1 /* 2 * ELF payload decoding support. 3 * 4 * Copyright (C) 2022 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA 20 */ 21 22 #include <l4/util/elf.h> 23 24 #include "elf.h" 25 26 27 28 /* Generic segment creation from program segments. */ 29 30 Segment *ProgramSegment::segment() 31 { 32 return new Segment( 33 region_address(), 34 region_size(), 35 region_flags(), 36 file_offset(), 37 file_contents()); 38 } 39 40 41 42 /* Program segment construction for 32- or 64-bit variants. */ 43 44 template <typename PROGRAM_HEADER> 45 ProgramSegmentVariant<PROGRAM_HEADER>::ProgramSegmentVariant(PROGRAM_HEADER *header) 46 : _header(header) 47 { 48 } 49 50 template <typename PROGRAM_HEADER> 51 bool ProgramSegmentVariant<PROGRAM_HEADER>::loadable() 52 { 53 return _header->p_type == PT_LOAD; 54 } 55 56 template <typename PROGRAM_HEADER> 57 offset_t ProgramSegmentVariant<PROGRAM_HEADER>::file_contents() 58 { 59 return _header->p_filesz; 60 } 61 62 template <typename PROGRAM_HEADER> 63 offset_t ProgramSegmentVariant<PROGRAM_HEADER>::file_offset() 64 { 65 return _header->p_offset; 66 } 67 68 template <typename PROGRAM_HEADER> 69 l4_addr_t ProgramSegmentVariant<PROGRAM_HEADER>::region_address() 70 { 71 return _header->p_vaddr; 72 } 73 74 template <typename PROGRAM_HEADER> 75 offset_t ProgramSegmentVariant<PROGRAM_HEADER>::region_size() 76 { 77 return _header->p_memsz; 78 } 79 80 template <typename PROGRAM_HEADER> 81 l4re_rm_flags_t ProgramSegmentVariant<PROGRAM_HEADER>::region_flags() 82 { 83 l4re_rm_flags_t flags = 0; 84 85 if (_header->p_flags & PF_R) 86 flags |= L4RE_RM_F_R; 87 if (_header->p_flags & PF_W) 88 flags |= L4RE_RM_F_W; 89 if (_header->p_flags & PF_X) 90 flags |= L4RE_RM_F_X; 91 92 return flags; 93 } 94 95 96 97 /* ELF payload construction for 32- or 64-bit variants. */ 98 99 template <typename HEADER, typename PROGRAM_HEADER> 100 PayloadVariant<HEADER, PROGRAM_HEADER>::PayloadVariant(HEADER *header) 101 : _header(header) 102 { 103 } 104 105 template <typename HEADER, typename PROGRAM_HEADER> 106 l4_addr_t PayloadVariant<HEADER, PROGRAM_HEADER>::entry_point() 107 { 108 return _header->e_entry; 109 } 110 111 template <typename HEADER, typename PROGRAM_HEADER> 112 offset_t PayloadVariant<HEADER, PROGRAM_HEADER>::header_extent() 113 { 114 return sizeof(HEADER); 115 } 116 117 template <typename HEADER, typename PROGRAM_HEADER> 118 offset_t PayloadVariant<HEADER, PROGRAM_HEADER>::program_header_extent() 119 { 120 return _header->e_phoff + _header->e_phentsize * _header->e_phnum; 121 } 122 123 template <typename HEADER, typename PROGRAM_HEADER> 124 unsigned int PayloadVariant<HEADER, PROGRAM_HEADER>::segments() 125 { 126 return _header->e_phnum; 127 } 128 129 template <typename HEADER, typename PROGRAM_HEADER> 130 ProgramSegment *PayloadVariant<HEADER, PROGRAM_HEADER>::segment(unsigned int i) 131 { 132 if (i >= segments()) 133 return NULL; 134 135 return new ProgramSegmentVariant<PROGRAM_HEADER>( 136 (PROGRAM_HEADER *) ((char *) _header + _header->e_phoff + 137 _header->e_phentsize * i)); 138 } 139 140 141 142 /* Return the appropriate payload object. */ 143 144 Payload *get_payload(char *buf) 145 { 146 switch (buf[EI_CLASS]) 147 { 148 case (char) 1: 149 return new PayloadVariant<Elf32_Ehdr, Elf32_Phdr>((Elf32_Ehdr *) buf); 150 case (char) 2: 151 return new PayloadVariant<Elf64_Ehdr, Elf64_Phdr>((Elf64_Ehdr *) buf); 152 default: 153 return NULL; 154 } 155 } 156 157 /* vim: tabstop=2 expandtab shiftwidth=2 158 */