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) 51 continue; 52 53 /* ELFv1 ABI for powerpc64 passes function descriptor 54 * pointers around, not function pointers. The function 55 * descriptors live in .opd, which is a non-executable segment. 56 * The PF_X check would therefore make all address checks fail, 57 * causing a crash in some instances. Don't skip over 58 * non-executable segments in the ELFv1 powerpc64 case. 59 */ 60 #if !defined(__powerpc64__) || (defined(_CALL_ELF) && _CALL_ELF == 2) 61 if ((ph->p_flags & PF_X) == 0) 62 continue; 63 #endif 64 65 if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr && 66 (uintptr_t)addr + sizeof(addr) < phdr_info->dlpi_addr + 67 ph->p_vaddr + ph->p_memsz) 68 break; 69 } 70 return (i != phdr_info->dlpi_phnum); 71 } 72 73 void 74 __libc_map_stacks_exec(void) 75 { 76 int mib[2]; 77 struct rlimit rlim; 78 u_long usrstack; 79 size_t len; 80 81 mib[0] = CTL_KERN; 82 mib[1] = KERN_USRSTACK; 83 len = sizeof(usrstack); 84 if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0) 85 == -1) 86 return; 87 if (getrlimit(RLIMIT_STACK, &rlim) == -1) 88 return; 89 mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur), 90 rlim.rlim_cur, _rtld_get_stack_prot()); 91 } 92 93 #pragma weak __pthread_map_stacks_exec 94 void 95 __pthread_map_stacks_exec(void) 96 { 97 98 ((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])(); 99 } 100