/src/libbpf/elfutils/libelf/gelf_getnote.c
Line | Count | Source (jump to first uncovered line) |
1 | | /* Get note information at the supplied offset. |
2 | | Copyright (C) 2007, 2014, 2015, 2018 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 | 0 | { |
43 | 0 | if (data == NULL) |
44 | 0 | return 0; |
45 | | |
46 | 0 | if (unlikely (data->d_type != ELF_T_NHDR && data->d_type != ELF_T_NHDR8)) |
47 | 0 | { |
48 | 0 | __libelf_seterrno (ELF_E_INVALID_HANDLE); |
49 | 0 | return 0; |
50 | 0 | } |
51 | | |
52 | | /* It's easy to handle this type. It has the same size for 32 and |
53 | | 64 bit objects. */ |
54 | 0 | assert (sizeof (GElf_Nhdr) == sizeof (Elf32_Nhdr)); |
55 | 0 | assert (sizeof (GElf_Nhdr) == sizeof (Elf64_Nhdr)); |
56 | | |
57 | 0 | 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 | 0 | if (unlikely (offset > data->d_size |
62 | 0 | || data->d_size - offset < sizeof (GElf_Nhdr))) |
63 | 0 | { |
64 | 0 | __libelf_seterrno (ELF_E_OFFSET_RANGE); |
65 | 0 | offset = 0; |
66 | 0 | } |
67 | 0 | else |
68 | 0 | { |
69 | 0 | const GElf_Nhdr *n = data->d_buf + offset; |
70 | 0 | offset += sizeof *n; |
71 | |
|
72 | 0 | if (offset > data->d_size) |
73 | 0 | offset = 0; |
74 | 0 | else |
75 | 0 | { |
76 | | /* This is slightly tricky, offset is guaranteed to be 4 |
77 | | byte aligned, which is what we need for the name_offset. |
78 | | And normally desc_offset is also 4 byte aligned, but not |
79 | | for GNU Property notes, then it should be 8. So align |
80 | | the offset, after adding the namesz, and include padding |
81 | | in descsz to get to the end. */ |
82 | 0 | *name_offset = offset; |
83 | 0 | if (n->n_namesz > data->d_size |
84 | 0 | || offset > data->d_size - n->n_namesz) |
85 | 0 | offset = 0; |
86 | 0 | else |
87 | 0 | { |
88 | 0 | offset += n->n_namesz; |
89 | | /* Include padding. Check below for overflow. */ |
90 | 0 | GElf_Word descsz = (data->d_type == ELF_T_NHDR8 |
91 | 0 | ? NOTE_ALIGN8 (n->n_descsz) |
92 | 0 | : NOTE_ALIGN4 (n->n_descsz)); |
93 | |
|
94 | 0 | if (data->d_type == ELF_T_NHDR8) |
95 | 0 | offset = NOTE_ALIGN8 (offset); |
96 | 0 | else |
97 | 0 | offset = NOTE_ALIGN4 (offset); |
98 | |
|
99 | 0 | if (unlikely (offset > data->d_size |
100 | 0 | || data->d_size - offset < descsz |
101 | 0 | || (descsz == 0 && n->n_descsz != 0))) |
102 | 0 | offset = 0; |
103 | 0 | else |
104 | 0 | { |
105 | 0 | *desc_offset = offset; |
106 | 0 | offset += descsz; |
107 | 0 | *result = *n; |
108 | 0 | } |
109 | 0 | } |
110 | 0 | } |
111 | 0 | } |
112 | |
|
113 | 0 | rwlock_unlock (((Elf_Data_Scn *) data)->s->elf->lock); |
114 | |
|
115 | 0 | return offset; |
116 | 0 | } |