/* Compressed section support (intended for debug sections). Copyright (C) 2008-2018 Free Software Foundation, Inc. This file is part of BFD, the Binary File Descriptor library. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ #include "sysdep.h" #include <zlib.h> #include "bfd.h" #include "libbfd.h" #include "safe-ctype.h" #define MAX_COMPRESSION_HEADER_SIZE 24 static bfd_boolean decompress_contents (bfd_byte *compressed_buffer, bfd_size_type compressed_size, bfd_byte *uncompressed_buffer, bfd_size_type uncompressed_size) { z_stream strm; int rc; /* It is possible the section consists of several compressed buffers concatenated together, so we uncompress in a loop. */ /* PR 18313: The state field in the z_stream structure is supposed to be invisible to the user (ie us), but some compilers will still complain about it being used without initialisation. So we first zero the entire z_stream structure and then set the fields that we need. */ memset (& strm, 0, sizeof strm); strm.avail_in = compressed_size; strm.next_in = (Bytef*) compressed_buffer; strm.avail_out = uncompressed_size; BFD_ASSERT (Z_OK == 0); rc = inflateInit (&strm); while (strm.avail_in > 0 && strm.avail_out > 0) { if (rc != Z_OK) break; strm.next_out = ((Bytef*) uncompressed_buffer + (uncompressed_size - strm.avail_out)); rc = inflate (&strm, Z_FINISH); if (rc != Z_STREAM_END) break; rc = inflateReset (&strm); } rc |= inflateEnd (&strm); return rc == Z_OK && strm.avail_out == 0; } /* Compress data of the size specified in @var{uncompressed_size} and pointed to by @var{uncompressed_buffer} using zlib and store as the contents field. This function assumes the contents field was allocated using bfd_malloc() or equivalent. Return the uncompressed size if the full section contents is compressed successfully. Otherwise return 0. */ static bfd_size_type bfd_compress_section_contents (bfd *abfd, sec_ptr sec, bfd_byte *uncompressed_buffer, bfd_size_type uncompressed_size) { uLong compressed_size; bfd_byte *buffer; bfd_size_type buffer_size; bfd_boolean decompress; int zlib_size = 0; int orig_compression_header_size; bfd_size_type orig_uncompressed_size; unsigned int orig_uncompressed_alignment_pow; int header_size = bfd_get_compression_header_size (abfd, NULL); bfd_boolean compressed = bfd_is_section_compressed_with_header (abfd, sec, &orig_compression_header_size, &orig_uncompressed_size, &orig_uncompressed_alignment_pow); /* Either ELF compression header or the 12-byte, "ZLIB" + 8-byte size, overhead in .zdebug* section. */ if (!header_size) header_size = 12; if (compressed) { /* We shouldn't decompress unsupported compressed section. */ if (orig_compression_header_size < 0) abort (); /* Different compression schemes. Just move the compressed section contents to the right position. */ if (orig_compression_header_size == 0) { /* Convert it from .zdebug* section. Get the uncompressed size first. We need to subtract the 12-byte overhead in .zdebug* section. Set orig_compression_header_size to the 12-bye overhead. */ orig_compression_header_size = 12; zlib_size = uncompressed_size - 12; } else { /* Convert it to .zdebug* section. */ zlib_size = uncompressed_size - orig_compression_header_size; } /* Add the header size. */ compressed_size = zlib_size + header_size; } else compressed_size = compressBound (uncompressed_size) + header_size; /* Uncompress if it leads to smaller size. */ if (compressed && compressed_size > orig_uncompressed_size) { decompress = TRUE; buffer_size = orig_uncompressed_size; } else { decompress = FALSE; buffer_size = compressed_size; } buffer = (bfd_byte *) bfd_alloc (abfd, buffer_size); if (buffer == NULL) return 0; if (compressed) { sec->size = orig_uncompressed_size; if (decompress) { if (!decompress_contents (uncompressed_buffer + orig_compression_header_size, zlib_size, buffer, buffer_size)) { bfd_set_error (bfd_error_bad_value); bfd_release (abfd, buffer); return 0; } free (uncompressed_buffer); bfd_set_section_alignment (abfd, sec, orig_uncompressed_alignment_pow); sec->contents = buffer; sec->compress_status = COMPRESS_SECTION_DONE; return orig_uncompressed_size; } else { bfd_update_compression_header (abfd, buffer, sec); memmove (buffer + header_size, uncompressed_buffer + orig_compression_header_size, zlib_size); } } else { if (compress ((Bytef*) buffer + header_size, &compressed_size, (const Bytef*) uncompressed_buffer, uncompressed_size) != Z_OK) { bfd_release (abfd, buffer); bfd_set_error (bfd_error_bad_value); return 0; } compressed_size += header_size; /* PR binutils/18087: If compression didn't make the section smaller, just keep it uncompressed. */ if (compressed_size < uncompressed_size) bfd_update_compression_header (abfd, buffer, sec); else { /* NOTE: There is a small memory leak here since uncompressed_buffer is malloced and won't be freed. */ bfd_release (abfd, buffer); sec->contents = uncompressed_buffer; sec->compress_status = COMPRESS_SECTION_NONE; return uncompressed_size; } } free (uncompressed_buffer); sec->contents = buffer; sec->size = compressed_size; sec->compress_status = COMPRESS_SECTION_DONE; return uncompressed_size; } /* FUNCTION bfd_get_full_section_contents SYNOPSIS bfd_boolean bfd_get_full_section_contents (bfd *abfd, asection *section, bfd_byte **ptr); DESCRIPTION Read all data from @var{section} in BFD @var{abfd}, decompress if needed, and store in @var{*ptr}. If @var{*ptr} is NULL, return @var{*ptr} with memory malloc'd by this function. Return @code{TRUE} if the full section contents is retrieved successfully. If the section has no contents then this function returns @code{TRUE} but @var{*ptr} is set to NULL. */ bfd_boolean bfd_get_full_section_contents (bfd *abfd, sec_ptr sec, bfd_byte **ptr) { bfd_size_type sz; bfd_byte *p = *ptr; bfd_boolean ret; bfd_size_type save_size; bfd_size_type save_rawsize; bfd_byte *compressed_buffer; unsigned int compression_header_size; if (abfd->direction != write_direction && sec->rawsize != 0) sz = sec->rawsize; else sz = sec->size; if (sz == 0) { *ptr = NULL; return TRUE; } switch (sec->compress_status) { case COMPRESS_SECTION_NONE: if (p == NULL) { p = (bfd_byte *) bfd_malloc (sz); if (p == NULL) { /* PR 20801: Provide a more helpful error message. */ if (bfd_get_error () == bfd_error_no_memory) _bfd_error_handler /* xgettext:c-format */ (_("error: %pB(%pA) is too large (%#" PRIx64 " bytes)"), abfd, sec, (uint64_t) sz); return FALSE; } } if (!bfd_get_section_contents (abfd, sec, p, 0, sz)) { if (*ptr != p) free (p); return FALSE; } *ptr = p; return TRUE; case DECOMPRESS_SECTION_SIZED: /* Read in the full compressed section contents. */ compressed_buffer = (bfd_byte *) bfd_malloc (sec->compressed_size); if (compressed_buffer == NULL) return FALSE; save_rawsize = sec->rawsize; save_size = sec->size; /* Clear rawsize, set size to compressed size and set compress_status to COMPRESS_SECTION_NONE. If the compressed size is bigger than the uncompressed size, bfd_get_section_contents will fail. */ sec->rawsize = 0; sec->size = sec->compressed_size; sec->compress_status = COMPRESS_SECTION_NONE; ret = bfd_get_section_contents (abfd, sec, compressed_buffer, 0, sec->compressed_size); /* Restore rawsize and size. */ sec->rawsize = save_rawsize; sec->size = save_size; sec->compress_status = DECOMPRESS_SECTION_SIZED; if (!ret) goto fail_compressed; if (p == NULL) p = (bfd_byte *) bfd_malloc (sz); if (p == NULL) goto fail_compressed; compression_header_size = bfd_get_compression_header_size (abfd, sec); if (compression_header_size == 0) /* Set header size to the zlib header size if it is a SHF_COMPRESSED section. */ compression_header_size = 12; if (!decompress_contents (compressed_buffer + compression_header_size, sec->compressed_size - compression_header_size, p, sz)) { bfd_set_error (bfd_error_bad_value); if (p != *ptr) free (p); fail_compressed: free (compressed_buffer); return FALSE; } free (compressed_buffer); *ptr = p; return TRUE; case COMPRESS_SECTION_DONE: if (sec->contents == NULL) return FALSE; if (p == NULL) { p = (bfd_byte *) bfd_malloc (sz); if (p == NULL) return FALSE; *ptr = p; } /* PR 17512; file: 5bc29788. */ if (p != sec->contents) memcpy (p, sec->contents, sz); return TRUE; default: abort (); } } /* FUNCTION bfd_cache_section_contents SYNOPSIS void bfd_cache_section_contents (asection *sec, void *contents); DESCRIPTION Stash @var(contents) so any following reads of @var(sec) do not need to decompress again. */ void bfd_cache_section_contents (asection *sec, void *contents) { if (sec->compress_status == DECOMPRESS_SECTION_SIZED) sec->compress_status = COMPRESS_SECTION_DONE; sec->contents = contents; sec->flags |= SEC_IN_MEMORY; } /* FUNCTION bfd_is_section_compressed_with_header SYNOPSIS bfd_boolean bfd_is_section_compressed_with_header (bfd *abfd, asection *section, int *compression_header_size_p, bfd_size_type *uncompressed_size_p, unsigned int *uncompressed_alignment_power_p); DESCRIPTION Return @code{TRUE} if @var{section} is compressed. Compression header size is returned in @var{compression_header_size_p}, uncompressed size is returned in @var{uncompressed_size_p} and the uncompressed data alignement power is returned in @var{uncompressed_align_pow_p}. If compression is unsupported, compression header size is returned with -1 and uncompressed size is returned with 0. */ bfd_boolean bfd_is_section_compressed_with_header (bfd *abfd, sec_ptr sec, int *compression_header_size_p, bfd_size_type *uncompressed_size_p, unsigned int *uncompressed_align_pow_p) { bfd_byte header[MAX_COMPRESSION_HEADER_SIZE]; int compression_header_size; int header_size; unsigned int saved = sec->compress_status; bfd_boolean compressed; *uncompressed_align_pow_p = 0; compression_header_size = bfd_get_compression_header_size (abfd, sec); if (compression_header_size > MAX_COMPRESSION_HEADER_SIZE) abort (); header_size = compression_header_size ? compression_header_size : 12; /* Don't decompress the section. */ sec->compress_status = COMPRESS_SECTION_NONE; /* Read the header. */ if (bfd_get_section_contents (abfd, sec, header, 0, header_size)) { if (compression_header_size == 0) /* In this case, it should be "ZLIB" followed by the uncompressed section size, 8 bytes in big-endian order. */ compressed = CONST_STRNEQ ((char*) header , "ZLIB"); else compressed = TRUE; } else compressed = FALSE; *uncompressed_size_p = sec->size; if (compressed) { if (compression_header_size != 0) { if (!bfd_check_compression_header (abfd, header, sec, uncompressed_size_p, uncompressed_align_pow_p)) compression_header_size = -1; } /* Check for the pathalogical case of a debug string section that contains the string ZLIB.... as the first entry. We assume that no uncompressed .debug_str section would ever be big enough to have the first byte of its (big-endian) size be non-zero. */ else if (strcmp (sec->name, ".debug_str") == 0 && ISPRINT (header[4])) compressed = FALSE; else *uncompressed_size_p = bfd_getb64 (header + 4); } /* Restore compress_status. */ sec->compress_status = saved; *compression_header_size_p = compression_header_size; return compressed; } /* FUNCTION bfd_is_section_compressed SYNOPSIS bfd_boolean bfd_is_section_compressed (bfd *abfd, asection *section); DESCRIPTION Return @code{TRUE} if @var{section} is compressed. */ bfd_boolean bfd_is_section_compressed (bfd *abfd, sec_ptr sec) { int compression_header_size; bfd_size_type uncompressed_size; unsigned int uncompressed_align_power; return (bfd_is_section_compressed_with_header (abfd, sec, &compression_header_size, &uncompressed_size, &uncompressed_align_power) && compression_header_size >= 0 && uncompressed_size > 0); } /* FUNCTION bfd_init_section_decompress_status SYNOPSIS bfd_boolean bfd_init_section_decompress_status (bfd *abfd, asection *section); DESCRIPTION Record compressed section size, update section size with decompressed size and set compress_status to DECOMPRESS_SECTION_SIZED. Return @code{FALSE} if the section is not a valid compressed section. Otherwise, return @code{TRUE}. */ bfd_boolean bfd_init_section_decompress_status (bfd *abfd, sec_ptr sec) { bfd_byte header[MAX_COMPRESSION_HEADER_SIZE]; int compression_header_size; int header_size; bfd_size_type uncompressed_size; unsigned int uncompressed_alignment_power = 0; compression_header_size = bfd_get_compression_header_size (abfd, sec); if (compression_header_size > MAX_COMPRESSION_HEADER_SIZE) abort (); header_size = compression_header_size ? compression_header_size : 12; /* Read the header. */ if (sec->rawsize != 0 || sec->contents != NULL || sec->compress_status != COMPRESS_SECTION_NONE || !bfd_get_section_contents (abfd, sec, header, 0, header_size)) { bfd_set_error (bfd_error_invalid_operation); return FALSE; } if (compression_header_size == 0) { /* In this case, it should be "ZLIB" followed by the uncompressed section size, 8 bytes in big-endian order. */ if (! CONST_STRNEQ ((char*) header, "ZLIB")) { bfd_set_error (bfd_error_wrong_format); return FALSE; } uncompressed_size = bfd_getb64 (header + 4); } else if (!bfd_check_compression_header (abfd, header, sec, &uncompressed_size, &uncompressed_alignment_power)) { bfd_set_error (bfd_error_wrong_format); return FALSE; } sec->compressed_size = sec->size; sec->size = uncompressed_size; bfd_set_section_alignment (abfd, sec, uncompressed_alignment_power); sec->compress_status = DECOMPRESS_SECTION_SIZED; return TRUE; } /* FUNCTION bfd_init_section_compress_status SYNOPSIS bfd_boolean bfd_init_section_compress_status (bfd *abfd, asection *section); DESCRIPTION If open for read, compress section, update section size with compressed size and set compress_status to COMPRESS_SECTION_DONE. Return @code{FALSE} if the section is not a valid compressed section. Otherwise, return @code{TRUE}. */ bfd_boolean bfd_init_section_compress_status (bfd *abfd, sec_ptr sec) { bfd_size_type uncompressed_size; bfd_byte *uncompressed_buffer; /* Error if not opened for read. */ if (abfd->direction != read_direction || sec->size == 0 || sec->rawsize != 0 || sec->contents != NULL || sec->compress_status != COMPRESS_SECTION_NONE) { bfd_set_error (bfd_error_invalid_operation); return FALSE; } /* Read in the full section contents and compress it. */ uncompressed_size = sec->size; uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size); /* PR 21431 */ if (uncompressed_buffer == NULL) return FALSE; if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer, 0, uncompressed_size)) return FALSE; uncompressed_size = bfd_compress_section_contents (abfd, sec, uncompressed_buffer, uncompressed_size); return uncompressed_size != 0; } /* FUNCTION bfd_compress_section SYNOPSIS bfd_boolean bfd_compress_section (bfd *abfd, asection *section, bfd_byte *uncompressed_buffer); DESCRIPTION If open for write, compress section, update section size with compressed size and set compress_status to COMPRESS_SECTION_DONE. Return @code{FALSE} if compression fail. Otherwise, return @code{TRUE}. */ bfd_boolean bfd_compress_section (bfd *abfd, sec_ptr sec, bfd_byte *uncompressed_buffer) { bfd_size_type uncompressed_size = sec->size; /* Error if not opened for write. */ if (abfd->direction != write_direction || uncompressed_size == 0 || uncompressed_buffer == NULL || sec->contents != NULL || sec->compressed_size != 0 || sec->compress_status != COMPRESS_SECTION_NONE) { bfd_set_error (bfd_error_invalid_operation); return FALSE; } /* Compress it. */ return bfd_compress_section_contents (abfd, sec, uncompressed_buffer, uncompressed_size) != 0; }