From: Utkarsh Verma <[email protected]> Add spapr_vof_partition.c which implements basic MBR and GPT partition table scanning to locate the PReP boot partition during VOF enabled boot.
AI-used-for: code Signed-off-by: Utkarsh Verma <[email protected]> --- Chaneglog: v2: - Added CRC validations for GPT. - Added bounds checking GPT header size. - Added new GPT_MAX_PARTITION to cap max partitions at 128 - Added bounds checking for the partition entry array against disk size for GPT. - Switched GPT entry to use a fixed-size buffer instead of g_malloc per entry. - Added validation for first_lba and last_lba in GPT before returning size. - Added validation for MBR PReP partition entries(start_lba/num_sectors) --- hw/ppc/meson.build | 5 +- hw/ppc/spapr_vof_partition.c | 272 +++++++++++++++++++++++++++++++++++ include/hw/ppc/spapr_vof.h | 14 ++ 3 files changed, 290 insertions(+), 1 deletion(-) create mode 100644 hw/ppc/spapr_vof_partition.c create mode 100644 include/hw/ppc/spapr_vof.h diff --git a/hw/ppc/meson.build b/hw/ppc/meson.build index 37aa535db2..68a5d2622f 100644 --- a/hw/ppc/meson.build +++ b/hw/ppc/meson.build @@ -93,6 +93,9 @@ ppc_ss.add(when: 'CONFIG_AMIGAONE', if_true: files('amigaone.c')) ppc_ss.add(when: 'CONFIG_PEGASOS', if_true: files('pegasos.c')) ppc_ss.add(when: 'CONFIG_VOF', if_true: files('vof.c')) -ppc_ss.add(when: ['CONFIG_VOF', 'CONFIG_PSERIES'], if_true: files('spapr_vof.c')) +ppc_ss.add(when: ['CONFIG_VOF', 'CONFIG_PSERIES'], if_true: files( + 'spapr_vof.c', + 'spapr_vof_partition.c', +)) hw_arch += {'ppc': ppc_ss} diff --git a/hw/ppc/spapr_vof_partition.c b/hw/ppc/spapr_vof_partition.c new file mode 100644 index 0000000000..b495a53d9d --- /dev/null +++ b/hw/ppc/spapr_vof_partition.c @@ -0,0 +1,272 @@ +/* + * QEMU PowerPC sPAPR VOF Partition Table Support. + * + * SPDX-License-Identifier: GPL-2.0-or-later + * + * This implements partition table detection for VOF boot, + * supporting MBR and GPT partition tables with focus on PReP boot partition. + */ + +#include "qemu/osdep.h" +#include "qemu/bswap.h" +#include "qemu/error-report.h" +#include "system/block-backend-io.h" +#include "hw/ppc/spapr_vof.h" +#include <zlib.h> + +#define SECTOR_SIZE 512 +#define MBR_PARTITION_ENTRY_SIZE 16 +#define MBR_PARTITION_TABLE_OFFSET 446 +#define MBR_NUM_PARTITIONS 4 + +#define PARTITION_TYPE_PREP 0x41 /* PReP Boot partition */ +#define PARTITION_TYPE_GPT 0xEE + +#define GPT_MAX_PARTITION 128 +#define GPT_SIGNATURE "EFI PART" +#define GPT_SIGNATURE_SIZE 8 + +/* PReP Boot: 9E1A2D38-C612-4316-AA26-8B49521E5A8B */ +static const uint8_t GUID_PREP_BOOT[16] = { + 0x38, 0x2D, 0x1A, 0x9E, 0x12, 0xC6, 0x16, 0x43, + 0xAA, 0x26, 0x8B, 0x49, 0x52, 0x1E, 0x5A, 0x8B +}; + +typedef struct MBRPartitionEntry { + uint8_t boot_flag; + uint8_t start_chs[3]; + uint8_t type; + uint8_t end_chs[3]; + uint32_t start_lba; + uint32_t num_sectors; +} QEMU_PACKED MBRPartitionEntry; + +typedef struct GPTHeader { + char signature[8]; + uint32_t revision; + uint32_t header_size; + uint32_t header_crc32; + uint32_t reserved; + uint64_t current_lba; + uint64_t backup_lba; + uint64_t first_usable_lba; + uint64_t last_usable_lba; + uint8_t disk_guid[16]; + uint64_t partition_entries_lba; + uint32_t num_partition_entries; + uint32_t partition_entry_size; + uint32_t partition_array_crc32; +} QEMU_PACKED GPTHeader; + +typedef struct GPTPartitionEntry { + uint8_t type_guid[16]; + uint8_t partition_guid[16]; + uint64_t first_lba; + uint64_t last_lba; + uint64_t attributes; + uint16_t name[36]; +} QEMU_PACKED GPTPartitionEntry; + +static bool find_prep_partition_gpt(BlockBackend *blk, + uint64_t *offset, uint64_t *size) +{ + uint8_t lba1[SECTOR_SIZE]; + GPTHeader *header; + uint32_t header_size; + GPTHeader header_copy; + uint32_t crc_stored; + uint32_t crc_computed; + uint64_t entries_lba; + uint32_t num_entries; + uint32_t entry_size; + int64_t disk_size; + uint64_t disk_last_lba; + uint32_t array_bytes; + g_autofree uint8_t *array_buf = NULL; + uint8_t buf[sizeof(GPTPartitionEntry)]; + GPTPartitionEntry *current_entry; + uint32_t i; + int ret; + + ret = blk_pread(blk, SECTOR_SIZE, SECTOR_SIZE, lba1, 0); + if (ret < 0) { + warn_report("GPT: failed to read LBA1 (ret=%d)", ret); + return false; + } + + header = (GPTHeader *)lba1; + + /* EFI PART signature validation */ + if (memcmp(header->signature, GPT_SIGNATURE, GPT_SIGNATURE_SIZE) != 0) { + return false; + } + + /* GPT header size validation */ + header_size = le32_to_cpu(header->header_size); + if (header_size < sizeof(GPTHeader) || header_size > SECTOR_SIZE) { + warn_report("GPT: invalid header size %u (expected %zu..%u)", + header_size, sizeof(GPTHeader), SECTOR_SIZE); + return false; + } + + /* CRC32 validation of GPT header */ + header_copy = *header; + header_copy.header_crc32 = 0; + crc_stored = le32_to_cpu(header->header_crc32); + crc_computed = crc32(0, (uint8_t *)&header_copy, header_size); + if (crc_computed != crc_stored) { + warn_report("GPT: header CRC32 mismatch (computed=0x%08x " + "stored=0x%08x)", crc_computed, crc_stored); + return false; + } + + entries_lba = le64_to_cpu(header->partition_entries_lba); + num_entries = le32_to_cpu(header->num_partition_entries); + entry_size = le32_to_cpu(header->partition_entry_size); + + /* + * Usually the PReP is the first partition and most systems commonly have + * 128 max partitions, so cap the scan at 128 + */ + if (num_entries > GPT_MAX_PARTITION) { + warn_report("GPT: num_partition_entries %u exceeds %u, " + "scanning only the first %u partitions", num_entries, + GPT_MAX_PARTITION, GPT_MAX_PARTITION); + num_entries = GPT_MAX_PARTITION; + } + + if (num_entries == 0) { + warn_report("GPT: partition table has no entries"); + return false; + } + + if (entry_size < sizeof(GPTPartitionEntry)) { + warn_report("GPT: partition entry size %u is too small", entry_size); + return false; + } + + disk_size = blk_getlength(blk); + if (disk_size <= 0) { + warn_report("GPT: failed to get disk size"); + return false; + } + disk_last_lba = (uint64_t)disk_size / SECTOR_SIZE - 1; + + if (entries_lba >= UINT64_MAX / SECTOR_SIZE || + entries_lba >= (uint64_t)disk_size / SECTOR_SIZE || + num_entries > ((uint64_t)disk_size - entries_lba * SECTOR_SIZE) + / entry_size) { + warn_report("GPT: partition entry array extends beyond disk"); + return false; + } + + /* CRC32 validation of GPT partition array */ + array_bytes = num_entries * entry_size; + array_buf = g_malloc(array_bytes); + crc_stored = le32_to_cpu(header->partition_array_crc32); + + ret = blk_pread(blk, entries_lba * SECTOR_SIZE, array_bytes, array_buf, 0); + if (ret < 0) { + warn_report("GPT: failed to read partition entry array for CRC " + "(ret=%d)", ret); + return false; + } + crc_computed = crc32(0, array_buf, array_bytes); + if (crc_computed != crc_stored) { + warn_report("GPT: partition array CRC32 mismatch (computed=0x%08x " + "stored=0x%08x)", crc_computed, crc_stored); + return false; + } + + for (i = 0; i < num_entries; i++) { + uint64_t current_entry_offset = entries_lba * SECTOR_SIZE + + (uint64_t)i * entry_size; + ret = blk_pread(blk, current_entry_offset, sizeof(buf), buf, 0); + if (ret < 0) { + warn_report("GPT: failed to read partition entry %u (ret=%d)", + i, ret); + return false; + } + + current_entry = (GPTPartitionEntry *)buf; + if (memcmp(current_entry->type_guid, GUID_PREP_BOOT, + sizeof(GUID_PREP_BOOT)) == 0) { + uint64_t first_lba = le64_to_cpu(current_entry->first_lba); + uint64_t last_lba = le64_to_cpu(current_entry->last_lba); + + if (last_lba < first_lba) { + warn_report("GPT: PReP entry has " + "last_lba (%"PRIu64") < first_lba (%"PRIu64"), " + "skipping", last_lba, first_lba); + continue; + } + if (first_lba > disk_last_lba || last_lba > disk_last_lba) { + warn_report("GPT: PReP entry LBA range [%"PRIu64", %"PRIu64"] " + "exceeds disk (%"PRIu64"), skipping", + first_lba, last_lba, disk_last_lba); + continue; + } + + *offset = first_lba * SECTOR_SIZE; + *size = (last_lba - first_lba + 1) * SECTOR_SIZE; + return true; + } + } + return false; +} + +static bool find_prep_partition_mbr(BlockBackend *blk, + uint64_t *offset, uint64_t *size) +{ + uint8_t mbr[SECTOR_SIZE]; + MBRPartitionEntry *entry; + int ret; + int i; + + ret = blk_pread(blk, 0, SECTOR_SIZE, mbr, 0); + if (ret < 0) { + warn_report("MBR: failed to read MBR sector (ret=%d)", ret); + return false; + } + + /* MBR boot signature: byte 510 = 0x55, byte 511 = 0xAA */ + if (mbr[510] != 0x55 || mbr[511] != 0xAA) { + warn_report("MBR: invalid boot signature (0x%02x 0x%02x), " + "expected 0x55 0xAA", mbr[510], mbr[511]); + return false; + } + + for (i = 0; i < MBR_NUM_PARTITIONS; i++) { + entry = (MBRPartitionEntry *)&mbr[MBR_PARTITION_TABLE_OFFSET + + i * MBR_PARTITION_ENTRY_SIZE]; + + if (entry->type == PARTITION_TYPE_GPT) { + return find_prep_partition_gpt(blk, offset, size); + } + + if (entry->type == PARTITION_TYPE_PREP) { + uint32_t start_lba = le32_to_cpu(entry->start_lba); + uint32_t num_sectors = le32_to_cpu(entry->num_sectors); + + if (start_lba == 0 || num_sectors == 0) { + warn_report("MBR: PReP partition entry %d has invalid " + "start_lba=%u or num_sectors=%u, skipping", + i, start_lba, num_sectors); + continue; + } + *offset = (uint64_t)start_lba * SECTOR_SIZE; + *size = (uint64_t)num_sectors * SECTOR_SIZE; + return true; + } + } + return false; +} + +bool spapr_vof_find_prep_partition(BlockBackend *blk, + uint64_t *offset, uint64_t *size) +{ + if (!blk) { + return false; + } + return find_prep_partition_mbr(blk, offset, size); +} diff --git a/include/hw/ppc/spapr_vof.h b/include/hw/ppc/spapr_vof.h new file mode 100644 index 0000000000..08787d2aeb --- /dev/null +++ b/include/hw/ppc/spapr_vof.h @@ -0,0 +1,14 @@ +/* + * QEMU PowerPC sPAPR VOF Support + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ +#ifndef HW_SPAPR_VOF_H +#define HW_SPAPR_VOF_H + +typedef struct BlockBackend BlockBackend; + +bool spapr_vof_find_prep_partition(BlockBackend *blk, + uint64_t *offset, uint64_t *size); + +#endif /* HW_SPAPR_VOF_H */ -- 2.55.0
