diff options
Diffstat (limited to 'libarchive/archive_read_support_format_rar5.c')
| -rw-r--r-- | libarchive/archive_read_support_format_rar5.c | 3452 |
1 files changed, 3452 insertions, 0 deletions
diff --git a/libarchive/archive_read_support_format_rar5.c b/libarchive/archive_read_support_format_rar5.c new file mode 100644 index 00000000..d891ff94 --- /dev/null +++ b/libarchive/archive_read_support_format_rar5.c @@ -0,0 +1,3452 @@ +/*- +* Copyright (c) 2018 Grzegorz Antoniak (http://antoniak.org) +* All rights reserved. +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* 1. Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* 2. Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in the +* documentation and/or other materials provided with the distribution. +* +* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR +* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +#include "archive_platform.h" + +#ifdef HAVE_ERRNO_H +#include <errno.h> +#endif +#include <time.h> +#ifdef HAVE_ZLIB_H +#include <zlib.h> /* crc32 */ +#endif + +#include "archive.h" +#ifndef HAVE_ZLIB_H +#include "archive_crc32.h" +#endif + +#include "archive_entry.h" +#include "archive_entry_locale.h" +#include "archive_ppmd7_private.h" +#include "archive_entry_private.h" +#include "archive_blake2.h" + +/*#define CHECK_CRC_ON_SOLID_SKIP*/ +/*#define DONT_FAIL_ON_CRC_ERROR*/ +/*#define DEBUG*/ + +#define rar5_min(a, b) (((a) > (b)) ? (b) : (a)) +#define rar5_max(a, b) (((a) > (b)) ? (a) : (b)) +#define rar5_countof(X) ((const ssize_t) (sizeof(X) / sizeof(*X))) + +#if defined DEBUG +#define DEBUG_CODE if(1) +#else +#define DEBUG_CODE if(0) +#endif + +/* Real RAR5 magic number is: + * + * 0x52, 0x61, 0x72, 0x21, 0x1a, 0x07, 0x01, 0x00 + * "Rar!→•☺·\x00" + * + * It's stored in `rar5_signature` after XOR'ing it with 0xA1, because I don't + * want to put this magic sequence in each binary that uses libarchive, so + * applications that scan through the file for this marker won't trigger on + * this "false" one. + * + * The array itself is decrypted in `rar5_init` function. */ + +unsigned char rar5_signature[] = { 243, 192, 211, 128, 187, 166, 160, 161 }; +const ssize_t rar5_signature_size = sizeof(rar5_signature); +const size_t g_unpack_buf_chunk_size = 1024; +const size_t g_unpack_window_size = 0x20000; + +struct file_header { + ssize_t bytes_remaining; + ssize_t unpacked_size; + int64_t last_offset; /* Used in sanity checks. */ + int64_t last_size; /* Used in sanity checks. */ + + uint8_t solid : 1; /* Is this a solid stream? */ + uint8_t service : 1; /* Is this file a service data? */ + + /* Optional time fields. */ + uint64_t e_mtime; + uint64_t e_ctime; + uint64_t e_atime; + uint32_t e_unix_ns; + + /* Optional hash fields. */ + uint32_t stored_crc32; + uint32_t calculated_crc32; + uint8_t blake2sp[32]; + blake2sp_state b2state; + char has_blake2; +}; + +enum FILTER_TYPE { + FILTER_DELTA = 0, /* Generic pattern. */ + FILTER_E8 = 1, /* Intel x86 code. */ + FILTER_E8E9 = 2, /* Intel x86 code. */ + FILTER_ARM = 3, /* ARM code. */ + FILTER_AUDIO = 4, /* Audio filter, not used in RARv5. */ + FILTER_RGB = 5, /* Color palette, not used in RARv5. */ + FILTER_ITANIUM = 6, /* Intel's Itanium, not used in RARv5. */ + FILTER_PPM = 7, /* Predictive pattern matching, not used in RARv5. */ + FILTER_NONE = 8, +}; + +struct filter_info { + int type; + int channels; + int pos_r; + + int64_t block_start; + ssize_t block_length; + uint16_t width; +}; + +struct data_ready { + char used; + const uint8_t* buf; + size_t size; + int64_t offset; +}; + +struct cdeque { + uint16_t beg_pos; + uint16_t end_pos; + uint16_t cap_mask; + uint16_t size; + size_t* arr; +}; + +struct decode_table { + uint32_t size; + int32_t decode_len[16]; + uint32_t decode_pos[16]; + uint32_t quick_bits; + uint8_t quick_len[1 << 10]; + uint16_t quick_num[1 << 10]; + uint16_t decode_num[306]; +}; + +struct comp_state { + /* Flag used to specify if unpacker needs to reinitialize the uncompression + * context. */ + uint8_t initialized : 1; + + /* Flag used when applying filters. */ + uint8_t all_filters_applied : 1; + + /* Flag used to skip file context reinitialization, used when unpacker is + * skipping through different multivolume archives. */ + uint8_t switch_multivolume : 1; + + /* Flag used to specify if unpacker has processed the whole data block or + * just a part of it. */ + uint8_t block_parsing_finished : 1; + + int notused : 4; + + int flags; /* Uncompression flags. */ + int method; /* Uncompression algorithm method. */ + int version; /* Uncompression algorithm version. */ + ssize_t window_size; /* Size of window_buf. */ + uint8_t* window_buf; /* Circular buffer used during + decompression. */ + uint8_t* filtered_buf; /* Buffer used when applying filters. */ + const uint8_t* block_buf; /* Buffer used when merging blocks. */ + size_t window_mask; /* Convinience field; window_size - 1. */ + int64_t write_ptr; /* This amount of data has been unpacked in + the window buffer. */ + int64_t last_write_ptr; /* This amount of data has been stored in + the output file. */ + int64_t last_unstore_ptr; /* Counter of bytes extracted during + unstoring. This is separate from + last_write_ptr because of how SERVICE + base blocks are handled during skipping + in solid multiarchive archives. */ + int64_t solid_offset; /* Additional offset inside the window + buffer, used in unpacking solid + archives. */ + ssize_t cur_block_size; /* Size of current data block. */ + int last_len; /* Flag used in lzss decompression. */ + + /* Decode tables used during lzss uncompression. */ + +#define HUFF_BC 20 + struct decode_table bd; /* huffman bit lengths */ +#define HUFF_NC 306 + struct decode_table ld; /* literals */ +#define HUFF_DC 64 + struct decode_table dd; /* distances */ +#define HUFF_LDC 16 + struct decode_table ldd; /* lower bits of distances */ +#define HUFF_RC 44 + struct decode_table rd; /* repeating distances */ +#define HUFF_TABLE_SIZE (HUFF_NC + HUFF_DC + HUFF_RC + HUFF_LDC) + + /* Circular deque for storing filters. */ + struct cdeque filters; + int64_t last_block_start; /* Used for sanity checking. */ + ssize_t last_block_length; /* Used for sanity checking. */ + + /* Distance cache used during lzss uncompression. */ + int dist_cache[4]; + + /* Data buffer stack. */ + struct data_ready dready[2]; +}; + +/* Bit reader state. */ +struct bit_reader { + int8_t bit_addr; /* Current bit pointer inside current byte. */ + int in_addr; /* Current byte pointer. */ +}; + +/* RARv5 block header structure. */ +struct compressed_block_header { + union { + struct { + uint8_t bit_size : 3; + uint8_t byte_count : 3; + uint8_t is_last_block : 1; + uint8_t is_table_present : 1; + } block_flags; + uint8_t block_flags_u8; + }; + + uint8_t block_cksum; +}; + +/* RARv5 main header structure. */ +struct main_header { + /* Does the archive contain solid streams? */ + uint8_t solid : 1; + + /* If this a multi-file archive? */ + uint8_t volume : 1; + uint8_t endarc : 1; + uint8_t notused : 5; + + int vol_no; +}; + +struct generic_header { + uint8_t split_after : 1; + uint8_t split_before : 1; + uint8_t padding : 6; + int size; + int last_header_id; +}; + +struct multivolume { + int expected_vol_no; + uint8_t* push_buf; +}; + +/* Main context structure. */ +struct rar5 { + int header_initialized; + + /* Set to 1 if current file is positioned AFTER the magic value + * of the archive file. This is used in header reading functions. */ + int skipped_magic; + + /* Set to not zero if we're in skip mode (either by calling rar5_data_skip + * function or when skipping over solid streams). Set to 0 when in + * extraction mode. This is used during checksum calculation functions. */ + int skip_mode; + + /* An offset to QuickOpen list. This is not supported by this unpacker, + * becuase we're focusing on streaming interface. QuickOpen is designed + * to make things quicker for non-stream interfaces, so it's not our + * use case. */ + uint64_t qlist_offset; + + /* An offset to additional Recovery data. This is not supported by this + * unpacker. Recovery data are additional Reed-Solomon codes that could + * be used to calculate bytes that are missing in archive or are + * corrupted. */ + uint64_t rr_offset; + + /* Various context variables grouped to different structures. */ + struct generic_header generic; + struct main_header main; + struct comp_state cstate; + struct file_header file; + struct bit_reader bits; + struct multivolume vol; + + /* The header of currently processed RARv5 block. Used in main + * decompression logic loop. */ + struct compressed_block_header last_block_hdr; +}; + +/* Forward function declarations. */ + +static int verify_global_checksums(struct archive_read* a); +static int rar5_read_data_skip(struct archive_read *a); +static int push_data_ready(struct archive_read* a, struct rar5* rar, + const uint8_t* buf, size_t size, int64_t offset); + +/* CDE_xxx = Circular Double Ended (Queue) return values. */ +enum CDE_RETURN_VALUES { + CDE_OK, CDE_ALLOC, CDE_PARAM, CDE_OUT_OF_BOUNDS, +}; + +/* Clears the contents of this circular deque. */ +static void cdeque_clear(struct cdeque* d) { + d->size = 0; + d->beg_pos = 0; + d->end_pos = 0; +} + +/* Creates a new circular deque object. Capacity must be power of 2: 8, 16, 32, + * 64, 256, etc. When the user will add another item above current capacity, + * the circular deque will overwrite the oldest entry. */ +static int cdeque_init(struct cdeque* d, int max_capacity_power_of_2) { + if(d == NULL || max_capacity_power_of_2 == 0) + return CDE_PARAM; + + d->cap_mask = max_capacity_power_of_2 - 1; + d->arr = NULL; + + if((max_capacity_power_of_2 & d->cap_mask) > 0) + return CDE_PARAM; + + cdeque_clear(d); + d->arr = malloc(sizeof(void*) * max_capacity_power_of_2); + + return d->arr ? CDE_OK : CDE_ALLOC; +} + +/* Return the current size (not capacity) of circular deque `d`. */ +static size_t cdeque_size(struct cdeque* d) { + return d->size; +} + +/* Returns the first element of current circular deque. Note that this function + * doesn't perform any bounds checking. If you need bounds checking, use + * `cdeque_front()` function instead. */ +static void cdeque_front_fast(struct cdeque* d, void** value) { + *value = (void*) d->arr[d->beg_pos]; +} + +/* Returns the first element of current circular deque. This function + * performs bounds checking. */ +static int cdeque_front(struct cdeque* d, void** value) { + if(d->size > 0) { + cdeque_front_fast(d, value); + return CDE_OK; + } else + return CDE_OUT_OF_BOUNDS; +} + +/* Pushes a new element into the end of this circular deque object. If current + * size will exceed capacity, the oldest element will be overwritten. */ +static int cdeque_push_back(struct cdeque* d, void* item) { + if(d == NULL) + return CDE_PARAM; + + if(d->size == d->cap_mask + 1) + return CDE_OUT_OF_BOUNDS; + + d->arr[d->end_pos] = (size_t) item; + d->end_pos = (d->end_pos + 1) & d->cap_mask; + d->size++; + + return CDE_OK; +} + +/* Pops a front element of this circular deque object and returns its value. + * This function doesn't perform any bounds checking. */ +static void cdeque_pop_front_fast(struct cdeque* d, void** value) { + *value = (void*) d->arr[d->beg_pos]; + d->beg_pos = (d->beg_pos + 1) & d->cap_mask; + d->size--; +} + +/* Pops a front element of this cicrular deque object and returns its value. + * This function performs bounds checking. */ +static int cdeque_pop_front(struct cdeque* d, void** value) { + if(!d || !value) + return CDE_PARAM; + + if(d->size == 0) + return CDE_OUT_OF_BOUNDS; + + cdeque_pop_front_fast(d, value); + return CDE_OK; +} + +/* Convinience function to cast filter_info** to void **. */ +static void** cdeque_filter_p(struct filter_info** f) { + return (void**) (size_t) f; +} + +/* Convinience function to cast filter_info* to void *. */ +static void* cdeque_filter(struct filter_info* f) { + return (void**) (size_t) f; +} + +/* Destroys this circular deque object. Dellocates the memory of the collection + * buffer, but doesn't deallocate the memory of any pointer passed to this + * deque as a value. */ +static void cdeque_free(struct cdeque* d) { + if(!d) + return; + + if(!d->arr) + return; + + free(d->arr); + + d->arr = NULL; + d->beg_pos = -1; + d->end_pos = -1; + d->cap_mask = 0; +} + +static inline struct rar5* get_context(struct archive_read* a) { + return (struct rar5*) a->format->data; +} + +// TODO: make sure these functions return a little endian number + +/* Convinience functions used by filter implementations. */ + +static uint32_t read_filter_data(struct rar5* rar, uint32_t offset) { + uint32_t* dptr = (uint32_t*) &rar->cstate.window_buf[offset]; + // TODO: bswap if big endian + return *dptr; +} + +static void write_filter_data(struct rar5* rar, uint32_t offset, + uint32_t value) +{ + uint32_t* dptr = (uint32_t*) &rar->cstate.filtered_buf[offset]; + // TODO: bswap if big endian + *dptr = value; +} + +static void circular_memcpy(uint8_t* dst, uint8_t* window, const int mask, + int64_t start, int64_t end) +{ + if((start & mask) > (end & mask)) { + ssize_t len1 = mask + 1 - (start & mask); + ssize_t len2 = end & mask; + + memcpy(dst, &window[start & mask], len1); + memcpy(dst + len1, window, len2); + } else { + memcpy(dst, &window[start & mask], (size_t) (end - start)); + } +} + +/* Allocates a new filter descriptor and adds it to the filter array. */ +static struct filter_info* add_new_filter(struct rar5* rar) { + struct filter_info* f = + (struct filter_info*) calloc(1, sizeof(struct filter_info)); + + if(!f) { + return NULL; + } + + cdeque_push_back(&rar->cstate.filters, cdeque_filter(f)); + return f; +} + +static int run_delta_filter(struct rar5* rar, struct filter_info* flt) { + int i; + ssize_t dest_pos, src_pos = 0; + + for(i = 0; i < flt->channels; i++) { + uint8_t prev_byte = 0; + for(dest_pos = i; + dest_pos < flt->block_length; + dest_pos += flt->channels) + { + uint8_t byte; + + byte = rar->cstate.window_buf[(rar->cstate.solid_offset + + flt->block_start + src_pos) & rar->cstate.window_mask]; + + prev_byte -= byte; + rar->cstate.filtered_buf[dest_pos] = prev_byte; + src_pos++; + } + } + + return ARCHIVE_OK; +} + +static int run_e8e9_filter(struct rar5* rar, struct filter_info* flt, + int extended) +{ + const uint32_t file_size = 0x1000000; + ssize_t i; + + circular_memcpy(rar->cstate.filtered_buf, + rar->cstate.window_buf, + rar->cstate.window_mask, + rar->cstate.solid_offset + flt->block_start, + rar->cstate.solid_offset + flt->block_start + flt->block_length); + + for(i = 0; i < flt->block_length - 4;) { + uint8_t b = rar->cstate.window_buf[(rar->cstate.solid_offset + + flt->block_start + i++) & rar->cstate.window_mask]; + + /* 0xE8 = x86's call <relative_addr_uint32> (function call) + * 0xE9 = x86's jmp <relative_addr_uint32> (unconditional jump) */ + if(b == 0xE8 || (extended && b == 0xE9)) { + + uint32_t addr; + uint32_t offset = (i + flt->block_start) % file_size; + + addr = read_filter_data(rar, (rar->cstate.solid_offset + + flt->block_start + i) & rar->cstate.window_mask); + + if(addr & 0x80000000) { + if(((addr + offset) & 0x80000000) == 0) { + write_filter_data(rar, i, addr + file_size); + } + } else { + if((addr - file_size) & 0x80000000) { + uint32_t naddr = addr - offset; + write_filter_data(rar, i, naddr); + } + } + + i += 4; + } + } + + return ARCHIVE_OK; +} + +static int run_arm_filter(struct rar5* rar, struct filter_info* flt) { + ssize_t i = 0; + uint32_t offset; + const int mask = rar->cstate.window_mask; + + circular_memcpy(rar->cstate.filtered_buf, + rar->cstate.window_buf, + rar->cstate.window_mask, + rar->cstate.solid_offset + flt->block_start, + rar->cstate.solid_offset + flt->block_start + flt->block_length); + + for(i = 0; i < flt->block_length - 3; i += 4) { + uint8_t* b = &rar->cstate.window_buf[(rar->cstate.solid_offset + + flt->block_start + i) & mask]; + + if(b[3] == 0xEB) { + /* 0xEB = ARM's BL (branch + link) instruction. */ + offset = read_filter_data(rar, (rar->cstate.solid_offset + + flt->block_start + i) & mask) & 0x00ffffff; + + offset -= (uint32_t) ((i + flt->block_start) / 4); + offset = (offset & 0x00ffffff) | 0xeb000000; + write_filter_data(rar, i, offset); + } + } + + return ARCHIVE_OK; +} + +static int run_filter(struct archive_read* a, struct filter_info* flt) { + int ret; + struct rar5* rar = get_context(a); + + if(rar->cstate.filtered_buf) + free(rar->cstate.filtered_buf); + + rar->cstate.filtered_buf = malloc(flt->block_length); + if(!rar->cstate.filtered_buf) { + archive_set_error(&a->archive, ENOMEM, "Can't allocate memory for " + "filter data."); + return ARCHIVE_FATAL; + } + + switch(flt->type) { + case FILTER_DELTA: + ret = run_delta_filter(rar, flt); + break; + + case FILTER_E8: + /* fallthrough */ + case FILTER_E8E9: + ret = run_e8e9_filter(rar, flt, flt->type == FILTER_E8E9); + break; + + case FILTER_ARM: + ret = run_arm_filter(rar, flt); + break; + + default: + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported filter type: 0x%02x", flt->type); + return ARCHIVE_FATAL; + } + + if(ret != ARCHIVE_OK) { + /* Filter has failed. */ + return ret; + } + + if(ARCHIVE_OK != push_data_ready(a, rar, rar->cstate.filtered_buf, + flt->block_length, rar->cstate.last_write_ptr)) + { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Stack overflow when submitting unpacked data"); + + return ARCHIVE_FATAL; + } + + rar->cstate.last_write_ptr += flt->block_length; + return ARCHIVE_OK; +} + +/* The `push_data` function submits the selected data range to the user. + * Next call of `use_data` will use the pointer, size and offset arguments + * that are specified here. These arguments are pushed to the FIFO stack here, + * and popped from the stack by the `use_data` function. */ +static void push_data(struct archive_read* a, struct rar5* rar, + const uint8_t* buf, int64_t idx_begin, int64_t idx_end) +{ + const int wmask = rar->cstate.window_mask; + const ssize_t solid_write_ptr = (rar->cstate.solid_offset + + rar->cstate.last_write_ptr) & wmask; + + idx_begin += rar->cstate.solid_offset; + idx_end += rar->cstate.solid_offset; + + /* Check if our unpacked data is wrapped inside the window circular buffer. + * If it's not wrapped, it can be copied out by using a single memcpy, + * but when it's wrapped, we need to copy the first part with one + * memcpy, and the second part with another memcpy. */ + + if((idx_begin & wmask) > (idx_end & wmask)) { + /* The data is wrapped (begin offset sis bigger than end offset). */ + const ssize_t frag1_size = rar->cstate.window_size - (idx_begin & wmask); + const ssize_t frag2_size = idx_end & wmask; + + /* Copy the first part of the buffer first. */ + push_data_ready(a, rar, buf + solid_write_ptr, frag1_size, + rar->cstate.last_write_ptr); + + /* Copy the second part of the buffer. */ + push_data_ready(a, rar, buf, frag2_size, + rar->cstate.last_write_ptr + frag1_size); + + rar->cstate.last_write_ptr += frag1_size + frag2_size; + } else { + /* Data is not wrapped, so we can just use one call to copy the + * data. */ + push_data_ready(a, rar, + buf + solid_write_ptr, + (idx_end - idx_begin) & wmask, + rar->cstate.last_write_ptr); + + rar->cstate.last_write_ptr += idx_end - idx_begin; + } +} + +/* Convinience function that submits the data to the user. It uses the + * unpack window buffer as a source location. */ +static void push_window_data(struct archive_read* a, struct rar5* rar, + int64_t idx_begin, int64_t idx_end) +{ + push_data(a, rar, rar->cstate.window_buf, idx_begin, idx_end); +} + +static int apply_filters(struct archive_read* a) { + struct filter_info* flt; + struct rar5* rar = get_context(a); + int ret; + + rar->cstate.all_filters_applied = 0; + + /* Get the first filter that can be applied to our data. The data needs to + * be fully unpacked before the filter can be run. */ + if(CDE_OK == + cdeque_front(&rar->cstate.filters, cdeque_filter_p(&flt))) + { + /* Check if our unpacked data fully covers this filter's range. */ + if(rar->cstate.write_ptr > flt->block_start && + rar->cstate.write_ptr >= flt->block_start + flt->block_length) + { + /* Check if we have some data pending to be written right before + * the filter's start offset. */ + if(rar->cstate.last_write_ptr == flt->block_start) { + /* Run the filter specified by descriptor `flt`. */ + ret = run_filter(a, flt); + if(ret != ARCHIVE_OK) { + /* Filter failure, return error. */ + return ret; + } + + /* Filter descriptor won't be needed anymore after it's used, + * so remove it from the filter list and free its memory. */ + (void) cdeque_pop_front(&rar->cstate.filters, + cdeque_filter_p(&flt)); + + free(flt); + } else { + /* We can't run filters yet, dump the memory right before the + * filter. */ + push_window_data(a, rar, rar->cstate.last_write_ptr, + flt->block_start); + } + + /* Return 'filter applied or not needed' state to the caller. */ + return ARCHIVE_RETRY; + } + } + + rar->cstate.all_filters_applied = 1; + return ARCHIVE_OK; +} + +static void dist_cache_push(struct rar5* rar, int value) { + int* q = rar->cstate.dist_cache; + + q[3] = q[2]; + q[2] = q[1]; + q[1] = q[0]; + q[0] = value; +} + +static int dist_cache_touch(struct rar5* rar, int index) { + int* q = rar->cstate.dist_cache; + int i, dist = q[index]; + + for(i = index; i > 0; i--) + q[i] = q[i - 1]; + + q[0] = dist; + return dist; +} + +static void free_filters(struct rar5* rar) { + struct cdeque* d = &rar->cstate.filters; + + /* Free any remaining filters. All filters should be naturally consumed by + * the unpacking function, so remaining filters after unpacking normally + * mean that unpacking wasn't successfull. But still of course we shouldn't + * leak memory in such case. */ + + /* cdeque_size() is a fast operation, so we can use it as a loop + * expression. */ + while(cdeque_size(d) > 0) { + struct filter_info* f = NULL; + + /* Pop_front will also decrease the collection's size. */ + if(CDE_OK == cdeque_pop_front(d, cdeque_filter_p(&f)) && f != NULL) + free(f); + } + + cdeque_clear(d); + + /* Also clear out the variables needed for sanity checking. */ + rar->cstate.last_block_start = 0; + rar->cstate.last_block_length = 0; +} + +static void reset_file_context(struct rar5* rar) { + memset(&rar->file, 0, sizeof(rar->file)); + blake2sp_init(&rar->file.b2state, 32); + + if(rar->main.solid) { + rar->cstate.solid_offset += rar->cstate.write_ptr; + } else { + rar->cstate.solid_offset = 0; + } + + rar->cstate.write_ptr = 0; + rar->cstate.last_write_ptr = 0; + rar->cstate.last_unstore_ptr = 0; + + free_filters(rar); +} + +static inline int get_archive_read(struct archive* a, + struct archive_read** ar) +{ + *ar = (struct archive_read*) a; + archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW, + "archive_read_support_format_rar5"); + + return ARCHIVE_OK; +} + +static int read_ahead(struct archive_read* a, size_t how_many, + const uint8_t** ptr) +{ + if(!ptr) + return 0; + + ssize_t avail = -1; + *ptr = __archive_read_ahead(a, how_many, &avail); + + if(*ptr == NULL) { + return 0; + } + + return 1; +} + +static int consume(struct archive_read* a, int64_t how_many) { + int ret; + + ret = + how_many == __archive_read_consume(a, how_many) + ? ARCHIVE_OK + : ARCHIVE_FATAL; + + return ret; +} + +/** + * Read a RAR5 variable sized numeric value. This value will be stored in + * `pvalue`. The `pvalue_len` argument points to a variable that will receive + * the byte count that was consumed in order to decode the `pvalue` value, plus + * one. + * + * pvalue_len is optional and can be NULL. + * + * NOTE: if `pvalue_len` is NOT NULL, the caller needs to manually consume + * the number of bytes that `pvalue_len` value contains. If the `pvalue_len` + * is NULL, this consuming operation is done automatically. + * + * Returns 1 if *pvalue was successfully read. + * Returns 0 if there was an error. In this case, *pvalue contains an + * invalid value. + */ + +static int read_var(struct archive_read* a, uint64_t* pvalue, + uint64_t* pvalue_len) +{ + uint64_t result = 0; + size_t shift, i; + const uint8_t* p; + uint8_t b; + + /* We will read maximum of 8 bytes. We don't have to handle the situation + * to read the RAR5 variable-sized value stored at the end of the file, + * because such situation will never happen. */ + if(!read_ahead(a, 8, &p)) + return 0; + + for(shift = 0, i = 0; i < 8; i++, shift += 7) { + b = p[i]; + + /* Strip the MSB from the input byte and add the resulting number + * to the `result`. */ + result += (b & 0x7F) << shift; + + /* MSB set to 1 means we need to continue decoding process. MSB set + * to 0 means we're done. + * + * This conditional checks for the second case. */ + if((b & 0x80) == 0) { + if(pvalue) { + *pvalue = result; + } + + /* If the caller has passed the `pvalue_len` pointer, store the + * number of consumed bytes in it and do NOT consume those bytes, + * since the caller has all the information it needs to perform + * the consuming process itself. */ + if(pvalue_len) { + *pvalue_len = 1 + i; + } else { + /* If the caller did not provide the `pvalue_len` pointer, + * it will not have the possibility to advance the file + * pointer, because it will not know how many bytes it needs + * to consume. This is why we handle such situation here + * autmatically. */ + if(ARCHIVE_OK != consume(a, 1 + i)) { + return 0; + } + } + + /* End of decoding process, return success. */ + return 1; + } + } + + /* The decoded value takes the maximum number of 8 bytes. It's a maximum + * number of bytes, so end decoding process here even if the first bit + * of last byte is 1. */ + if(pvalue) { + *pvalue = result; + } + + if(pvalue_len) { + *pvalue_len = 9; + } else { + if(ARCHIVE_OK != consume(a, 9)) { + return 0; + } + } + + return 1; +} + +static int read_var_sized(struct archive_read* a, size_t* pvalue, + size_t* pvalue_len) +{ + uint64_t v; + uint64_t v_size; + + const int ret = pvalue_len + ? read_var(a, &v, &v_size) + : read_var(a, &v, NULL); + + if(ret == 1 && pvalue) { + *pvalue = (size_t) v; + } + + if(pvalue_len) { + /* Possible data truncation should be safe. */ + *pvalue_len = (size_t) v_size; + } + + return ret; +} + +static int read_bits_32(struct rar5* rar, const uint8_t* p, uint32_t* value) { + uint32_t bits = p[rar->bits.in_addr] << 24; + bits |= p[rar->bits.in_addr + 1] << 16; + bits |= p[rar->bits.in_addr + 2] << 8; + bits |= p[rar->bits.in_addr + 3]; + bits <<= rar->bits.bit_addr; + bits |= p[rar->bits.in_addr + 4] >> (8 - rar->bits.bit_addr); + *value = bits; + return ARCHIVE_OK; +} + +static int read_bits_16(struct rar5* rar, const uint8_t* p, uint16_t* value) { + int bits = (int) p[rar->bits.in_addr] << 16; + bits |= (int) p[rar->bits.in_addr + 1] << 8; + bits |= (int) p[rar->bits.in_addr + 2]; + bits >>= (8 - rar->bits.bit_addr); + *value = bits & 0xffff; + return ARCHIVE_OK; +} + +static void skip_bits(struct rar5* rar, int bits) { + const int new_bits = rar->bits.bit_addr + bits; + rar->bits.in_addr += new_bits >> 3; + rar->bits.bit_addr = new_bits & 7; +} + +/* n = up to 16 */ +static int read_consume_bits(struct rar5* rar, const uint8_t* p, int n, + int* value) +{ + uint16_t v; + int ret, num; + + if(n == 0 || n > 16) { + /* This is a programmer error and should never happen in runtime. */ + return ARCHIVE_FATAL; + } + + ret = read_bits_16(rar, p, &v); + if(ret != ARCHIVE_OK) + return ret; + + num = (int) v; + num >>= 16 - n; + + skip_bits(rar, n); + + if(value) + *value = num; + + return ARCHIVE_OK; +} + +static int read_u32(struct archive_read* a, uint32_t* pvalue) { + const uint8_t* p; + if(!read_ahead(a, 4, &p)) + return 0; + + *pvalue = *(const uint32_t*)p; + + return ARCHIVE_OK == consume(a, 4) ? 1 : 0; +} + +static int read_u64(struct archive_read* a, uint64_t* pvalue) { + const uint8_t* p; + if(!read_ahead(a, 8, &p)) + return 0; + + *pvalue = *(const uint64_t*)p; + + return ARCHIVE_OK == consume(a, 8) ? 1 : 0; +} + +static int bid_standard(struct archive_read* a) { + const uint8_t* p; + + if(!read_ahead(a, rar5_signature_size, &p)) + return -1; + + if(!memcmp(rar5_signature, p, rar5_signature_size)) + return 30; + + return -1; +} + +static int rar5_bid(struct archive_read* a, int best_bid) { + int my_bid; + + if(best_bid > 30) + return -1; + + my_bid = bid_standard(a); + if(my_bid > -1) { + return my_bid; + } + + return -1; +} + +static int rar5_options(struct archive_read *a, const char *key, const char *val) { + (void) a; + (void) key; + (void) val; + + /* No options supported in this version. Return the ARCHIVE_WARN code to + * signal the options supervisor that the unpacker didn't handle setting + * this option. */ + + return ARCHIVE_WARN; +} + +static void init_header(struct archive_read* a) { + a->archive.archive_format = ARCHIVE_FORMAT_RAR_V5; + a->archive.archive_format_name = "RAR5"; +} + +enum HEADER_FLAGS { + HFL_EXTRA_DATA = 0x0001, HFL_DATA = 0x0002, HFL_SKIP_IF_UNKNOWN = 0x0004, + HFL_SPLIT_BEFORE = 0x0008, HFL_SPLIT_AFTER = 0x0010, HFL_CHILD = 0x0020, + HFL_INHERITED = 0x0040 +}; + +static int process_main_locator_extra_block(struct archive_read* a, + struct rar5* rar) +{ + uint64_t locator_flags; + + if(!read_var(a, &locator_flags, NULL)) { + return ARCHIVE_EOF; + } + + enum LOCATOR_FLAGS { + QLIST = 0x01, RECOVERY = 0x02, + }; + + if(locator_flags & QLIST) { + if(!read_var(a, &rar->qlist_offset, NULL)) { + return ARCHIVE_EOF; + } + + /* qlist is not used */ + } + + if(locator_flags & RECOVERY) { + if(!read_var(a, &rar->rr_offset, NULL)) { + return ARCHIVE_EOF; + } + + /* rr is not used */ + } + + return ARCHIVE_OK; +} + +static int parse_file_extra_hash(struct archive_read* a, struct rar5* rar, + ssize_t* extra_data_size) +{ + size_t hash_type; + size_t value_len; + + if(!read_var_sized(a, &hash_type, &value_len)) + return ARCHIVE_EOF; + + *extra_data_size -= value_len; + if(ARCHIVE_OK != consume(a, value_len)) { + return ARCHIVE_EOF; + } + + enum HASH_TYPE { + BLAKE2sp = 0x00 + }; + + /* The file uses BLAKE2sp checksum algorithm instead of plain old + * CRC32. */ + if(hash_type == BLAKE2sp) { + const uint8_t* p; + const int hash_size = sizeof(rar->file.blake2sp); + + if(!read_ahead(a, hash_size, &p)) + return ARCHIVE_EOF; + + rar->file.has_blake2 = 1; + memcpy(&rar->file.blake2sp, p, hash_size); + + if(ARCHIVE_OK != consume(a, hash_size)) { + return ARCHIVE_EOF; + } + + *extra_data_size -= hash_size; + } else { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported hash type (0x%02x)", (int) hash_type); + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +static uint64_t time_win_to_unix(uint64_t win_time) { + const size_t ns_in_sec = 10000000; + const uint64_t sec_to_unix = 11644473600LL; + return win_time / ns_in_sec - sec_to_unix; +} + +static int parse_htime_item(struct archive_read* a, char unix_time, + uint64_t* where, ssize_t* extra_data_size) +{ + if(unix_time) { + uint32_t time_val; + if(!read_u32(a, &time_val)) + return ARCHIVE_EOF; + + *extra_data_size -= 4; + *where = (uint64_t) time_val; + } else { + uint64_t windows_time; + if(!read_u64(a, &windows_time)) + return ARCHIVE_EOF; + + *where = time_win_to_unix(windows_time); + *extra_data_size -= 8; + } + + return ARCHIVE_OK; +} + +static int parse_file_extra_htime(struct archive_read* a, + struct archive_entry* e, struct rar5* rar, + ssize_t* extra_data_size) +{ + char unix_time = 0; + size_t flags; + size_t value_len; + + enum HTIME_FLAGS { + IS_UNIX = 0x01, + HAS_MTIME = 0x02, + HAS_CTIME = 0x04, + HAS_ATIME = 0x08, + HAS_UNIX_NS = 0x10, + }; + + if(!read_var_sized(a, &flags, &value_len)) + return ARCHIVE_EOF; + + *extra_data_size -= value_len; + if(ARCHIVE_OK != consume(a, value_len)) { + return ARCHIVE_EOF; + } + + unix_time = flags & IS_UNIX; + + if(flags & HAS_MTIME) { + parse_htime_item(a, unix_time, &rar->file.e_mtime, extra_data_size); + archive_entry_set_mtime(e, rar->file.e_mtime, 0); + } + + if(flags & HAS_CTIME) { + parse_htime_item(a, unix_time, &rar->file.e_ctime, extra_data_size); + archive_entry_set_ctime(e, rar->file.e_ctime, 0); + } + + if(flags & HAS_ATIME) { + parse_htime_item(a, unix_time, &rar->file.e_atime, extra_data_size); + archive_entry_set_atime(e, rar->file.e_atime, 0); + } + + if(flags & HAS_UNIX_NS) { + if(!read_u32(a, &rar->file.e_unix_ns)) + return ARCHIVE_EOF; + + *extra_data_size -= 4; + } + + return ARCHIVE_OK; +} + +static int process_head_file_extra(struct archive_read* a, + struct archive_entry* e, struct rar5* rar, + ssize_t extra_data_size) +{ + size_t extra_field_size; + size_t extra_field_id; + int ret = ARCHIVE_FATAL; + size_t var_size; + + enum EXTRA { + CRYPT = 0x01, HASH = 0x02, HTIME = 0x03, VERSION_ = 0x04, + REDIR = 0x05, UOWNER = 0x06, SUBDATA = 0x07 + }; + + while(extra_data_size > 0) { + if(!read_var_sized(a, &extra_field_size, &var_size)) + return ARCHIVE_EOF; + + extra_data_size -= var_size; + if(ARCHIVE_OK != consume(a, var_size)) { + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &extra_field_id, &var_size)) + return ARCHIVE_EOF; + + extra_data_size -= var_size; + if(ARCHIVE_OK != consume(a, var_size)) { + return ARCHIVE_EOF; + } + + switch(extra_field_id) { + case HASH: + ret = parse_file_extra_hash(a, rar, &extra_data_size); + break; + case HTIME: + ret = parse_file_extra_htime(a, e, rar, &extra_data_size); + break; + case CRYPT: + /* fallthrough */ + case VERSION_: + /* fallthrough */ + case REDIR: + /* fallthrough */ + case UOWNER: + /* fallthrough */ + case SUBDATA: + /* fallthrough */ + default: + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unknown extra field in file/service block: 0x%02x", + (int) extra_field_id); + return ARCHIVE_FATAL; + } + } + + if(ret != ARCHIVE_OK) { + /* Attribute not implemented. */ + return ret; + } + + return ARCHIVE_OK; +} + +static int process_head_file(struct archive_read* a, struct rar5* rar, + struct archive_entry* entry, size_t block_flags) +{ + ssize_t extra_data_size = 0; + size_t data_size, file_flags, file_attr, compression_info, host_os, + name_size; + uint64_t unpacked_size; + uint32_t mtime = 0, crc; + int c_method = 0, c_version = 0, is_dir; + char name_utf8_buf[2048 * 4]; + const uint8_t* p; + + memset(entry, 0, sizeof(struct archive_entry)); + + /* Do not reset file context if we're switching archives. */ + if(!rar->cstate.switch_multivolume) { + reset_file_context(rar); + } + + if(block_flags & HFL_EXTRA_DATA) { + size_t edata_size; + if(!read_var_sized(a, &edata_size, NULL)) + return ARCHIVE_EOF; + + /* Intentional type cast from unsigned to signed. */ + extra_data_size = (ssize_t) edata_size; + } + + if(block_flags & HFL_DATA) { + if(!read_var_sized(a, &data_size, NULL)) + return ARCHIVE_EOF; + + rar->file.bytes_remaining = data_size; + } else { + rar->file.bytes_remaining = 0; + + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "no data found in file/service block"); + return ARCHIVE_FATAL; + } + + enum FILE_FLAGS { + DIRECTORY = 0x0001, UTIME = 0x0002, CRC32 = 0x0004, + UNKNOWN_UNPACKED_SIZE = 0x0008, + }; + + enum COMP_INFO_FLAGS { + SOLID = 0x0040, + }; + + if(!read_var_sized(a, &file_flags, NULL)) + return ARCHIVE_EOF; + + if(!read_var(a, &unpacked_size, NULL)) + return ARCHIVE_EOF; + + if(file_flags & UNKNOWN_UNPACKED_SIZE) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Files with unknown unpacked size are not supported"); + return ARCHIVE_FATAL; + } + + is_dir = (int) (file_flags & DIRECTORY); + + if(!read_var_sized(a, &file_attr, NULL)) + return ARCHIVE_EOF; + + if(file_flags & UTIME) { + if(!read_u32(a, &mtime)) + return ARCHIVE_EOF; + } + + if(file_flags & CRC32) { + if(!read_u32(a, &crc)) + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &compression_info, NULL)) + return ARCHIVE_EOF; + + c_method = (int) (compression_info >> 7) & 0x7; + c_version = (int) (compression_info & 0x3f); + + rar->cstate.window_size = is_dir ? + 0 : + g_unpack_window_size << ((compression_info >> 10) & 15); + rar->cstate.method = c_method; + rar->cstate.version = c_version + 50; + + rar->file.solid = (compression_info & SOLID) > 0; + rar->file.service = 0; + + if(!read_var_sized(a, &host_os, NULL)) + return ARCHIVE_EOF; + + enum HOST_OS { + HOST_WINDOWS = 0, + HOST_UNIX = 1, + }; + + if(host_os == HOST_WINDOWS) { + /* Host OS is Windows */ + + unsigned short mode = 0660; + + if(is_dir) + mode |= AE_IFDIR; + else + mode |= AE_IFREG; + + archive_entry_set_mode(entry, mode); + } else if(host_os == HOST_UNIX) { + /* Host OS is Unix */ + archive_entry_set_mode(entry, (unsigned short) file_attr); + } else { + /* Unknown host OS */ + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported Host OS: 0x%02x", (int) host_os); + + return ARCHIVE_FATAL; + } + + if(!read_var_sized(a, &name_size, NULL)) + return ARCHIVE_EOF; + + if(!read_ahead(a, name_size, &p)) + return ARCHIVE_EOF; + + if(name_size > 2047) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Filename is too long"); + + return ARCHIVE_FATAL; + } + + if(name_size == 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "No filename specified"); + + return ARCHIVE_FATAL; + } + + memcpy(name_utf8_buf, p, name_size); + name_utf8_buf[name_size] = 0; + if(ARCHIVE_OK != consume(a, name_size)) { + return ARCHIVE_EOF; + } + + if(extra_data_size > 0) { + int ret = process_head_file_extra(a, entry, rar, extra_data_size); + + /* Sanity check. */ + if(extra_data_size < 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "File extra data size is not zero"); + return ARCHIVE_FATAL; + } + + if(ret != ARCHIVE_OK) + return ret; + } + + if((file_flags & UNKNOWN_UNPACKED_SIZE) == 0) { + rar->file.unpacked_size = (ssize_t) unpacked_size; + archive_entry_set_size(entry, unpacked_size); + } + + if(file_flags & UTIME) { + archive_entry_set_mtime(entry, (time_t) mtime, 0); + } + + if(file_flags & CRC32) { + rar->file.stored_crc32 = crc; + } + + archive_entry_update_pathname_utf8(entry, name_utf8_buf); + + if(!rar->cstate.switch_multivolume) { + /* Do not reinitialize unpacking state if we're switching archives. */ + rar->cstate.block_parsing_finished = 1; + rar->cstate.all_filters_applied = 1; + rar->cstate.initialized = 0; + } + + if(rar->generic.split_before > 0) { + /* If now we're standing on a header that has a 'split before' mark, + * it means we're standing on a 'continuation' file header. Signal + * the caller that if it wants to move to another file, it must call + * rar5_read_header() function again. */ + + return ARCHIVE_RETRY; + } else { + return ARCHIVE_OK; + } +} + +static int process_head_service(struct archive_read* a, struct rar5* rar, + struct archive_entry* entry, size_t block_flags) +{ + /* Process this SERVICE block the same way as FILE blocks. */ + int ret = process_head_file(a, rar, entry, block_flags); + if(ret != ARCHIVE_OK) + return ret; + + rar->file.service = 1; + + /* But skip the data part automatically. It's no use for the user anyway. + * It contains only service data, not even needed to properly unpack the + * file. */ + ret = rar5_read_data_skip(a); + if(ret != ARCHIVE_OK) + return ret; + + /* After skipping, try parsing another block automatically. */ + return ARCHIVE_RETRY; +} + +static int process_head_main(struct archive_read* a, struct rar5* rar, + struct archive_entry* entry, size_t block_flags) +{ + (void) entry; + + int ret; + size_t extra_data_size, + extra_field_size, + extra_field_id, + archive_flags; + + if(block_flags & HFL_EXTRA_DATA) { + if(!read_var_sized(a, &extra_data_size, NULL)) + return ARCHIVE_EOF; + } else { + extra_data_size = 0; + } + + if(!read_var_sized(a, &archive_flags, NULL)) { + return ARCHIVE_EOF; + } + + enum MAIN_FLAGS { + VOLUME = 0x0001, /* multi-volume archive */ + VOLUME_NUMBER = 0x0002, /* volume number, first vol doesnt have it */ + SOLID = 0x0004, /* solid archive */ + PROTECT = 0x0008, /* contains Recovery info */ + LOCK = 0x0010, /* readonly flag, not used */ + }; + + rar->main.volume = (archive_flags & VOLUME) > 0; + rar->main.solid = (archive_flags & SOLID) > 0; + + if(archive_flags & VOLUME_NUMBER) { + size_t v; + if(!read_var_sized(a, &v, NULL)) { + return ARCHIVE_EOF; + } + + rar->main.vol_no = (int) v; + } else { + rar->main.vol_no = 0; + } + + if(rar->vol.expected_vol_no > 0 && + rar->main.vol_no != rar->vol.expected_vol_no) + { + /* Returning EOF instead of FATAL because of strange libarchive + * behavior. When opening multiple files via + * archive_read_open_filenames(), after reading up the whole last file, + * the __archive_read_ahead function wraps up to the first archive + * instead of returning EOF. */ + return ARCHIVE_EOF; + } + + if(extra_data_size == 0) { + /* Early return. */ + return ARCHIVE_OK; + } + + if(!read_var_sized(a, &extra_field_size, NULL)) { + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &extra_field_id, NULL)) { + return ARCHIVE_EOF; + } + + if(extra_field_size == 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Invalid extra field size"); + return ARCHIVE_FATAL; + } + + enum MAIN_EXTRA { + // Just one attribute here. + LOCATOR = 0x01, + }; + + switch(extra_field_id) { + case LOCATOR: + ret = process_main_locator_extra_block(a, rar); + if(ret != ARCHIVE_OK) { + /* Error while parsing main locator extra block. */ + return ret; + } + + break; + default: + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported extra type (0x%02x)", (int) extra_field_id); + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +static int scan_for_signature(struct archive_read* a); + +/* Base block processing function. A 'base block' is a RARv5 header block + * that tells the reader what kind of data is stored inside the block. + * + * From the birds-eye view a RAR file looks file this: + * + * <magic><base_block_1><base_block_2>...<base_block_n> + * + * There are a few types of base blocks. Those types are specified inside + * the 'switch' statement in this function. For example purposes, I'll write + * how a standard RARv5 file could look like here: + * + * <magic><MAIN><FILE><FILE><FILE><SERVICE><ENDARC> + * + * The structure above could describe an archive file with 3 files in it, + * one service "QuickOpen" block (that is ignored by this parser), and an + * end of file base block marker. + * + * If the file is stored in multiple archive files ("multiarchive"), it might + * look like this: + * + * .part01.rar: <magic><MAIN><FILE><ENDARC> + * .part02.rar: <magic><MAIN><FILE><ENDARC> + * .part03.rar: <magic><MAIN><FILE><ENDARC> + * + * This example could describe 3 RAR files that contain ONE archived file. + * Or it could describe 3 RAR files that contain 3 different files. Or 3 + * RAR files than contain 2 files. It all depends what metadata is stored in + * the headers of <FILE> blocks. + * + * Each <FILE> block contains info about its size, the name of the file it's + * storing inside, and whether this FILE block is a continuation block of + * previous archive ('split before'), and is this FILE block should be + * continued in another archive ('split after'). By parsing the 'split before' + * and 'split after' flags, we're able to tell if multiple <FILE> base blocks + * are describing one file, or multiple files (with the same filename, for + * example). + * + * One thing to note is that if we're parsing the first <FILE> block, and + * we see 'split after' flag, then we need to jump over to another <FILE> + * block to be able to decompress rest of the data. To do this, we need + * to skip the <ENDARC> block, then switch to another file, then skip the + * <magic> block, <MAIN> block, and then we're standing on the proper + * <FILE> block. + */ + +static int process_base_block(struct archive_read* a, + struct archive_entry* entry) +{ + struct rar5* rar = get_context(a); + uint32_t hdr_crc, computed_crc; + size_t raw_hdr_size, hdr_size_len, hdr_size; + size_t header_id, header_flags; + const uint8_t* p; + int ret; + + /* Skip any unprocessed data for this file. */ + if(rar->file.bytes_remaining) { + ret = rar5_read_data_skip(a); + if(ret != ARCHIVE_OK) { + return ret; + } + } + + /* Read the expected CRC32 checksum. */ + if(!read_u32(a, &hdr_crc)) { + return ARCHIVE_EOF; + } + + /* Read header size. */ + if(!read_var_sized(a, &raw_hdr_size, &hdr_size_len)) { + return ARCHIVE_EOF; + } + + /* Sanity check, maximum header size for RAR5 is 2MB. */ + if(raw_hdr_size > (2 * 1024 * 1024)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Base block header is too large"); + + return ARCHIVE_FATAL; + } + + hdr_size = raw_hdr_size + hdr_size_len; + + /* Read the whole header data into memory, maximum memory use here is + * 2MB. */ + if(!read_ahead(a, hdr_size, &p)) { + return ARCHIVE_EOF; + } + + /* Verify the CRC32 of the header data. */ + computed_crc = (uint32_t) crc32(0, p, (int) hdr_size); + if(computed_crc != hdr_crc) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Header CRC error"); + + return ARCHIVE_FATAL; + } + + /* If the checksum is OK, we proceed with parsing. */ + if(ARCHIVE_OK != consume(a, hdr_size_len)) { + return ARCHIVE_EOF; + } + + if(!read_var_sized(a, &header_id, NULL)) + return ARCHIVE_EOF; + + if(!read_var_sized(a, &header_flags, NULL)) + return ARCHIVE_EOF; + + rar->generic.split_after = (header_flags & HFL_SPLIT_AFTER) > 0; + rar->generic.split_before = (header_flags & HFL_SPLIT_BEFORE) > 0; + rar->generic.size = hdr_size; + rar->generic.last_header_id = header_id; + rar->main.endarc = 0; + + /* Those are possible header ids in RARv5. */ + enum HEADER_TYPE { + HEAD_MARK = 0x00, HEAD_MAIN = 0x01, HEAD_FILE = 0x02, + HEAD_SERVICE = 0x03, HEAD_CRYPT = 0x04, HEAD_ENDARC = 0x05, + HEAD_UNKNOWN = 0xff, + }; + + switch(header_id) { + case HEAD_MAIN: + ret = process_head_main(a, rar, entry, header_flags); + + /* Main header doesn't have any files in it, so it's pointless + * to return to the caller. Retry to next header, which should be + * HEAD_FILE/HEAD_SERVICE. */ + if(ret == ARCHIVE_OK) + return ARCHIVE_RETRY; + + return ret; + case HEAD_SERVICE: + ret = process_head_service(a, rar, entry, header_flags); + return ret; + case HEAD_FILE: + ret = process_head_file(a, rar, entry, header_flags); + return ret; + case HEAD_CRYPT: + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Encryption is not supported"); + return ARCHIVE_FATAL; + case HEAD_ENDARC: + rar->main.endarc = 1; + + /* After encountering an end of file marker, we need to take + * into consideration if this archive is continued in another + * file (i.e. is it part01.rar: is there a part02.rar?) */ + if(rar->main.volume) { + /* In case there is part02.rar, position the read pointer + * in a proper place, so we can resume parsing. */ + + ret = scan_for_signature(a); + if(ret == ARCHIVE_FATAL) { + return ARCHIVE_EOF; + } else { + rar->vol.expected_vol_no = rar->main.vol_no + 1; + return ARCHIVE_OK; + } + } else { + return ARCHIVE_EOF; + } + case HEAD_MARK: + return ARCHIVE_EOF; + default: + if((header_flags & HFL_SKIP_IF_UNKNOWN) == 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Header type error"); + return ARCHIVE_FATAL; + } else { + /* If the block is marked as 'skip if unknown', do as the flag + * says: skip the block instead on failing on it. */ + return ARCHIVE_RETRY; + } + } + +#if !defined WIN32 + // Not reached. + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Internal unpacker error"); + return ARCHIVE_FATAL; +#endif +} + +static int skip_base_block(struct archive_read* a) { + int ret; + struct rar5* rar = get_context(a); + + struct archive_entry entry; + ret = process_base_block(a, &entry); + + if(rar->generic.last_header_id == 2 && rar->generic.split_before > 0) + return ARCHIVE_OK; + + if(ret == ARCHIVE_OK) + return ARCHIVE_RETRY; + else + return ret; +} + +static int rar5_read_header(struct archive_read *a, + struct archive_entry *entry) +{ + struct rar5* rar = get_context(a); + int ret; + + if(rar->header_initialized == 0) { + init_header(a); + rar->header_initialized = 1; + } + + if(rar->skipped_magic == 0) { + if(ARCHIVE_OK != consume(a, rar5_signature_size)) { + return ARCHIVE_EOF; + } + + rar->skipped_magic = 1; + } + + do { + ret = process_base_block(a, entry); + } while(ret == ARCHIVE_RETRY || + (rar->main.endarc > 0 && ret == ARCHIVE_OK)); + + return ret; +} + +static void init_unpack(struct rar5* rar) { + rar->file.calculated_crc32 = 0; + rar->cstate.window_mask = rar->cstate.window_size - 1; + + if(rar->cstate.window_buf) + free(rar->cstate.window_buf); + + if(rar->cstate.filtered_buf) + free(rar->cstate.filtered_buf); + + rar->cstate.window_buf = calloc(1, rar->cstate.window_size); + rar->cstate.filtered_buf = calloc(1, rar->cstate.window_size); + + rar->cstate.write_ptr = 0; + rar->cstate.last_write_ptr = 0; + + memset(&rar->cstate.bd, 0, sizeof(rar->cstate.bd)); + memset(&rar->cstate.ld, 0, sizeof(rar->cstate.ld)); + memset(&rar->cstate.dd, 0, sizeof(rar->cstate.dd)); + memset(&rar->cstate.ldd, 0, sizeof(rar->cstate.ldd)); + memset(&rar->cstate.rd, 0, sizeof(rar->cstate.rd)); +} + +static void update_crc(struct rar5* rar, const uint8_t* p, size_t to_read) { + int verify_crc; + + if(rar->skip_mode) { +#if defined CHECK_CRC_ON_SOLID_SKIP + verify_crc = 1; +#else + verify_crc = 0; +#endif + } else + verify_crc = 1; + + if(verify_crc) { + /* Don't update CRC32 if the file doesn't have the `stored_crc32` info + filled in. */ + if(rar->file.stored_crc32 > 0) { + rar->file.calculated_crc32 = + crc32(rar->file.calculated_crc32, p, to_read); + } + + /* Check if the file uses an optional BLAKE2sp checksum algorithm. */ + if(rar->file.has_blake2 > 0) { + /* Return value of the `update` function is always 0, so we can + * explicitly ignore it here. */ + (void) blake2sp_update(&rar->file.b2state, p, to_read); + } + } +} + +static int create_decode_tables(uint8_t* bit_length, + struct decode_table* table, + int size) +{ + int code, upper_limit = 0, i, lc[16]; + uint32_t decode_pos_clone[rar5_countof(table->decode_pos)]; + ssize_t cur_len, quick_data_size; + + memset(&lc, 0, sizeof(lc)); + memset(table->decode_num, 0, sizeof(table->decode_num)); + table->size = size; + table->quick_bits = size == HUFF_NC ? 10 : 7; + + for(i = 0; i < size; i++) { + lc[bit_length[i] & 15]++; + } + + lc[0] = 0; + table->decode_pos[0] = 0; + table->decode_len[0] = 0; + + for(i = 1; i < 16; i++) { + upper_limit += lc[i]; + + table->decode_len[i] = upper_limit << (16 - i); + table->decode_pos[i] = table->decode_pos[i - 1] + lc[i - 1]; + + upper_limit <<= 1; + } + + memcpy(decode_pos_clone, table->decode_pos, sizeof(decode_pos_clone)); + + for(i = 0; i < size; i++) { + uint8_t clen = bit_length[i] & 15; + if(clen > 0) { + int last_pos = decode_pos_clone[clen]; + table->decode_num[last_pos] = i; + decode_pos_clone[clen]++; + } + } + + quick_data_size = 1 << table->quick_bits; + cur_len = 1; + for(code = 0; code < quick_data_size; code++) { + int bit_field = code << (16 - table->quick_bits); + int dist, pos; + + while(cur_len < rar5_countof(table->decode_len) && + bit_field >= table->decode_len[cur_len]) { + cur_len++; + } + + table->quick_len[code] = (uint8_t) cur_len; + + dist = bit_field - table->decode_len[cur_len - 1]; + dist >>= (16 - cur_len); + + pos = table->decode_pos[cur_len] + dist; + if(cur_len < rar5_countof(table->decode_pos) && pos < size) { + table->quick_num[code] = table->decode_num[pos]; + } else { + table->quick_num[code] = 0; + } + } + + return ARCHIVE_OK; +} + +static int decode_number(struct archive_read* a, struct decode_table* table, + const uint8_t* p, uint16_t* num) +{ + int i, bits, dist; + uint16_t bitfield; + uint32_t pos; + struct rar5* rar = get_context(a); + + if(ARCHIVE_OK != read_bits_16(rar, p, &bitfield)) { + return ARCHIVE_EOF; + } + + bitfield &= 0xfffe; + + if(bitfield < table->decode_len[table->quick_bits]) { + int code = bitfield >> (16 - table->quick_bits); + skip_bits(rar, table->quick_len[code]); + *num = table->quick_num[code]; + return ARCHIVE_OK; + } + + bits = 15; + + for(i = table->quick_bits + 1; i < 15; i++) { + if(bitfield < table->decode_len[i]) { + bits = i; + break; + } + } + + skip_bits(rar, bits); + + dist = bitfield - table->decode_len[bits - 1]; + dist >>= (16 - bits); + pos = table->decode_pos[bits] + dist; + + if(pos >= table->size) + pos = 0; + + *num = table->decode_num[pos]; + return ARCHIVE_OK; +} + +/* Reads and parses Huffman tables from the beginning of the block. */ +static int parse_tables(struct archive_read* a, struct rar5* rar, + const uint8_t* p) +{ + int ret, value, i, w, idx = 0; + uint8_t bit_length[HUFF_BC], + table[HUFF_TABLE_SIZE], + nibble_mask = 0xF0, + nibble_shift = 4; + + enum { ESCAPE = 15 }; + + /* The data for table generation is compressed using a simple RLE-like + * algorithm when storing zeroes, so we need to unpack it first. */ + for(w = 0, i = 0; w < HUFF_BC;) { + value = (p[i] & nibble_mask) >> nibble_shift; + + if(nibble_mask == 0x0F) + ++i; + + nibble_mask ^= 0xFF; + nibble_shift ^= 4; + + /* Values smaller than 15 is data, so we write it directly. Value 15 + * is a flag telling us that we need to unpack more bytes. */ + if(value == ESCAPE) { + value = (p[i] & nibble_mask) >> nibble_shift; + if(nibble_mask == 0x0F) + ++i; + nibble_mask ^= 0xFF; + nibble_shift ^= 4; + + if(value == 0) { + /* We sometimes need to write the actual value of 15, so this + * case handles that. */ + bit_length[w++] = ESCAPE; + } else { + int k; + + /* Fill zeroes. */ + for(k = 0; k < value + 2; k++) { + bit_length[w++] = 0; + } + } + } else { + bit_length[w++] = value; + } + } + + rar->bits.in_addr = i; + rar->bits.bit_addr = nibble_shift ^ 4; + + ret = create_decode_tables(bit_length, &rar->cstate.bd, HUFF_BC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Decoding huffman tables failed"); + return ARCHIVE_FATAL; + } + + for(i = 0; i < HUFF_TABLE_SIZE;) { + uint16_t num; + + ret = decode_number(a, &rar->cstate.bd, p, &num); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Decoding huffman tables failed"); + return ARCHIVE_FATAL; + } + + if(num < 16) { + /* 0..15: store directly */ + table[i] = (uint8_t) num; + i++; + continue; + } + + if(num < 18) { + /* 16..17: repeat previous code */ + uint16_t n; + if(ARCHIVE_OK != read_bits_16(rar, p, &n)) + return ARCHIVE_EOF; + + if(num == 16) { + n >>= 13; + n += 3; + skip_bits(rar, 3); + } else { + n >>= 9; + n += 11; + skip_bits(rar, 7); + } + + if(i > 0) { + while(n-- > 0 && i < HUFF_TABLE_SIZE) { + table[i] = table[i - 1]; + i++; + } + } else { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unexpected error when decoding huffman tables"); + return ARCHIVE_FATAL; + } + + continue; + } + + /* other codes: fill with zeroes `n` times */ + uint16_t n; + if(ARCHIVE_OK != read_bits_16(rar, p, &n)) + return ARCHIVE_EOF; + + if(num == 18) { + n >>= 13; + n += 3; + skip_bits(rar, 3); + } else { + n >>= 9; + n += 11; + skip_bits(rar, 7); + } + + while(n-- > 0 && i < HUFF_TABLE_SIZE) + table[i++] = 0; + } + + ret = create_decode_tables(&table[idx], &rar->cstate.ld, HUFF_NC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create literal table"); + return ARCHIVE_FATAL; + } + + idx += HUFF_NC; + + ret = create_decode_tables(&table[idx], &rar->cstate.dd, HUFF_DC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create distance table"); + return ARCHIVE_FATAL; + } + + idx += HUFF_DC; + + ret = create_decode_tables(&table[idx], &rar->cstate.ldd, HUFF_LDC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create lower bits of distances table"); + return ARCHIVE_FATAL; + } + + idx += HUFF_LDC; + + ret = create_decode_tables(&table[idx], &rar->cstate.rd, HUFF_RC); + if(ret != ARCHIVE_OK) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Failed to create repeating distances table"); + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +/* Parses the block header, verifies its CRC byte, and saves the header + * fields inside the `hdr` pointer. */ +static int parse_block_header(struct archive_read* a, const uint8_t* p, + ssize_t* block_size, struct compressed_block_header* hdr) +{ + memcpy(hdr, p, sizeof(struct compressed_block_header)); + + if(hdr->block_flags.byte_count > 2) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported block header size (was %d, max is 2)", + hdr->block_flags.byte_count); + return ARCHIVE_FATAL; + } + + /* This should probably use bit reader interface in order to be more + * future-proof. */ + *block_size = 0; + switch(hdr->block_flags.byte_count) { + /* 1-byte block size */ + case 0: + *block_size = *(const uint8_t*) &p[2]; + break; + + /* 2-byte block size */ + case 1: + *block_size = *(const uint16_t*) &p[2]; + break; + + /* 3-byte block size */ + case 2: + *block_size = *(const uint32_t*) &p[2]; + *block_size &= 0x00FFFFFF; + break; + + /* Other block sizes are not supported. This case is not reached, + * because we have an 'if' guard before the switch that makes sure + * of it. */ + default: + return ARCHIVE_FATAL; + } + + /* Verify the block header checksum. 0x5A is a magic value and is always + * constant. */ + uint8_t calculated_cksum = 0x5A + ^ (uint8_t) hdr->block_flags_u8 + ^ (uint8_t) *block_size + ^ (uint8_t) (*block_size >> 8) + ^ (uint8_t) (*block_size >> 16); + + if(calculated_cksum != hdr->block_cksum) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Block checksum error: got 0x%02x, expected 0x%02x", + hdr->block_cksum, calculated_cksum); + + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +/* Convinience function used during filter processing. */ +static int parse_filter_data(struct rar5* rar, const uint8_t* p, + uint32_t* filter_data) +{ + int i, bytes; + uint32_t data = 0; + + if(ARCHIVE_OK != read_consume_bits(rar, p, 2, &bytes)) + return ARCHIVE_EOF; + + bytes++; + + for(i = 0; i < bytes; i++) { + uint16_t byte; + + if(ARCHIVE_OK != read_bits_16(rar, p, &byte)) { + return ARCHIVE_EOF; + } + + data += (byte >> 8) << (i * 8); + skip_bits(rar, 8); + } + + *filter_data = data; + return ARCHIVE_OK; +} + +/* Function is used during sanity checking. */ +static int is_valid_filter_block_start(struct rar5* rar, + uint32_t start) +{ + const int64_t block_start = (ssize_t) start + rar->cstate.write_ptr; + const int64_t last_bs = rar->cstate.last_block_start; + const ssize_t last_bl = rar->cstate.last_block_length; + + if(last_bs == 0 || last_bl == 0) { + /* We didn't have any filters yet, so accept this offset. */ + return 1; + } + + if(block_start >= last_bs + last_bl) { + /* Current offset is bigger than last block's end offset, so + * accept current offset. */ + return 1; + } + + /* Any other case is not a normal situation and we should fail. */ + return 0; +} + +/* The function will create a new filter, read its parameters from the input + * stream and add it to the filter collection. */ +static int parse_filter(struct archive_read* ar, const uint8_t* p) { + uint32_t block_start, block_length; + uint16_t filter_type; + struct rar5* rar = get_context(ar); + + /* Read the parameters from the input stream. */ + if(ARCHIVE_OK != parse_filter_data(rar, p, &block_start)) + return ARCHIVE_EOF; + + if(ARCHIVE_OK != parse_filter_data(rar, p, &block_length)) + return ARCHIVE_EOF; + + if(ARCHIVE_OK != read_bits_16(rar, p, &filter_type)) + return ARCHIVE_EOF; + + filter_type >>= 13; + skip_bits(rar, 3); + + /* Perform some sanity checks on this filter parameters. Note that we + * allow only DELTA, E8/E9 and ARM filters here, because rest of filters + * are not used in RARv5. */ + + if(block_length < 4 || + block_length > 0x400000 || + filter_type > FILTER_ARM || + !is_valid_filter_block_start(rar, block_start)) + { + archive_set_error(&ar->archive, ARCHIVE_ERRNO_FILE_FORMAT, "Invalid " + "filter encountered"); + return ARCHIVE_FATAL; + } + + /* Allocate a new filter. */ + struct filter_info* filt = add_new_filter(rar); + if(filt == NULL) { + archive_set_error(&ar->archive, ENOMEM, "Can't allocate memory for a " + "filter descriptor."); + return ARCHIVE_FATAL; + } + + filt->type = filter_type; + filt->block_start = rar->cstate.write_ptr + block_start; + filt->block_length = block_length; + + rar->cstate.last_block_start = filt->block_start; + rar->cstate.last_block_length = filt->block_length; + + /* Read some more data in case this is a DELTA filter. Other filter types + * don't require any additional data over what was already read. */ + if(filter_type == FILTER_DELTA) { + int channels; + + if(ARCHIVE_OK != read_consume_bits(rar, p, 5, &channels)) + return ARCHIVE_EOF; + + filt->channels = channels + 1; + } + + return ARCHIVE_OK; +} + +static int decode_code_length(struct rar5* rar, const uint8_t* p, + uint16_t code) +{ + int lbits, length = 2; + if(code < 8) { + lbits = 0; + length += code; + } else { + lbits = code / 4 - 1; + length += (4 | (code & 3)) << lbits; + } + + if(lbits > 0) { + int add; + + if(ARCHIVE_OK != read_consume_bits(rar, p, lbits, &add)) + return -1; + + length += add; + } + + return length; +} + +static int copy_string(struct archive_read* a, int len, int dist) { + struct rar5* rar = get_context(a); + const int cmask = rar->cstate.window_mask; + const int64_t write_ptr = rar->cstate.write_ptr + rar->cstate.solid_offset; + int i; + + /* The unpacker spends most of the time in this function. It would be + * a good idea to introduce some optimizations here. + * + * Just remember that this loop treats buffers that overlap differently + * than buffers that do not overlap. This is why a simple memcpy(3) call + * will not be enough. */ + + for(i = 0; i < len; i++) { + const ssize_t write_idx = (write_ptr + i) & cmask; + const ssize_t read_idx = (write_ptr + i - dist) & cmask; + rar->cstate.window_buf[write_idx] = rar->cstate.window_buf[read_idx]; + } + + rar->cstate.write_ptr += len; + return ARCHIVE_OK; +} + +static int do_uncompress_block(struct archive_read* a, const uint8_t* p) { + struct rar5* rar = get_context(a); + uint16_t num; + int ret; + + const int cmask = rar->cstate.window_mask; + const struct compressed_block_header* hdr = &rar->last_block_hdr; + const uint8_t bit_size = 1 + hdr->block_flags.bit_size; + + while(1) { + if(rar->cstate.write_ptr - rar->cstate.last_write_ptr > + (rar->cstate.window_size >> 1)) { + + /* Don't allow growing data by more than half of the window size + * at a time. In such case, break the loop; next call to this + * function will continue processing from this moment. */ + + break; + } + + if(rar->bits.in_addr > rar->cstate.cur_block_size - 1 || + (rar->bits.in_addr == rar->cstate.cur_block_size - 1 && + rar->bits.bit_addr >= bit_size)) + { + /* If the program counter is here, it means the function has + * finished processing the block. */ + rar->cstate.block_parsing_finished = 1; + break; + } + + /* Decode the next literal. */ + if(ARCHIVE_OK != decode_number(a, &rar->cstate.ld, p, &num)) { + return ARCHIVE_EOF; + } + + /* Num holds a decompression literal, or 'command code'. + * + * - Values lower than 256 are just bytes. Those codes can be stored + * in the output buffer directly. + * + * - Code 256 defines a new filter, which is later used to transform + * the data block accordingly to the filter type. The data block + * needs to be fully uncompressed first. + * + * - Code bigger than 257 and smaller than 262 define a repetition + * pattern that should be copied from an already uncompressed chunk + * of data. + */ + + if(num < 256) { + /* Directly store the byte. */ + + int64_t write_idx = rar->cstate.solid_offset + + rar->cstate.write_ptr++; + + rar->cstate.window_buf[write_idx & cmask] = (uint8_t) num; + continue; + } else if(num >= 262) { + uint16_t dist_slot; + int len = decode_code_length(rar, p, num - 262), + dbits, + dist = 1; + + if(len == -1) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Failed to decode the code length"); + + return ARCHIVE_FATAL; + } + + if(ARCHIVE_OK != decode_number(a, &rar->cstate.dd, p, &dist_slot)) + { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Failed to decode the distance slot"); + + return ARCHIVE_FATAL; + } + + if(dist_slot < 4) { + dbits = 0; + dist += dist_slot; + } else { + dbits = dist_slot / 2 - 1; + dist += (2 | (dist_slot & 1)) << dbits; + } + + if(dbits > 0) { + if(dbits >= 4) { + uint32_t add = 0; + uint16_t low_dist; + + if(dbits > 4) { + if(ARCHIVE_OK != read_bits_32(rar, p, &add)) { + /* Return EOF if we can't read more data. */ + return ARCHIVE_EOF; + } + + skip_bits(rar, dbits - 4); + add = (add >> (36 - dbits)) << 4; + dist += add; + } + + if(ARCHIVE_OK != decode_number(a, &rar->cstate.ldd, p, + &low_dist)) + { + archive_set_error(&a->archive, + ARCHIVE_ERRNO_PROGRAMMER, + "Failed to decode the distance slot"); + + return ARCHIVE_FATAL; + } + + dist += low_dist; + } else { + /* dbits is one of [0,1,2,3] */ + int add; + + if(ARCHIVE_OK != read_consume_bits(rar, p, dbits, &add)) { + /* Return EOF if we can't read more data. */ + return ARCHIVE_EOF; + } + + dist += add; + } + } + + if(dist > 0x100) { + len++; + + if(dist > 0x2000) { + len++; + + if(dist > 0x40000) { + len++; + } + } + } + + dist_cache_push(rar, dist); + rar->cstate.last_len = len; + + if(ARCHIVE_OK != copy_string(a, len, dist)) + return ARCHIVE_FATAL; + + continue; + } else if(num == 256) { + /* Create a filter. */ + ret = parse_filter(a, p); + if(ret != ARCHIVE_OK) + return ret; + + continue; + } else if(num == 257) { + if(rar->cstate.last_len != 0) { + if(ARCHIVE_OK != copy_string(a, rar->cstate.last_len, + rar->cstate.dist_cache[0])) + { + return ARCHIVE_FATAL; + } + } + + continue; + } else if(num < 262) { + const int index = num - 258; + const int dist = dist_cache_touch(rar, index); + + uint16_t len_slot; + int len; + + if(ARCHIVE_OK != decode_number(a, &rar->cstate.rd, p, &len_slot)) { + return ARCHIVE_FATAL; + } + + len = decode_code_length(rar, p, len_slot); + rar->cstate.last_len = len; + + if(ARCHIVE_OK != copy_string(a, len, dist)) + return ARCHIVE_FATAL; + + continue; + } + + /* The program counter shouldn't reach here. */ + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Unsupported block code: 0x%02x", num); + + return ARCHIVE_FATAL; + } + + return ARCHIVE_OK; +} + +/* Binary search for the RARv5 signature. */ +static int scan_for_signature(struct archive_read* a) { + const uint8_t* p; + const int chunk_size = 512; + ssize_t i; + + /* If we're here, it means we're on an 'unknown territory' data. + * There's no indication what kind of data we're reading here. It could be + * some text comment, any kind of binary data, digital sign, dragons, etc. + * + * We want to find a valid RARv5 magic header inside this unknown data. */ + + /* Is it possible in libarchive to just skip everything until the + * end of the file? If so, it would be a better approach than the + * current implementation of this function. */ + + while(1) { + if(!read_ahead(a, chunk_size, &p)) + return ARCHIVE_EOF; + + for(i = 0; i < chunk_size - rar5_signature_size; i++) { + if(memcmp(&p[i], rar5_signature, rar5_signature_size) == 0) { + /* Consume the number of bytes we've used to search for the + * signature, as well as the number of bytes used by the + * signature itself. After this we should be standing on a + * valid base block header. */ + (void) consume(a, i + rar5_signature_size); + return ARCHIVE_OK; + } + } + + consume(a, chunk_size); + } + + return ARCHIVE_FATAL; +} + +/* This function will switch the multivolume archive file to another file, + * i.e. from part03 to part 04. */ +static int advance_multivolume(struct archive_read* a) { + int lret; + struct rar5* rar = get_context(a); + + /* A small state machine that will skip unnecessary data, needed to + * switch from one multivolume to another. Such skipping is needed if + * we want to be an stream-oriented (instead of file-oriented) + * unpacker. + * + * The state machine starts with `rar->main.endarc` == 0. It also + * assumes that current stream pointer points to some base block header. + * + * The `endarc` field is being set when the base block parsing function + * encounters the 'end of archive' marker. + */ + + while(1) { + if(rar->main.endarc == 1) { + rar->main.endarc = 0; + while(ARCHIVE_RETRY == skip_base_block(a)); + break; + } else { + /* Skip current base block. In order to properly skip it, + * we really need to simply parse it and discard the results. */ + + lret = skip_base_block(a); + + /* The `skip_base_block` function tells us if we should continue + * with skipping, or we should stop skipping. We're trying to skip + * everything up to a base FILE block. */ + + if(lret != ARCHIVE_RETRY) { + /* If there was an error during skipping, or we have just + * skipped a FILE base block... */ + + if(rar->main.endarc == 0) { + return lret; + } else { + continue; + } + } + } + } + + return ARCHIVE_OK; +} + +/* Merges the partial block from the first multivolume archive file, and + * partial block from the second multivolume archive file. The result is + * a chunk of memory containing the whole block, and the stream pointer + * is advanced to the next block in the second multivolume archive file. */ +static int merge_block(struct archive_read* a, ssize_t block_size, + const uint8_t** p) +{ + struct rar5* rar = get_context(a); + ssize_t cur_block_size, partial_offset = 0; + const uint8_t* lp; + int ret; + + /* Set a flag that we're in the switching mode. */ + rar->cstate.switch_multivolume = 1; + + /* Reallocate the memory which will hold the whole block. */ + if(rar->vol.push_buf) + free((void*) rar->vol.push_buf); + + rar->vol.push_buf = malloc(block_size); + if(!rar->vol.push_buf) { + archive_set_error(&a->archive, ENOMEM, "Can't allocate memory for a " + "merge block buffer."); + return ARCHIVE_FATAL; + } + + /* A single block can span across multiple multivolume archive files, + * so we use a loop here. This loop will consume enough multivolume + * archive files until the whole block is read. */ + + while(1) { + /* Get the size of current block chunk in this multivolume archive + * file and read it. */ + cur_block_size = + rar5_min(rar->file.bytes_remaining, block_size - partial_offset); + + if(!read_ahead(a, cur_block_size, &lp)) + return ARCHIVE_EOF; + + /* Sanity check; there should never be a situation where this function + * reads more data than the block's size. */ + if(partial_offset + cur_block_size > block_size) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Consumed too much data when merging blocks."); + return ARCHIVE_FATAL; + } + + /* Merge previous block chunk with current block chunk, or create + * first block chunk if this is our first iteration. */ + memcpy(&rar->vol.push_buf[partial_offset], lp, cur_block_size); + + /* Advance the stream read pointer by this block chunk size. */ + if(ARCHIVE_OK != consume(a, cur_block_size)) + return ARCHIVE_EOF; + + /* Update the pointers. `partial_offset` contains information about + * the sum of merged block chunks. */ + partial_offset += cur_block_size; + rar->file.bytes_remaining -= cur_block_size; + + /* If `partial_offset` is the same as `block_size`, this means we've + * merged all block chunks and we have a valid full block. */ + if(partial_offset == block_size) { + break; + } + + /* If we don't have any bytes to read, this means we should switch + * to another multivolume archive file. */ + if(rar->file.bytes_remaining == 0) { + ret = advance_multivolume(a); + if(ret != ARCHIVE_OK) + return ret; + } + } + + *p = rar->vol.push_buf; + + /* If we're here, we can resume unpacking by processing the block pointed + * to by the `*p` memory pointer. */ + + return ARCHIVE_OK; +} + +static int process_block(struct archive_read* a) { + const uint8_t* p; + struct rar5* rar = get_context(a); + int ret; + + /* If we don't have any data to be processed, this most probably means + * we need to switch to the next volume. */ + if(rar->main.volume && rar->file.bytes_remaining == 0) { + ret = advance_multivolume(a); + if(ret != ARCHIVE_OK) + return ret; + } + + if(rar->cstate.block_parsing_finished) { + ssize_t block_size; + + rar->cstate.block_parsing_finished = 0; + + /* The header size won't be bigger than 6 bytes. */ + if(!read_ahead(a, 6, &p)) { + /* Failed to prefetch data block header. */ + return ARCHIVE_EOF; + } + + /* + * Read block_size by parsing block header. Validate the header by + * calculating CRC byte stored inside the header. Size of the header is + * not constant (block size can be stored either in 1 or 2 bytes), + * that's why block size is left out from the `compressed_block_header` + * structure and returned by `parse_block_header` as the second + * argument. */ + + ret = parse_block_header(a, p, &block_size, &rar->last_block_hdr); + if(ret != ARCHIVE_OK) + return ret; + + /* Skip block header. Next data is huffman tables, if present. */ + ssize_t to_skip = sizeof(struct compressed_block_header) + + rar->last_block_hdr.block_flags.byte_count + 1; + + if(ARCHIVE_OK != consume(a, to_skip)) + return ARCHIVE_EOF; + + rar->file.bytes_remaining -= to_skip; + + /* The block size gives information about the whole block size, but + * the block could be stored in split form when using multi-volume + * archives. In this case, the block size will be bigger than the + * actual data stored in this file. Remaining part of the data will + * be in another file. */ + + ssize_t cur_block_size = + rar5_min(rar->file.bytes_remaining, block_size); + + if(block_size > rar->file.bytes_remaining) { + /* If current blocks' size is bigger than our data size, this + * means we have a multivolume archive. In this case, skip + * all base headers until the end of the file, proceed to next + * "partXXX.rar" volume, find its signature, skip all headers up + * to the first FILE base header, and continue from there. + * + * Note that `merge_block` will update the `rar` context structure + * quite extensively. */ + + ret = merge_block(a, block_size, &p); + if(ret != ARCHIVE_OK) { + return ret; + } + + cur_block_size = block_size; + + /* Current stream pointer should be now directly *after* the + * block that spanned through multiple archive files. `p` pointer + * should have the data of the *whole* block (merged from + * partial blocks stored in multiple archives files). */ + } else { + rar->cstate.switch_multivolume = 0; + + /* Read the whole block size into memory. This can take up to + * 8 megabytes of memory in theoretical cases. Might be worth to + * optimize this and use a standard chunk of 4kb's. */ + + if(!read_ahead(a, 4 + cur_block_size, &p)) { + /* Failed to prefetch block data. */ + return ARCHIVE_EOF; + } + } + + rar->cstate.block_buf = p; + rar->cstate.cur_block_size = cur_block_size; + + rar->bits.in_addr = 0; + rar->bits.bit_addr = 0; + + if(rar->last_block_hdr.block_flags.is_table_present) { + /* Load Huffman tables. */ + ret = parse_tables(a, rar, p); + if(ret != ARCHIVE_OK) { + /* Error during decompression of Huffman tables. */ + return ret; + } + } + } else { + p = rar->cstate.block_buf; + } + + /* Uncompress the block, or a part of it, depending on how many bytes + * will be generated by uncompressing the block. + * + * In case too many bytes will be generated, calling this function again + * will resume the uncompression operation. */ + ret = do_uncompress_block(a, p); + if(ret != ARCHIVE_OK) { + return ret; + } + + if(rar->cstate.block_parsing_finished && + rar->cstate.switch_multivolume == 0 && + rar->cstate.cur_block_size > 0) + { + /* If we're processing a normal block, consume the whole block. We + * can do this because we've already read the whole block to memory. + */ + if(ARCHIVE_OK != consume(a, rar->cstate.cur_block_size)) + return ARCHIVE_FATAL; + + rar->file.bytes_remaining -= rar->cstate.cur_block_size; + } else if(rar->cstate.switch_multivolume) { + /* Don't consume the block if we're doing multivolume processing. + * The volume switching function will consume the proper count of + * bytes instead. */ + + rar->cstate.switch_multivolume = 0; + } + + return ARCHIVE_OK; +} + +/* Pops the `buf`, `size` and `offset` from the "data ready" stack. + * + * Returns ARCHIVE_OK when those arguments can be used, ARCHIVE_RETRY + * when there is no data on the stack. */ +static int use_data(struct rar5* rar, const void** buf, size_t* size, + int64_t* offset) +{ + int i; + + for(i = 0; i < rar5_countof(rar->cstate.dready); i++) { + struct data_ready *d = &rar->cstate.dready[i]; + + if(d->used) { + if(buf) *buf = d->buf; + if(size) *size = d->size; + if(offset) *offset = d->offset; + + d->used = 0; + return ARCHIVE_OK; + } + } + + return ARCHIVE_RETRY; +} + +/* Pushes the `buf`, `size` and `offset` arguments to the rar->cstate.dready + * FIFO stack. Those values will be popped from this stack by the `use_data` + * function. */ +static int push_data_ready(struct archive_read* a, struct rar5* rar, + const uint8_t* buf, size_t size, int64_t offset) +{ + int i; + + /* Don't push if we're in skip mode. This is needed because solid + * streams need full processing even if we're skipping data. After fully + * processing the stream, we need to discard the generated bytes, because + * we're interested only in the side effect: building up the internal + * window circular buffer. This window buffer will be used later during + * unpacking of requested data. */ + if(rar->skip_mode) + return ARCHIVE_OK; + + /* Sanity check. */ + if(offset != rar->file.last_offset + rar->file.last_size) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, "Sanity " + "check error: output stream is not continuous"); + return ARCHIVE_FATAL; + } + + for(i = 0; i < rar5_countof(rar->cstate.dready); i++) { + struct data_ready* d = &rar->cstate.dready[i]; + if(!d->used) { + d->used = 1; + d->buf = buf; + d->size = size; + d->offset = offset; + + /* These fields are used only in sanity checking. */ + rar->file.last_offset = offset; + rar->file.last_size = size; + + /* Calculate the checksum of this new block before submitting + * data to libarchive's engine. */ + update_crc(rar, d->buf, d->size); + + return ARCHIVE_OK; + } + } + + /* Program counter will reach this code if the `rar->cstate.data_ready` + * stack will be filled up so that no new entries will be allowed. The + * code shouldn't allow such situation to occur. So we treat this case + * as an internal error. */ + + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, "Error: " + "premature end of data_ready stack"); + return ARCHIVE_FATAL; +} + +/* This function uncompresses the data that is stored in the <FILE> base + * block. + * + * The FILE base block looks like this: + * + * <header><huffman tables><block_1><block_2>...<block_n> + * + * The <header> is a block header, that is parsed in parse_block_header(). + * It's a "compressed_block_header" structure, containing metadata needed + * to know when we should stop looking for more <block_n> blocks. + * + * <huffman tables> contain data needed to set up the huffman tables, needed + * for the actual decompression. + * + * Each <block_n> consists of series of literals: + * + * <literal><literal><literal>...<literal> + * + * Those literals generate the uncompression data. They operate on a circular + * buffer, sometimes writing raw data into it, sometimes referencing + * some previous data inside this buffer, and sometimes declaring a filter + * that will need to be executed on the data stored in the circular buffer. + * It all depends on the literal that is used. + * + * Sometimes blocks produce output data, sometimes they don't. For example, for + * some huge files that use lots of filters, sometimes a block is filled with + * only filter declaration literals. Such blocks won't produce any data in the + * circular buffer. + * + * Sometimes blocks will produce 4 bytes of data, and sometimes 1 megabyte, + * because a literal can reference previously decompressed data. For example, + * there can be a literal that says: 'append a byte 0xFE here', and after + * it another literal can say 'append 1 megabyte of data from circular buffer + * offset 0x12345'. This is how RAR format handles compressing repeated + * patterns. + * + * The RAR compressor creates those literals and the actual efficiency of + * compression depends on what those literals are. The literals can also + * be seen as a kind of a non-turing-complete virtual machine that simply + * tells the decompressor what it should do. + * */ + +static int do_uncompress_file(struct archive_read* a) { + struct rar5* rar = get_context(a); + int ret; + int64_t max_end_pos; + + if(!rar->cstate.initialized) { + /* Don't perform full context reinitialization if we're processing + * a solid archive. */ + if(!rar->main.solid || !rar->cstate.window_buf) { + init_unpack(rar); + } + + rar->cstate.initialized = 1; + } + + if(rar->cstate.all_filters_applied == 1) { + /* We use while(1) here, but standard case allows for just 1 iteration. + * The loop will iterate if process_block() didn't generate any data at + * all. This can happen if the block contains only filter definitions + * (this is common in big files). */ + + while(1) { + ret = process_block(a); + if(ret == ARCHIVE_EOF || ret == ARCHIVE_FATAL) + return ret; + + if(rar->cstate.last_write_ptr == rar->cstate.write_ptr) { + /* The block didn't generate any new data, so just process + * a new block. */ + continue; + } + + /* The block has generated some new data, so break the loop. */ + break; + } + } + + /* Try to run filters. If filters won't be applied, it means that + * insufficient data was generated. */ + ret = apply_filters(a); + if(ret == ARCHIVE_RETRY) { + return ARCHIVE_OK; + } else if(ret == ARCHIVE_FATAL) { + return ARCHIVE_FATAL; + } + + /* If apply_filters() will return ARCHIVE_OK, we can continue here. */ + + if(cdeque_size(&rar->cstate.filters) > 0) { + /* Check if we can write something before hitting first filter. */ + struct filter_info* flt; + + /* Get the block_start offset from the first filter. */ + if(CDE_OK != cdeque_front(&rar->cstate.filters, cdeque_filter_p(&flt))) + { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Can't read first filter"); + return ARCHIVE_FATAL; + } + + max_end_pos = rar5_min(flt->block_start, rar->cstate.write_ptr); + } else { + /* There are no filters defined, or all filters were applied. This + * means we can just store the data without any postprocessing. */ + max_end_pos = rar->cstate.write_ptr; + } + + if(max_end_pos == rar->cstate.last_write_ptr) { + /* We can't write anything yet. The block uncompression function did + * not generate enough data, and no filter can be applied. At the same + * time we don't have any data that can be stored without filter + * postprocessing. This means we need to wait for more data to be + * generated, so we can apply the filters. + * + * Signal the caller that we need more data to be able to do anything. + */ + return ARCHIVE_RETRY; + } else { + /* We can write the data before hitting the first filter. So let's + * do it. The push_window_data() function will effectively return + * the selected data block to the user application. */ + push_window_data(a, rar, rar->cstate.last_write_ptr, max_end_pos); + rar->cstate.last_write_ptr = max_end_pos; + } + + return ARCHIVE_OK; +} + +static int uncompress_file(struct archive_read* a) { + int ret; + + while(1) { + /* Sometimes the uncompression function will return a 'retry' signal. + * If this will happen, we have to retry the function. */ + ret = do_uncompress_file(a); + if(ret != ARCHIVE_RETRY) + return ret; + } +} + + +static int do_unstore_file(struct archive_read* a, + struct rar5* rar, + const void** buf, + size_t* size, + int64_t* offset) +{ + const uint8_t* p; + + if(rar->file.bytes_remaining == 0 && rar->main.volume > 0 && + rar->generic.split_after > 0) + { + int ret; + + rar->cstate.switch_multivolume = 1; + ret = advance_multivolume(a); + rar->cstate.switch_multivolume = 0; + + if(ret != ARCHIVE_OK) { + /* Failed to advance to next multivolume archive file. */ + return ret; + } + } + + size_t to_read = rar5_min(rar->file.bytes_remaining, 64 * 1024); + + if(!read_ahead(a, to_read, &p)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, "I/O error " + "when unstoring file"); + return ARCHIVE_FATAL; + } + + if(ARCHIVE_OK != consume(a, to_read)) { + return ARCHIVE_EOF; + } + + if(buf) *buf = p; + if(size) *size = to_read; + if(offset) *offset = rar->cstate.last_unstore_ptr; + + rar->file.bytes_remaining -= to_read; + rar->cstate.last_unstore_ptr += to_read; + + update_crc(rar, p, to_read); + return ARCHIVE_OK; +} + +static int do_unpack(struct archive_read* a, struct rar5* rar, + const void** buf, size_t* size, int64_t* offset) +{ + enum COMPRESSION_METHOD { + STORE = 0, FASTEST = 1, FAST = 2, NORMAL = 3, GOOD = 4, BEST = 5 + }; + + if(rar->file.service > 0) { + return do_unstore_file(a, rar, buf, size, offset); + } else { + switch(rar->cstate.method) { + case STORE: + return do_unstore_file(a, rar, buf, size, offset); + case FASTEST: + /* fallthrough */ + case FAST: + /* fallthrough */ + case NORMAL: + /* fallthrough */ + case GOOD: + /* fallthrough */ + case BEST: + return uncompress_file(a); + default: + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Compression method not supported: 0x%08x", + rar->cstate.method); + + return ARCHIVE_FATAL; + } + } + +#if !defined WIN32 + /* Not reached. */ + return ARCHIVE_OK; +#endif +} + +static int verify_checksums(struct archive_read* a) { + int verify_crc; + struct rar5* rar = get_context(a); + + /* Check checksums only when actually unpacking the data. There's no need + * to calculate checksum when we're skipping data in solid archives + * (skipping in solid archives is the same thing as unpacking compressed + * data and discarding the result). */ + + if(!rar->skip_mode) { + /* Always check checkums if we're not in skip mode */ + verify_crc = 1; + } else { + /* We can override the logic above with a compile-time option + * NO_CRC_ON_SOLID_SKIP. This option is used during debugging, and it + * will check checksums of unpacked data even when we're skipping it. + */ + +#if defined CHECK_CRC_ON_SOLID_SKIP + /* Debug case */ + verify_crc = 1; +#else + /* Normal case */ + verify_crc = 0; +#endif + } + + if(verify_crc) { + /* During unpacking, on each unpacked block we're calling the + * update_crc() function. Since we are here, the unpacking process is + * already over and we can check if calculated checksum (CRC32 or + * BLAKE2sp) is the same as what is stored in the archive. + */ + if(rar->file.stored_crc32 > 0) { + /* Check CRC32 only when the file contains a CRC32 value for this + * file. */ + + if(rar->file.calculated_crc32 != rar->file.stored_crc32) { + /* Checksums do not match; the unpacked file is corrupted. */ + + DEBUG_CODE { + printf("Checksum error: CRC32 (was: %08x, expected: %08x)\n", + rar->file.calculated_crc32, rar->file.stored_crc32); + } + +#ifndef DONT_FAIL_ON_CRC_ERROR + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Checksum error: CRC32"); + return ARCHIVE_FATAL; +#endif + } else { + DEBUG_CODE { + printf("Checksum OK: CRC32 (%08x/%08x)\n", + rar->file.stored_crc32, + rar->file.calculated_crc32); + } + } + } + + if(rar->file.has_blake2 > 0) { + /* BLAKE2sp is an optional checksum algorithm that is added to + * RARv5 archives when using the `-htb` switch during creation of + * archive. + * + * We now finalize the hash calculation by calling the `final` + * function. This will generate the final hash value we can use to + * compare it with the BLAKE2sp checksum that is stored in the + * archive. + * + * The return value of this `final` function is not very helpful, + * as it guards only against improper use. This is why we're + * explicitly ignoring it. */ + + uint8_t b2_buf[32]; + (void) blake2sp_final(&rar->file.b2state, b2_buf, 32); + + if(memcmp(&rar->file.blake2sp, b2_buf, 32) != 0) { +#ifndef DONT_FAIL_ON_CRC_ERROR + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Checksum error: BLAKE2"); + + return ARCHIVE_FATAL; +#endif + } + } + } + + /* Finalization for this file has been successfully completed. */ + return ARCHIVE_OK; +} + +static int verify_global_checksums(struct archive_read* a) { + return verify_checksums(a); +} + +static int rar5_read_data(struct archive_read *a, const void **buff, + size_t *size, int64_t *offset) { + int ret; + struct rar5* rar = get_context(a); + + if(!rar->skip_mode && (rar->cstate.last_write_ptr > rar->file.unpacked_size)) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER, + "Unpacker has written too many bytes"); + return ARCHIVE_FATAL; + } + + ret = use_data(rar, buff, size, offset); + if(ret == ARCHIVE_OK) + return ret; + + ret = do_unpack(a, rar, buff, size, offset); + if(ret != ARCHIVE_OK) { + return ret; + } + + if(rar->file.bytes_remaining == 0 && + rar->cstate.last_write_ptr == rar->file.unpacked_size) + { + /* If all bytes of current file were processed, run finalization. + * + * Finalization will check checksum against proper values. If + * some of the checksums will not match, we'll return an error + * value in the last `archive_read_data` call to signal an error + * to the user. */ + + return verify_global_checksums(a); + } + + return ARCHIVE_OK; +} + +static int rar5_read_data_skip(struct archive_read *a) { + struct rar5* rar = get_context(a); + + if(rar->main.solid) { + /* In solid archives, instead of skipping the data, we need to extract + * it, and dispose the result. The side effect of this operation will + * be setting up the initial window buffer state needed to be able to + * extract the selected file. */ + + int ret; + + /* Make sure to process all blocks in the compressed stream. */ + while(rar->file.bytes_remaining > 0) { + /* Setting the "skip mode" will allow us to skip checksum checks + * during data skipping. Checking the checksum of skipped data + * isn't really necessary and it's only slowing things down. + * + * This is incremented instead of setting to 1 because this data + * skipping function can be called recursively. */ + rar->skip_mode++; + + /* We're disposing 1 block of data, so we use triple NULLs in + * arguments. + */ + ret = rar5_read_data(a, NULL, NULL, NULL); + + /* Turn off "skip mode". */ + rar->skip_mode--; + + if(ret < 0) { + /* Propagate any potential error conditions to the caller. */ + return ret; + } + } + } else { + /* In standard archives, we can just jump over the compressed stream. + * Each file in non-solid archives starts from an empty window buffer. + */ + + if(ARCHIVE_OK != consume(a, rar->file.bytes_remaining)) { + return ARCHIVE_FATAL; + } + + rar->file.bytes_remaining = 0; + } + + return ARCHIVE_OK; +} + +static int64_t rar5_seek_data(struct archive_read *a, int64_t offset, + int whence) +{ + (void) a; + (void) offset; + (void) whence; + + /* We're a streaming unpacker, and we don't support seeking. */ + + return ARCHIVE_FATAL; +} + +static int rar5_cleanup(struct archive_read *a) { + struct rar5* rar = get_context(a); + + if(rar->cstate.window_buf) + free(rar->cstate.window_buf); + + if(rar->cstate.filtered_buf) + free(rar->cstate.filtered_buf); + + if(rar->vol.push_buf) + free(rar->vol.push_buf); + + free_filters(rar); + cdeque_free(&rar->cstate.filters); + + free(rar); + a->format->data = NULL; + + return ARCHIVE_OK; +} + +static int rar5_capabilities(struct archive_read * a) { + (void) a; + return 0; +} + +static int rar5_has_encrypted_entries(struct archive_read *_a) { + (void) _a; + + /* Unsupported for now. */ + return ARCHIVE_READ_FORMAT_ENCRYPTION_UNSUPPORTED; +} + +static int rar5_init(struct rar5* rar) { + ssize_t i; + + memset(rar, 0, sizeof(struct rar5)); + + /* Decrypt the magic signature pattern. Check the comment near the + * `rar5_signature` symbol to read the rationale behind this. */ + + if(rar5_signature[0] == 243) { + for(i = 0; i < rar5_signature_size; i++) { + rar5_signature[i] ^= 0xA1; + } + } + + if(CDE_OK != cdeque_init(&rar->cstate.filters, 8192)) + return ARCHIVE_FATAL; + + return ARCHIVE_OK; +} + +int archive_read_support_format_rar5(struct archive *_a) { + struct archive_read* ar; + int ret; + struct rar5* rar; + + if(ARCHIVE_OK != (ret = get_archive_read(_a, &ar))) + return ret; + + rar = malloc(sizeof(*rar)); + if(rar == NULL) { + archive_set_error(&ar->archive, ENOMEM, "Can't allocate rar5 data"); + return ARCHIVE_FATAL; + } + + if(ARCHIVE_OK != rar5_init(rar)) { + archive_set_error(&ar->archive, ENOMEM, "Can't allocate rar5 filter " + "buffer"); + return ARCHIVE_FATAL; + } + + ret = __archive_read_register_format(ar, + rar, + "rar5", + rar5_bid, + rar5_options, + rar5_read_header, + rar5_read_data, + rar5_read_data_skip, + rar5_seek_data, + rar5_cleanup, + rar5_capabilities, + rar5_has_encrypted_entries); + + if(ret != ARCHIVE_OK) { + (void) rar5_cleanup(ar); + } + + return ret; +} |