2013-12-30 22:16:18 +01:00
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/*
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* elf header parsing.
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*
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* Copyright (C) 2013 Google, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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2014-03-05 19:12:09 +01:00
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#include "elfparsing.h"
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2013-12-30 22:16:18 +01:00
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#include "common.h"
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#include "cbfs.h"
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/*
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* Short form: this is complicated, but we've tried making it simple
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* and we keep hitting problems with our ELF parsing.
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*
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* The ELF parsing situation has always been a bit tricky. In fact,
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* we (and most others) have been getting it wrong in small ways for
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* years. Recently this has caused real trouble for the ARM V8 build.
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* In this file we attempt to finally get it right for all variations
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* of endian-ness and word size and target architectures and
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* architectures we might get run on. Phew!. To do this we borrow a
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* page from the FreeBSD NFS xdr model (see elf_ehdr and elf_phdr),
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* the Plan 9 endianness functions (see xdr.c), and Go interfaces (see
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* how we use buffer structs in this file). This ends up being a bit
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* wordy at the lowest level, but greatly simplifies the elf parsing
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* code and removes a common source of bugs, namely, forgetting to
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* flip type endianness when referencing a struct member.
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*
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* ELF files can have four combinations of data layout: 32/64, and
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* big/little endian. Further, to add to the fun, depending on the
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* word size, the size of the ELF structs varies. The coreboot SELF
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* format is simpler in theory: it's supposed to be always BE, and the
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* various struct members allow room for growth: the entry point is
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* always 64 bits, for example, so the size of a SELF struct is
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* constant, regardless of target architecture word size. Hence, we
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* need to do some transformation of the ELF files.
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*
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* A given architecture, realistically, only supports one of the four
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* combinations at a time as the 'native' format. Hence, our code has
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* been sprinkled with every variation of [nh]to[hn][sll] over the
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* years. We've never quite gotten it all right, however, and a quick
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* pass over this code revealed another bug. It's all worked because,
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* until now, all the working platforms that had CBFS were 32 LE. Even then,
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* however, bugs crept in: we recently realized that we're not
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* transforming the entry point to big format when we store into the
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* SELF image.
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*
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* The problem is essentially an XDR operation:
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* we have something in a foreign format and need to transform it.
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* It's most like XDR because:
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* 1) the byte order can be wrong
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* 2) the word size can be wrong
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* 3) the size of elements in the stream depends on the value
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* of other elements in the stream
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* it's not like XDR because:
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* 1) the byte order can be right
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* 2) the word size can be right
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* 3) the struct members are all on a natural alignment
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*
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* Hence, this new approach. To cover word size issues, we *always*
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* transform the two structs we care about, the file header and
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* program header, into a native struct in the 64 bit format:
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*
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* [32,little] -> [Elf64_Ehdr, Elf64_Phdr]
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* [64,little] -> [Elf64_Ehdr, Elf64_Phdr]
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* [32,big] -> [Elf64_Ehdr, Elf64_Phdr]
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* [64,big] -> [Elf64_Ehdr, Elf64_Phdr]
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* Then we just use those structs, and all the need for inline ntoh* goes away,
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* as well as all the chances for error.
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* This works because all the SELF structs have fields large enough for
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* the largest ELF 64 struct members, and all the Elf64 struct members
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* are at least large enough for all ELF 32 struct members.
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* We end up with one function to do all our ELF parsing, and two functions
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* to transform the headers. For the put case, we also have
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* XDR functions, and hopefully we'll never again spend 5 years with the
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* wrong endian-ness on an output value :-)
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* This should work for all word sizes and endianness we hope to target.
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* I *really* don't want to be here for 128 bit addresses.
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*
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* The parse functions are called with a pointer to an input buffer
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* struct. One might ask: are there enough bytes in the input buffer?
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* We know there need to be at *least* sizeof(Elf32_Ehdr) +
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* sizeof(Elf32_Phdr) bytes. Realistically, there has to be some data
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* too. If we start to worry, though we have not in the past, we
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* might apply the simple test: the input buffer needs to be at least
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* sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) bytes because, even if it's
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* ELF 32, there's got to be *some* data! This is not theoretically
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* accurate but it is actually good enough in practice. It allows the
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* header transformation code to ignore the possibility of underrun.
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*
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2018-08-23 18:08:20 +02:00
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* We also must accommodate different ELF files, and hence formats,
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2013-12-30 22:16:18 +01:00
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* in the same cbfs invocation. We might load a 64-bit payload
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* on a 32-bit machine; we might even have a mixed armv7/armv8
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* SOC or even a system with an x86/ARM!
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*
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* A possibly problematic (though unlikely to be so) assumption
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* is that we expect the BIOS to remain in the lowest 32 bits
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* of the physical address space. Since ARMV8 has standardized
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* on that, and x86_64 also has, this seems a safe assumption.
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*
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* To repeat, ELF structs are different sizes because ELF struct
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* members are different sizes, depending on values in the ELF file
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* header. For this we use the functions defined in xdr.c, which
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* consume bytes, convert the endianness, and advance the data pointer
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* in the buffer struct.
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*/
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2014-03-05 19:01:36 +01:00
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static int iself(const void *input)
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{
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const Elf32_Ehdr *ehdr = input;
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return !memcmp(ehdr->e_ident, ELFMAG, 4);
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}
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2013-12-30 22:16:18 +01:00
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/* Get the ident array, so we can figure out
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* endian-ness, word size, and in future other useful
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* parameters
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*/
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static void
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elf_eident(struct buffer *input, Elf64_Ehdr *ehdr)
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{
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2014-03-05 05:08:05 +01:00
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bgets(input, ehdr->e_ident, sizeof(ehdr->e_ident));
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2013-12-30 22:16:18 +01:00
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}
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2014-03-05 05:08:05 +01:00
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static int
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check_size(const struct buffer *b, size_t offset, size_t size, const char *desc)
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{
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if (size == 0)
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return 0;
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if (offset >= buffer_size(b) || (offset + size) > buffer_size(b)) {
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ERROR("The file is not large enough for the '%s'. "
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2014-03-16 00:15:57 +01:00
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"%zu bytes @ offset %zu, input %zu bytes.\n",
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2014-03-05 05:08:05 +01:00
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desc, size, offset, buffer_size(b));
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return -1;
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}
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return 0;
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}
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2013-12-30 22:16:18 +01:00
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static void
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elf_ehdr(struct buffer *input, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
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{
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ehdr->e_type = xdr->get16(input);
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ehdr->e_machine = xdr->get16(input);
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ehdr->e_version = xdr->get32(input);
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if (bit64){
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ehdr->e_entry = xdr->get64(input);
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ehdr->e_phoff = xdr->get64(input);
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ehdr->e_shoff = xdr->get64(input);
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} else {
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ehdr->e_entry = xdr->get32(input);
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ehdr->e_phoff = xdr->get32(input);
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ehdr->e_shoff = xdr->get32(input);
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}
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ehdr->e_flags = xdr->get32(input);
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ehdr->e_ehsize = xdr->get16(input);
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ehdr->e_phentsize = xdr->get16(input);
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ehdr->e_phnum = xdr->get16(input);
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ehdr->e_shentsize = xdr->get16(input);
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ehdr->e_shnum = xdr->get16(input);
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ehdr->e_shstrndx = xdr->get16(input);
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}
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static void
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elf_phdr(struct buffer *pinput, Elf64_Phdr *phdr,
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int entsize, struct xdr *xdr, int bit64)
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{
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/*
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* The entsize need not be sizeof(*phdr).
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* Hence, it is easier to keep a copy of the input,
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* as the xdr functions may not advance the input
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* pointer the full entsize; rather than get tricky
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* we just advance it below.
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*/
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2014-03-05 05:08:05 +01:00
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struct buffer input;
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buffer_clone(&input, pinput);
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2013-12-30 22:16:18 +01:00
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if (bit64){
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phdr->p_type = xdr->get32(&input);
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phdr->p_flags = xdr->get32(&input);
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phdr->p_offset = xdr->get64(&input);
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phdr->p_vaddr = xdr->get64(&input);
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phdr->p_paddr = xdr->get64(&input);
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phdr->p_filesz = xdr->get64(&input);
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phdr->p_memsz = xdr->get64(&input);
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phdr->p_align = xdr->get64(&input);
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} else {
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phdr->p_type = xdr->get32(&input);
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phdr->p_offset = xdr->get32(&input);
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phdr->p_vaddr = xdr->get32(&input);
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phdr->p_paddr = xdr->get32(&input);
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phdr->p_filesz = xdr->get32(&input);
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phdr->p_memsz = xdr->get32(&input);
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phdr->p_flags = xdr->get32(&input);
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phdr->p_align = xdr->get32(&input);
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}
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2014-03-05 05:08:05 +01:00
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buffer_seek(pinput, entsize);
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2013-12-30 22:16:18 +01:00
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}
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static void
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elf_shdr(struct buffer *pinput, Elf64_Shdr *shdr,
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int entsize, struct xdr *xdr, int bit64)
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{
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/*
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* The entsize need not be sizeof(*shdr).
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* Hence, it is easier to keep a copy of the input,
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* as the xdr functions may not advance the input
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* pointer the full entsize; rather than get tricky
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* we just advance it below.
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*/
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struct buffer input = *pinput;
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if (bit64){
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shdr->sh_name = xdr->get32(&input);
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shdr->sh_type = xdr->get32(&input);
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shdr->sh_flags = xdr->get64(&input);
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shdr->sh_addr = xdr->get64(&input);
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shdr->sh_offset = xdr->get64(&input);
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shdr->sh_size= xdr->get64(&input);
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shdr->sh_link = xdr->get32(&input);
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shdr->sh_info = xdr->get32(&input);
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shdr->sh_addralign = xdr->get64(&input);
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shdr->sh_entsize = xdr->get64(&input);
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} else {
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shdr->sh_name = xdr->get32(&input);
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shdr->sh_type = xdr->get32(&input);
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shdr->sh_flags = xdr->get32(&input);
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shdr->sh_addr = xdr->get32(&input);
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shdr->sh_offset = xdr->get32(&input);
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shdr->sh_size = xdr->get32(&input);
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shdr->sh_link = xdr->get32(&input);
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shdr->sh_info = xdr->get32(&input);
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shdr->sh_addralign = xdr->get32(&input);
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shdr->sh_entsize = xdr->get32(&input);
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}
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2014-03-05 05:08:05 +01:00
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buffer_seek(pinput, entsize);
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}
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2014-03-05 20:09:55 +01:00
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static int
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phdr_read(const struct buffer *in, struct parsed_elf *pelf,
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struct xdr *xdr, int bit64)
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2014-03-05 05:08:05 +01:00
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{
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struct buffer b;
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Elf64_Phdr *phdr;
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2014-03-05 20:09:55 +01:00
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Elf64_Ehdr *ehdr;
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2014-03-05 05:08:05 +01:00
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int i;
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2014-03-05 20:09:55 +01:00
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ehdr = &pelf->ehdr;
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2014-03-05 05:08:05 +01:00
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/* cons up an input buffer for the headers.
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* Note that the program headers can be anywhere,
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* per the ELF spec, You'd be surprised how many ELF
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* readers miss this little detail.
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*/
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util/cbfstool: Prevent overflow of 16 bit multiplications
Considering the following integer multiplication:
u64 = u16 * u16
What on earth, one might wonder, is the problem with this? Well, due to
C's unfortunately abstruse integer semantics, both u16's are implicitly
converted to int before the multiplication, which cannot hold
all possible values of a u16 * u16. Even worse, after overflow the
intermediate result will be a negative number, which during the
conversion to a u64 will be sign-extended to a huge integer. Not good.
The solution is to manually cast one of the u16 to a u32 or u64, which
are large enough to not have any overflow and will prevent the implicit
conversion. The type of the u64 is preferred, though a u32 is used
instead of size_t, since that can change depending on the platform.
Change-Id: I5391221d46d620d0e5bd629e2f9680be7a53342e
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 12297{03,04,05,06,07,08,09,10}
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33986
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2019-07-02 22:38:38 +02:00
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buffer_splice(&b, in, ehdr->e_phoff,
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(uint32_t)ehdr->e_phentsize * ehdr->e_phnum);
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2014-03-05 05:08:05 +01:00
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if (check_size(in, ehdr->e_phoff, buffer_size(&b), "program headers"))
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2014-03-05 20:09:55 +01:00
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return -1;
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2014-03-05 05:08:05 +01:00
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/* gather up all the phdrs.
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* We do them all at once because there is more
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* than one loop over all the phdrs.
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*/
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2014-03-05 21:54:13 +01:00
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phdr = calloc(ehdr->e_phnum, sizeof(*phdr));
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2014-03-07 22:23:05 +01:00
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for (i = 0; i < ehdr->e_phnum; i++) {
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DEBUG("Parsing segment %d\n", i);
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2014-03-05 05:08:05 +01:00
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elf_phdr(&b, &phdr[i], ehdr->e_phentsize, xdr, bit64);
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2014-03-07 22:23:05 +01:00
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/* Ensure the contents are valid within the elf file. */
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if (check_size(in, phdr[i].p_offset, phdr[i].p_filesz,
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2014-08-09 16:58:00 +02:00
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"segment contents")) {
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free(phdr);
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2014-03-05 20:09:55 +01:00
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return -1;
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2014-08-09 16:58:00 +02:00
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}
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2014-03-07 22:23:05 +01:00
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}
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2014-03-05 20:09:55 +01:00
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pelf->phdr = phdr;
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return 0;
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2014-03-05 05:08:05 +01:00
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}
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2014-03-05 20:09:55 +01:00
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|
|
static int
|
|
|
|
shdr_read(const struct buffer *in, struct parsed_elf *pelf,
|
|
|
|
struct xdr *xdr, int bit64)
|
2014-03-05 05:08:05 +01:00
|
|
|
{
|
|
|
|
struct buffer b;
|
|
|
|
Elf64_Shdr *shdr;
|
2014-03-05 20:09:55 +01:00
|
|
|
Elf64_Ehdr *ehdr;
|
2014-03-05 05:08:05 +01:00
|
|
|
int i;
|
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
ehdr = &pelf->ehdr;
|
|
|
|
|
2014-03-05 05:08:05 +01:00
|
|
|
/* cons up an input buffer for the section headers.
|
|
|
|
* Note that the section headers can be anywhere,
|
|
|
|
* per the ELF spec, You'd be surprised how many ELF
|
|
|
|
* readers miss this little detail.
|
|
|
|
*/
|
util/cbfstool: Prevent overflow of 16 bit multiplications
Considering the following integer multiplication:
u64 = u16 * u16
What on earth, one might wonder, is the problem with this? Well, due to
C's unfortunately abstruse integer semantics, both u16's are implicitly
converted to int before the multiplication, which cannot hold
all possible values of a u16 * u16. Even worse, after overflow the
intermediate result will be a negative number, which during the
conversion to a u64 will be sign-extended to a huge integer. Not good.
The solution is to manually cast one of the u16 to a u32 or u64, which
are large enough to not have any overflow and will prevent the implicit
conversion. The type of the u64 is preferred, though a u32 is used
instead of size_t, since that can change depending on the platform.
Change-Id: I5391221d46d620d0e5bd629e2f9680be7a53342e
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 12297{03,04,05,06,07,08,09,10}
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33986
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2019-07-02 22:38:38 +02:00
|
|
|
buffer_splice(&b, in, ehdr->e_shoff,
|
|
|
|
(uint32_t)ehdr->e_shentsize * ehdr->e_shnum);
|
2014-03-05 05:08:05 +01:00
|
|
|
if (check_size(in, ehdr->e_shoff, buffer_size(&b), "section headers"))
|
2014-03-05 20:09:55 +01:00
|
|
|
return -1;
|
2014-03-05 05:08:05 +01:00
|
|
|
|
|
|
|
/* gather up all the shdrs. */
|
2014-03-05 21:54:13 +01:00
|
|
|
shdr = calloc(ehdr->e_shnum, sizeof(*shdr));
|
2014-03-07 22:23:05 +01:00
|
|
|
for (i = 0; i < ehdr->e_shnum; i++) {
|
|
|
|
DEBUG("Parsing section %d\n", i);
|
2014-03-05 05:08:05 +01:00
|
|
|
elf_shdr(&b, &shdr[i], ehdr->e_shentsize, xdr, bit64);
|
2014-03-07 22:23:05 +01:00
|
|
|
}
|
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
pelf->shdr = shdr;
|
|
|
|
|
|
|
|
return 0;
|
2013-12-30 22:16:18 +01:00
|
|
|
}
|
|
|
|
|
2014-03-05 20:57:30 +01:00
|
|
|
static int
|
|
|
|
reloc_read(const struct buffer *in, struct parsed_elf *pelf,
|
|
|
|
struct xdr *xdr, int bit64)
|
|
|
|
{
|
|
|
|
struct buffer b;
|
|
|
|
Elf64_Word i;
|
|
|
|
Elf64_Ehdr *ehdr;
|
|
|
|
|
|
|
|
ehdr = &pelf->ehdr;
|
|
|
|
pelf->relocs = calloc(ehdr->e_shnum, sizeof(Elf64_Rela *));
|
|
|
|
|
|
|
|
/* Allocate array for each section that contains relocation entries. */
|
|
|
|
for (i = 0; i < ehdr->e_shnum; i++) {
|
|
|
|
Elf64_Shdr *shdr;
|
|
|
|
Elf64_Rela *rela;
|
|
|
|
Elf64_Xword j;
|
|
|
|
Elf64_Xword nrelocs;
|
|
|
|
int is_rela;
|
|
|
|
|
|
|
|
shdr = &pelf->shdr[i];
|
|
|
|
|
|
|
|
/* Only process REL and RELA sections. */
|
|
|
|
if (shdr->sh_type != SHT_REL && shdr->sh_type != SHT_RELA)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
DEBUG("Checking relocation section %u\n", i);
|
|
|
|
|
|
|
|
/* Ensure the section that relocations apply is a valid. */
|
|
|
|
if (shdr->sh_info >= ehdr->e_shnum ||
|
|
|
|
shdr->sh_info == SHN_UNDEF) {
|
|
|
|
ERROR("Relocations apply to an invalid section: %u\n",
|
|
|
|
shdr[i].sh_info);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
is_rela = shdr->sh_type == SHT_RELA;
|
|
|
|
|
|
|
|
/* Determine the number relocations in this section. */
|
|
|
|
nrelocs = shdr->sh_size / shdr->sh_entsize;
|
|
|
|
|
|
|
|
pelf->relocs[i] = calloc(nrelocs, sizeof(Elf64_Rela));
|
|
|
|
|
|
|
|
buffer_splice(&b, in, shdr->sh_offset, shdr->sh_size);
|
|
|
|
if (check_size(in, shdr->sh_offset, buffer_size(&b),
|
|
|
|
"relocation section")) {
|
|
|
|
ERROR("Relocation section %u failed.\n", i);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
rela = pelf->relocs[i];
|
|
|
|
for (j = 0; j < nrelocs; j++) {
|
|
|
|
if (bit64) {
|
|
|
|
rela->r_offset = xdr->get64(&b);
|
|
|
|
rela->r_info = xdr->get64(&b);
|
|
|
|
if (is_rela)
|
|
|
|
rela->r_addend = xdr->get64(&b);
|
|
|
|
} else {
|
|
|
|
uint32_t r_info;
|
|
|
|
|
|
|
|
rela->r_offset = xdr->get32(&b);
|
|
|
|
r_info = xdr->get32(&b);
|
|
|
|
rela->r_info = ELF64_R_INFO(ELF32_R_SYM(r_info),
|
|
|
|
ELF32_R_TYPE(r_info));
|
|
|
|
if (is_rela)
|
|
|
|
rela->r_addend = xdr->get32(&b);
|
|
|
|
}
|
|
|
|
rela++;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2014-03-05 21:33:42 +01:00
|
|
|
static int strtab_read(const struct buffer *in, struct parsed_elf *pelf)
|
|
|
|
{
|
|
|
|
Elf64_Ehdr *ehdr;
|
|
|
|
Elf64_Word i;
|
|
|
|
|
|
|
|
ehdr = &pelf->ehdr;
|
|
|
|
|
|
|
|
if (ehdr->e_shstrndx >= ehdr->e_shnum) {
|
|
|
|
ERROR("Section header string table index out of range: %d\n",
|
|
|
|
ehdr->e_shstrndx);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* For each section of type SHT_STRTAB create a symtab buffer. */
|
|
|
|
pelf->strtabs = calloc(ehdr->e_shnum, sizeof(struct buffer *));
|
|
|
|
|
|
|
|
for (i = 0; i < ehdr->e_shnum; i++) {
|
|
|
|
struct buffer *b;
|
|
|
|
Elf64_Shdr *shdr = &pelf->shdr[i];
|
|
|
|
|
|
|
|
if (shdr->sh_type != SHT_STRTAB)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
b = calloc(1, sizeof(*b));
|
|
|
|
buffer_splice(b, in, shdr->sh_offset, shdr->sh_size);
|
|
|
|
if (check_size(in, shdr->sh_offset, buffer_size(b), "strtab")) {
|
|
|
|
ERROR("STRTAB section not within bounds: %d\n", i);
|
2014-08-09 16:58:00 +02:00
|
|
|
free(b);
|
2014-03-05 21:33:42 +01:00
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
pelf->strtabs[i] = b;
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2014-03-05 23:41:27 +01:00
|
|
|
static int
|
|
|
|
symtab_read(const struct buffer *in, struct parsed_elf *pelf,
|
|
|
|
struct xdr *xdr, int bit64)
|
|
|
|
{
|
|
|
|
Elf64_Ehdr *ehdr;
|
|
|
|
Elf64_Shdr *shdr;
|
2017-09-03 13:04:41 +02:00
|
|
|
Elf64_Half shnum;
|
|
|
|
Elf64_Xword i;
|
2014-03-05 23:41:27 +01:00
|
|
|
Elf64_Xword nsyms;
|
|
|
|
Elf64_Sym *sym;
|
|
|
|
struct buffer b;
|
|
|
|
|
|
|
|
ehdr = &pelf->ehdr;
|
|
|
|
|
|
|
|
shdr = NULL;
|
2017-09-03 13:04:41 +02:00
|
|
|
for (shnum = 0; shnum < ehdr->e_shnum; shnum++) {
|
|
|
|
if (pelf->shdr[shnum].sh_type != SHT_SYMTAB)
|
2014-03-05 23:41:27 +01:00
|
|
|
continue;
|
|
|
|
|
|
|
|
if (shdr != NULL) {
|
|
|
|
ERROR("Multiple symbol sections found. %u and %u\n",
|
2017-09-03 13:04:41 +02:00
|
|
|
(unsigned int)(shdr - pelf->shdr), shnum);
|
2014-03-05 23:41:27 +01:00
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
2017-09-03 13:04:41 +02:00
|
|
|
shdr = &pelf->shdr[shnum];
|
2014-03-05 23:41:27 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
if (shdr == NULL) {
|
|
|
|
ERROR("No symbol table found.\n");
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
buffer_splice(&b, in, shdr->sh_offset, shdr->sh_size);
|
|
|
|
if (check_size(in, shdr->sh_offset, buffer_size(&b), "symtab"))
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
nsyms = shdr->sh_size / shdr->sh_entsize;
|
|
|
|
|
|
|
|
pelf->syms = calloc(nsyms, sizeof(Elf64_Sym));
|
|
|
|
|
|
|
|
for (i = 0; i < nsyms; i++) {
|
|
|
|
sym = &pelf->syms[i];
|
|
|
|
|
|
|
|
if (bit64) {
|
|
|
|
sym->st_name = xdr->get32(&b);
|
|
|
|
sym->st_info = xdr->get8(&b);
|
|
|
|
sym->st_other = xdr->get8(&b);
|
|
|
|
sym->st_shndx = xdr->get16(&b);
|
|
|
|
sym->st_value = xdr->get64(&b);
|
|
|
|
sym->st_size = xdr->get64(&b);
|
|
|
|
} else {
|
|
|
|
sym->st_name = xdr->get32(&b);
|
|
|
|
sym->st_value = xdr->get32(&b);
|
|
|
|
sym->st_size = xdr->get32(&b);
|
|
|
|
sym->st_info = xdr->get8(&b);
|
|
|
|
sym->st_other = xdr->get8(&b);
|
|
|
|
sym->st_shndx = xdr->get16(&b);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
|
2013-12-30 22:16:18 +01:00
|
|
|
{
|
|
|
|
struct xdr *xdr = &xdr_le;
|
|
|
|
int bit64 = 0;
|
2014-03-05 05:08:05 +01:00
|
|
|
struct buffer input;
|
2014-03-05 20:09:55 +01:00
|
|
|
Elf64_Ehdr *ehdr;
|
2014-03-05 05:08:05 +01:00
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
/* Zero out the parsed elf structure. */
|
|
|
|
memset(pelf, 0, sizeof(*pelf));
|
2013-12-30 22:16:18 +01:00
|
|
|
|
2014-03-05 05:08:05 +01:00
|
|
|
if (!iself(buffer_get(pinput))) {
|
2017-07-05 13:28:24 +02:00
|
|
|
DEBUG("The stage file is not in ELF format!\n");
|
2013-12-30 22:16:18 +01:00
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
buffer_clone(&input, pinput);
|
|
|
|
ehdr = &pelf->ehdr;
|
2013-12-30 22:16:18 +01:00
|
|
|
elf_eident(&input, ehdr);
|
|
|
|
bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
|
|
|
|
/* Assume LE unless we are sure otherwise.
|
|
|
|
* We're not going to take on the task of
|
|
|
|
* fully validating the ELF file. That way
|
|
|
|
* lies madness.
|
|
|
|
*/
|
|
|
|
if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
|
|
|
|
xdr = &xdr_be;
|
|
|
|
|
|
|
|
elf_ehdr(&input, ehdr, xdr, bit64);
|
|
|
|
|
2014-03-05 20:57:30 +01:00
|
|
|
/* Relocation processing requires section header parsing. */
|
|
|
|
if (flags & ELF_PARSE_RELOC)
|
|
|
|
flags |= ELF_PARSE_SHDR;
|
|
|
|
|
2014-03-05 21:33:42 +01:00
|
|
|
/* String table processing requires section header parsing. */
|
|
|
|
if (flags & ELF_PARSE_STRTAB)
|
|
|
|
flags |= ELF_PARSE_SHDR;
|
|
|
|
|
2014-03-05 23:41:27 +01:00
|
|
|
/* Symbole table processing requires section header parsing. */
|
|
|
|
if (flags & ELF_PARSE_SYMTAB)
|
|
|
|
flags |= ELF_PARSE_SHDR;
|
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
if ((flags & ELF_PARSE_PHDR) && phdr_read(pinput, pelf, xdr, bit64))
|
|
|
|
goto fail;
|
|
|
|
|
|
|
|
if ((flags & ELF_PARSE_SHDR) && shdr_read(pinput, pelf, xdr, bit64))
|
|
|
|
goto fail;
|
|
|
|
|
2014-03-05 20:57:30 +01:00
|
|
|
if ((flags & ELF_PARSE_RELOC) && reloc_read(pinput, pelf, xdr, bit64))
|
|
|
|
goto fail;
|
|
|
|
|
2014-03-05 21:33:42 +01:00
|
|
|
if ((flags & ELF_PARSE_STRTAB) && strtab_read(pinput, pelf))
|
|
|
|
goto fail;
|
|
|
|
|
2014-03-05 23:41:27 +01:00
|
|
|
if ((flags & ELF_PARSE_SYMTAB) && symtab_read(pinput, pelf, xdr, bit64))
|
|
|
|
goto fail;
|
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
fail:
|
|
|
|
parsed_elf_destroy(pelf);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
void parsed_elf_destroy(struct parsed_elf *pelf)
|
|
|
|
{
|
2014-03-05 21:33:42 +01:00
|
|
|
Elf64_Half i;
|
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
free(pelf->phdr);
|
|
|
|
free(pelf->shdr);
|
2014-03-05 20:57:30 +01:00
|
|
|
if (pelf->relocs != NULL) {
|
|
|
|
for (i = 0; i < pelf->ehdr.e_shnum; i++)
|
|
|
|
free(pelf->relocs[i]);
|
|
|
|
}
|
|
|
|
free(pelf->relocs);
|
2014-03-05 21:33:42 +01:00
|
|
|
|
|
|
|
if (pelf->strtabs != NULL) {
|
|
|
|
for (i = 0; i < pelf->ehdr.e_shnum; i++)
|
|
|
|
free(pelf->strtabs[i]);
|
|
|
|
}
|
|
|
|
free(pelf->strtabs);
|
2014-03-05 23:41:27 +01:00
|
|
|
free(pelf->syms);
|
2014-03-05 20:09:55 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Get the headers from the buffer.
|
|
|
|
* Return -1 in the event of an error.
|
|
|
|
* The section headers are optional; if NULL
|
|
|
|
* is passed in for pshdr they won't be parsed.
|
|
|
|
* We don't (yet) make payload parsing optional
|
|
|
|
* because we've never seen a use case.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
elf_headers(const struct buffer *pinput,
|
|
|
|
Elf64_Ehdr *ehdr,
|
|
|
|
Elf64_Phdr **pphdr,
|
|
|
|
Elf64_Shdr **pshdr)
|
|
|
|
{
|
|
|
|
struct parsed_elf pelf;
|
|
|
|
int flags;
|
|
|
|
|
|
|
|
flags = ELF_PARSE_PHDR;
|
|
|
|
|
|
|
|
if (pshdr != NULL)
|
|
|
|
flags |= ELF_PARSE_SHDR;
|
|
|
|
|
|
|
|
if (parse_elf(pinput, &pelf, flags))
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
/* Copy out the parsed elf header. */
|
|
|
|
memcpy(ehdr, &pelf.ehdr, sizeof(*ehdr));
|
|
|
|
|
|
|
|
*pphdr = calloc(ehdr->e_phnum, sizeof(Elf64_Phdr));
|
|
|
|
memcpy(*pphdr, pelf.phdr, ehdr->e_phnum * sizeof(Elf64_Phdr));
|
2013-12-30 22:16:18 +01:00
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
if (pshdr != NULL) {
|
|
|
|
*pshdr = calloc(ehdr->e_shnum, sizeof(Elf64_Shdr));
|
|
|
|
memcpy(*pshdr, pelf.shdr, ehdr->e_shnum * sizeof(Elf64_Shdr));
|
|
|
|
}
|
2013-12-30 22:16:18 +01:00
|
|
|
|
2014-03-05 20:09:55 +01:00
|
|
|
parsed_elf_destroy(&pelf);
|
2013-12-30 22:16:18 +01:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
2014-03-11 17:48:56 +01:00
|
|
|
|
|
|
|
/* ELF Writing Support
|
|
|
|
*
|
|
|
|
* The ELF file is written according to the following layout:
|
|
|
|
* +------------------+
|
|
|
|
* | ELF Header |
|
|
|
|
* +------------------+
|
|
|
|
* | Section Headers |
|
|
|
|
* +------------------+
|
|
|
|
* | Program Headers |
|
|
|
|
* +------------------+
|
|
|
|
* | String table |
|
|
|
|
* +------------------+ <- 4KiB Aligned
|
|
|
|
* | Code/Data |
|
|
|
|
* +------------------+
|
|
|
|
*/
|
|
|
|
|
2015-10-27 22:21:55 +01:00
|
|
|
void elf_init_eheader(Elf64_Ehdr *ehdr, int machine, int nbits, int endian)
|
|
|
|
{
|
|
|
|
memset(ehdr, 0, sizeof(*ehdr));
|
|
|
|
ehdr->e_ident[EI_MAG0] = ELFMAG0;
|
|
|
|
ehdr->e_ident[EI_MAG1] = ELFMAG1;
|
|
|
|
ehdr->e_ident[EI_MAG2] = ELFMAG2;
|
|
|
|
ehdr->e_ident[EI_MAG3] = ELFMAG3;
|
|
|
|
ehdr->e_ident[EI_CLASS] = nbits;
|
|
|
|
ehdr->e_ident[EI_DATA] = endian;
|
|
|
|
ehdr->e_ident[EI_VERSION] = EV_CURRENT;
|
|
|
|
ehdr->e_type = ET_EXEC;
|
|
|
|
ehdr->e_machine = machine;
|
|
|
|
ehdr->e_version = EV_CURRENT;
|
|
|
|
if (nbits == ELFCLASS64) {
|
|
|
|
ehdr->e_ehsize = sizeof(Elf64_Ehdr);
|
|
|
|
ehdr->e_phentsize = sizeof(Elf64_Phdr);
|
|
|
|
ehdr->e_shentsize = sizeof(Elf64_Shdr);
|
|
|
|
} else {
|
|
|
|
ehdr->e_ehsize = sizeof(Elf32_Ehdr);
|
|
|
|
ehdr->e_phentsize = sizeof(Elf32_Phdr);
|
|
|
|
ehdr->e_shentsize = sizeof(Elf32_Shdr);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2020-01-29 13:31:16 +01:00
|
|
|
/* Arbitrary maximum number of sections. */
|
2014-03-11 17:48:56 +01:00
|
|
|
#define MAX_SECTIONS 16
|
|
|
|
struct elf_writer_section {
|
|
|
|
Elf64_Shdr shdr;
|
|
|
|
struct buffer content;
|
|
|
|
const char *name;
|
|
|
|
};
|
|
|
|
|
2015-10-28 17:26:40 +01:00
|
|
|
struct elf_writer_string_table {
|
|
|
|
size_t next_offset;
|
|
|
|
size_t max_size;
|
|
|
|
char *buffer;
|
|
|
|
};
|
|
|
|
|
|
|
|
struct elf_writer_sym_table {
|
|
|
|
size_t max_entries;
|
|
|
|
size_t num_entries;
|
|
|
|
Elf64_Sym *syms;
|
|
|
|
};
|
|
|
|
|
|
|
|
#define MAX_REL_NAME 32
|
|
|
|
struct elf_writer_rel {
|
|
|
|
size_t num_entries;
|
|
|
|
size_t max_entries;
|
|
|
|
Elf64_Rel *rels;
|
|
|
|
struct elf_writer_section *sec;
|
|
|
|
char name[MAX_REL_NAME];
|
|
|
|
};
|
|
|
|
|
2014-03-11 17:48:56 +01:00
|
|
|
struct elf_writer
|
|
|
|
{
|
|
|
|
Elf64_Ehdr ehdr;
|
|
|
|
struct xdr *xdr;
|
|
|
|
size_t num_secs;
|
|
|
|
struct elf_writer_section sections[MAX_SECTIONS];
|
2015-10-28 17:26:40 +01:00
|
|
|
struct elf_writer_rel rel_sections[MAX_SECTIONS];
|
2014-03-11 17:48:56 +01:00
|
|
|
Elf64_Phdr *phdrs;
|
2015-10-28 17:26:40 +01:00
|
|
|
struct elf_writer_section *shstrtab_sec;
|
|
|
|
struct elf_writer_section *strtab_sec;
|
|
|
|
struct elf_writer_section *symtab_sec;
|
|
|
|
struct elf_writer_string_table strtab;
|
|
|
|
struct elf_writer_sym_table symtab;
|
2014-03-11 17:48:56 +01:00
|
|
|
int bit64;
|
|
|
|
};
|
|
|
|
|
2015-10-28 17:26:40 +01:00
|
|
|
static size_t section_index(struct elf_writer *ew,
|
|
|
|
struct elf_writer_section *sec)
|
|
|
|
{
|
|
|
|
return sec - &ew->sections[0];
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct elf_writer_section *last_section(struct elf_writer *ew)
|
|
|
|
{
|
|
|
|
return &ew->sections[ew->num_secs - 1];
|
|
|
|
}
|
|
|
|
|
|
|
|
static void strtab_init(struct elf_writer *ew, size_t size)
|
|
|
|
{
|
|
|
|
struct buffer b;
|
|
|
|
Elf64_Shdr shdr;
|
|
|
|
|
|
|
|
/* Start adding strings after the initial NUL entry. */
|
|
|
|
ew->strtab.next_offset = 1;
|
|
|
|
ew->strtab.max_size = size;
|
|
|
|
ew->strtab.buffer = calloc(1, ew->strtab.max_size);
|
|
|
|
|
|
|
|
buffer_init(&b, NULL, ew->strtab.buffer, ew->strtab.max_size);
|
|
|
|
memset(&shdr, 0, sizeof(shdr));
|
|
|
|
shdr.sh_type = SHT_STRTAB;
|
|
|
|
shdr.sh_addralign = 1;
|
|
|
|
shdr.sh_size = ew->strtab.max_size;
|
|
|
|
elf_writer_add_section(ew, &shdr, &b, ".strtab");
|
|
|
|
ew->strtab_sec = last_section(ew);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void symtab_init(struct elf_writer *ew, size_t max_entries)
|
|
|
|
{
|
|
|
|
struct buffer b;
|
|
|
|
Elf64_Shdr shdr;
|
|
|
|
|
|
|
|
memset(&shdr, 0, sizeof(shdr));
|
|
|
|
shdr.sh_type = SHT_SYMTAB;
|
|
|
|
|
|
|
|
if (ew->bit64) {
|
|
|
|
shdr.sh_entsize = sizeof(Elf64_Sym);
|
|
|
|
shdr.sh_addralign = sizeof(Elf64_Addr);
|
|
|
|
} else {
|
|
|
|
shdr.sh_entsize = sizeof(Elf32_Sym);
|
|
|
|
shdr.sh_addralign = sizeof(Elf32_Addr);
|
|
|
|
}
|
|
|
|
|
|
|
|
shdr.sh_size = shdr.sh_entsize * max_entries;
|
|
|
|
|
|
|
|
ew->symtab.syms = calloc(max_entries, sizeof(Elf64_Sym));
|
|
|
|
ew->symtab.num_entries = 1;
|
|
|
|
ew->symtab.max_entries = max_entries;
|
|
|
|
|
|
|
|
buffer_init(&b, NULL, ew->symtab.syms, shdr.sh_size);
|
|
|
|
|
|
|
|
elf_writer_add_section(ew, &shdr, &b, ".symtab");
|
|
|
|
ew->symtab_sec = last_section(ew);
|
|
|
|
}
|
|
|
|
|
2014-03-11 17:48:56 +01:00
|
|
|
struct elf_writer *elf_writer_init(const Elf64_Ehdr *ehdr)
|
|
|
|
{
|
|
|
|
struct elf_writer *ew;
|
|
|
|
Elf64_Shdr shdr;
|
|
|
|
struct buffer empty_buffer;
|
|
|
|
|
|
|
|
if (!iself(ehdr))
|
|
|
|
return NULL;
|
|
|
|
|
|
|
|
ew = calloc(1, sizeof(*ew));
|
|
|
|
|
|
|
|
memcpy(&ew->ehdr, ehdr, sizeof(ew->ehdr));
|
|
|
|
|
|
|
|
ew->bit64 = ew->ehdr.e_ident[EI_CLASS] == ELFCLASS64;
|
|
|
|
|
|
|
|
/* Set the endinan ops. */
|
|
|
|
if (ew->ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
|
|
|
|
ew->xdr = &xdr_be;
|
|
|
|
else
|
|
|
|
ew->xdr = &xdr_le;
|
|
|
|
|
|
|
|
/* Reset count and offsets */
|
|
|
|
ew->ehdr.e_phoff = 0;
|
|
|
|
ew->ehdr.e_shoff = 0;
|
|
|
|
ew->ehdr.e_shnum = 0;
|
|
|
|
ew->ehdr.e_phnum = 0;
|
|
|
|
|
|
|
|
memset(&empty_buffer, 0, sizeof(empty_buffer));
|
|
|
|
memset(&shdr, 0, sizeof(shdr));
|
|
|
|
|
|
|
|
/* Add SHT_NULL section header. */
|
|
|
|
shdr.sh_type = SHT_NULL;
|
|
|
|
elf_writer_add_section(ew, &shdr, &empty_buffer, NULL);
|
|
|
|
|
|
|
|
/* Add section header string table and maintain reference to it. */
|
|
|
|
shdr.sh_type = SHT_STRTAB;
|
|
|
|
elf_writer_add_section(ew, &shdr, &empty_buffer, ".shstrtab");
|
2015-10-28 17:26:40 +01:00
|
|
|
ew->shstrtab_sec = last_section(ew);
|
|
|
|
ew->ehdr.e_shstrndx = section_index(ew, ew->shstrtab_sec);
|
|
|
|
|
|
|
|
/* Add a small string table and symbol table. */
|
|
|
|
strtab_init(ew, 4096);
|
|
|
|
symtab_init(ew, 100);
|
2014-03-11 17:48:56 +01:00
|
|
|
|
|
|
|
return ew;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Clean up any internal state represented by ew. Aftewards the elf_writer
|
|
|
|
* is invalid.
|
2016-08-05 21:04:55 +02:00
|
|
|
* It is safe to call elf_writer_destroy with ew as NULL. It returns without
|
|
|
|
* performing any action.
|
2014-03-11 17:48:56 +01:00
|
|
|
*/
|
|
|
|
void elf_writer_destroy(struct elf_writer *ew)
|
|
|
|
{
|
2015-10-28 17:26:40 +01:00
|
|
|
int i;
|
2016-08-05 21:04:55 +02:00
|
|
|
if (ew == NULL)
|
|
|
|
return;
|
2014-03-11 17:48:56 +01:00
|
|
|
if (ew->phdrs != NULL)
|
|
|
|
free(ew->phdrs);
|
2015-10-28 17:26:40 +01:00
|
|
|
free(ew->strtab.buffer);
|
|
|
|
free(ew->symtab.syms);
|
|
|
|
for (i = 0; i < MAX_SECTIONS; i++)
|
|
|
|
free(ew->rel_sections[i].rels);
|
2014-03-11 17:48:56 +01:00
|
|
|
free(ew);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Add a section to the ELF file. Section type, flags, and memsize are
|
|
|
|
* maintained from the passed in Elf64_Shdr. The buffer represents the
|
|
|
|
* content of the section while the name is the name of section itself.
|
|
|
|
* Returns < 0 on error, 0 on success.
|
|
|
|
*/
|
|
|
|
int elf_writer_add_section(struct elf_writer *ew, const Elf64_Shdr *shdr,
|
|
|
|
struct buffer *contents, const char *name)
|
|
|
|
{
|
|
|
|
struct elf_writer_section *newsh;
|
|
|
|
|
|
|
|
if (ew->num_secs == MAX_SECTIONS)
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
newsh = &ew->sections[ew->num_secs];
|
|
|
|
ew->num_secs++;
|
|
|
|
|
|
|
|
memcpy(&newsh->shdr, shdr, sizeof(newsh->shdr));
|
|
|
|
newsh->shdr.sh_offset = 0;
|
|
|
|
|
|
|
|
newsh->name = name;
|
|
|
|
if (contents != NULL)
|
|
|
|
buffer_clone(&newsh->content, contents);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void ehdr_write(struct elf_writer *ew, struct buffer *m)
|
|
|
|
{
|
|
|
|
int i;
|
|
|
|
|
|
|
|
for (i = 0; i < EI_NIDENT; i++)
|
|
|
|
ew->xdr->put8(m, ew->ehdr.e_ident[i]);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_type);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_machine);
|
|
|
|
ew->xdr->put32(m, ew->ehdr.e_version);
|
|
|
|
if (ew->bit64) {
|
|
|
|
ew->xdr->put64(m, ew->ehdr.e_entry);
|
|
|
|
ew->xdr->put64(m, ew->ehdr.e_phoff);
|
|
|
|
ew->xdr->put64(m, ew->ehdr.e_shoff);
|
|
|
|
} else {
|
|
|
|
ew->xdr->put32(m, ew->ehdr.e_entry);
|
|
|
|
ew->xdr->put32(m, ew->ehdr.e_phoff);
|
|
|
|
ew->xdr->put32(m, ew->ehdr.e_shoff);
|
|
|
|
}
|
|
|
|
ew->xdr->put32(m, ew->ehdr.e_flags);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_ehsize);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_phentsize);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_phnum);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_shentsize);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_shnum);
|
|
|
|
ew->xdr->put16(m, ew->ehdr.e_shstrndx);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void shdr_write(struct elf_writer *ew, size_t n, struct buffer *m)
|
|
|
|
{
|
|
|
|
struct xdr *xdr = ew->xdr;
|
|
|
|
int bit64 = ew->bit64;
|
|
|
|
struct elf_writer_section *sec = &ew->sections[n];
|
|
|
|
Elf64_Shdr *shdr = &sec->shdr;
|
|
|
|
|
|
|
|
xdr->put32(m, shdr->sh_name);
|
|
|
|
xdr->put32(m, shdr->sh_type);
|
|
|
|
if (bit64) {
|
2014-08-22 21:05:00 +02:00
|
|
|
xdr->put64(m, shdr->sh_flags);
|
2014-03-11 17:48:56 +01:00
|
|
|
xdr->put64(m, shdr->sh_addr);
|
|
|
|
xdr->put64(m, shdr->sh_offset);
|
|
|
|
xdr->put64(m, shdr->sh_size);
|
|
|
|
xdr->put32(m, shdr->sh_link);
|
|
|
|
xdr->put32(m, shdr->sh_info);
|
|
|
|
xdr->put64(m, shdr->sh_addralign);
|
|
|
|
xdr->put64(m, shdr->sh_entsize);
|
|
|
|
} else {
|
2014-08-22 21:05:00 +02:00
|
|
|
xdr->put32(m, shdr->sh_flags);
|
2014-03-11 17:48:56 +01:00
|
|
|
xdr->put32(m, shdr->sh_addr);
|
|
|
|
xdr->put32(m, shdr->sh_offset);
|
|
|
|
xdr->put32(m, shdr->sh_size);
|
|
|
|
xdr->put32(m, shdr->sh_link);
|
|
|
|
xdr->put32(m, shdr->sh_info);
|
|
|
|
xdr->put32(m, shdr->sh_addralign);
|
|
|
|
xdr->put32(m, shdr->sh_entsize);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static void
|
|
|
|
phdr_write(struct elf_writer *ew, struct buffer *m, Elf64_Phdr *phdr)
|
|
|
|
{
|
|
|
|
if (ew->bit64) {
|
|
|
|
ew->xdr->put32(m, phdr->p_type);
|
|
|
|
ew->xdr->put32(m, phdr->p_flags);
|
|
|
|
ew->xdr->put64(m, phdr->p_offset);
|
|
|
|
ew->xdr->put64(m, phdr->p_vaddr);
|
|
|
|
ew->xdr->put64(m, phdr->p_paddr);
|
|
|
|
ew->xdr->put64(m, phdr->p_filesz);
|
|
|
|
ew->xdr->put64(m, phdr->p_memsz);
|
|
|
|
ew->xdr->put64(m, phdr->p_align);
|
|
|
|
} else {
|
|
|
|
ew->xdr->put32(m, phdr->p_type);
|
|
|
|
ew->xdr->put32(m, phdr->p_offset);
|
|
|
|
ew->xdr->put32(m, phdr->p_vaddr);
|
|
|
|
ew->xdr->put32(m, phdr->p_paddr);
|
|
|
|
ew->xdr->put32(m, phdr->p_filesz);
|
|
|
|
ew->xdr->put32(m, phdr->p_memsz);
|
|
|
|
ew->xdr->put32(m, phdr->p_flags);
|
|
|
|
ew->xdr->put32(m, phdr->p_align);
|
|
|
|
}
|
|
|
|
|
|
|
|
}
|
|
|
|
|
2015-10-28 16:09:07 +01:00
|
|
|
static int section_consecutive(struct elf_writer *ew, Elf64_Half secidx)
|
|
|
|
{
|
|
|
|
Elf64_Half i;
|
|
|
|
struct elf_writer_section *prev_alloc = NULL;
|
|
|
|
|
|
|
|
if (secidx == 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
for (i = 0; i < secidx; i++) {
|
|
|
|
if (ew->sections[i].shdr.sh_flags & SHF_ALLOC)
|
|
|
|
prev_alloc = &ew->sections[i];
|
|
|
|
}
|
|
|
|
|
|
|
|
if (prev_alloc == NULL)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (prev_alloc->shdr.sh_addr + prev_alloc->shdr.sh_size ==
|
|
|
|
ew->sections[secidx].shdr.sh_addr)
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void write_phdrs(struct elf_writer *ew, struct buffer *phdrs)
|
|
|
|
{
|
|
|
|
Elf64_Half i;
|
|
|
|
Elf64_Phdr phdr;
|
|
|
|
size_t num_written = 0;
|
2016-06-16 13:40:24 +02:00
|
|
|
size_t num_needs_write = 0;
|
2015-10-28 16:09:07 +01:00
|
|
|
|
|
|
|
for (i = 0; i < ew->num_secs; i++) {
|
|
|
|
struct elf_writer_section *sec = &ew->sections[i];
|
|
|
|
|
|
|
|
if (!(sec->shdr.sh_flags & SHF_ALLOC))
|
|
|
|
continue;
|
|
|
|
|
|
|
|
if (!section_consecutive(ew, i)) {
|
|
|
|
/* Write out previously set phdr. */
|
2016-06-16 13:40:24 +02:00
|
|
|
if (num_needs_write != num_written) {
|
2015-10-28 16:09:07 +01:00
|
|
|
phdr_write(ew, phdrs, &phdr);
|
|
|
|
num_written++;
|
|
|
|
}
|
|
|
|
phdr.p_type = PT_LOAD;
|
|
|
|
phdr.p_offset = sec->shdr.sh_offset;
|
|
|
|
phdr.p_vaddr = sec->shdr.sh_addr;
|
|
|
|
phdr.p_paddr = sec->shdr.sh_addr;
|
|
|
|
phdr.p_filesz = buffer_size(&sec->content);
|
|
|
|
phdr.p_memsz = sec->shdr.sh_size;
|
|
|
|
phdr.p_flags = 0;
|
|
|
|
if (sec->shdr.sh_flags & SHF_EXECINSTR)
|
|
|
|
phdr.p_flags |= PF_X | PF_R;
|
|
|
|
if (sec->shdr.sh_flags & SHF_WRITE)
|
|
|
|
phdr.p_flags |= PF_W;
|
|
|
|
phdr.p_align = sec->shdr.sh_addralign;
|
2016-06-16 13:40:24 +02:00
|
|
|
num_needs_write++;
|
|
|
|
|
2015-10-28 16:09:07 +01:00
|
|
|
} else {
|
|
|
|
/* Accumulate file size and memsize. The assumption
|
|
|
|
* is that each section is either NOBITS or full
|
|
|
|
* (sh_size == file size). This is standard in that
|
|
|
|
* an ELF section doesn't have a file size component. */
|
|
|
|
if (sec->shdr.sh_flags & SHF_EXECINSTR)
|
|
|
|
phdr.p_flags |= PF_X | PF_R;
|
|
|
|
if (sec->shdr.sh_flags & SHF_WRITE)
|
|
|
|
phdr.p_flags |= PF_W;
|
|
|
|
phdr.p_filesz += buffer_size(&sec->content);
|
|
|
|
phdr.p_memsz += sec->shdr.sh_size;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Write out the last phdr. */
|
2016-06-16 13:40:24 +02:00
|
|
|
if (num_needs_write != num_written) {
|
2015-10-28 16:09:07 +01:00
|
|
|
phdr_write(ew, phdrs, &phdr);
|
2016-06-16 13:40:24 +02:00
|
|
|
num_written++;
|
|
|
|
}
|
|
|
|
assert(num_written == ew->ehdr.e_phnum);
|
2015-10-28 16:09:07 +01:00
|
|
|
}
|
|
|
|
|
2015-10-28 17:26:40 +01:00
|
|
|
static void fixup_symbol_table(struct elf_writer *ew)
|
|
|
|
{
|
|
|
|
struct elf_writer_section *sec = ew->symtab_sec;
|
|
|
|
|
|
|
|
/* If there is only the NULL section, mark section as inactive. */
|
|
|
|
if (ew->symtab.num_entries == 1) {
|
|
|
|
sec->shdr.sh_type = SHT_NULL;
|
|
|
|
sec->shdr.sh_size = 0;
|
|
|
|
} else {
|
|
|
|
size_t i;
|
|
|
|
struct buffer wr;
|
|
|
|
|
|
|
|
buffer_clone(&wr, &sec->content);
|
|
|
|
/* To appease xdr. */
|
|
|
|
buffer_set_size(&wr, 0);
|
|
|
|
for (i = 0; i < ew->symtab.num_entries; i++) {
|
|
|
|
/* Create local copy as were over-writing backing
|
|
|
|
* store of the symbol. */
|
|
|
|
Elf64_Sym sym = ew->symtab.syms[i];
|
|
|
|
if (ew->bit64) {
|
|
|
|
ew->xdr->put32(&wr, sym.st_name);
|
|
|
|
ew->xdr->put8(&wr, sym.st_info);
|
|
|
|
ew->xdr->put8(&wr, sym.st_other);
|
|
|
|
ew->xdr->put16(&wr, sym.st_shndx);
|
|
|
|
ew->xdr->put64(&wr, sym.st_value);
|
|
|
|
ew->xdr->put64(&wr, sym.st_size);
|
|
|
|
} else {
|
|
|
|
ew->xdr->put32(&wr, sym.st_name);
|
|
|
|
ew->xdr->put32(&wr, sym.st_value);
|
|
|
|
ew->xdr->put32(&wr, sym.st_size);
|
|
|
|
ew->xdr->put8(&wr, sym.st_info);
|
|
|
|
ew->xdr->put8(&wr, sym.st_other);
|
|
|
|
ew->xdr->put16(&wr, sym.st_shndx);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Update section size. */
|
|
|
|
sec->shdr.sh_size = sec->shdr.sh_entsize;
|
|
|
|
sec->shdr.sh_size *= ew->symtab.num_entries;
|
|
|
|
|
|
|
|
/* Fix up sh_link to point to string table. */
|
|
|
|
sec->shdr.sh_link = section_index(ew, ew->strtab_sec);
|
|
|
|
/* sh_info is supposed to be 1 greater than symbol table
|
|
|
|
* index of last local binding. Just use max symbols. */
|
|
|
|
sec->shdr.sh_info = ew->symtab.num_entries;
|
|
|
|
}
|
|
|
|
|
|
|
|
buffer_set_size(&sec->content, sec->shdr.sh_size);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void fixup_relocations(struct elf_writer *ew)
|
|
|
|
{
|
|
|
|
int i;
|
|
|
|
Elf64_Xword type;
|
|
|
|
|
|
|
|
switch (ew->ehdr.e_machine) {
|
|
|
|
case EM_386:
|
|
|
|
type = R_386_32;
|
|
|
|
break;
|
2018-11-26 15:54:21 +01:00
|
|
|
case EM_X86_64:
|
|
|
|
type = R_AMD64_64;
|
|
|
|
break;
|
2015-10-28 17:26:40 +01:00
|
|
|
case EM_ARM:
|
|
|
|
type = R_ARM_ABS32;
|
|
|
|
break;
|
|
|
|
case EM_AARCH64:
|
|
|
|
type = R_AARCH64_ABS64;
|
|
|
|
break;
|
|
|
|
case EM_MIPS:
|
|
|
|
type = R_MIPS_32;
|
|
|
|
break;
|
|
|
|
case EM_RISCV:
|
|
|
|
type = R_RISCV_32;
|
|
|
|
break;
|
2015-12-11 19:19:52 +01:00
|
|
|
case EM_PPC64:
|
|
|
|
type = R_PPC64_ADDR32;
|
|
|
|
break;
|
2015-10-28 17:26:40 +01:00
|
|
|
default:
|
|
|
|
ERROR("Unable to handle relocations for e_machine %x\n",
|
|
|
|
ew->ehdr.e_machine);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
for (i = 0; i < MAX_SECTIONS; i++) {
|
|
|
|
struct elf_writer_rel *rel_sec = &ew->rel_sections[i];
|
|
|
|
struct elf_writer_section *sec = rel_sec->sec;
|
|
|
|
struct buffer writer;
|
|
|
|
size_t j;
|
|
|
|
|
|
|
|
if (sec == NULL)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
/* Update section header size as well as content size. */
|
|
|
|
buffer_init(&sec->content, sec->content.name, rel_sec->rels,
|
|
|
|
rel_sec->num_entries * sec->shdr.sh_entsize);
|
|
|
|
sec->shdr.sh_size = buffer_size(&sec->content);
|
|
|
|
buffer_clone(&writer, &sec->content);
|
|
|
|
/* To make xdr happy. */
|
|
|
|
buffer_set_size(&writer, 0);
|
|
|
|
|
|
|
|
for (j = 0; j < ew->rel_sections[i].num_entries; j++) {
|
|
|
|
/* Make copy as we're overwriting backing store. */
|
|
|
|
Elf64_Rel rel = rel_sec->rels[j];
|
|
|
|
rel.r_info = ELF64_R_INFO(ELF64_R_SYM(rel.r_info),
|
|
|
|
ELF64_R_TYPE(type));
|
|
|
|
|
|
|
|
if (ew->bit64) {
|
|
|
|
ew->xdr->put64(&writer, rel.r_offset);
|
|
|
|
ew->xdr->put64(&writer, rel.r_info);
|
|
|
|
} else {
|
|
|
|
Elf32_Rel rel32;
|
|
|
|
rel32.r_offset = rel.r_offset;
|
|
|
|
rel32.r_info =
|
|
|
|
ELF32_R_INFO(ELF64_R_SYM(rel.r_info),
|
|
|
|
ELF64_R_TYPE(rel.r_info));
|
|
|
|
ew->xdr->put32(&writer, rel32.r_offset);
|
|
|
|
ew->xdr->put32(&writer, rel32.r_info);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-03-11 17:48:56 +01:00
|
|
|
/*
|
|
|
|
* Serialize the ELF file to the output buffer. Return < 0 on error,
|
|
|
|
* 0 on success.
|
|
|
|
*/
|
|
|
|
int elf_writer_serialize(struct elf_writer *ew, struct buffer *out)
|
|
|
|
{
|
|
|
|
Elf64_Half i;
|
|
|
|
Elf64_Xword metadata_size;
|
|
|
|
Elf64_Xword program_size;
|
|
|
|
Elf64_Off shstroffset;
|
|
|
|
size_t shstrlen;
|
|
|
|
struct buffer metadata;
|
|
|
|
struct buffer phdrs;
|
|
|
|
struct buffer data;
|
|
|
|
struct buffer *strtab;
|
|
|
|
|
|
|
|
INFO("Writing %zu sections.\n", ew->num_secs);
|
|
|
|
|
2015-10-28 17:26:40 +01:00
|
|
|
/* Perform any necessary work for special sections. */
|
|
|
|
fixup_symbol_table(ew);
|
|
|
|
fixup_relocations(ew);
|
|
|
|
|
2014-03-11 17:48:56 +01:00
|
|
|
/* Determine size of sections to be written. */
|
|
|
|
program_size = 0;
|
|
|
|
/* Start with 1 byte for first byte of section header string table. */
|
|
|
|
shstrlen = 1;
|
|
|
|
for (i = 0; i < ew->num_secs; i++) {
|
|
|
|
struct elf_writer_section *sec = &ew->sections[i];
|
|
|
|
|
2015-10-28 16:09:07 +01:00
|
|
|
if (sec->shdr.sh_flags & SHF_ALLOC) {
|
|
|
|
if (!section_consecutive(ew, i))
|
|
|
|
ew->ehdr.e_phnum++;
|
|
|
|
}
|
2014-03-11 17:48:56 +01:00
|
|
|
|
|
|
|
program_size += buffer_size(&sec->content);
|
|
|
|
|
|
|
|
/* Keep track of the length sections' names. */
|
|
|
|
if (sec->name != NULL) {
|
|
|
|
sec->shdr.sh_name = shstrlen;
|
|
|
|
shstrlen += strlen(sec->name) + 1;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
ew->ehdr.e_shnum = ew->num_secs;
|
|
|
|
metadata_size = 0;
|
|
|
|
metadata_size += ew->ehdr.e_ehsize;
|
util/cbfstool: Prevent overflow of 16 bit multiplications
Considering the following integer multiplication:
u64 = u16 * u16
What on earth, one might wonder, is the problem with this? Well, due to
C's unfortunately abstruse integer semantics, both u16's are implicitly
converted to int before the multiplication, which cannot hold
all possible values of a u16 * u16. Even worse, after overflow the
intermediate result will be a negative number, which during the
conversion to a u64 will be sign-extended to a huge integer. Not good.
The solution is to manually cast one of the u16 to a u32 or u64, which
are large enough to not have any overflow and will prevent the implicit
conversion. The type of the u64 is preferred, though a u32 is used
instead of size_t, since that can change depending on the platform.
Change-Id: I5391221d46d620d0e5bd629e2f9680be7a53342e
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 12297{03,04,05,06,07,08,09,10}
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33986
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2019-07-02 22:38:38 +02:00
|
|
|
metadata_size += (Elf64_Xword)ew->ehdr.e_shnum * ew->ehdr.e_shentsize;
|
|
|
|
metadata_size += (Elf64_Xword)ew->ehdr.e_phnum * ew->ehdr.e_phentsize;
|
2014-03-11 17:48:56 +01:00
|
|
|
shstroffset = metadata_size;
|
|
|
|
/* Align up section header string size and metadata size to 4KiB */
|
|
|
|
metadata_size = ALIGN(metadata_size + shstrlen, 4096);
|
|
|
|
|
|
|
|
if (buffer_create(out, metadata_size + program_size, "elfout")) {
|
|
|
|
ERROR("Could not create output buffer for ELF.\n");
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
INFO("Created %zu output buffer for ELF file.\n", buffer_size(out));
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Write out ELF header. Section headers come right after ELF header
|
|
|
|
* followed by the program headers. Buffers need to be created first
|
|
|
|
* to do the writing.
|
|
|
|
*/
|
|
|
|
ew->ehdr.e_shoff = ew->ehdr.e_ehsize;
|
|
|
|
ew->ehdr.e_phoff = ew->ehdr.e_shoff +
|
util/cbfstool: Prevent overflow of 16 bit multiplications
Considering the following integer multiplication:
u64 = u16 * u16
What on earth, one might wonder, is the problem with this? Well, due to
C's unfortunately abstruse integer semantics, both u16's are implicitly
converted to int before the multiplication, which cannot hold
all possible values of a u16 * u16. Even worse, after overflow the
intermediate result will be a negative number, which during the
conversion to a u64 will be sign-extended to a huge integer. Not good.
The solution is to manually cast one of the u16 to a u32 or u64, which
are large enough to not have any overflow and will prevent the implicit
conversion. The type of the u64 is preferred, though a u32 is used
instead of size_t, since that can change depending on the platform.
Change-Id: I5391221d46d620d0e5bd629e2f9680be7a53342e
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 12297{03,04,05,06,07,08,09,10}
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33986
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2019-07-02 22:38:38 +02:00
|
|
|
(Elf64_Off)ew->ehdr.e_shnum * ew->ehdr.e_shentsize;
|
2014-03-11 17:48:56 +01:00
|
|
|
|
|
|
|
buffer_splice(&metadata, out, 0, metadata_size);
|
|
|
|
buffer_splice(&phdrs, out, ew->ehdr.e_phoff,
|
util/cbfstool: Prevent overflow of 16 bit multiplications
Considering the following integer multiplication:
u64 = u16 * u16
What on earth, one might wonder, is the problem with this? Well, due to
C's unfortunately abstruse integer semantics, both u16's are implicitly
converted to int before the multiplication, which cannot hold
all possible values of a u16 * u16. Even worse, after overflow the
intermediate result will be a negative number, which during the
conversion to a u64 will be sign-extended to a huge integer. Not good.
The solution is to manually cast one of the u16 to a u32 or u64, which
are large enough to not have any overflow and will prevent the implicit
conversion. The type of the u64 is preferred, though a u32 is used
instead of size_t, since that can change depending on the platform.
Change-Id: I5391221d46d620d0e5bd629e2f9680be7a53342e
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 12297{03,04,05,06,07,08,09,10}
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33986
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2019-07-02 22:38:38 +02:00
|
|
|
(uint32_t)ew->ehdr.e_phnum * ew->ehdr.e_phentsize);
|
2014-03-11 17:48:56 +01:00
|
|
|
buffer_splice(&data, out, metadata_size, program_size);
|
|
|
|
/* Set up the section header string table contents. */
|
2015-10-28 17:26:40 +01:00
|
|
|
strtab = &ew->shstrtab_sec->content;
|
2014-03-11 17:48:56 +01:00
|
|
|
buffer_splice(strtab, out, shstroffset, shstrlen);
|
2015-10-28 17:26:40 +01:00
|
|
|
ew->shstrtab_sec->shdr.sh_size = shstrlen;
|
2014-03-11 17:48:56 +01:00
|
|
|
|
|
|
|
/* Reset current locations. */
|
|
|
|
buffer_set_size(&metadata, 0);
|
|
|
|
buffer_set_size(&data, 0);
|
|
|
|
buffer_set_size(&phdrs, 0);
|
|
|
|
buffer_set_size(strtab, 0);
|
|
|
|
|
|
|
|
/* ELF Header */
|
|
|
|
ehdr_write(ew, &metadata);
|
|
|
|
|
|
|
|
/* Write out section headers, section strings, section content, and
|
|
|
|
* program headers. */
|
|
|
|
ew->xdr->put8(strtab, 0);
|
|
|
|
for (i = 0; i < ew->num_secs; i++) {
|
|
|
|
struct elf_writer_section *sec = &ew->sections[i];
|
|
|
|
|
2015-10-28 17:26:40 +01:00
|
|
|
/* Update section offsets. Be sure to not update SHN_UNDEF. */
|
|
|
|
if (sec == ew->shstrtab_sec)
|
2014-03-11 17:48:56 +01:00
|
|
|
sec->shdr.sh_offset = shstroffset;
|
2015-10-28 17:26:40 +01:00
|
|
|
else if (i != SHN_UNDEF)
|
2014-03-11 17:48:56 +01:00
|
|
|
sec->shdr.sh_offset = buffer_size(&data) +
|
|
|
|
metadata_size;
|
2015-10-28 17:26:40 +01:00
|
|
|
|
2014-03-11 17:48:56 +01:00
|
|
|
shdr_write(ew, i, &metadata);
|
|
|
|
|
|
|
|
/* Add section name to string table. */
|
|
|
|
if (sec->name != NULL)
|
|
|
|
bputs(strtab, sec->name, strlen(sec->name) + 1);
|
|
|
|
|
2015-10-28 17:26:40 +01:00
|
|
|
/* Output section data for all sections but SHN_UNDEF and
|
|
|
|
* section header string table. */
|
|
|
|
if (i != SHN_UNDEF && sec != ew->shstrtab_sec)
|
|
|
|
bputs(&data, buffer_get(&sec->content),
|
|
|
|
buffer_size(&sec->content));
|
|
|
|
}
|
|
|
|
|
|
|
|
write_phdrs(ew, &phdrs);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Add a string to the string table returning index on success, < 0 on error. */
|
|
|
|
static int elf_writer_add_string(struct elf_writer *ew, const char *new)
|
|
|
|
{
|
|
|
|
size_t current_offset;
|
|
|
|
size_t new_len;
|
|
|
|
|
|
|
|
for (current_offset = 0; current_offset < ew->strtab.next_offset; ) {
|
|
|
|
const char *str = ew->strtab.buffer + current_offset;
|
|
|
|
size_t len = strlen(str) + 1;
|
|
|
|
|
|
|
|
if (!strcmp(str, new))
|
|
|
|
return current_offset;
|
|
|
|
current_offset += len;
|
|
|
|
}
|
|
|
|
|
|
|
|
new_len = strlen(new) + 1;
|
|
|
|
|
|
|
|
if (current_offset + new_len > ew->strtab.max_size) {
|
|
|
|
ERROR("No space for string in .strtab.\n");
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
memcpy(ew->strtab.buffer + current_offset, new, new_len);
|
|
|
|
ew->strtab.next_offset = current_offset + new_len;
|
|
|
|
|
|
|
|
return current_offset;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int elf_writer_section_index(struct elf_writer *ew, const char *name)
|
|
|
|
{
|
|
|
|
size_t i;
|
|
|
|
|
|
|
|
for (i = 0; i < ew->num_secs; i++) {
|
|
|
|
if (ew->sections[i].name == NULL)
|
2014-03-11 17:48:56 +01:00
|
|
|
continue;
|
2015-10-28 17:26:40 +01:00
|
|
|
if (!strcmp(ew->sections[i].name, name))
|
|
|
|
return i;
|
|
|
|
}
|
|
|
|
|
|
|
|
ERROR("ELF Section not found: %s\n", name);
|
2014-03-11 17:48:56 +01:00
|
|
|
|
2015-10-28 17:26:40 +01:00
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
int elf_writer_add_symbol(struct elf_writer *ew, const char *name,
|
|
|
|
const char *section_name,
|
|
|
|
Elf64_Addr value, Elf64_Word size,
|
|
|
|
int binding, int type)
|
|
|
|
{
|
2015-10-31 01:35:20 +01:00
|
|
|
int i;
|
2015-10-28 17:26:40 +01:00
|
|
|
Elf64_Sym sym = {
|
|
|
|
.st_value = value,
|
|
|
|
.st_size = size,
|
|
|
|
.st_info = ELF64_ST_INFO(binding, type),
|
|
|
|
};
|
|
|
|
|
|
|
|
if (ew->symtab.max_entries == ew->symtab.num_entries) {
|
|
|
|
ERROR("No more symbol entries left.\n");
|
|
|
|
return -1;
|
2014-03-11 17:48:56 +01:00
|
|
|
}
|
|
|
|
|
2015-10-31 01:35:20 +01:00
|
|
|
i = elf_writer_add_string(ew, name);
|
|
|
|
if (i < 0)
|
2015-10-28 17:26:40 +01:00
|
|
|
return -1;
|
2015-10-31 01:35:20 +01:00
|
|
|
sym.st_name = i;
|
2015-10-28 17:26:40 +01:00
|
|
|
|
2015-10-31 01:35:20 +01:00
|
|
|
i = elf_writer_section_index(ew, section_name);
|
|
|
|
if (i < 0)
|
2015-10-28 17:26:40 +01:00
|
|
|
return -1;
|
2015-10-31 01:35:20 +01:00
|
|
|
sym.st_shndx = i;
|
2015-10-28 17:26:40 +01:00
|
|
|
|
|
|
|
ew->symtab.syms[ew->symtab.num_entries++] = sym;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int elf_sym_index(struct elf_writer *ew, const char *sym)
|
|
|
|
{
|
2015-10-31 01:35:20 +01:00
|
|
|
int j;
|
2015-10-28 17:26:40 +01:00
|
|
|
size_t i;
|
|
|
|
Elf64_Word st_name;
|
|
|
|
|
|
|
|
/* Determine index of symbol in the string table. */
|
2015-10-31 01:35:20 +01:00
|
|
|
j = elf_writer_add_string(ew, sym);
|
|
|
|
if (j < 0)
|
2015-10-28 17:26:40 +01:00
|
|
|
return -1;
|
|
|
|
|
2015-10-31 01:35:20 +01:00
|
|
|
st_name = j;
|
2015-10-28 17:26:40 +01:00
|
|
|
|
|
|
|
for (i = 0; i < ew->symtab.num_entries; i++)
|
|
|
|
if (ew->symtab.syms[i].st_name == st_name)
|
|
|
|
return i;
|
|
|
|
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct elf_writer_rel *rel_section(struct elf_writer *ew,
|
|
|
|
const Elf64_Rel *r)
|
|
|
|
{
|
|
|
|
Elf64_Sym *sym;
|
|
|
|
struct elf_writer_rel *rel;
|
|
|
|
Elf64_Shdr shdr;
|
|
|
|
struct buffer b;
|
|
|
|
|
|
|
|
sym = &ew->symtab.syms[ELF64_R_SYM(r->r_info)];
|
|
|
|
|
|
|
|
/* Determine if section has been initialized yet. */
|
|
|
|
rel = &ew->rel_sections[sym->st_shndx];
|
|
|
|
if (rel->sec != NULL)
|
|
|
|
return rel;
|
|
|
|
|
|
|
|
memset(&shdr, 0, sizeof(shdr));
|
|
|
|
shdr.sh_type = SHT_REL;
|
|
|
|
shdr.sh_link = section_index(ew, ew->symtab_sec);
|
|
|
|
shdr.sh_info = sym->st_shndx;
|
|
|
|
|
|
|
|
if (ew->bit64) {
|
|
|
|
shdr.sh_addralign = sizeof(Elf64_Addr);
|
|
|
|
shdr.sh_entsize = sizeof(Elf64_Rel);
|
|
|
|
} else {
|
|
|
|
shdr.sh_addralign = sizeof(Elf32_Addr);
|
|
|
|
shdr.sh_entsize = sizeof(Elf32_Rel);
|
|
|
|
}
|
|
|
|
|
|
|
|
if ((strlen(".rel") + strlen(ew->sections[sym->st_shndx].name) + 1) >
|
|
|
|
MAX_REL_NAME) {
|
|
|
|
ERROR("Rel Section name won't fit\n");
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
strcat(rel->name, ".rel");
|
|
|
|
strcat(rel->name, ew->sections[sym->st_shndx].name);
|
|
|
|
buffer_init(&b, rel->name, NULL, 0);
|
|
|
|
|
|
|
|
elf_writer_add_section(ew, &shdr, &b, rel->name);
|
|
|
|
rel->sec = last_section(ew);
|
|
|
|
|
|
|
|
return rel;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int add_rel(struct elf_writer_rel *rel_sec, const Elf64_Rel *rel)
|
|
|
|
{
|
|
|
|
if (rel_sec->num_entries == rel_sec->max_entries) {
|
|
|
|
size_t num = rel_sec->max_entries * 2;
|
|
|
|
Elf64_Rel *old_rels;
|
|
|
|
|
|
|
|
if (num == 0)
|
|
|
|
num = 128;
|
|
|
|
|
|
|
|
old_rels = rel_sec->rels;
|
|
|
|
rel_sec->rels = calloc(num, sizeof(Elf64_Rel));
|
|
|
|
|
|
|
|
memcpy(rel_sec->rels, old_rels,
|
|
|
|
rel_sec->num_entries * sizeof(Elf64_Rel));
|
|
|
|
free(old_rels);
|
|
|
|
|
|
|
|
rel_sec->max_entries = num;
|
|
|
|
}
|
|
|
|
|
|
|
|
rel_sec->rels[rel_sec->num_entries] = *rel;
|
|
|
|
rel_sec->num_entries++;
|
2015-10-28 16:09:07 +01:00
|
|
|
|
2014-03-11 17:48:56 +01:00
|
|
|
return 0;
|
|
|
|
}
|
2015-10-28 17:26:40 +01:00
|
|
|
|
|
|
|
int elf_writer_add_rel(struct elf_writer *ew, const char *sym, Elf64_Addr addr)
|
|
|
|
{
|
|
|
|
Elf64_Rel rel;
|
|
|
|
Elf64_Xword sym_info;
|
|
|
|
int sym_index;
|
|
|
|
struct elf_writer_rel *rel_sec;
|
|
|
|
|
|
|
|
sym_index = elf_sym_index(ew, sym);
|
|
|
|
|
|
|
|
if (sym_index < 0) {
|
|
|
|
ERROR("Unable to locate symbol: %s\n", sym);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
sym_info = sym_index;
|
|
|
|
|
|
|
|
/* The relocation type will get fixed prior to serialization. */
|
|
|
|
rel.r_offset = addr;
|
|
|
|
rel.r_info = ELF64_R_INFO(sym_info, 0);
|
|
|
|
|
|
|
|
rel_sec = rel_section(ew, &rel);
|
|
|
|
|
|
|
|
if (rel_sec == NULL)
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
return add_rel(rel_sec, &rel);
|
|
|
|
}
|
2017-12-18 22:50:22 +01:00
|
|
|
|
|
|
|
int elf_program_file_size(const struct buffer *input, size_t *file_size)
|
|
|
|
{
|
|
|
|
Elf64_Ehdr ehdr;
|
|
|
|
Elf64_Phdr *phdr;
|
|
|
|
int i;
|
|
|
|
size_t loadable_file_size = 0;
|
|
|
|
|
|
|
|
if (elf_headers(input, &ehdr, &phdr, NULL))
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
for (i = 0; i < ehdr.e_phnum; i++) {
|
|
|
|
if (phdr[i].p_type != PT_LOAD)
|
|
|
|
continue;
|
|
|
|
loadable_file_size += phdr[i].p_filesz;
|
|
|
|
}
|
|
|
|
|
|
|
|
*file_size = loadable_file_size;
|
|
|
|
|
|
|
|
free(phdr);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|