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 /* Program segment construction for 32- or 64-bit variants. */ 29 30 template <typename PROGRAM_HEADER> 31 ProgramSegmentVariant<PROGRAM_HEADER>::ProgramSegmentVariant(PROGRAM_HEADER *header) 32 : _header(header) 33 { 34 init(); 35 } 36 37 template <typename PROGRAM_HEADER> 38 bool ProgramSegmentVariant<PROGRAM_HEADER>::loadable() 39 { 40 return _header->p_type == PT_LOAD; 41 } 42 43 template <typename PROGRAM_HEADER> 44 offset_t ProgramSegmentVariant<PROGRAM_HEADER>::file_contents() 45 { 46 return _header->p_filesz; 47 } 48 49 template <typename PROGRAM_HEADER> 50 offset_t ProgramSegmentVariant<PROGRAM_HEADER>::file_offset() 51 { 52 return _header->p_offset; 53 } 54 55 template <typename PROGRAM_HEADER> 56 l4_addr_t ProgramSegmentVariant<PROGRAM_HEADER>::region_address() 57 { 58 return _header->p_vaddr; 59 } 60 61 template <typename PROGRAM_HEADER> 62 offset_t ProgramSegmentVariant<PROGRAM_HEADER>::region_size() 63 { 64 return _header->p_memsz; 65 } 66 67 template <typename PROGRAM_HEADER> 68 l4re_rm_flags_t ProgramSegmentVariant<PROGRAM_HEADER>::region_flags() 69 { 70 l4re_rm_flags_t flags = 0; 71 72 if (_header->p_flags & PF_R) 73 flags |= L4RE_RM_F_R; 74 if (_header->p_flags & PF_W) 75 flags |= L4RE_RM_F_W; 76 if (_header->p_flags & PF_X) 77 flags |= L4RE_RM_F_X; 78 79 return flags; 80 } 81 82 83 84 /* Generic payload destruction. */ 85 86 Payload::~Payload() 87 { 88 if (_segments != NULL) 89 { 90 for (unsigned int i = 0; i < segments(); i++) 91 delete _segments[i]; 92 } 93 } 94 95 unsigned int Payload::segments() 96 { 97 return 0; 98 } 99 100 101 102 /* ELF payload construction for 32- or 64-bit variants. */ 103 104 template <typename HEADER, typename PROGRAM_HEADER> 105 PayloadVariant<HEADER, PROGRAM_HEADER>::PayloadVariant(HEADER *header) 106 : _header(header) 107 { 108 } 109 110 template <typename HEADER, typename PROGRAM_HEADER> 111 l4_addr_t PayloadVariant<HEADER, PROGRAM_HEADER>::entry_point() 112 { 113 return _header->e_entry; 114 } 115 116 template <typename HEADER, typename PROGRAM_HEADER> 117 offset_t PayloadVariant<HEADER, PROGRAM_HEADER>::header_extent() 118 { 119 return sizeof(HEADER); 120 } 121 122 template <typename HEADER, typename PROGRAM_HEADER> 123 offset_t PayloadVariant<HEADER, PROGRAM_HEADER>::program_header_extent() 124 { 125 return _header->e_phoff + _header->e_phentsize * _header->e_phnum; 126 } 127 128 template <typename HEADER, typename PROGRAM_HEADER> 129 unsigned int PayloadVariant<HEADER, PROGRAM_HEADER>::segments() 130 { 131 return _header->e_phnum; 132 } 133 134 template <typename HEADER, typename PROGRAM_HEADER> 135 Segment *PayloadVariant<HEADER, PROGRAM_HEADER>::segment(unsigned int i) 136 { 137 if (i >= segments()) 138 return NULL; 139 140 if (_segments == NULL) 141 { 142 _segments = new Segment *[segments()]; 143 144 for (unsigned int j = 0; j < segments(); j++) 145 _segments[j] = NULL; 146 } 147 148 Segment *segment = _segments[i]; 149 150 if (segment == NULL) 151 { 152 segment = new ProgramSegmentVariant<PROGRAM_HEADER>( 153 (PROGRAM_HEADER *) ((char *) _header + _header->e_phoff + 154 _header->e_phentsize * i)); 155 _segments[i] = segment; 156 } 157 158 return segment; 159 } 160 161 162 163 /* Return the appropriate payload object. */ 164 165 Payload *exec_open_payload(char *buf) 166 { 167 switch (buf[EI_CLASS]) 168 { 169 case (char) 1: 170 return new PayloadVariant<Elf32_Ehdr, Elf32_Phdr>((Elf32_Ehdr *) buf); 171 case (char) 2: 172 return new PayloadVariant<Elf64_Ehdr, Elf64_Phdr>((Elf64_Ehdr *) buf); 173 default: 174 return NULL; 175 } 176 } 177 178 /* vim: tabstop=2 expandtab shiftwidth=2 179 */