xref: /freebsd/lib/libc/gen/elf_utils.c (revision 56e53cb8ef000c3ef72337a4095987a932cdedef)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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  * $FreeBSD$
29  */
30 
31 #include <sys/types.h>
32 #include <sys/mman.h>
33 #include <sys/resource.h>
34 #include <sys/sysctl.h>
35 #include <link.h>
36 #include <stddef.h>
37 #include "libc_private.h"
38 
39 int __elf_phdr_match_addr(struct dl_phdr_info *, void *);
40 void __pthread_map_stacks_exec(void);
41 
42 int
43 __elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
44 {
45 	const Elf_Phdr *ph;
46 	int i;
47 
48 	for (i = 0; i < phdr_info->dlpi_phnum; i++) {
49 		ph = &phdr_info->dlpi_phdr[i];
50 		if (ph->p_type != PT_LOAD || (ph->p_flags & PF_X) == 0)
51 			continue;
52 		if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
53 		    (uintptr_t)addr + sizeof(addr) < phdr_info->dlpi_addr +
54 		    ph->p_vaddr + ph->p_memsz)
55 			break;
56 	}
57 	return (i != phdr_info->dlpi_phnum);
58 }
59 
60 void
61 __libc_map_stacks_exec(void)
62 {
63 	int mib[2];
64 	struct rlimit rlim;
65 	u_long usrstack;
66 	size_t len;
67 
68 	mib[0] = CTL_KERN;
69 	mib[1] = KERN_USRSTACK;
70 	len = sizeof(usrstack);
71 	if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0)
72 	    == -1)
73 		return;
74 	if (getrlimit(RLIMIT_STACK, &rlim) == -1)
75 		return;
76 	mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
77 	    rlim.rlim_cur, _rtld_get_stack_prot());
78 }
79 
80 #pragma weak __pthread_map_stacks_exec
81 void
82 __pthread_map_stacks_exec(void)
83 {
84 
85 	((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
86 }
87