->fw_vernum;
  86
  87         log_debug("version=%s\n", state->fw_version);
  88
  89         return 0;
  90 }
  91
  92 int vbe_simple_read_state(struct udevice *dev, struct simple_state *state)
  93 {
  94         ALLOC_CACHE_ALIGN_BUFFER(u8, buf, MMC_MAX_BLOCK_LEN);
  95         struct simple_priv *priv = dev_get_priv(dev);
  96         struct blk_desc *desc;
  97         char devname[16];
  98         const char *end;
  99         int devnum;
 100         int ret;
 101
 102         /* First figure out the block device */
 103         log_debug("storage=%s\n", priv->storage);
 104         devnum = trailing_strtoln_end(priv->storage, NULL, &end);
 105         if (devnum == -1)
 106                 return log_msg_ret("num", -ENODEV);
 107         if (end - priv->storage >= sizeof(devname))
 108                 return log_msg_ret("end", -E2BIG);
 109         strlcpy(devname, priv->storage, end - priv->storage + 1);
 110         log_debug("dev=%s, %x\n", devname, devnum);
 111
 112         desc = blk_get_dev(devname, devnum);
 113         if (!desc)
 114                 return log_msg_ret("get", -ENXIO);
 115
 116         ret = simple_read_version(dev, desc, buf, state);
 117         if (ret)
 118                 return log_msg_ret("ver", ret);
 119
 120         ret = simple_read_nvdata(dev, desc, buf, state);
 121         if (ret)
 122                 return log_msg_ret("nvd", ret);
 123
 124         return 0;
 125 }
 126
 127 static int vbe_simple_get_state_desc(struct udevice *dev, char *buf,
 128                                      int maxsize)
 129 {
 130         struct simple_state state;
 131         int ret;
 132
 133         ret = vbe_simple_read_state(dev, &state);
 134         if (ret)
 135                 return log_msg_ret("read", ret);
 136
 137         if (maxsize < 30)
 138                 return -ENOSPC;
 139         snprintf(buf, maxsize, "Version: %s\nVernum: %x/%x", state.fw_version,
 140                  state.fw_vernum >> FWVER_KEY_SHIFT,
 141                  state.fw_vernum & FWVER_FW_MASK);
 142
 143         return 0;
 144 }
 145
 146 static int vbe_simple_read_bootflow(struct udevice *dev, struct bootflow *bflow)
 147 {
 148         int ret;
 149
 150         if (CONFIG_IS_ENABLED(BOOTMETH_VBE_SIMPLE_FW)) {
 151                 if (vbe_phase() == VBE_PHASE_FIRMWARE) {
 152                         ret = vbe_simple_read_bootflow_fw(dev, bflow);
 153                         if (ret)
 154                                 return log_msg_ret("fw", ret);
 155                         return 0;
 156                 }
 157         }
 158
 159         return -EINVAL;
 160 }
 161
 162 static int vbe_simple_read_file(struct udevice *dev, struct bootflow *bflow,
 163                                 const char *file_path, ulong addr, ulong *sizep)
 164 {
 165         int ret;
 166
 167         if (vbe_phase() == VBE_PHASE_OS) {
 168                 ret = bootmeth_common_read_file(dev, bflow, file_path, addr,
 169                                                 sizep);
 170                 if (ret)
 171                         return log_msg_ret("os", ret);
 172         }
 173
 174         /* To be implemented */
 175         return -EINVAL;
 176 }
 177
 178 static struct bootmeth_ops bootmeth_vbe_simple_ops = {
 179         .get_state_desc = vbe_simple_get_state_desc,
 180         .read_bootflow  = vbe_simple_read_bootflow,
 181         .read_file      = vbe_simple_read_file,
 182 };
 183
 184 static int bootmeth_vbe_simple_probe(struct udevice *dev)
 185 {
 186         struct simple_priv *priv = dev_get_priv(dev);
 187
 188         memset(priv, '\0', sizeof(*priv));
 189         if (dev_read_u32(dev, "area-start", &priv->area_start) ||
 190             dev_read_u32(dev, "area-size", &priv->area_size) ||
 191             dev_read_u32(dev, "version-offset", &priv->version_offset) ||
 192             dev_read_u32(dev, "version-size", &priv->version_size) ||
 193             dev_read_u32(dev, "state-offset", &priv->state_offset) ||
 194             dev_read_u32(dev, "state-size", &priv->state_size))
 195                 return log_msg_ret("read", -EINVAL);
 196         dev_read_u32(dev, "skip-offset", &priv->skip_offset);
 197         priv->storage = strdup(dev_read_string(dev, "storage"));
 198         if (!priv->storage)
 199                 return log_msg_ret("str", -EINVAL);
 200
 201         return 0;
 202 }
 203
 204 static int bootmeth_vbe_simple_bind(struct udevice *dev)
 205 {
 206         struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
 207
 208         plat->desc = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
 209                 "VBE simple" : "vbe-simple";
 210         plat->flags = BOOTMETHF_GLOBAL;
 211
 212         return 0;
 213 }
 214
 215 #if CONFIG_IS_ENABLED(OF_REAL)
 216 static const struct udevice_id generic_simple_vbe_simple_ids[] = {
 217         { .compatible = "fwupd,vbe-simple" },
 218         { }
 219 };
 220 #endif
 221
 222 U_BOOT_DRIVER(vbe_simple) = {
 223         .name   = "vbe_simple",
 224         .id     = UCLASS_BOOTMETH,
 225         .of_match = of_match_ptr(generic_simple_vbe_simple_ids),
 226         .ops    = &bootmeth_vbe_simple_ops,
 227         .bind   = bootmeth_vbe_simple_bind,
 228         .probe  = bootmeth_vbe_simple_probe,
 229         .flags  = DM_FLAG_PRE_RELOC,
 230         .priv_auto      = sizeof(struct simple_priv),
 231 };