26d8253ac6
members of the ELF Executable Header inside the library-private
`struct _Elf' descriptor and only update the underlying Elf{32,64}_Ehdr
structure on an elf_update(3) call. These fields of the Ehdr
structure are technically `out of bounds' for an application program
per the ELF(3) API, but we've seen applications that initialize
a new Ehdr structure using memcpy(), messing up the library's
invariants. [1]
Implement elf_getphnum() and handle ELF objects with more than
64K program header table entries.
Reported by: jb [1]
100 lines
2.8 KiB
C
100 lines
2.8 KiB
C
/*-
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* Copyright (c) 2006 Joseph Koshy
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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. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <gelf.h>
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#include "_libelf.h"
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static unsigned long
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_libelf_sum(unsigned long c, const unsigned char *s, size_t size)
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{
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if (s == NULL || size == 0)
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return (c);
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while (size--)
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c += *s++;
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return (c);
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}
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unsigned long
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_libelf_checksum(Elf *e, int elfclass)
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{
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size_t shn;
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Elf_Scn *scn;
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Elf_Data *d;
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unsigned long checksum;
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GElf_Ehdr eh;
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GElf_Shdr shdr;
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if (e == NULL) {
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LIBELF_SET_ERROR(ARGUMENT, 0);
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return (0L);
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}
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if (e->e_class != elfclass) {
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LIBELF_SET_ERROR(CLASS, 0);
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return (0L);
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}
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if (gelf_getehdr(e, &eh) == NULL)
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return (0);
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/*
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* Iterate over all sections in the ELF file, computing the
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* checksum along the way.
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*
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* The first section is always SHN_UNDEF and can be skipped.
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* Non-allocatable sections are skipped, as are sections that
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* could be affected by utilities such as strip(1).
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*/
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checksum = 0;
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for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) {
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if ((scn = elf_getscn(e, shn)) == NULL)
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return (0);
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if (gelf_getshdr(scn, &shdr) == NULL)
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return (0);
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if ((shdr.sh_flags & SHF_ALLOC) == 0 ||
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shdr.sh_type == SHT_DYNAMIC ||
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shdr.sh_type == SHT_DYNSYM)
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continue;
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d = NULL;
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while ((d = elf_rawdata(scn, d)) != NULL)
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checksum = _libelf_sum(checksum,
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(unsigned char *) d->d_buf, d->d_size);
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}
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/*
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* Return a 16-bit checksum compatible with Solaris.
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*/
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return (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL));
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}
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