42e09be9c2
do not participate in the global symbols namespace, but rtld locks are still replaced and functions are interposed. In particular, __pthread_map_stacks_exec is resolved to the libc version. If a library is loaded later, which requires adjustment of the stack protection mode, rtld calls into libc __pthread_map_stacks_exec due to the symbols scope. The libc version might recurse into binder and recursively acquire rtld bind lock, causing the hang. Make libc __pthread_map_stacks_exec() interposed, which synchronizes rtld locks and version of the stack exec hook when libthr loaded, regardless of the symbol scope control or symbol resolution order. The __pthread_map_stacks_exec() symbol is removed from the private version in libthr since libc symbol now operates correctly in presence of libthr. Reported and tested by: markj Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
85 lines
2.6 KiB
C
85 lines
2.6 KiB
C
/*
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* Copyright (c) 2010 Konstantin Belousov <kib@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/resource.h>
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#include <sys/sysctl.h>
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#include <link.h>
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#include <stddef.h>
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#include "libc_private.h"
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int __elf_phdr_match_addr(struct dl_phdr_info *, void *);
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void __pthread_map_stacks_exec(void);
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int
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__elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
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{
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const Elf_Phdr *ph;
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int i;
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for (i = 0; i < phdr_info->dlpi_phnum; i++) {
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ph = &phdr_info->dlpi_phdr[i];
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if (ph->p_type != PT_LOAD || (ph->p_flags & PF_X) == 0)
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continue;
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if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
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(uintptr_t)addr + sizeof(addr) < phdr_info->dlpi_addr +
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ph->p_vaddr + ph->p_memsz)
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break;
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}
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return (i != phdr_info->dlpi_phnum);
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}
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void
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__libc_map_stacks_exec(void)
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{
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int mib[2];
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struct rlimit rlim;
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u_long usrstack;
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size_t len;
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mib[0] = CTL_KERN;
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mib[1] = KERN_USRSTACK;
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len = sizeof(usrstack);
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if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0)
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== -1)
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return;
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if (getrlimit(RLIMIT_STACK, &rlim) == -1)
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return;
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mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
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rlim.rlim_cur, _rtld_get_stack_prot());
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}
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#pragma weak __pthread_map_stacks_exec
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void
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__pthread_map_stacks_exec(void)
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{
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((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
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}
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