diff options
Diffstat (limited to 'util/cbfstool')
| -rw-r--r-- | util/cbfstool/Makefile.inc | 1 | ||||
| -rw-r--r-- | util/cbfstool/cbfs.h | 5 | ||||
| -rw-r--r-- | util/cbfstool/cbfstool.c | 5 | ||||
| -rw-r--r-- | util/cbfstool/elf.h | 2 | ||||
| -rw-r--r-- | util/cbfstool/platform_fixups.c | 121 |
5 files changed, 134 insertions, 0 deletions
diff --git a/util/cbfstool/Makefile.inc b/util/cbfstool/Makefile.inc index 7a13a793a3..5b49fe80ad 100644 --- a/util/cbfstool/Makefile.inc +++ b/util/cbfstool/Makefile.inc @@ -22,6 +22,7 @@ cbfsobj += elfheaders.o cbfsobj += rmodule.o cbfsobj += xdr.o cbfsobj += partitioned_file.o +cbfsobj += platform_fixups.o # COMMONLIB cbfsobj += cbfs_private.o cbfsobj += fsp_relocate.o diff --git a/util/cbfstool/cbfs.h b/util/cbfstool/cbfs.h index 7f07751a8f..67dc6163f0 100644 --- a/util/cbfstool/cbfs.h +++ b/util/cbfstool/cbfs.h @@ -72,4 +72,9 @@ void xdr_segs(struct buffer *output, void xdr_get_seg(struct cbfs_payload_segment *out, struct cbfs_payload_segment *in); +/* platform_fixups.c */ +typedef int (*platform_fixup_func)(struct buffer *buffer, size_t offset); +platform_fixup_func platform_fixups_probe(struct buffer *buffer, size_t offset, + const char *region_name); + #endif diff --git a/util/cbfstool/cbfstool.c b/util/cbfstool/cbfstool.c index c55838b6a6..16654d96a0 100644 --- a/util/cbfstool/cbfstool.c +++ b/util/cbfstool/cbfstool.c @@ -129,6 +129,7 @@ struct mh_cache { const char *region; size_t offset; struct vb2_hash cbfs_hash; + platform_fixup_func fixup; bool initialized; }; @@ -185,6 +186,8 @@ static struct mh_cache *get_mh_cache(void) } mhc.cbfs_hash = anchor->cbfs_hash; mhc.offset = (void *)anchor - buffer_get(&buffer); + mhc.fixup = platform_fixups_probe(&buffer, mhc.offset, + mhc.region); return &mhc; } @@ -223,6 +226,8 @@ static int update_anchor(struct mh_cache *mhc, uint8_t *fmap_hash) metadata_hash_anchor_fmap_hash(anchor), fmap_hash, vb2_digest_size(anchor->cbfs_hash.algo)); } + if (mhc->fixup && mhc->fixup(&buffer, mhc->offset) != 0) + return -1; if (!partitioned_file_write_region(param.image_file, &buffer)) return -1; return 0; diff --git a/util/cbfstool/elf.h b/util/cbfstool/elf.h index 2549e0431e..e2d0421929 100644 --- a/util/cbfstool/elf.h +++ b/util/cbfstool/elf.h @@ -561,6 +561,8 @@ typedef struct #define PF_W (1 << 1) /* Segment is writable */ #define PF_R (1 << 2) /* Segment is readable */ #define PF_MASKOS 0x0ff00000 /* OS-specific */ +#define PF_QC_SG_MASK 0x07000000 /* Qualcomm "segment" types */ +#define PF_QC_SG_HASH 0x02000000 /* Qualcomm hash segment */ #define PF_MASKPROC 0xf0000000 /* Processor-specific */ /* Legal values for note segment descriptor types for core files. */ diff --git a/util/cbfstool/platform_fixups.c b/util/cbfstool/platform_fixups.c new file mode 100644 index 0000000000..ea2d3161a2 --- /dev/null +++ b/util/cbfstool/platform_fixups.c @@ -0,0 +1,121 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include "cbfs.h" +#include "cbfs_sections.h" +#include "elfparsing.h" + +/* + * NOTE: This currently only implements support for MBN version 6 (as used by sc7180). Support + * for other MBN versions could probably be added but may require more parsing to tell them + * apart, and minor modifications (e.g. different hash algorithm). Add later as needed. + */ +static void *qualcomm_find_hash(struct buffer *in, size_t bb_offset, struct vb2_hash *real_hash) +{ + struct buffer elf; + buffer_clone(&elf, in); + + /* When buffer_size(&elf) becomes this small, we know we've searched through 32KiB (or + the whole bootblock) without finding anything, so we know we can stop looking. */ + size_t search_end_size = MIN(0, buffer_size(in) - 32 * KiB); + + /* To identify a Qualcomm image, first we find the GPT header... */ + while (buffer_size(&elf) > search_end_size && + !buffer_check_magic(&elf, "EFI PART", 8)) + buffer_seek(&elf, 512); + + /* ...then shortly afterwards there's an ELF header... */ + while (buffer_size(&elf) > search_end_size && + !buffer_check_magic(&elf, ELFMAG, 4)) + buffer_seek(&elf, 512); + + if (buffer_size(&elf) <= search_end_size) + return NULL; /* Doesn't seem to be a Qualcomm image. */ + + struct parsed_elf pelf; + if (parse_elf(&elf, &pelf, ELF_PARSE_PHDR)) + return NULL; /* Not an ELF -- guess not a Qualcomm MBN after all? */ + + /* Qualcomm stores an array of SHA-384 hashes in a special ELF segment. One special one + to start with, and then one for each segment in order. */ + void *bb_hash = NULL; + void *hashtable = NULL; + int i; + int bb_segment = -1; + for (i = 0; i < pelf.ehdr.e_phnum; i++) { + Elf64_Phdr *ph = &pelf.phdr[i]; + if ((ph->p_flags & PF_QC_SG_MASK) == PF_QC_SG_HASH) { + if ((int)ph->p_filesz != + (pelf.ehdr.e_phnum + 1) * VB2_SHA384_DIGEST_SIZE) { + ERROR("fixups: Qualcomm hash segment has wrong size!\n"); + goto destroy_elf; + } /* Found the table with the hashes -- store its address. */ + hashtable = buffer_get(&elf) + ph->p_offset; + } else if (bb_segment < 0 && ph->p_offset + ph->p_filesz < buffer_size(&elf) && + buffer_offset(&elf) + ph->p_offset <= bb_offset && + buffer_offset(&elf) + ph->p_offset + ph->p_filesz > bb_offset) { + bb_segment = i; /* Found the bootblock segment -- store its index. */ + } + } + if (!hashtable) /* ELF but no special QC hash segment -- guess not QC after all? */ + goto destroy_elf; + if (bb_segment < 0) { /* Can assume it's QC if we found the special segment. */ + ERROR("fixups: Cannot find bootblock code in Qualcomm MBN!\n"); + goto destroy_elf; + } + + /* Pass out the actual hash of the current bootblock segment in |real_hash|. */ + if (vb2_hash_calculate(buffer_get(&elf) + pelf.phdr[bb_segment].p_offset, + pelf.phdr[bb_segment].p_filesz, VB2_HASH_SHA384, real_hash)) { + ERROR("fixups: vboot digest error\n"); + goto destroy_elf; + } /* Return pointer to where the bootblock hash needs to go in Qualcomm's table. */ + bb_hash = hashtable + (bb_segment + 1) * VB2_SHA384_DIGEST_SIZE; + +destroy_elf: + parsed_elf_destroy(&pelf); + return bb_hash; +} + +static bool qualcomm_probe(struct buffer *buffer, size_t offset) +{ + struct vb2_hash real_hash; + void *table_hash = qualcomm_find_hash(buffer, offset, &real_hash); + if (!table_hash) + return false; + + if (memcmp(real_hash.raw, table_hash, VB2_SHA384_DIGEST_SIZE)) { + ERROR("fixups: Identified Qualcomm MBN, but existing hash doesn't match!\n"); + return false; + } + + return true; +} + +static int qualcomm_fixup(struct buffer *buffer, size_t offset) +{ + struct vb2_hash real_hash; + void *table_hash = qualcomm_find_hash(buffer, offset, &real_hash); + if (!table_hash) { + ERROR("fixups: Cannot find Qualcomm MBN headers anymore!\n"); + return -1; + } + + memcpy(table_hash, real_hash.raw, VB2_SHA384_DIGEST_SIZE); + INFO("fixups: Updated Qualcomm MBN header bootblock hash.\n"); + return 0; +} + +platform_fixup_func platform_fixups_probe(struct buffer *buffer, size_t offset, + const char *region_name) +{ + if (!strcmp(region_name, SECTION_NAME_BOOTBLOCK)) { + if (qualcomm_probe(buffer, offset)) + return qualcomm_fixup; + } else if (!strcmp(region_name, SECTION_NAME_PRIMARY_CBFS)) { + /* TODO: add fixups for primary CBFS bootblock platforms, if needed */ + } else { + ERROR("%s called for unexpected FMAP region %s!\n", __func__, region_name); + } + + return NULL; +} |