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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef __FEC_PRIVATE_H__
     18 #define __FEC_PRIVATE_H__
     19 
     20 #include <errno.h>
     21 #include <fcntl.h>
     22 #include <memory>
     23 #include <new>
     24 #include <pthread.h>
     25 #include <stdio.h>
     26 #include <string>
     27 #include <string.h>
     28 #include <sys/syscall.h>
     29 #include <unistd.h>
     30 #include <vector>
     31 
     32 #include <utils/Compat.h>
     33 #include <mincrypt/rsa.h>
     34 #include <openssl/sha.h>
     35 #include <fec/io.h>
     36 #include <fec/ecc.h>
     37 
     38 /* processing parameters */
     39 #define WORK_MIN_THREADS 1
     40 #define WORK_MAX_THREADS 64
     41 
     42 /* verity parameters */
     43 #define VERITY_CACHE_BLOCKS 4096
     44 #define VERITY_NO_CACHE UINT64_MAX
     45 
     46 /* verity definitions */
     47 #define VERITY_METADATA_SIZE (8 * FEC_BLOCKSIZE)
     48 #define VERITY_TABLE_ARGS 10 /* mandatory arguments */
     49 #define VERITY_MIN_TABLE_SIZE (VERITY_TABLE_ARGS * 2) /* for a sanity check */
     50 #define VERITY_MAX_TABLE_SIZE (VERITY_METADATA_SIZE - sizeof(verity_header))
     51 
     52 /* verity header and metadata */
     53 #define VERITY_MAGIC 0xB001B001
     54 #define VERITY_MAGIC_DISABLE 0x46464F56
     55 #define VERITY_VERSION 0
     56 #define VERITY_TABLE_FIELDS 10
     57 #define VERITY_TABLE_VERSION 1
     58 
     59 struct verity_header {
     60     uint32_t magic;
     61     uint32_t version;
     62     uint8_t signature[RSANUMBYTES];
     63     uint32_t length;
     64 };
     65 
     66 /* file handle */
     67 struct ecc_info {
     68     bool valid;
     69     int roots;
     70     int rsn;
     71     uint32_t size;
     72     uint64_t blocks;
     73     uint64_t rounds;
     74     uint64_t start; /* offset in file */
     75 };
     76 
     77 struct verity_info {
     78     bool disabled;
     79     char *table;
     80     uint32_t hash_data_blocks;
     81     uint32_t hash_size;
     82     uint64_t hash_data_offset;
     83     uint64_t hash_start;
     84     uint8_t *hash;
     85     uint32_t salt_size;
     86     uint8_t *salt;
     87     uint64_t data_blocks;
     88     uint64_t metadata_start; /* offset in file */
     89     uint8_t zero_hash[SHA256_DIGEST_LENGTH];
     90     verity_header header;
     91     verity_header ecc_header;
     92 };
     93 
     94 struct verity_block_info {
     95     uint64_t index;
     96     bool valid;
     97 };
     98 
     99 struct fec_handle {
    100     ecc_info ecc;
    101     int fd;
    102     int flags; /* additional flags passed to fec_open */
    103     int mode; /* mode for open(2) */
    104     pthread_mutex_t mutex;
    105     uint64_t errors;
    106     uint64_t data_size;
    107     uint64_t pos;
    108     uint64_t size;
    109     verity_info verity;
    110 };
    111 
    112 /* I/O helpers */
    113 extern bool raw_pread(fec_handle *f, void *buf, size_t count,
    114         uint64_t offset);
    115 extern bool raw_pwrite(fec_handle *f, const void *buf, size_t count,
    116         uint64_t offset);
    117 
    118 /* processing functions */
    119 typedef ssize_t (*read_func)(fec_handle *f, uint8_t *dest, size_t count,
    120         uint64_t offset, size_t *errors);
    121 
    122 extern ssize_t process(fec_handle *f, uint8_t *buf, size_t count,
    123         uint64_t offset, read_func func);
    124 
    125 /* verity functions */
    126 extern uint64_t verity_get_size(uint64_t file_size, uint32_t *verity_levels,
    127         uint32_t *level_hashes);
    128 
    129 extern int verity_parse_header(fec_handle *f, uint64_t offset);
    130 
    131 extern bool verity_check_block(fec_handle *f, const uint8_t *expected,
    132         const uint8_t *block);
    133 
    134 /* helper macros */
    135 #ifndef unlikely
    136     #define unlikely(x) __builtin_expect(!!(x), 0)
    137     #define likely(x)   __builtin_expect(!!(x), 1)
    138 #endif
    139 
    140 #ifndef stringify
    141     #define __stringify(x) #x
    142     #define stringify(x) __stringify(x)
    143 #endif
    144 
    145 /*  warnings, errors, debug output */
    146 #ifdef FEC_NO_KLOG
    147     #define __log(func, type, format, args...) \
    148         fprintf(stderr, "fec: <%d> " type ": %s: " format "\n", \
    149             (int)syscall(SYS_gettid), __FUNCTION__,  ##args)
    150 #else
    151     #include <cutils/klog.h>
    152 
    153     #define __log(func, type, format, args...) \
    154         KLOG_##func("fec", "<%d> " type ": %s: " format "\n", \
    155             (int)syscall(SYS_gettid), __FUNCTION__, ##args)
    156 #endif
    157 
    158 #ifdef NDEBUG
    159     #define debug(format, args...)
    160 #else
    161     #define debug(format, args...) __log(DEBUG, "debug", format, ##args)
    162 #endif
    163 
    164 #define warn(format, args...) __log(WARNING, "warning", format, ##args)
    165 #define error(format, args...) __log(ERROR, "error", format, ##args)
    166 
    167 #define check(p) \
    168     if (unlikely(!(p))) { \
    169         error("`%s' failed", #p); \
    170         errno = EFAULT; \
    171         return -1; \
    172     }
    173 
    174 #endif /* __FEC_PRIVATE_H__ */
    175