freebsd-dev/lib/libc/gen/elf_utils.c
John Baldwin 97bdc65f27 Don't assume objects in program sections have a size of a pointer.
The size of the object at 'addr' is unknown and might be smaller than
the size of a pointer (e.g. some x86 instructions are smaller than a
pointer).  Instead, just check that the address is in the bounds of
the program header.

Reported by:	CHERI (indirectly)
Reviewed by:	kib, brooks
Obtained from:	CheriBSD
MFC after:	1 week
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D26279
2020-09-02 20:43:08 +00:00

123 lines
3.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2010 Konstantin Belousov <kib@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/sysctl.h>
#include <link.h>
#include <stddef.h>
#include <string.h>
#include "libc_private.h"
#include "static_tls.h"
void __pthread_map_stacks_exec(void);
void __pthread_distribute_static_tls(size_t, void *, size_t, size_t);
int
__elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
{
const Elf_Phdr *ph;
int i;
for (i = 0; i < phdr_info->dlpi_phnum; i++) {
ph = &phdr_info->dlpi_phdr[i];
if (ph->p_type != PT_LOAD)
continue;
/* ELFv1 ABI for powerpc64 passes function descriptor
* pointers around, not function pointers. The function
* descriptors live in .opd, which is a non-executable segment.
* The PF_X check would therefore make all address checks fail,
* causing a crash in some instances. Don't skip over
* non-executable segments in the ELFv1 powerpc64 case.
*/
#if !defined(__powerpc64__) || (defined(_CALL_ELF) && _CALL_ELF == 2)
if ((ph->p_flags & PF_X) == 0)
continue;
#endif
if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
(uintptr_t)addr < phdr_info->dlpi_addr +
ph->p_vaddr + ph->p_memsz)
break;
}
return (i != phdr_info->dlpi_phnum);
}
void
__libc_map_stacks_exec(void)
{
int mib[2];
struct rlimit rlim;
u_long usrstack;
size_t len;
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof(usrstack);
if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0)
== -1)
return;
if (getrlimit(RLIMIT_STACK, &rlim) == -1)
return;
mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
rlim.rlim_cur, _rtld_get_stack_prot());
}
#pragma weak __pthread_map_stacks_exec
void
__pthread_map_stacks_exec(void)
{
((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
}
void
__libc_distribute_static_tls(size_t offset, void *src, size_t len,
size_t total_len)
{
uintptr_t tlsbase;
tlsbase = _libc_get_static_tls_base(offset);
memcpy((void *)tlsbase, src, len);
memset((char *)tlsbase + len, 0, total_len - len);
}
#pragma weak __pthread_distribute_static_tls
void
__pthread_distribute_static_tls(size_t offset, void *src, size_t len,
size_t total_len)
{
((void (*)(size_t, void *, size_t, size_t))__libc_interposing[
INTERPOS_distribute_static_tls])(offset, src, len, total_len);
}