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Support patching DTB/DTBO partition format

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This commit is contained in:
topjohnwu 2019-12-02 04:34:21 -05:00
parent 72edbfc455
commit 8d21988656
3 changed files with 174 additions and 108 deletions
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160
native/jni/magiskboot/dtb.cpp
View File

@ -1,93 +1,20 @@
#include <unistd.h>
#include <sys/mman.h>
#include <bitset>
#include <vector>
#include <map>
extern "C" {
#include <libfdt.h>
}
#include <utils.h>
#include <bitset>
#include <vector>
#include <map>
#include "magiskboot.h"
#include "dtb.h"
using namespace std;
#define DTB_MAGIC "\xd0\x0d\xfe\xed"
#define QCDT_MAGIC "QCDT"
#define DTBH_MAGIC "DTBH"
#define PXADT_MAGIC "PXA-DT"
#define PXA19xx_MAGIC "PXA-19xx"
#define SPRD_MAGIC "SPRD"
struct qcdt_hdr {
char magic[4]; /* "QCDT" */
uint32_t version; /* QCDT version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct qctable_v1 {
uint32_t cpu_info[3]; /* Some CPU info */
uint32_t offset; /* DTB offset in QCDT */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct qctable_v2 {
uint32_t cpu_info[4]; /* Some CPU info */
uint32_t offset; /* DTB offset in QCDT */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct qctable_v3 {
uint32_t cpu_info[8]; /* Some CPU info */
uint32_t offset; /* DTB offset in QCDT */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct dtbh_hdr {
char magic[4]; /* "DTBH" */
uint32_t version; /* DTBH version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct bhtable_v2 {
uint32_t cpu_info[5]; /* Some CPU info */
uint32_t offset; /* DTB offset in DTBH */
uint32_t len; /* DTB size */
uint32_t space; /* 0x00000020 */
} __attribute__((packed));
struct pxadt_hdr {
char magic[6]; /* "PXA-DT" */
uint32_t version; /* PXA-* version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct pxa19xx_hdr {
char magic[8]; /* "PXA-19xx" */
uint32_t version; /* PXA-* version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct pxatable_v1 {
uint32_t cpu_info[2]; /* Some CPU info */
uint32_t offset; /* DTB offset in PXA-* */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct sprd_hdr {
char magic[4]; /* "SPRD" */
uint32_t version; /* SPRD version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct sprdtable_v1 {
uint32_t cpu_info[3]; /* Some CPU info */
uint32_t offset; /* DTB offset in SPRD */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct dtb_blob {
struct fdt_blob {
void *fdt;
uint32_t offset;
uint32_t len;
@ -206,7 +133,7 @@ static void dtb_print(const char *file, bool fstab) {
// Loop through all the dtbs
int dtb_num = 0;
for (int i = 0; i < size; ++i) {
if (memcmp(dtb + i, DTB_MAGIC, 4) == 0) {
if (memcmp(dtb + i, FDT_MAGIC_STR, 4) == 0) {
auto fdt = dtb + i;
if (fstab) {
int node = find_fstab(fdt);
@ -266,19 +193,33 @@ static bool fdt_patch(Iter first, Iter last) {
template <class Table, class Header>
static int dtb_patch(const Header *hdr, const char *in, const char *out) {
map<uint32_t, dtb_blob> dtb_map;
map<uint32_t, fdt_blob> dtb_map;
auto buf = reinterpret_cast<const uint8_t *>(hdr);
auto tables = reinterpret_cast<const Table *>(hdr + 1);
constexpr bool is_dt_table = std::is_same_v<Header, dt_table_header>;
using endian_conv = uint32_t (*)(uint32_t);
endian_conv be_to_le;
endian_conv le_to_be;
if constexpr (is_dt_table) {
be_to_le = fdt32_to_cpu;
le_to_be = cpu_to_fdt32;
} else {
be_to_le = le_to_be = [](uint32_t x) -> auto { return x; };
}
// Collect all dtbs
for (int i = 0; i < hdr->num_dtbs; ++i) {
if (dtb_map.find(tables[i].offset) == dtb_map.end()) {
auto blob = buf + tables[i].offset;
int size = fdt_totalsize(blob);
auto num_dtb = be_to_le(hdr->num_dtbs);
for (int i = 0; i < num_dtb; ++i) {
auto offset = be_to_le(tables[i].offset);
if (dtb_map.count(offset) == 0) {
auto blob = buf + offset;
uint32_t size = fdt_totalsize(blob);
auto fdt = xmalloc(size + 256);
memcpy(fdt, blob, size);
fdt_open_into(fdt, fdt, size + 256);
dtb_map[tables[i].offset] = { fdt, tables[i].offset };
dtb_map[offset] = { fdt, offset };
}
}
if (dtb_map.empty())
@ -292,18 +233,23 @@ static int dtb_patch(const Header *hdr, const char *in, const char *out) {
unlink(in);
int fd = xopen(out, O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0644);
uint32_t total_size = 0;
// Copy headers and tables
xwrite(fd, buf, dtb_map.begin()->first);
total_size += xwrite(fd, buf, dtb_map.begin()->first);
// mmap rw to patch table values retroactively
auto mmap_sz = lseek(fd, 0, SEEK_CUR);
auto addr = (uint8_t *) xmmap(nullptr, mmap_sz, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
// Guess page size using gcd
auto it = dtb_map.begin();
uint32_t page_size = (it++)->first;
for (; it != dtb_map.end(); ++it)
page_size = binary_gcd(page_size, it->first);
// Guess alignment using gcd
uint32_t align = 1;
if constexpr (!is_dt_table) {
auto it = dtb_map.begin();
align = (it++)->first;
for (; it != dtb_map.end(); ++it)
align = binary_gcd(align, it->first);
}
// Write dtbs
for (auto &val : dtb_map) {
@ -311,18 +257,23 @@ static int dtb_patch(const Header *hdr, const char *in, const char *out) {
auto fdt = val.second.fdt;
fdt_pack(fdt);
int size = fdt_totalsize(fdt);
xwrite(fd, fdt, size);
val.second.len = do_align(size, page_size);
write_zero(fd, align_off(lseek(fd, 0, SEEK_CUR), page_size));
total_size += xwrite(fd, fdt, size);
val.second.len = do_align(size, align);
write_zero(fd, align_off(lseek(fd, 0, SEEK_CUR), align));
// total_size += align_off(lseek(fd, 0, SEEK_CUR), align); /* Not needed */
free(fdt);
}
// Patch tables
// Patch headers
if constexpr (is_dt_table) {
auto hdr_rw = reinterpret_cast<Header *>(addr);
hdr_rw->total_size = le_to_be(total_size);
}
auto tables_rw = reinterpret_cast<Table *>(addr + sizeof(Header));
for (int i = 0; i < hdr->num_dtbs; ++i) {
auto &blob = dtb_map[tables_rw[i].offset];
tables_rw[i].offset = blob.offset;
tables_rw[i].len = blob.len;
for (int i = 0; i < num_dtb; ++i) {
auto &blob = dtb_map[be_to_le(tables_rw[i].offset)];
tables_rw[i].offset = le_to_be(blob.offset);
tables_rw[i].len = le_to_be(blob.len);
}
munmap(addr, mmap_sz);
@ -393,10 +344,19 @@ static int dtb_patch(const char *in, const char *out) {
default:
return 1;
}
} else if (MATCH(DT_TABLE_MAGIC)) {
auto hdr = reinterpret_cast<dt_table_header *>(dtb);
switch (hdr->version) {
case 0:
fprintf(stderr, "DT_TABLE v0\n");
return dtb_patch<dt_table_entry>(hdr, in, out);
default:
return 1;
}
} else {
vector<uint8_t *> fdt_list;
for (int i = 0; i < dtb_sz; ++i) {
if (memcmp(dtb + i, DTB_MAGIC, 4) == 0) {
if (memcmp(dtb + i, FDT_MAGIC_STR, 4) == 0) {
int len = fdt_totalsize(dtb + i);
auto fdt = static_cast<uint8_t *>(xmalloc(len + 256));
memcpy(fdt, dtb + i, len);

104
native/jni/magiskboot/dtb.h Normal file
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@ -0,0 +1,104 @@
#pragma once
#include <stdint.h>
#define FDT_MAGIC_STR "\xd0\x0d\xfe\xed"
#define DT_TABLE_MAGIC "\xd7\xb7\xab\x1e"
#define QCDT_MAGIC "QCDT"
#define DTBH_MAGIC "DTBH"
#define PXADT_MAGIC "PXA-DT"
#define PXA19xx_MAGIC "PXA-19xx"
#define SPRD_MAGIC "SPRD"
struct qcdt_hdr {
char magic[4]; /* "QCDT" */
uint32_t version; /* QCDT version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct qctable_v1 {
uint32_t cpu_info[3]; /* Some CPU info */
uint32_t offset; /* DTB offset in QCDT */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct qctable_v2 {
uint32_t cpu_info[4]; /* Some CPU info */
uint32_t offset; /* DTB offset in QCDT */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct qctable_v3 {
uint32_t cpu_info[8]; /* Some CPU info */
uint32_t offset; /* DTB offset in QCDT */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct dtbh_hdr {
char magic[4]; /* "DTBH" */
uint32_t version; /* DTBH version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct bhtable_v2 {
uint32_t cpu_info[5]; /* Some CPU info */
uint32_t offset; /* DTB offset in DTBH */
uint32_t len; /* DTB size */
uint32_t space; /* 0x00000020 */
} __attribute__((packed));
struct pxadt_hdr {
char magic[6]; /* "PXA-DT" */
uint32_t version; /* PXA-* version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct pxa19xx_hdr {
char magic[8]; /* "PXA-19xx" */
uint32_t version; /* PXA-* version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct pxatable_v1 {
uint32_t cpu_info[2]; /* Some CPU info */
uint32_t offset; /* DTB offset in PXA-* */
uint32_t len; /* DTB size */
} __attribute__((packed));
struct sprd_hdr {
char magic[4]; /* "SPRD" */
uint32_t version; /* SPRD version */
uint32_t num_dtbs; /* Number of DTBs */
} __attribute__((packed));
struct sprdtable_v1 {
uint32_t cpu_info[3]; /* Some CPU info */
uint32_t offset; /* DTB offset in SPRD */
uint32_t len; /* DTB size */
} __attribute__((packed));
/* AOSP DTB/DTBO partition layout */
struct dt_table_header {
uint32_t magic; /* DT_TABLE_MAGIC */
uint32_t total_size; /* includes dt_table_header + all dt_table_entry */
uint32_t header_size; /* sizeof(dt_table_header) */
uint32_t dt_entry_size; /* sizeof(dt_table_entry) */
uint32_t num_dtbs; /* number of dt_table_entry */
uint32_t dt_entries_offset; /* offset to the first dt_table_entry */
uint32_t page_size; /* flash page size we assume */
uint32_t version; /* DTBO image version */
} __attribute__((packed));
struct dt_table_entry {
uint32_t len; /* DTB size */
uint32_t offset;
uint32_t id;
uint32_t rev;
uint32_t flags;
uint32_t custom[3];
} __attribute__((packed));

18
native/jni/magiskboot/pattern.cpp
View File

@ -16,13 +16,14 @@ static int check_verity_pattern(const char *s) {
return -1;
if (s[skip] == '=') {
while (s[skip] != '\0' && s[skip] != ' ' && s[skip] != '\n' && s[skip] != ',') ++skip;
while (s[skip] != '\0' && s[skip] != ' ' && s[skip] != '\n' && s[skip] != ',')
++skip;
}
return skip;
}
static int check_encryption_pattern(const char *s) {
static const char *encrypt_list[] = { "forceencrypt", "forcefdeorfbe" };
constexpr const char *encrypt_list[] = { "forceencrypt", "forcefdeorfbe" };
for (auto enc : encrypt_list) {
int len = strlen(enc);
if (strncmp(s, enc, len) == 0)
@ -33,26 +34,27 @@ static int check_encryption_pattern(const char *s) {
char *patch_verity(const void *buf, uint32_t &size, bool inplace) {
auto src = static_cast<const char *>(buf);
auto dest = (char *)(inplace ? buf : xmalloc(size));
int src_size = size;
bool found = false;
auto patched = (char *)(inplace ? buf : xmalloc(size));
int write = 0;
for (int read = 0; read < src_size; ++read, ++write) {
for (int read = 0; read < src_size;) {
if (int skip; (skip = check_verity_pattern(src + read)) > 0) {
fprintf(stderr, "Found pattern [%.*s]\n", skip, src + read);
size -= skip;
read += skip;
found = true;
} else {
dest[write++] = src[read++];
}
patched[write] = src[read];
}
patched[write] = '\0';
dest[write] = '\0';
if (!found) {
if (!inplace)
free(patched);
free(dest);
return nullptr;
}
return patched;
return dest;
}
void patch_encryption(void *buf, uint32_t &size) {