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 void __pthread_distribute_static_tls(size_t, void *, size_t, size_t);
45
46 int
__elf_phdr_match_addr(struct dl_phdr_info * phdr_info,void * addr)47 __elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
48 {
49 const Elf_Phdr *ph;
50 int i;
51
52 for (i = 0; i < phdr_info->dlpi_phnum; i++) {
53 ph = &phdr_info->dlpi_phdr[i];
54 if (ph->p_type != PT_LOAD)
55 continue;
56
57 /* ELFv1 ABI for powerpc64 passes function descriptor
58 * pointers around, not function pointers. The function
59 * descriptors live in .opd, which is a non-executable segment.
60 * The PF_X check would therefore make all address checks fail,
61 * causing a crash in some instances. Don't skip over
62 * non-executable segments in the ELFv1 powerpc64 case.
63 */
64 #if !defined(__powerpc64__) || (defined(_CALL_ELF) && _CALL_ELF == 2)
65 if ((ph->p_flags & PF_X) == 0)
66 continue;
67 #endif
68
69 if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
70 (uintptr_t)addr < phdr_info->dlpi_addr +
71 ph->p_vaddr + ph->p_memsz)
72 break;
73 }
74 return (i != phdr_info->dlpi_phnum);
75 }
76
77 void
__libc_map_stacks_exec(void)78 __libc_map_stacks_exec(void)
79 {
80 int mib[2];
81 struct rlimit rlim;
82 u_long usrstack, stacksz;
83 size_t len;
84
85 if (_elf_aux_info(AT_USRSTACKBASE, &usrstack, sizeof(usrstack)) != 0) {
86 mib[0] = CTL_KERN;
87 mib[1] = KERN_USRSTACK;
88 len = sizeof(usrstack);
89 if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1)
90 return;
91 }
92 if (_elf_aux_info(AT_USRSTACKLIM, &stacksz, sizeof(stacksz)) != 0) {
93 if (getrlimit(RLIMIT_STACK, &rlim) == -1)
94 return;
95 stacksz = rlim.rlim_cur;
96 }
97 mprotect((void *)(uintptr_t)(usrstack - stacksz), stacksz,
98 _rtld_get_stack_prot());
99 }
100
101 #pragma weak __pthread_map_stacks_exec
102 void
__pthread_map_stacks_exec(void)103 __pthread_map_stacks_exec(void)
104 {
105
106 ((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
107 }
108
109 void
__libc_distribute_static_tls(size_t offset,void * src,size_t len,size_t total_len)110 __libc_distribute_static_tls(size_t offset, void *src, size_t len,
111 size_t total_len)
112 {
113 char *tlsbase;
114
115 #ifdef TLS_VARIANT_I
116 tlsbase = (char *)_tcb_get() + offset;
117 #else
118 tlsbase = (char *)_tcb_get() - offset;
119 #endif
120 memcpy(tlsbase, src, len);
121 memset(tlsbase + len, 0, total_len - len);
122 }
123
124 #pragma weak __pthread_distribute_static_tls
125 void
__pthread_distribute_static_tls(size_t offset,void * src,size_t len,size_t total_len)126 __pthread_distribute_static_tls(size_t offset, void *src, size_t len,
127 size_t total_len)
128 {
129
130 ((void (*)(size_t, void *, size_t, size_t))__libc_interposing[
131 INTERPOS_distribute_static_tls])(offset, src, len, total_len);
132 }
133