1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2010 Konstantin Belousov <kib@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Neither the name of the author nor the names of any co-contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/auxv.h>
31 #include <sys/mman.h>
32 #include <sys/resource.h>
33 #include <sys/sysctl.h>
34
35 #include <machine/tls.h>
36
37 #include <link.h>
38 #include <stddef.h>
39 #include <string.h>
40
41 #include "libc_private.h"
42
43 void __pthread_map_stacks_exec(void);
44
45 int
__elf_phdr_match_addr(struct dl_phdr_info * phdr_info,void * addr)46 __elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
47 {
48 const Elf_Phdr *ph;
49 int i;
50
51 for (i = 0; i < phdr_info->dlpi_phnum; i++) {
52 ph = &phdr_info->dlpi_phdr[i];
53 if (ph->p_type != PT_LOAD)
54 continue;
55
56 /* ELFv1 ABI for powerpc64 passes function descriptor
57 * pointers around, not function pointers. The function
58 * descriptors live in .opd, which is a non-executable segment.
59 * The PF_X check would therefore make all address checks fail,
60 * causing a crash in some instances. Don't skip over
61 * non-executable segments in the ELFv1 powerpc64 case.
62 */
63 #if !defined(__powerpc64__) || (defined(_CALL_ELF) && _CALL_ELF == 2)
64 if ((ph->p_flags & PF_X) == 0)
65 continue;
66 #endif
67
68 if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
69 (uintptr_t)addr < phdr_info->dlpi_addr +
70 ph->p_vaddr + ph->p_memsz)
71 break;
72 }
73 return (i != phdr_info->dlpi_phnum);
74 }
75
76 void
__libc_map_stacks_exec(void)77 __libc_map_stacks_exec(void)
78 {
79 int mib[2];
80 struct rlimit rlim;
81 u_long usrstack, stacksz;
82 size_t len;
83
84 if (_elf_aux_info(AT_USRSTACKBASE, &usrstack, sizeof(usrstack)) != 0) {
85 mib[0] = CTL_KERN;
86 mib[1] = KERN_USRSTACK;
87 len = sizeof(usrstack);
88 if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1)
89 return;
90 }
91 if (_elf_aux_info(AT_USRSTACKLIM, &stacksz, sizeof(stacksz)) != 0) {
92 if (getrlimit(RLIMIT_STACK, &rlim) == -1)
93 return;
94 stacksz = rlim.rlim_cur;
95 }
96 mprotect((void *)(uintptr_t)(usrstack - stacksz), stacksz,
97 _rtld_get_stack_prot());
98 }
99
100 #pragma weak __pthread_map_stacks_exec
101 void
__pthread_map_stacks_exec(void)102 __pthread_map_stacks_exec(void)
103 {
104
105 ((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
106 }
107