1 /* Get note information at the supplied offset. 2 Copyright (C) 2007, 2014, 2015 Red Hat, Inc. 3 This file is part of elfutils. 4 5 This file is free software; you can redistribute it and/or modify 6 it under the terms of either 7 8 * the GNU Lesser General Public License as published by the Free 9 Software Foundation; either version 3 of the License, or (at 10 your option) any later version 11 12 or 13 14 * the GNU General Public License as published by the Free 15 Software Foundation; either version 2 of the License, or (at 16 your option) any later version 17 18 or both in parallel, as here. 19 20 elfutils is distributed in the hope that it will be useful, but 21 WITHOUT ANY WARRANTY; without even the implied warranty of 22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 23 General Public License for more details. 24 25 You should have received copies of the GNU General Public License and 26 the GNU Lesser General Public License along with this program. If 27 not, see <http://www.gnu.org/licenses/>. */ 28 29 #ifdef HAVE_CONFIG_H 30 # include <config.h> 31 #endif 32 33 #include <assert.h> 34 #include <gelf.h> 35 #include <string.h> 36 37 #include "libelfP.h" 38 39 size_t 40 gelf_getnote (Elf_Data *data, size_t offset, GElf_Nhdr *result, 41 size_t *name_offset, size_t *desc_offset) 42 { 43 if (data == NULL) 44 return 0; 45 46 if (unlikely (data->d_type != ELF_T_NHDR)) 47 { 48 __libelf_seterrno (ELF_E_INVALID_HANDLE); 49 return 0; 50 } 51 52 /* It's easy to handle this type. It has the same size for 32 and 53 64 bit objects. */ 54 assert (sizeof (GElf_Nhdr) == sizeof (Elf32_Nhdr)); 55 assert (sizeof (GElf_Nhdr) == sizeof (Elf64_Nhdr)); 56 57 rwlock_rdlock (((Elf_Data_Scn *) data)->s->elf->lock); 58 59 /* The data is already in the correct form. Just make sure the 60 offset is OK. */ 61 if (unlikely (offset > data->d_size 62 || data->d_size - offset < sizeof (GElf_Nhdr))) 63 { 64 __libelf_seterrno (ELF_E_OFFSET_RANGE); 65 offset = 0; 66 } 67 else 68 { 69 const GElf_Nhdr *n = data->d_buf + offset; 70 offset += sizeof *n; 71 72 /* Include padding. Check below for overflow. */ 73 GElf_Word namesz = NOTE_ALIGN (n->n_namesz); 74 GElf_Word descsz = NOTE_ALIGN (n->n_descsz); 75 76 if (unlikely (offset > data->d_size 77 || data->d_size - offset < namesz 78 || (namesz == 0 && n->n_namesz != 0))) 79 offset = 0; 80 else 81 { 82 *name_offset = offset; 83 offset += namesz; 84 if (unlikely (offset > data->d_size 85 || data->d_size - offset < descsz 86 || (descsz == 0 && n->n_descsz != 0))) 87 offset = 0; 88 else 89 { 90 *desc_offset = offset; 91 offset += descsz; 92 *result = *n; 93 } 94 } 95 } 96 97 rwlock_unlock (((Elf_Data_Scn *) data)->s->elf->lock); 98 99 return offset; 100 } 101
