Adding upstream version 252.22.upstream/252.22

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 285 insertions, 0 deletions

diff --git a/src/boot/efi/xbootldr.c b/src/boot/efi/xbootldr.c
new file mode 100644
index 0000000..7fef909
--- /dev/null
+++ b/src/boot/efi/xbootldr.c
@@ -0,0 +1,285 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <efi.h>
+#include <efigpt.h>
+#include <efilib.h>
+
+#include "util.h"
+#include "xbootldr.h"
+
+union GptHeaderBuffer {
+        EFI_PARTITION_TABLE_HEADER gpt_header;
+        uint8_t space[CONST_ALIGN_TO(sizeof(EFI_PARTITION_TABLE_HEADER), 512)];
+};
+
+static EFI_DEVICE_PATH *path_replace_hd(
+                const EFI_DEVICE_PATH *path,
+                const EFI_DEVICE_PATH *node,
+                const HARDDRIVE_DEVICE_PATH *new_node) {
+
+        /* Create a new device path as a copy of path, while chopping off the remainder starting at the given
+         * node. If new_node is provided, it is appended at the end of the new path. */
+
+        assert(path);
+        assert(node);
+
+        size_t len = (uint8_t *) node - (uint8_t *) path, new_node_len = 0;
+        if (new_node)
+                new_node_len = DevicePathNodeLength(&new_node->Header);
+
+        EFI_DEVICE_PATH *ret = xmalloc(len + new_node_len + END_DEVICE_PATH_LENGTH);
+        EFI_DEVICE_PATH *end = mempcpy(ret, path, len);
+
+        if (new_node)
+                end = mempcpy(end, new_node, new_node_len);
+
+        SetDevicePathEndNode(end);
+        return ret;
+}
+
+static bool verify_gpt(union GptHeaderBuffer *gpt_header_buffer, EFI_LBA lba_expected) {
+        EFI_PARTITION_TABLE_HEADER *h;
+        uint32_t crc32, crc32_saved;
+        EFI_STATUS err;
+
+        assert(gpt_header_buffer);
+
+        h = &gpt_header_buffer->gpt_header;
+
+        /* Some superficial validation of the GPT header */
+        if (memcmp(&h->Header.Signature, "EFI PART", sizeof(h->Header.Signature)) != 0)
+                return false;
+
+        if (h->Header.HeaderSize < 92 || h->Header.HeaderSize > 512)
+                return false;
+
+        if (h->Header.Revision != 0x00010000U)
+                return false;
+
+        /* Calculate CRC check */
+        crc32_saved = h->Header.CRC32;
+        h->Header.CRC32 = 0;
+        err = BS->CalculateCrc32(gpt_header_buffer, h->Header.HeaderSize, &crc32);
+        h->Header.CRC32 = crc32_saved;
+        if (err != EFI_SUCCESS || crc32 != crc32_saved)
+                return false;
+
+        if (h->MyLBA != lba_expected)
+                return false;
+
+        if ((h->SizeOfPartitionEntry % sizeof(EFI_PARTITION_ENTRY)) != 0)
+                return false;
+
+        if (h->NumberOfPartitionEntries <= 0 || h->NumberOfPartitionEntries > 1024)
+                return false;
+
+        /* overflow check */
+        if (h->SizeOfPartitionEntry > UINTN_MAX / h->NumberOfPartitionEntries)
+                return false;
+
+        return true;
+}
+
+static EFI_STATUS try_gpt(
+                EFI_BLOCK_IO_PROTOCOL *block_io,
+                EFI_LBA lba,
+                EFI_LBA *ret_backup_lba, /* May be changed even on error! */
+                HARDDRIVE_DEVICE_PATH *ret_hd) {
+
+        _cleanup_free_ EFI_PARTITION_ENTRY *entries = NULL;
+        union GptHeaderBuffer gpt;
+        EFI_STATUS err;
+        uint32_t crc32;
+        UINTN size;
+
+        assert(block_io);
+        assert(ret_hd);
+
+        /* Read the GPT header */
+        err = block_io->ReadBlocks(
+                        block_io,
+                        block_io->Media->MediaId,
+                        lba,
+                        sizeof(gpt), &gpt);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        /* Indicate the location of backup LBA even if the rest of the header is corrupt. */
+        if (ret_backup_lba)
+                *ret_backup_lba = gpt.gpt_header.AlternateLBA;
+
+        if (!verify_gpt(&gpt, lba))
+                return EFI_NOT_FOUND;
+
+        /* Now load the GPT entry table */
+        size = ALIGN_TO((UINTN) gpt.gpt_header.SizeOfPartitionEntry * (UINTN) gpt.gpt_header.NumberOfPartitionEntries, 512);
+        entries = xmalloc(size);
+
+        err = block_io->ReadBlocks(
+                        block_io,
+                        block_io->Media->MediaId,
+                        gpt.gpt_header.PartitionEntryLBA,
+                        size, entries);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        /* Calculate CRC of entries array, too */
+        err = BS->CalculateCrc32(entries, size, &crc32);
+        if (err != EFI_SUCCESS || crc32 != gpt.gpt_header.PartitionEntryArrayCRC32)
+                return EFI_CRC_ERROR;
+
+        /* Now we can finally look for xbootloader partitions. */
+        for (UINTN i = 0; i < gpt.gpt_header.NumberOfPartitionEntries; i++) {
+                EFI_PARTITION_ENTRY *entry =
+                                (EFI_PARTITION_ENTRY *) ((uint8_t *) entries + gpt.gpt_header.SizeOfPartitionEntry * i);
+
+                if (memcmp(&entry->PartitionTypeGUID, XBOOTLDR_GUID, sizeof(entry->PartitionTypeGUID)) != 0)
+                        continue;
+
+                if (entry->EndingLBA < entry->StartingLBA) /* Bogus? */
+                        continue;
+
+                *ret_hd = (HARDDRIVE_DEVICE_PATH) {
+                        .Header = {
+                                .Type = MEDIA_DEVICE_PATH,
+                                .SubType = MEDIA_HARDDRIVE_DP,
+                        },
+                        .PartitionNumber = i + 1,
+                        .PartitionStart = entry->StartingLBA,
+                        .PartitionSize = entry->EndingLBA - entry->StartingLBA + 1,
+                        .MBRType = MBR_TYPE_EFI_PARTITION_TABLE_HEADER,
+                        .SignatureType = SIGNATURE_TYPE_GUID,
+                };
+                memcpy(ret_hd->Signature, &entry->UniquePartitionGUID, sizeof(ret_hd->Signature));
+
+                /* HARDDRIVE_DEVICE_PATH has padding, which at least OVMF does not like. */
+                SetDevicePathNodeLength(
+                                &ret_hd->Header,
+                                offsetof(HARDDRIVE_DEVICE_PATH, SignatureType) + sizeof(ret_hd->SignatureType));
+
+                return EFI_SUCCESS;
+        }
+
+        /* This GPT was fully valid, but we didn't find what we are looking for. This
+         * means there's no reason to check the second copy of the GPT header */
+        return EFI_NOT_FOUND;
+}
+
+static EFI_STATUS find_device(EFI_HANDLE *device, EFI_DEVICE_PATH **ret_device_path) {
+        EFI_STATUS err;
+
+        assert(device);
+        assert(ret_device_path);
+
+        EFI_DEVICE_PATH *partition_path;
+        err = BS->HandleProtocol(device, &DevicePathProtocol, (void **) &partition_path);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        /* Find the (last) partition node itself. */
+        EFI_DEVICE_PATH *part_node = NULL;
+        for (EFI_DEVICE_PATH *node = partition_path; !IsDevicePathEnd(node); node = NextDevicePathNode(node)) {
+                if (DevicePathType(node) != MEDIA_DEVICE_PATH)
+                        continue;
+
+                if (DevicePathSubType(node) != MEDIA_HARDDRIVE_DP)
+                        continue;
+
+                part_node = node;
+        }
+
+        if (!part_node)
+                return EFI_NOT_FOUND;
+
+        /* Chop off the partition part, leaving us with the full path to the disk itself. */
+        _cleanup_free_ EFI_DEVICE_PATH *disk_path = NULL;
+        EFI_DEVICE_PATH *p = disk_path = path_replace_hd(partition_path, part_node, NULL);
+
+        EFI_HANDLE disk_handle;
+        EFI_BLOCK_IO_PROTOCOL *block_io;
+        err = BS->LocateDevicePath(&BlockIoProtocol, &p, &disk_handle);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        /* The drivers for other partitions on this drive may not be initialized on fastboot firmware, so we
+         * have to ask the firmware to do just that. */
+        (void) BS->ConnectController(disk_handle, NULL, NULL, true);
+
+        err = BS->HandleProtocol(disk_handle, &BlockIoProtocol, (void **)&block_io);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        /* Filter out some block devices early. (We only care about block devices that aren't
+         * partitions themselves — we look for GPT partition tables to parse after all —, and only
+         * those which contain a medium and have at least 2 blocks.) */
+        if (block_io->Media->LogicalPartition ||
+            !block_io->Media->MediaPresent ||
+            block_io->Media->LastBlock <= 1)
+                return EFI_NOT_FOUND;
+
+        /* Try several copies of the GPT header, in case one is corrupted */
+        EFI_LBA backup_lba = 0;
+        for (UINTN nr = 0; nr < 3; nr++) {
+                EFI_LBA lba;
+
+                /* Read the first copy at LBA 1 and then try the backup GPT header pointed
+                 * to by the first header if that one was corrupted. As a last resort,
+                 * try the very last LBA of this block device. */
+                if (nr == 0)
+                        lba = 1;
+                else if (nr == 1 && backup_lba != 0)
+                        lba = backup_lba;
+                else if (nr == 2 && backup_lba != block_io->Media->LastBlock)
+                        lba = block_io->Media->LastBlock;
+                else
+                        continue;
+
+                HARDDRIVE_DEVICE_PATH hd;
+                err = try_gpt(
+                        block_io, lba,
+                        nr == 0 ? &backup_lba : NULL, /* Only get backup LBA location from first GPT header. */
+                        &hd);
+                if (err != EFI_SUCCESS) {
+                        /* GPT was valid but no XBOOT loader partition found. */
+                        if (err == EFI_NOT_FOUND)
+                                break;
+                        /* Bad GPT, try next one. */
+                        continue;
+                }
+
+                /* Patch in the data we found */
+                *ret_device_path = path_replace_hd(partition_path, part_node, &hd);
+                return EFI_SUCCESS;
+        }
+
+        /* No xbootloader partition found */
+        return EFI_NOT_FOUND;
+}
+
+EFI_STATUS xbootldr_open(EFI_HANDLE *device, EFI_HANDLE *ret_device, EFI_FILE **ret_root_dir) {
+        _cleanup_free_ EFI_DEVICE_PATH *partition_path = NULL;
+        EFI_HANDLE new_device;
+        EFI_FILE *root_dir;
+        EFI_STATUS err;
+
+        assert(device);
+        assert(ret_device);
+        assert(ret_root_dir);
+
+        err = find_device(device, &partition_path);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        EFI_DEVICE_PATH *dp = partition_path;
+        err = BS->LocateDevicePath(&BlockIoProtocol, &dp, &new_device);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        err = open_volume(new_device, &root_dir);
+        if (err != EFI_SUCCESS)
+                return err;
+
+        *ret_device = new_device;
+        *ret_root_dir = root_dir;
+        return EFI_SUCCESS;
+}