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d61ef735 | 1 | /* Determine if address is inside object load segments. |
6d7e8eda | 2 | Copyright (C) 1996-2023 Free Software Foundation, Inc. |
d61ef735 CD |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
d61ef735 CD |
18 | |
19 | #include <link.h> | |
20 | #include <elf.h> | |
21 | ||
22 | /* Return non-zero if ADDR lies within one of L's loadable segments. | |
23 | We have three cases we care about. | |
24 | ||
25 | Case 1: addr is above a segment. | |
26 | +==================+<- l_map_end | |
27 | | |<- addr | |
28 | |------------------|<- l_addr + p_vaddr + p_memsz | |
29 | | | | |
30 | | | | |
31 | |------------------|<- l_addr + p_vaddr | |
32 | |------------------|<- l_addr | |
33 | | | | |
34 | +==================+<- l_map_start | |
35 | ||
36 | Case 2: addr is within a segments. | |
37 | +==================+<- l_map_end | |
38 | | | | |
39 | |------------------|<- l_addr + p_vaddr + p_memsz | |
40 | | |<- addr | |
41 | | | | |
42 | |------------------|<- l_addr + p_vaddr | |
43 | |------------------|<- l_addr | |
44 | | | | |
45 | +==================+<- l_map_start | |
46 | ||
47 | Case 3: addr is below a segments. | |
48 | +==================+<- l_map_end | |
49 | | | | |
50 | |------------------|<- l_addr + p_vaddr + p_memsz | |
51 | | | | |
52 | | | | |
53 | |------------------|<- l_addr + p_vaddr | |
54 | |------------------|<- l_addr | |
55 | | |<- addr | |
56 | +==================+<- l_map_start | |
57 | ||
58 | All the arithmetic is unsigned and we shift all the values down by | |
59 | l_addr + p_vaddr and then compare the normalized addr to the range | |
60 | of interest i.e. 0 <= addr < p_memsz. | |
61 | ||
62 | */ | |
63 | int | |
d61ef735 CD |
64 | _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr) |
65 | { | |
66 | int n = l->l_phnum; | |
67 | const ElfW(Addr) reladdr = addr - l->l_addr; | |
68 | ||
69 | while (--n >= 0) | |
70 | if (l->l_phdr[n].p_type == PT_LOAD | |
71 | && reladdr - l->l_phdr[n].p_vaddr < l->l_phdr[n].p_memsz) | |
72 | return 1; | |
73 | return 0; | |
74 | } |