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 <string.h> 38 #include "libc_private.h" 39 #include "static_tls.h" 40 41 int __elf_phdr_match_addr(struct dl_phdr_info *, void *); 42 void __pthread_map_stacks_exec(void); 43 void __pthread_distribute_static_tls(size_t, void *, size_t, size_t); 44 45 int 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 + sizeof(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 77 __libc_map_stacks_exec(void) 78 { 79 int mib[2]; 80 struct rlimit rlim; 81 u_long usrstack; 82 size_t len; 83 84 mib[0] = CTL_KERN; 85 mib[1] = KERN_USRSTACK; 86 len = sizeof(usrstack); 87 if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0) 88 == -1) 89 return; 90 if (getrlimit(RLIMIT_STACK, &rlim) == -1) 91 return; 92 mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur), 93 rlim.rlim_cur, _rtld_get_stack_prot()); 94 } 95 96 #pragma weak __pthread_map_stacks_exec 97 void 98 __pthread_map_stacks_exec(void) 99 { 100 101 ((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])(); 102 } 103 104 void 105 __libc_distribute_static_tls(size_t offset, void *src, size_t len, 106 size_t total_len) 107 { 108 uintptr_t tlsbase; 109 110 tlsbase = _libc_get_static_tls_base(offset); 111 memcpy((void *)tlsbase, src, len); 112 memset((char *)tlsbase + len, 0, total_len - len); 113 } 114 115 #pragma weak __pthread_distribute_static_tls 116 void 117 __pthread_distribute_static_tls(size_t offset, void *src, size_t len, 118 size_t total_len) 119 { 120 121 ((void (*)(size_t, void *, size_t, size_t))__libc_interposing[ 122 INTERPOS_distribute_static_tls])(offset, src, len, total_len); 123 } 124