diff options
Diffstat (limited to 'src/elflint.c')
| -rw-r--r-- | src/elflint.c | 2617 |
1 files changed, 2617 insertions, 0 deletions
diff --git a/src/elflint.c b/src/elflint.c new file mode 100644 index 00000000..03572377 --- /dev/null +++ b/src/elflint.c @@ -0,0 +1,2617 @@ +/* Pedantic checking of ELF files compliance with gABI/psABI spec. + Copyright (C) 2001, 2002, 2003, 2004, 2005 Red Hat, Inc. + Written by Ulrich Drepper <drepper@redhat.com>, 2001. + + This program is Open Source software; you can redistribute it and/or + modify it under the terms of the Open Software License version 1.0 as + published by the Open Source Initiative. + + You should have received a copy of the Open Software License along + with this program; if not, you may obtain a copy of the Open Software + License version 1.0 from http://www.opensource.org/licenses/osl.php or + by writing the Open Source Initiative c/o Lawrence Rosen, Esq., + 3001 King Ranch Road, Ukiah, CA 95482. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <argp.h> +#include <assert.h> +#include <byteswap.h> +#include <endian.h> +#include <error.h> +#include <fcntl.h> +#include <gelf.h> +#include <inttypes.h> +#include <libintl.h> +#include <locale.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/param.h> + +#include <elf-knowledge.h> +#include <system.h> +#include "../libebl/libeblP.h" + + +/* Name and version of program. */ +static void print_version (FILE *stream, struct argp_state *state); +void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version; + +/* Bug report address. */ +const char *argp_program_bug_address = PACKAGE_BUGREPORT; + +#define ARGP_strict 300 +#define ARGP_gnuld 301 + +/* Definitions of arguments for argp functions. */ +static const struct argp_option options[] = +{ + + { "strict", ARGP_strict, NULL, 0, + N_("Be extremely strict, flag level 2 features."), 0 }, + { "quiet", 'q', NULL, 0, N_("Do not print anything if successful"), 0 }, + { "debuginfo", 'd', NULL, 0, N_("Binary is a separate debuginfo file"), 0 }, + { "gnu-ld", ARGP_gnuld, NULL, 0, + N_("Binary has been created with GNU ld and is therefore known to be \ +broken in certain ways"), 0 }, + { NULL, 0, NULL, 0, NULL, 0 } +}; + +/* Short description of program. */ +static const char doc[] = N_("\ +Pedantic checking of ELF files compliance with gABI/psABI spec."); + +/* Strings for arguments in help texts. */ +static const char args_doc[] = N_("FILE..."); + +/* Prototype for option handler. */ +static error_t parse_opt (int key, char *arg, struct argp_state *state); + +/* Data structure to communicate with argp functions. */ +static struct argp argp = +{ + options, parse_opt, args_doc, doc, NULL, NULL, NULL +}; + + +/* Declarations of local functions. */ +static void process_file (int fd, Elf *elf, const char *prefix, + const char *suffix, const char *fname, size_t size, + bool only_one); +static void process_elf_file (Elf *elf, const char *prefix, const char *suffix, + const char *fname, size_t size, bool only_one); + +/* Report an error. */ +#define ERROR(str, args...) \ + do { \ + printf (str, ##args); \ + ++error_count; \ + } while (0) +static unsigned int error_count; + +/* True if we should perform very strict testing. */ +static bool be_strict; + +/* True if no message is to be printed if the run is succesful. */ +static bool be_quiet; + +/* True if binary is from strip -f, not a normal ELF file. */ +static bool is_debuginfo; + +/* True if binary is assumed to be generated with GNU ld. */ +static bool gnuld; + +/* Index of section header string table. */ +static uint32_t shstrndx; + +/* Array to count references in section groups. */ +static int *scnref; + + +int +main (int argc, char *argv[]) +{ + /* Set locale. */ + setlocale (LC_ALL, ""); + + /* Initialize the message catalog. */ + textdomain (PACKAGE); + + /* Parse and process arguments. */ + int remaining; + argp_parse (&argp, argc, argv, 0, &remaining, NULL); + + /* Before we start tell the ELF library which version we are using. */ + elf_version (EV_CURRENT); + + /* Now process all the files given at the command line. */ + bool only_one = remaining + 1 == argc; + do + { + /* Open the file. */ + int fd = open (argv[remaining], O_RDONLY); + if (fd == -1) + { + error (0, errno, gettext ("cannot open input file")); + continue; + } + + /* Create an `Elf' descriptor. */ + Elf *elf = elf_begin (fd, ELF_C_READ_MMAP, NULL); + if (elf == NULL) + ERROR (gettext ("cannot generate Elf descriptor: %s\n"), + elf_errmsg (-1)); + else + { + unsigned int prev_error_count = error_count; + struct stat64 st; + + if (fstat64 (fd, &st) != 0) + { + printf ("cannot stat '%s': %m\n", argv[remaining]); + close (fd); + continue; + } + + process_file (fd, elf, NULL, NULL, argv[remaining], st.st_size, + only_one); + + /* Now we can close the descriptor. */ + if (elf_end (elf) != 0) + ERROR (gettext ("error while closing Elf descriptor: %s\n"), + elf_errmsg (-1)); + + if (prev_error_count == error_count && !be_quiet) + puts (gettext ("No errors")); + } + + close (fd); + } + while (++remaining < argc); + + return error_count != 0; +} + + +/* Handle program arguments. */ +static error_t +parse_opt (int key, char *arg __attribute__ ((unused)), + struct argp_state *state __attribute__ ((unused))) +{ + switch (key) + { + case ARGP_strict: + be_strict = true; + break; + + case 'q': + be_quiet = true; + break; + + case 'd': + is_debuginfo = true; + + case ARGP_gnuld: + gnuld = true; + break; + + case ARGP_KEY_NO_ARGS: + fputs (gettext ("Missing file name.\n"), stderr); + argp_help (&argp, stderr, ARGP_HELP_SEE | ARGP_HELP_EXIT_ERR, + program_invocation_short_name); + exit (1); + + default: + return ARGP_ERR_UNKNOWN; + } + return 0; +} + + +/* Print the version information. */ +static void +print_version (FILE *stream, struct argp_state *state __attribute__ ((unused))) +{ + fprintf (stream, "elflint (%s) %s\n", PACKAGE_NAME, VERSION); + fprintf (stream, gettext ("\ +Copyright (C) %s Red Hat, Inc.\n\ +This is free software; see the source for copying conditions. There is NO\n\ +warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\ +"), "2005"); + fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper"); +} + + +/* Process one file. */ +static void +process_file (int fd, Elf *elf, const char *prefix, const char *suffix, + const char *fname, size_t size, bool only_one) +{ + /* We can handle two types of files: ELF files and archives. */ + Elf_Kind kind = elf_kind (elf); + + switch (kind) + { + case ELF_K_ELF: + /* Yes! It's an ELF file. */ + process_elf_file (elf, prefix, suffix, fname, size, only_one); + break; + + case ELF_K_AR: + { + Elf *subelf; + Elf_Cmd cmd = ELF_C_READ_MMAP; + size_t prefix_len = prefix == NULL ? 0 : strlen (prefix); + size_t fname_len = strlen (fname) + 1; + char new_prefix[prefix_len + 1 + fname_len]; + char new_suffix[(suffix == NULL ? 0 : strlen (suffix)) + 2]; + char *cp = new_prefix; + + /* Create the full name of the file. */ + if (prefix != NULL) + { + cp = mempcpy (cp, prefix, prefix_len); + *cp++ = '('; + strcpy (stpcpy (new_suffix, suffix), ")"); + } + else + new_suffix[0] = '\0'; + memcpy (cp, fname, fname_len); + + /* It's an archive. We process each file in it. */ + while ((subelf = elf_begin (fd, cmd, elf)) != NULL) + { + kind = elf_kind (subelf); + + /* Call this function recursively. */ + if (kind == ELF_K_ELF || kind == ELF_K_AR) + { + Elf_Arhdr *arhdr = elf_getarhdr (subelf); + assert (arhdr != NULL); + + process_file (fd, subelf, new_prefix, new_suffix, + arhdr->ar_name, arhdr->ar_size, false); + } + + /* Get next archive element. */ + cmd = elf_next (subelf); + if (elf_end (subelf) != 0) + ERROR (gettext (" error while freeing sub-ELF descriptor: %s\n"), + elf_errmsg (-1)); + } + } + break; + + default: + /* We cannot do anything. */ + ERROR (gettext ("\ +Not an ELF file - it has the wrong magic bytes at the start")); + break; + } +} + + +static const char * +section_name (Ebl *ebl, int idx) +{ + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + + shdr = gelf_getshdr (elf_getscn (ebl->elf, idx), &shdr_mem); + + return elf_strptr (ebl->elf, shstrndx, shdr->sh_name); +} + + +static const int valid_e_machine[] = + { + EM_M32, EM_SPARC, EM_386, EM_68K, EM_88K, EM_860, EM_MIPS, EM_S370, + EM_MIPS_RS3_LE, EM_PARISC, EM_VPP500, EM_SPARC32PLUS, EM_960, EM_PPC, + EM_PPC64, EM_S390, EM_V800, EM_FR20, EM_RH32, EM_RCE, EM_ARM, + EM_FAKE_ALPHA, EM_SH, EM_SPARCV9, EM_TRICORE, EM_ARC, EM_H8_300, + EM_H8_300H, EM_H8S, EM_H8_500, EM_IA_64, EM_MIPS_X, EM_COLDFIRE, + EM_68HC12, EM_MMA, EM_PCP, EM_NCPU, EM_NDR1, EM_STARCORE, EM_ME16, + EM_ST100, EM_TINYJ, EM_X86_64, EM_PDSP, EM_FX66, EM_ST9PLUS, EM_ST7, + EM_68HC16, EM_68HC11, EM_68HC08, EM_68HC05, EM_SVX, EM_ST19, EM_VAX, + EM_CRIS, EM_JAVELIN, EM_FIREPATH, EM_ZSP, EM_MMIX, EM_HUANY, EM_PRISM, + EM_AVR, EM_FR30, EM_D10V, EM_D30V, EM_V850, EM_M32R, EM_MN10300, + EM_MN10200, EM_PJ, EM_OPENRISC, EM_ARC_A5, EM_XTENSA + }; +#define nvalid_e_machine \ + (sizeof (valid_e_machine) / sizeof (valid_e_machine[0])) + + +/* Number of sections. */ +static unsigned int shnum; + + +static void +check_elf_header (Ebl *ebl, GElf_Ehdr *ehdr, size_t size) +{ + char buf[512]; + size_t cnt; + + /* Check e_ident field. */ + if (ehdr->e_ident[EI_MAG0] != ELFMAG0) + ERROR ("e_ident[%d] != '%c'\n", EI_MAG0, ELFMAG0); + if (ehdr->e_ident[EI_MAG1] != ELFMAG1) + ERROR ("e_ident[%d] != '%c'\n", EI_MAG1, ELFMAG1); + if (ehdr->e_ident[EI_MAG2] != ELFMAG2) + ERROR ("e_ident[%d] != '%c'\n", EI_MAG2, ELFMAG2); + if (ehdr->e_ident[EI_MAG3] != ELFMAG3) + ERROR ("e_ident[%d] != '%c'\n", EI_MAG3, ELFMAG3); + + if (ehdr->e_ident[EI_CLASS] != ELFCLASS32 + && ehdr->e_ident[EI_CLASS] != ELFCLASS64) + ERROR (gettext ("e_ident[%d] == %d is no known class\n"), + EI_CLASS, ehdr->e_ident[EI_CLASS]); + + if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB + && ehdr->e_ident[EI_DATA] != ELFDATA2MSB) + ERROR (gettext ("e_ident[%d] == %d is no known data encoding\n"), + EI_DATA, ehdr->e_ident[EI_DATA]); + + if (ehdr->e_ident[EI_VERSION] != EV_CURRENT) + ERROR (gettext ("unknown ELF header version number e_ident[%d] == %d\n"), + EI_VERSION, ehdr->e_ident[EI_VERSION]); + + /* We currently don't handle any OS ABIs. */ + if (ehdr->e_ident[EI_OSABI] != ELFOSABI_NONE) + ERROR (gettext ("unsupported OS ABI e_ident[%d] == \"%s\"\n"), + EI_OSABI, + ebl_osabi_name (ebl, ehdr->e_ident[EI_OSABI], buf, sizeof (buf))); + + /* No ABI versions other than zero supported either. */ + if (ehdr->e_ident[EI_ABIVERSION] != 0) + ERROR (gettext ("unsupport ABI version e_ident[%d] == %d\n"), + EI_ABIVERSION, ehdr->e_ident[EI_ABIVERSION]); + + for (cnt = EI_PAD; cnt < EI_NIDENT; ++cnt) + if (ehdr->e_ident[cnt] != 0) + ERROR (gettext ("e_ident[%zu] is not zero\n"), cnt); + + /* Check the e_type field. */ + if (ehdr->e_type != ET_REL && ehdr->e_type != ET_EXEC + && ehdr->e_type != ET_DYN && ehdr->e_type != ET_CORE) + ERROR (gettext ("unknown object file type %d\n"), ehdr->e_type); + + /* Check the e_machine field. */ + for (cnt = 0; cnt < nvalid_e_machine; ++cnt) + if (valid_e_machine[cnt] == ehdr->e_machine) + break; + if (cnt == nvalid_e_machine) + ERROR (gettext ("unknown machine type %d\n"), ehdr->e_machine); + + /* Check the e_version field. */ + if (ehdr->e_version != EV_CURRENT) + ERROR (gettext ("unknown object file version\n")); + + /* Check the e_phoff and e_phnum fields. */ + if (ehdr->e_phoff == 0) + { + if (ehdr->e_phnum != 0) + ERROR (gettext ("invalid program header offset\n")); + else if (ehdr->e_type == ET_EXEC || ehdr->e_type == ET_DYN) + ERROR (gettext ("\ +executables and DSOs cannot have zero program header offset\n")); + } + else if (ehdr->e_phnum == 0) + ERROR (gettext ("invalid number of program header entries\n")); + + /* Check the e_shoff field. */ + shnum = ehdr->e_shnum; + shstrndx = ehdr->e_shstrndx; + if (ehdr->e_shoff == 0) + { + if (ehdr->e_shnum != 0) + ERROR (gettext ("invalid section header table offset\n")); + else if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN + && ehdr->e_type != ET_CORE) + ERROR (gettext ("section header table must be present\n")); + } + else + { + if (ehdr->e_shnum == 0) + { + /* Get the header of the zeroth section. The sh_size field + might contain the section number. */ + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + + shdr = gelf_getshdr (elf_getscn (ebl->elf, 0), &shdr_mem); + if (shdr != NULL) + { + /* The error will be reported later. */ + if (shdr->sh_size == 0) + ERROR (gettext ("\ +invalid number of section header table entries\n")); + else + shnum = shdr->sh_size; + } + } + + if (ehdr->e_shstrndx == SHN_XINDEX) + { + /* Get the header of the zeroth section. The sh_size field + might contain the section number. */ + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + + shdr = gelf_getshdr (elf_getscn (ebl->elf, 0), &shdr_mem); + if (shdr != NULL) + { + /* The error will be reported later. */ + if (shdr->sh_link >= shnum) + ERROR (gettext ("invalid section header index\n")); + else + shstrndx = shdr->sh_link; + } + } + else if (shstrndx >= shnum) + ERROR (gettext ("invalid section header index\n")); + } + + /* Check the e_flags field. */ + if (!ebl_machine_flag_check (ebl, ehdr->e_flags)) + ERROR (gettext ("invalid machine flags: %s\n"), + ebl_machine_flag_name (ebl, ehdr->e_flags, buf, sizeof (buf))); + + /* Check e_ehsize, e_phentsize, and e_shentsize fields. */ + if (gelf_getclass (ebl->elf) == ELFCLASS32) + { + if (ehdr->e_ehsize != 0 && ehdr->e_ehsize != sizeof (Elf32_Ehdr)) + ERROR (gettext ("invalid ELF header size: %hd\n"), ehdr->e_ehsize); + + if (ehdr->e_phentsize != 0 && ehdr->e_phentsize != sizeof (Elf32_Phdr)) + ERROR (gettext ("invalid program header size: %hd\n"), + ehdr->e_phentsize); + else if (ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize > size) + ERROR (gettext ("invalid program header position or size\n")); + + if (ehdr->e_shentsize != 0 && ehdr->e_shentsize != sizeof (Elf32_Shdr)) + ERROR (gettext ("invalid section header size: %hd\n"), + ehdr->e_shentsize); + else if (ehdr->e_shoff + ehdr->e_shnum * ehdr->e_shentsize > size) + ERROR (gettext ("invalid section header position or size\n")); + } + else if (gelf_getclass (ebl->elf) == ELFCLASS64) + { + if (ehdr->e_ehsize != 0 && ehdr->e_ehsize != sizeof (Elf64_Ehdr)) + ERROR (gettext ("invalid ELF header size: %hd\n"), ehdr->e_ehsize); + + if (ehdr->e_phentsize != 0 && ehdr->e_phentsize != sizeof (Elf64_Phdr)) + ERROR (gettext ("invalid program header size: %hd\n"), + ehdr->e_phentsize); + else if (ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize > size) + ERROR (gettext ("invalid program header position or size\n")); + + if (ehdr->e_shentsize != 0 && ehdr->e_shentsize != sizeof (Elf64_Shdr)) + ERROR (gettext ("invalid section header size: %hd\n"), + ehdr->e_shentsize); + else if (ehdr->e_shoff + ehdr->e_shnum * ehdr->e_shentsize > size) + ERROR (gettext ("invalid section header position or size\n")); + } +} + + +/* Check that there is a section group section with index < IDX which + contains section IDX and that there is exactly one. */ +static void +check_scn_group (Ebl *ebl, int idx) +{ + if (scnref[idx] == 0) + { + /* No reference so far. Search following sections, maybe the + order is wrong. */ + size_t cnt; + + for (cnt = idx + 1; cnt < shnum; ++cnt) + { + Elf_Scn *scn; + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + Elf_Data *data; + Elf32_Word *grpdata; + size_t inner; + + scn = elf_getscn (ebl->elf, cnt); + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + /* We cannot get the section header so we cannot check it. + The error to get the section header will be shown + somewhere else. */ + continue; + + if (shdr->sh_type != SHT_GROUP) + continue; + + data = elf_getdata (scn, NULL); + if (data == NULL || data->d_size < sizeof (Elf32_Word)) + /* Cannot check the section. */ + continue; + + grpdata = (Elf32_Word *) data->d_buf; + for (inner = 1; inner < data->d_size / sizeof (Elf32_Word); ++inner) + if (grpdata[inner] == (Elf32_Word) idx) + goto out; + } + + out: + if (cnt == shnum) + ERROR (gettext ("\ +section [%2d] '%s': section with SHF_GROUP flag set not part of a section group\n"), + idx, section_name (ebl, idx)); + else + ERROR (gettext ("\ +section [%2d] '%s': section group [%2zu] '%s' does not preceed group member\n"), + idx, section_name (ebl, idx), + cnt, section_name (ebl, cnt)); + } +} + + +static void +check_symtab (Ebl *ebl, GElf_Ehdr *ehdr, int idx) +{ + bool no_xndx_warned = false; + int no_pt_tls = 0; + + Elf_Scn *scn = elf_getscn (ebl->elf, idx); + GElf_Shdr shdr_mem; + GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); + GElf_Shdr strshdr_mem; + GElf_Shdr *strshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link), + &strshdr_mem); + if (shdr == NULL || strshdr == NULL) + return; + Elf_Data *data = elf_getdata (scn, NULL); + if (data == NULL) + { + ERROR (gettext ("section [%2d] '%s': cannot get section data\n"), + idx, section_name (ebl, idx)); + return; + } + + if (strshdr->sh_type != SHT_STRTAB) + ERROR (gettext ("section [%2d] '%s': referenced as string table for section [%2d] '%s' but type is not SHT_STRTAB\n"), + shdr->sh_link, section_name (ebl, shdr->sh_link), + idx, section_name (ebl, idx)); + + /* Search for an extended section index table section. */ + size_t cnt; + GElf_Shdr xndxshdr_mem; + GElf_Shdr *xndxshdr = NULL; + Elf_Data *xndxdata = NULL; + Elf32_Word xndxscnidx = 0; + for (cnt = 1; cnt < shnum; ++cnt) + if (cnt != (size_t) idx) + { + Elf_Scn *xndxscn = elf_getscn (ebl->elf, cnt); + xndxshdr = gelf_getshdr (xndxscn, &xndxshdr_mem); + xndxdata = elf_getdata (xndxscn, NULL); + xndxscnidx = elf_ndxscn (xndxscn); + + if (xndxshdr == NULL || xndxdata == NULL) + continue; + + if (xndxshdr->sh_type == SHT_SYMTAB_SHNDX + && xndxshdr->sh_link == (GElf_Word) idx) + break; + } + if (cnt == shnum) + { + xndxshdr = NULL; + xndxdata = NULL; + } + + if (shdr->sh_entsize != gelf_fsize (ebl->elf, ELF_T_SYM, 1, EV_CURRENT)) + ERROR (gettext ("\ +section [%2zu] '%s': entry size is does not match ElfXX_Sym\n"), + cnt, section_name (ebl, cnt)); + + /* Test the zeroth entry. */ + GElf_Sym sym_mem; + Elf32_Word xndx; + GElf_Sym *sym = gelf_getsymshndx (data, xndxdata, 0, &sym_mem, &xndx); + if (sym == NULL) + ERROR (gettext ("section [%2d] '%s': cannot get symbol %d: %s\n"), + idx, section_name (ebl, idx), 0, elf_errmsg (-1)); + else + { + if (sym->st_name != 0) + ERROR (gettext ("section [%2d] '%s': '%s' in zeroth entry not zero\n"), + idx, section_name (ebl, idx), "st_name"); + if (sym->st_value != 0) + ERROR (gettext ("section [%2d] '%s': '%s' in zeroth entry not zero\n"), + idx, section_name (ebl, idx), "st_value"); + if (sym->st_size != 0) + ERROR (gettext ("section [%2d] '%s': '%s' in zeroth entry not zero\n"), + idx, section_name (ebl, idx), "st_size"); + if (sym->st_info != 0) + ERROR (gettext ("section [%2d] '%s': '%s' in zeroth entry not zero\n"), + idx, section_name (ebl, idx), "st_info"); + if (sym->st_other != 0) + ERROR (gettext ("section [%2d] '%s': '%s' in zeroth entry not zero\n"), + idx, section_name (ebl, idx), "st_other"); + if (sym->st_shndx != 0) + ERROR (gettext ("section [%2d] '%s': '%s' in zeroth entry not zero\n"), + idx, section_name (ebl, idx), "st_shndx"); + if (xndxdata != NULL && xndx != 0) + ERROR (gettext ("\ +section [%2d] '%s': XINDEX for zeroth entry not zero\n"), + xndxscnidx, section_name (ebl, xndxscnidx)); + } + + for (cnt = 1; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt) + { + sym = gelf_getsymshndx (data, xndxdata, cnt, &sym_mem, &xndx); + if (sym == NULL) + { + ERROR (gettext ("section [%2d] '%s': cannot get symbol %zu: %s\n"), + idx, section_name (ebl, idx), cnt, elf_errmsg (-1)); + continue; + } + + const char *name = NULL; + if (sym->st_name >= strshdr->sh_size) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: invalid name value\n"), + idx, section_name (ebl, idx), cnt); + else + { + name = elf_strptr (ebl->elf, shdr->sh_link, sym->st_name); + assert (name != NULL); + } + + if (sym->st_shndx == SHN_XINDEX) + { + if (xndxdata == NULL) + { + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: too large section index but no extended section index section\n"), + idx, section_name (ebl, idx), cnt); + no_xndx_warned = true; + } + else if (xndx < SHN_LORESERVE) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: XINDEX used for index which would fit in st_shndx (%" PRIu32 ")\n"), + xndxscnidx, section_name (ebl, xndxscnidx), cnt, + xndx); + } + else if ((sym->st_shndx >= SHN_LORESERVE + // && sym->st_shndx <= SHN_HIRESERVE always true + && sym->st_shndx != SHN_ABS + && sym->st_shndx != SHN_COMMON) + || (sym->st_shndx >= shnum + && (sym->st_shndx < SHN_LORESERVE + /* || sym->st_shndx > SHN_HIRESERVE always false */))) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: invalid section index\n"), + idx, section_name (ebl, idx), cnt); + else + xndx = sym->st_shndx; + + if (GELF_ST_TYPE (sym->st_info) >= STT_NUM) + ERROR (gettext ("section [%2d] '%s': symbol %zu: unknown type\n"), + idx, section_name (ebl, idx), cnt); + + if (GELF_ST_BIND (sym->st_info) >= STB_NUM) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: unknown symbol binding\n"), + idx, section_name (ebl, idx), cnt); + + if (xndx == SHN_COMMON) + { + /* Common symbols can only appear in relocatable files. */ + if (ehdr->e_type != ET_REL) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: COMMON only allowed in relocatable files\n"), + idx, section_name (ebl, idx), cnt); + if (cnt < shdr->sh_info) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: local COMMON symbols are nonsense\n"), + idx, section_name (ebl, idx), cnt); + if (GELF_R_TYPE (sym->st_info) == STT_FUNC) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: function in COMMON section is nonsense\n"), + idx, section_name (ebl, idx), cnt); + } + else if (xndx > 0 && xndx < shnum) + { + GElf_Shdr destshdr_mem; + GElf_Shdr *destshdr; + + destshdr = gelf_getshdr (elf_getscn (ebl->elf, xndx), &destshdr_mem); + if (destshdr != NULL) + { + if (GELF_ST_TYPE (sym->st_info) != STT_TLS) + { + if ((sym->st_value - destshdr->sh_addr) > destshdr->sh_size) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: st_value out of bounds\n"), + idx, section_name (ebl, idx), cnt); + else if ((sym->st_value - destshdr->sh_addr + sym->st_size) + > destshdr->sh_size) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu does not fit completely in referenced section [%2d] '%s'\n"), + idx, section_name (ebl, idx), cnt, + (int) xndx, section_name (ebl, xndx)); + } + else + { + if ((destshdr->sh_flags & SHF_TLS) == 0) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: referenced section [%2d] '%s' does not have SHF_TLS flag set\n"), + idx, section_name (ebl, idx), cnt, + (int) xndx, section_name (ebl, xndx)); + + if (ehdr->e_type == ET_REL) + { + /* For object files the symbol value must fall + into the section. */ + if (sym->st_value > destshdr->sh_size) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: st_value out of bounds of referenced section [%2d] '%s'\n"), + idx, section_name (ebl, idx), cnt, + (int) xndx, section_name (ebl, xndx)); + else if (sym->st_value + sym->st_size + > destshdr->sh_size) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu does not fit completely in referenced section [%2d] '%s'\n"), + idx, section_name (ebl, idx), cnt, + (int) xndx, section_name (ebl, xndx)); + } + else + { + GElf_Phdr phdr_mem; + GElf_Phdr *phdr = NULL; + int pcnt; + + for (pcnt = 0; pcnt < ehdr->e_phnum; ++pcnt) + { + phdr = gelf_getphdr (ebl->elf, pcnt, &phdr_mem); + if (phdr != NULL && phdr->p_type == PT_TLS) + break; + } + + if (pcnt == ehdr->e_phnum) + { + if (no_pt_tls++ == 0) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: TLS symbol but no TLS program header entry\n"), + idx, section_name (ebl, idx), cnt); + } + else + { + if (sym->st_value + < destshdr->sh_offset - phdr->p_offset) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: st_value short of referenced section [%2d] '%s'\n"), + idx, section_name (ebl, idx), cnt, + (int) xndx, section_name (ebl, xndx)); + else if (sym->st_value + > (destshdr->sh_offset - phdr->p_offset + + destshdr->sh_size)) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: st_value out of bounds of referenced section [%2d] '%s'\n"), + idx, section_name (ebl, idx), cnt, + (int) xndx, section_name (ebl, xndx)); + else if (sym->st_value + sym->st_size + > (destshdr->sh_offset - phdr->p_offset + + destshdr->sh_size)) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu does not fit completely in referenced section [%2d] '%s'\n"), + idx, section_name (ebl, idx), cnt, + (int) xndx, section_name (ebl, xndx)); + } + } + } + } + } + + if (GELF_ST_BIND (sym->st_info) == STB_LOCAL) + { + if (cnt >= shdr->sh_info) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: local symbol outside range described in sh_info\n"), + idx, section_name (ebl, idx), cnt); + } + else + { + if (cnt < shdr->sh_info) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: non-local symbol outside range described in sh_info\n"), + idx, section_name (ebl, idx), cnt); + } + + if (GELF_ST_TYPE (sym->st_info) == STT_SECTION + && GELF_ST_BIND (sym->st_info) != STB_LOCAL) + ERROR (gettext ("\ +section [%2d] '%s': symbol %zu: non-local section symbol\n"), + idx, section_name (ebl, idx), cnt); + + if (name != NULL) + { + if (strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0) + { + /* Check that address and size match the global offset + table. We have to locate the GOT by searching for a + section named ".got". */ + Elf_Scn *gscn = NULL; + GElf_Addr addr = 0; + GElf_Xword size = 0; + bool found = false; + + while ((gscn = elf_nextscn (ebl->elf, gscn)) != NULL) + { + GElf_Shdr gshdr_mem; + GElf_Shdr *gshdr = gelf_getshdr (gscn, &gshdr_mem); + assert (gshdr != NULL); + + const char *sname = elf_strptr (ebl->elf, ehdr->e_shstrndx, + gshdr->sh_name); + if (sname != NULL) + { + if (strcmp (sname, ".got.plt") == 0) + { + addr = gshdr->sh_addr; + size = gshdr->sh_size; + found = true; + break; + } + if (strcmp (sname, ".got") == 0) + { + addr = gshdr->sh_addr; + size = gshdr->sh_size; + found = true; + /* Do not stop looking. There might be a + .got.plt section. */ + } + } + } + + if (found) + { + /* Found it. */ + if (sym->st_value != addr) + /* This test is more strict than the psABIs which + usually allow the symbol to be in the middle of + the .got section, allowing negative offsets. */ + ERROR (gettext ("\ +section [%2d] '%s': _GLOBAL_OFFSET_TABLE_ symbol value %#" PRIx64 " does not match .got section address %#" PRIx64 "\n"), + idx, section_name (ebl, idx), + (uint64_t) sym->st_value, (uint64_t) addr); + + if (!gnuld && sym->st_size != size) + ERROR (gettext ("\ +section [%2d] '%s': _GLOBAL_OFFSET_TABLE_ symbol size %" PRIu64 " does not match .got section size %" PRIu64 "\n"), + idx, section_name (ebl, idx), + (uint64_t) sym->st_size, (uint64_t) size); + } + else + ERROR (gettext ("\ +section [%2d] '%s': _GLOBAL_OFFSET_TABLE_ symbol present, but no .got section\n"), + idx, section_name (ebl, idx)); + } + else if (strcmp (name, "_DYNAMIC") == 0) + { + /* Check that address and size match the dynamic + section. We locate the dynamic section via the + program header entry. */ + int pcnt; + + for (pcnt = 0; pcnt < ehdr->e_phnum; ++pcnt) + { + GElf_Phdr phdr_mem; + GElf_Phdr *phdr = gelf_getphdr (ebl->elf, pcnt, &phdr_mem); + + if (phdr != NULL && phdr->p_type == PT_DYNAMIC) + { + if (sym->st_value != phdr->p_vaddr) + ERROR (gettext ("\ +section [%2d] '%s': _DYNAMIC_ symbol value %#" PRIx64 " does not match dynamic segment address %#" PRIx64 "\n"), + idx, section_name (ebl, idx), + (uint64_t) sym->st_value, + (uint64_t) phdr->p_vaddr); + + if (!gnuld && sym->st_size != phdr->p_memsz) + ERROR (gettext ("\ +section [%2d] '%s': _DYNAMIC symbol size %" PRIu64 " does not match dynamic segment size %" PRIu64 "\n"), + idx, section_name (ebl, idx), + (uint64_t) sym->st_size, + (uint64_t) phdr->p_memsz); + + break; + } + } + } + } + } +} + + +static bool +is_rel_dyn (Ebl *ebl, GElf_Ehdr *ehdr, int idx, GElf_Shdr *shdr, bool rela) +{ + /* If this is no executable or DSO it cannot be a .rel.dyn section. */ + if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) + return false; + + /* Check the section name. Unfortunately necessary. */ + if (strcmp (section_name (ebl, idx), rela ? ".rela.dyn" : ".rel.dyn")) + return false; + + /* When a .rel.dyn section is used a DT_RELCOUNT dynamic section + entry can be present as well. */ + Elf_Scn *scn = NULL; + while ((scn = elf_nextscn (ebl->elf, scn)) != NULL) + { + GElf_Shdr rcshdr_mem; + const GElf_Shdr *rcshdr = gelf_getshdr (scn, &rcshdr_mem); + assert (rcshdr != NULL); + + if (rcshdr->sh_type == SHT_DYNAMIC) + { + /* Found the dynamic section. Look through it. */ + Elf_Data *d = elf_getdata (scn, NULL); + size_t cnt; + + for (cnt = 1; cnt < rcshdr->sh_size / rcshdr->sh_entsize; ++cnt) + { + GElf_Dyn dyn_mem; + GElf_Dyn *dyn = gelf_getdyn (d, cnt, &dyn_mem); + assert (dyn != NULL); + + if (dyn->d_tag == DT_RELCOUNT) + { + /* Found it. One last check: does the number + specified number of relative relocations exceed + the total number of relocations? */ + if (dyn->d_un.d_val > shdr->sh_size / shdr->sh_entsize) + ERROR (gettext ("\ +section [%2d] '%s': DT_RELCOUNT value %d too high for this section\n"), + idx, section_name (ebl, idx), + (int) dyn->d_un.d_val); + } + } + + break; + } + } + + return true; +} + + +static void +check_rela (Ebl *ebl, GElf_Ehdr *ehdr, int idx) +{ + Elf_Scn *scn; + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + Elf_Data *data; + GElf_Shdr destshdr_mem; + GElf_Shdr *destshdr = NULL; + size_t cnt; + bool reldyn = false; + bool known_broken = gnuld; + + scn = elf_getscn (ebl->elf, idx); + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + return; + data = elf_getdata (scn, NULL); + if (data == NULL) + { + ERROR (gettext ("section [%2d] '%s': cannot get section data\n"), + idx, section_name (ebl, idx)); + return; + } + + /* Check whether the link to the section we relocate is reasonable. */ + if (shdr->sh_info >= shnum) + ERROR (gettext ("section [%2d] '%s': invalid destination section index\n"), + idx, section_name (ebl, idx)); + else + { + destshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_info), + &destshdr_mem); + if (destshdr != NULL) + { + if(destshdr->sh_type != SHT_PROGBITS + && destshdr->sh_type != SHT_NOBITS) + { + reldyn = is_rel_dyn (ebl, ehdr, idx, shdr, true); + if (!reldyn) + ERROR (gettext ("\ +section [%2d] '%s': invalid destination section type\n"), + idx, section_name (ebl, idx)); + else + { + /* There is no standard, but we require that .rela.dyn + sections have a sh_info value of zero. */ + if (shdr->sh_info != 0) + ERROR (gettext ("\ +section [%2d] '%s': sh_info should be zero\n"), + idx, section_name (ebl, idx)); + } + } + + if ((destshdr->sh_flags & (SHF_MERGE | SHF_STRINGS)) != 0) + ERROR (gettext ("\ +section [%2d] '%s': no relocations for merge-able sections possible\n"), + idx, section_name (ebl, idx)); + } + } + + if (shdr->sh_entsize != gelf_fsize (ebl->elf, ELF_T_RELA, 1, EV_CURRENT)) + ERROR (gettext ("\ +section [%2d] '%s': section entry size does not match ElfXX_Rela\n"), + idx, section_name (ebl, idx)); + + Elf_Scn *symscn = elf_getscn (ebl->elf, shdr->sh_link); + GElf_Shdr symshdr_mem; + GElf_Shdr *symshdr = gelf_getshdr (symscn, &symshdr_mem); + Elf_Data *symdata = elf_getdata (symscn, NULL); + + for (cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt) + { + GElf_Rela rela_mem; + GElf_Rela *rela; + + rela = gelf_getrela (data, cnt, &rela_mem); + if (rela == NULL) + { + ERROR (gettext ("\ +section [%2d] '%s': cannot get relocation %zu: %s\n"), + idx, section_name (ebl, idx), cnt, elf_errmsg (-1)); + continue; + } + + if (!ebl_reloc_type_check (ebl, GELF_R_TYPE (rela->r_info))) + ERROR (gettext ("section [%2d] '%s': relocation %zu: invalid type\n"), + idx, section_name (ebl, idx), cnt); + else if (!ebl_reloc_valid_use (ebl, GELF_R_TYPE (rela->r_info))) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: relocation type invalid for the file type\n"), + idx, section_name (ebl, idx), cnt); + + if (symshdr != NULL + && ((GELF_R_SYM (rela->r_info) + 1) + * gelf_fsize (ebl->elf, ELF_T_SYM, 1, EV_CURRENT) + > symshdr->sh_size)) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: invalid symbol index\n"), + idx, section_name (ebl, idx), cnt); + + if (ebl_gotpc_reloc_check (ebl, GELF_R_TYPE (rela->r_info))) + { + const char *name; + char buf[64]; + GElf_Sym sym_mem; + GElf_Sym *sym = gelf_getsym (symdata, GELF_R_SYM (rela->r_info), + &sym_mem); + if (sym != NULL + /* Get the name for the symbol. */ + && (name = elf_strptr (ebl->elf, symshdr->sh_link, sym->st_name)) + && strcmp (name, "_GLOBAL_OFFSET_TABLE_") !=0 ) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: only symbol '_GLOBAL_OFFSET_TABLE_' can be used with %s\n"), + idx, section_name (ebl, idx), cnt, + ebl_reloc_type_name (ebl, GELF_R_SYM (rela->r_info), + buf, sizeof (buf))); + } + + if (reldyn) + { + // XXX TODO Check .rel.dyn section addresses. + } + else if (!known_broken) + { + if (destshdr != NULL + && (rela->r_offset - destshdr->sh_addr) >= destshdr->sh_size) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: offset out of bounds\n"), + idx, section_name (ebl, idx), cnt); + } + + if (symdata != NULL + && ebl_copy_reloc_p (ebl, GELF_R_TYPE (rela->r_info))) + { + /* Make sure the referenced symbol is an object or unspecified. */ + GElf_Sym sym_mem; + GElf_Sym *sym = gelf_getsym (symdata, GELF_R_SYM (rela->r_info), + &sym_mem); + if (sym != NULL + && GELF_ST_TYPE (sym->st_info) != STT_NOTYPE + && GELF_ST_TYPE (sym->st_info) != STT_OBJECT) + { + char buf[64]; + ERROR (gettext ("section [%2d] '%s': relocation %zu: copy relocation against symbol of type %s\n"), + idx, section_name (ebl, idx), cnt, + ebl_symbol_type_name (ebl, GELF_ST_TYPE (sym->st_info), + buf, sizeof (buf))); + } + } + } +} + + +static void +check_rel (Ebl *ebl, GElf_Ehdr *ehdr, int idx) +{ + Elf_Scn *scn; + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + Elf_Data *data; + GElf_Shdr destshdr_mem; + GElf_Shdr *destshdr = NULL; + size_t cnt; + bool reldyn = false; + bool known_broken = gnuld; + + scn = elf_getscn (ebl->elf, idx); + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + return; + data = elf_getdata (scn, NULL); + if (data == NULL) + { + ERROR (gettext ("section [%2d] '%s': cannot get section data\n"), + idx, section_name (ebl, idx)); + return; + } + + /* Check whether the link to the section we relocate is reasonable. */ + if (shdr->sh_info >= shnum) + ERROR (gettext ("section [%2d] '%s': invalid destination section index\n"), + idx, section_name (ebl, idx)); + else + { + destshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_info), + &destshdr_mem); + if (destshdr != NULL) + { + if (destshdr->sh_type != SHT_PROGBITS + && destshdr->sh_type != SHT_NOBITS) + { + reldyn = is_rel_dyn (ebl, ehdr, idx, shdr, false); + if (!reldyn) + ERROR (gettext ("\ +section [%2d] '%s': invalid destination section type\n"), + idx, section_name (ebl, idx)); + else + { + /* There is no standard, but we require that .rela.dyn + sections have a sh_info value of zero. */ + if (shdr->sh_info != 0) + ERROR (gettext ("\ +section [%2d] '%s': sh_info should be zero\n"), + idx, section_name (ebl, idx)); + } + } + + if ((destshdr->sh_flags & (SHF_MERGE | SHF_STRINGS)) != 0) + ERROR (gettext ("\ +section [%2d] '%s': no relocations for merge-able sections possible\n"), + idx, section_name (ebl, idx)); + } + } + + if (shdr->sh_entsize != gelf_fsize (ebl->elf, ELF_T_REL, 1, EV_CURRENT)) + ERROR (gettext ("\ +section [%2d] '%s': section entry size does not match ElfXX_Rel\n"), + idx, section_name (ebl, idx)); + + Elf_Scn *symscn = elf_getscn (ebl->elf, shdr->sh_link); + GElf_Shdr symshdr_mem; + GElf_Shdr *symshdr = gelf_getshdr (symscn, &symshdr_mem); + Elf_Data *symdata = elf_getdata (symscn, NULL); + + for (cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt) + { + GElf_Rel rel_mem; + GElf_Rel *rel; + + rel = gelf_getrel (data, cnt, &rel_mem); + if (rel == NULL) + { + ERROR (gettext ("\ +section [%2d] '%s': cannot get relocation %zu: %s\n"), + idx, section_name (ebl, idx), cnt, elf_errmsg (-1)); + continue; + } + + if (!ebl_reloc_type_check (ebl, GELF_R_TYPE (rel->r_info))) + ERROR (gettext ("section [%2d] '%s': relocation %zu: invalid type\n"), + idx, section_name (ebl, idx), cnt); + else if (!ebl_reloc_valid_use (ebl, GELF_R_TYPE (rel->r_info))) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: relocation type invalid for the file type\n"), + idx, section_name (ebl, idx), cnt); + + if (symshdr != NULL + && ((GELF_R_SYM (rel->r_info) + 1) + * gelf_fsize (ebl->elf, ELF_T_SYM, 1, EV_CURRENT) + > symshdr->sh_size)) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: invalid symbol index\n"), + idx, section_name (ebl, idx), cnt); + + if (ebl_gotpc_reloc_check (ebl, GELF_R_TYPE (rel->r_info))) + { + const char *name; + char buf[64]; + GElf_Sym sym_mem; + GElf_Sym *sym = gelf_getsym (symdata, GELF_R_SYM (rel->r_info), + &sym_mem); + if (sym != NULL + /* Get the name for the symbol. */ + && (name = elf_strptr (ebl->elf, symshdr->sh_link, sym->st_name)) + && strcmp (name, "_GLOBAL_OFFSET_TABLE_") !=0 ) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: only symbol '_GLOBAL_OFFSET_TABLE_' can be used with %s\n"), + idx, section_name (ebl, idx), cnt, + ebl_reloc_type_name (ebl, GELF_R_SYM (rel->r_info), + buf, sizeof (buf))); + } + + if (reldyn) + { + // XXX TODO Check .rel.dyn section addresses. + } + else if (!known_broken) + { + if (destshdr != NULL + && GELF_R_TYPE (rel->r_info) != 0 + && (rel->r_offset - destshdr->sh_addr) >= destshdr->sh_size) + ERROR (gettext ("\ +section [%2d] '%s': relocation %zu: offset out of bounds\n"), + idx, section_name (ebl, idx), cnt); + } + + if (symdata != NULL + && ebl_copy_reloc_p (ebl, GELF_R_TYPE (rel->r_info))) + { + /* Make sure the referenced symbol is an object or unspecified. */ + GElf_Sym sym_mem; + GElf_Sym *sym = gelf_getsym (symdata, GELF_R_SYM (rel->r_info), + &sym_mem); + if (sym != NULL + && GELF_ST_TYPE (sym->st_info) != STT_NOTYPE + && GELF_ST_TYPE (sym->st_info) != STT_OBJECT) + { + char buf[64]; + ERROR (gettext ("section [%2d] '%s': relocation %zu: copy relocation against symbol of type %s\n"), + idx, section_name (ebl, idx), cnt, + ebl_symbol_type_name (ebl, GELF_ST_TYPE (sym->st_info), + buf, sizeof (buf))); + } + } + } +} + + +/* Number of dynamic sections. */ +static int ndynamic; + + +static void +check_dynamic (Ebl *ebl, int idx) +{ + Elf_Scn *scn; + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + Elf_Data *data; + GElf_Shdr strshdr_mem; + GElf_Shdr *strshdr; + size_t cnt; + static const bool dependencies[DT_NUM][DT_NUM] = + { + [DT_NEEDED] = { [DT_STRTAB] = true }, + [DT_PLTRELSZ] = { [DT_JMPREL] = true }, + [DT_HASH] = { [DT_SYMTAB] = true }, + [DT_STRTAB] = { [DT_STRSZ] = true }, + [DT_SYMTAB] = { [DT_STRTAB] = true, [DT_HASH] = true, + [DT_SYMENT] = true }, + [DT_RELA] = { [DT_RELASZ] = true, [DT_RELAENT] = true }, + [DT_RELASZ] = { [DT_RELA] = true }, + [DT_RELAENT] = { [DT_RELA] = true }, + [DT_STRSZ] = { [DT_STRTAB] = true }, + [DT_SYMENT] = { [DT_SYMTAB] = true }, + [DT_SONAME] = { [DT_STRTAB] = true }, + [DT_RPATH] = { [DT_STRTAB] = true }, + [DT_REL] = { [DT_RELSZ] = true, [DT_RELENT] = true }, + [DT_RELSZ] = { [DT_REL] = true }, + [DT_RELENT] = { [DT_REL] = true }, + [DT_JMPREL] = { [DT_PLTRELSZ] = true, [DT_PLTREL] = true }, + [DT_RUNPATH] = { [DT_STRTAB] = true }, + [DT_PLTREL] = { [DT_JMPREL] = true }, + [DT_PLTRELSZ] = { [DT_JMPREL] = true } + }; + bool has_dt[DT_NUM]; + static const bool level2[DT_NUM] = + { + [DT_RPATH] = true, + [DT_SYMBOLIC] = true, + [DT_TEXTREL] = true, + [DT_BIND_NOW] = true + }; + static const bool mandatory[DT_NUM] = + { + [DT_NULL] = true, + [DT_HASH] = true, + [DT_STRTAB] = true, + [DT_SYMTAB] = true, + [DT_STRSZ] = true, + [DT_SYMENT] = true + }; + GElf_Addr reladdr = 0; + GElf_Word relsz = 0; + GElf_Addr pltreladdr = 0; + GElf_Word pltrelsz = 0; + + memset (has_dt, '\0', sizeof (has_dt)); + + if (++ndynamic == 2) + ERROR (gettext ("more than one dynamic section present\n")); + + scn = elf_getscn (ebl->elf, idx); + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + return; + data = elf_getdata (scn, NULL); + if (data == NULL) + { + ERROR (gettext ("section [%2d] '%s': cannot get section data\n"), + idx, section_name (ebl, idx)); + return; + } + + strshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link), &strshdr_mem); + if (strshdr != NULL && strshdr->sh_type != SHT_STRTAB) + ERROR (gettext ("\ +section [%2d] '%s': referenced as string table for section [%2d] '%s' but type is not SHT_STRTAB\n"), + shdr->sh_link, section_name (ebl, shdr->sh_link), + idx, section_name (ebl, idx)); + + if (shdr->sh_entsize != gelf_fsize (ebl->elf, ELF_T_DYN, 1, EV_CURRENT)) + ERROR (gettext ("\ +section [%2d] '%s': section entry size does not match ElfXX_Dyn\n"), + idx, section_name (ebl, idx)); + + if (shdr->sh_info != 0) + ERROR (gettext ("section [%2d] '%s': sh_info not zero\n"), + idx, section_name (ebl, idx)); + + bool non_null_warned = false; + for (cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt) + { + GElf_Dyn dyn_mem; + GElf_Dyn *dyn; + + dyn = gelf_getdyn (data, cnt, &dyn_mem); + if (dyn == NULL) + { + ERROR (gettext ("\ +section [%2d] '%s': cannot get dynamic section entry %zu: %s\n"), + idx, section_name (ebl, idx), cnt, elf_errmsg (-1)); + continue; + } + + if (has_dt[DT_NULL] && dyn->d_tag != DT_NULL && ! non_null_warned) + { + ERROR (gettext ("\ +section [%2d] '%s': non-DT_NULL entries follow DT_NULL entry\n"), + idx, section_name (ebl, idx)); + non_null_warned = true; + } + + if (!ebl_dynamic_tag_check (ebl, dyn->d_tag)) + ERROR (gettext ("section [%2d] '%s': entry %zu: unknown tag\n"), + idx, section_name (ebl, idx), cnt); + + if (dyn->d_tag >= 0 && dyn->d_tag < DT_NUM) + { + if (has_dt[dyn->d_tag] + && dyn->d_tag != DT_NEEDED + && dyn->d_tag != DT_NULL + && dyn->d_tag != DT_POSFLAG_1) + { + char buf[50]; + ERROR (gettext ("\ +section [%2d] '%s': entry %zu: more than one entry with tag %s\n"), + idx, section_name (ebl, idx), cnt, + ebl_dynamic_tag_name (ebl, dyn->d_tag, + buf, sizeof (buf))); + } + + if (be_strict && level2[dyn->d_tag]) + { + char buf[50]; + ERROR (gettext ("\ +section [%2d] '%s': entry %zu: level 2 tag %s used\n"), + idx, section_name (ebl, idx), cnt, + ebl_dynamic_tag_name (ebl, dyn->d_tag, + buf, sizeof (buf))); + } + + has_dt[dyn->d_tag] = true; + } + + if (dyn->d_tag == DT_PLTREL && dyn->d_un.d_val != DT_REL + && dyn->d_un.d_val != DT_RELA) + ERROR (gettext ("\ +section [%2d] '%s': entry %zu: DT_PLTREL value must be DT_REL or DT_RELA\n"), + idx, section_name (ebl, idx), cnt); + + if (dyn->d_tag == DT_REL) + reladdr = dyn->d_un.d_ptr; + if (dyn->d_tag == DT_RELSZ) + relsz = dyn->d_un.d_val; + if (dyn->d_tag == DT_JMPREL) + pltreladdr = dyn->d_un.d_ptr; + if (dyn->d_tag == DT_PLTRELSZ) + pltrelsz = dyn->d_un.d_val; + } + + for (cnt = 1; cnt < DT_NUM; ++cnt) + if (has_dt[cnt]) + { + int inner; + + for (inner = 0; inner < DT_NUM; ++inner) + if (dependencies[cnt][inner] && ! has_dt[inner]) + { + char buf1[50]; + char buf2[50]; + + ERROR (gettext ("\ +section [%2d] '%s': contains %s entry but not %s\n"), + idx, section_name (ebl, idx), + ebl_dynamic_tag_name (ebl, cnt, buf1, sizeof (buf1)), + ebl_dynamic_tag_name (ebl, inner, buf2, sizeof (buf2))); + } + } + else + { + if (mandatory[cnt]) + { + char buf[50]; + ERROR (gettext ("\ +section [%2d] '%s': mandatory tag %s not present\n"), + idx, section_name (ebl, idx), + ebl_dynamic_tag_name (ebl, cnt, buf, sizeof (buf))); + } + } + + /* Check the rel/rela tags. At least one group must be available. */ + if ((has_dt[DT_RELA] || has_dt[DT_RELASZ] || has_dt[DT_RELAENT]) + && (!has_dt[DT_RELA] || !has_dt[DT_RELASZ] || !has_dt[DT_RELAENT])) + ERROR (gettext ("\ +section [%2d] '%s': not all of %s, %s, and %s are present\n"), + idx, section_name (ebl, idx), + "DT_RELA", "DT_RELASZ", "DT_RELAENT"); + + if ((has_dt[DT_REL] || has_dt[DT_RELSZ] || has_dt[DT_RELENT]) + && (!has_dt[DT_REL] || !has_dt[DT_RELSZ] || !has_dt[DT_RELENT])) + ERROR (gettext ("\ +section [%2d] '%s': not all of %s, %s, and %s are present\n"), + idx, section_name (ebl, idx), + "DT_REL", "DT_RELSZ", "DT_RELENT"); +} + + +static void +check_symtab_shndx (Ebl *ebl, int idx) +{ + Elf_Scn *scn; + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + GElf_Shdr symshdr_mem; + GElf_Shdr *symshdr; + Elf_Scn *symscn; + size_t cnt; + Elf_Data *data; + Elf_Data *symdata; + + scn = elf_getscn (ebl->elf, idx); + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + return; + + symscn = elf_getscn (ebl->elf, shdr->sh_link); + symshdr = gelf_getshdr (symscn, &symshdr_mem); + if (symshdr != NULL && symshdr->sh_type != SHT_SYMTAB) + ERROR (gettext ("\ +section [%2d] '%s': extended section index section not for symbol table\n"), + idx, section_name (ebl, idx)); + symdata = elf_getdata (symscn, NULL); + if (symdata == NULL) + ERROR (gettext ("cannot get data for symbol section\n")); + + if (shdr->sh_entsize != sizeof (Elf32_Word)) + ERROR (gettext ("\ +section [%2d] '%s': entry size does not match Elf32_Word\n"), + idx, section_name (ebl, idx)); + + if (symshdr != NULL + && (shdr->sh_size / shdr->sh_entsize + < symshdr->sh_size / symshdr->sh_entsize)) + ERROR (gettext ("\ +section [%2d] '%s': extended index table too small for symbol table\n"), + idx, section_name (ebl, idx)); + + if (shdr->sh_info != 0) + ERROR (gettext ("section [%2d] '%s': sh_info not zero\n"), + idx, section_name (ebl, idx)); + + for (cnt = idx + 1; cnt < shnum; ++cnt) + { + GElf_Shdr rshdr_mem; + GElf_Shdr *rshdr; + + rshdr = gelf_getshdr (elf_getscn (ebl->elf, cnt), &rshdr_mem); + if (rshdr != NULL && rshdr->sh_type == SHT_SYMTAB_SHNDX + && rshdr->sh_link == shdr->sh_link) + { + ERROR (gettext ("\ +section [%2d] '%s': extended section index in section [%2zu] '%s' refers to same symbol table\n"), + idx, section_name (ebl, idx), + cnt, section_name (ebl, cnt)); + break; + } + } + + data = elf_getdata (scn, NULL); + + if (*((Elf32_Word *) data->d_buf) != 0) + ERROR (gettext ("symbol 0 should have zero extended section index\n")); + + for (cnt = 1; cnt < data->d_size / sizeof (Elf32_Word); ++cnt) + { + Elf32_Word xndx = ((Elf32_Word *) data->d_buf)[cnt]; + + if (xndx != 0) + { + GElf_Sym sym_data; + GElf_Sym *sym = gelf_getsym (symdata, cnt, &sym_data); + if (sym == NULL) + { + ERROR (gettext ("cannot get data for symbol %zu\n"), cnt); + continue; + } + + if (sym->st_shndx != SHN_XINDEX) + ERROR (gettext ("\ +extended section index is %" PRIu32 " but symbol index is not XINDEX\n"), + (uint32_t) xndx); + } + } +} + + +static void +check_hash (Ebl *ebl, int idx) +{ + Elf_Scn *scn; + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + Elf_Data *data; + Elf32_Word nbucket; + Elf32_Word nchain; + GElf_Shdr symshdr_mem; + GElf_Shdr *symshdr; + + scn = elf_getscn (ebl->elf, idx); + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + return; + data = elf_getdata (scn, NULL); + if (data == NULL) + { + ERROR (gettext ("section [%2d] '%s': cannot get section data\n"), + idx, section_name (ebl, idx)); + return; + } + + symshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link), &symshdr_mem); + if (symshdr != NULL && symshdr->sh_type != SHT_DYNSYM) + ERROR (gettext ("\ +section [%2d] '%s': hash table not for dynamic symbol table\n"), + idx, section_name (ebl, idx)); + + if (shdr->sh_entsize != sizeof (Elf32_Word)) + ERROR (gettext ("\ +section [%2d] '%s': entry size does not match Elf32_Word\n"), + idx, section_name (ebl, idx)); + + if ((shdr->sh_flags & SHF_ALLOC) == 0) + ERROR (gettext ("section [%2d] '%s': not marked to be allocated\n"), + idx, section_name (ebl, idx)); + + if (shdr->sh_size < 2 * shdr->sh_entsize) + { + ERROR (gettext ("\ +section [%2d] '%s': hash table has not even room for nbucket and nchain\n"), + idx, section_name (ebl, idx)); + return; + } + + nbucket = ((Elf32_Word *) data->d_buf)[0]; + nchain = ((Elf32_Word *) data->d_buf)[1]; + + if (shdr->sh_size < (2 + nbucket + nchain) * shdr->sh_entsize) + ERROR (gettext ("\ +section [%2d] '%s': hash table section is too small (is %ld, expected %ld)\n"), + idx, section_name (ebl, idx), (long int) shdr->sh_size, + (long int) ((2 + nbucket + nchain) * shdr->sh_entsize)); + + if (symshdr != NULL) + { + size_t symsize = symshdr->sh_size / symshdr->sh_entsize; + size_t cnt; + + if (nchain < symshdr->sh_size / symshdr->sh_entsize) + ERROR (gettext ("section [%2d] '%s': chain array not large enough\n"), + idx, section_name (ebl, idx)); + + for (cnt = 2; cnt < 2 + nbucket; ++cnt) + if (((Elf32_Word *) data->d_buf)[cnt] >= symsize) + ERROR (gettext ("\ +section [%2d] '%s': hash bucket reference %zu out of bounds\n"), + idx, section_name (ebl, idx), cnt - 2); + + for (; cnt < 2 + nbucket + nchain; ++cnt) + if (((Elf32_Word *) data->d_buf)[cnt] >= symsize) + ERROR (gettext ("\ +section [%2d] '%s': hash chain reference %zu out of bounds\n"), + idx, section_name (ebl, idx), cnt - 2 - nbucket); + } +} + + +static void +check_null (Ebl *ebl, GElf_Shdr *shdr, int idx) +{ +#define TEST(name, extra) \ + if (extra && shdr->sh_##name != 0) \ + ERROR (gettext ("section [%2d] '%s': nonzero sh_%s for NULL section\n"), \ + idx, section_name (ebl, idx), #name) + + TEST (name, 1); + TEST (flags, 1); + TEST (addr, 1); + TEST (offset, 1); + TEST (size, idx != 0); + TEST (link, idx != 0); + TEST (info, 1); + TEST (addralign, 1); + TEST (entsize, 1); +} + + +static void +check_group (Ebl *ebl, GElf_Ehdr *ehdr, GElf_Shdr *shdr, int idx) +{ + if (ehdr->e_type != ET_REL) + { + ERROR (gettext ("\ +section [%2d] '%s': section groups only allowed in relocatable object files\n"), + idx, section_name (ebl, idx)); + return; + } + + /* Check that sh_link is an index of a symbol table. */ + GElf_Shdr symshdr_mem; + GElf_Shdr *symshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link), + &symshdr_mem); + if (symshdr == NULL) + ERROR (gettext ("section [%2d] '%s': cannot get symbol table: %s\n"), + idx, section_name (ebl, idx), elf_errmsg (-1)); + else + { + if (symshdr->sh_type != SHT_SYMTAB) + ERROR (gettext ("\ +section [%2d] '%s': section reference in sh_link is no symbol table\n"), + idx, section_name (ebl, idx)); + + if (shdr->sh_info >= symshdr->sh_size / gelf_fsize (ebl->elf, ELF_T_SYM, + 1, EV_CURRENT)) + ERROR (gettext ("\ +section [%2d] '%s': invalid symbol index in sh_info\n"), + idx, section_name (ebl, idx)); + + if (shdr->sh_flags != 0) + ERROR (gettext ("section [%2d] '%s': sh_flags not zero\n"), + idx, section_name (ebl, idx)); + + if (be_strict + && shdr->sh_entsize != elf32_fsize (ELF_T_WORD, 1, EV_CURRENT)) + ERROR (gettext ("section [%2d] '%s': sh_flags not set correctly\n"), + idx, section_name (ebl, idx)); + } + + Elf_Data *data = elf_getdata (elf_getscn (ebl->elf, idx), NULL); + if (data == NULL) + ERROR (gettext ("section [%2d] '%s': cannot get data: %s\n"), + idx, section_name (ebl, idx), elf_errmsg (-1)); + else + { + size_t elsize = elf32_fsize (ELF_T_WORD, 1, EV_CURRENT); + size_t cnt; + Elf32_Word val; + + if (data->d_size % elsize != 0) + ERROR (gettext ("\ +section [%2d] '%s': section size not multiple of sizeof(Elf32_Word)\n"), + idx, section_name (ebl, idx)); + + if (data->d_size < elsize) + ERROR (gettext ("\ +section [%2d] '%s': section group without flags word\n"), + idx, section_name (ebl, idx)); + else if (be_strict) + { + if (data->d_size < 2 * elsize) + ERROR (gettext ("\ +section [%2d] '%s': section group without member\n"), + idx, section_name (ebl, idx)); + else if (data->d_size < 3 * elsize) + ERROR (gettext ("\ +section [%2d] '%s': section group with only one member\n"), + idx, section_name (ebl, idx)); + } + +#if ALLOW_UNALIGNED + val = *((Elf32_Word *) data->d_buf); +#else + memcpy (&val, data->d_buf, elsize); +#endif + if ((val & ~GRP_COMDAT) != 0) + ERROR (gettext ("section [%2d] '%s': unknown section group flags\n"), + idx, section_name (ebl, idx)); + + for (cnt = elsize; cnt < data->d_size; cnt += elsize) + { +#if ALLOW_UNALIGNED + val = *((Elf32_Word *) ((char *) data->d_buf + cnt)); +#else + memcpy (&val, (char *) data->d_buf + cnt, elsize); +#endif + + if (val > shnum) + ERROR (gettext ("\ +section [%2d] '%s': section index %Zu out of range\n"), + idx, section_name (ebl, idx), cnt / elsize); + else + { + GElf_Shdr refshdr_mem; + GElf_Shdr *refshdr; + + refshdr = gelf_getshdr (elf_getscn (ebl->elf, val), + &refshdr_mem); + if (refshdr == NULL) + ERROR (gettext ("\ +section [%2d] '%s': cannot get section header for element %zu: %s\n"), + idx, section_name (ebl, idx), cnt / elsize, + elf_errmsg (-1)); + else + { + if (refshdr->sh_type == SHT_GROUP) + ERROR (gettext ("\ +section [%2d] '%s': section group contains another group [%2d] '%s'\n"), + idx, section_name (ebl, idx), + val, section_name (ebl, val)); + + if ((refshdr->sh_flags & SHF_GROUP) == 0) + ERROR (gettext ("\ +section [%2d] '%s': element %Zu references section [%2d] '%s' without SHF_GROUP flag set\n"), + idx, section_name (ebl, idx), cnt / elsize, + val, section_name (ebl, val)); + } + + if (++scnref[val] == 2) + ERROR (gettext ("\ +section [%2d] '%s' is contained in more than one section group\n"), + val, section_name (ebl, val)); + } + } + } +} + + +static bool has_loadable_segment; +static bool has_interp_segment; + +static const struct +{ + const char *name; + size_t namelen; + GElf_Word type; + enum { unused, exact, atleast } attrflag; + GElf_Word attr; + GElf_Word attr2; +} special_sections[] = + { + /* See figure 4-14 in the gABI. */ + { ".bss", 5, SHT_NOBITS, exact, SHF_ALLOC | SHF_WRITE, 0 }, + { ".comment", 8, SHT_PROGBITS, exact, 0, 0 }, + { ".data", 6, SHT_PROGBITS, exact, SHF_ALLOC | SHF_WRITE, 0 }, + { ".data1", 7, SHT_PROGBITS, exact, SHF_ALLOC | SHF_WRITE, 0 }, + { ".debug", 7, SHT_PROGBITS, exact, 0, 0 }, + { ".dynamic", 9, SHT_DYNAMIC, atleast, SHF_ALLOC, SHF_WRITE }, + { ".dynstr", 8, SHT_STRTAB, exact, SHF_ALLOC, 0 }, + { ".dynsym", 8, SHT_DYNSYM, exact, SHF_ALLOC, 0 }, + { ".fini", 6, SHT_PROGBITS, exact, SHF_ALLOC | SHF_EXECINSTR, 0 }, + { ".fini_array", 12, SHT_FINI_ARRAY, exact, SHF_ALLOC | SHF_WRITE, 0 }, + { ".got", 5, SHT_PROGBITS, unused, 0, 0 }, // XXX more info? + { ".hash", 6, SHT_HASH, exact, SHF_ALLOC, 0 }, + { ".init", 6, SHT_PROGBITS, exact, SHF_ALLOC | SHF_EXECINSTR, 0 }, + { ".init_array", 12, SHT_INIT_ARRAY, exact, SHF_ALLOC | SHF_WRITE, 0 }, + { ".interp", 8, SHT_PROGBITS, atleast, 0, SHF_ALLOC }, // XXX more tests? + { ".line", 6, SHT_PROGBITS, exact, 0, 0 }, + { ".note", 6, SHT_NOTE, exact, 0, 0 }, + { ".plt", 5, SHT_PROGBITS, unused, 0, 0 }, // XXX more tests + { ".preinit_array", 15, SHT_PREINIT_ARRAY, exact, SHF_ALLOC | SHF_WRITE, 0 }, + { ".rela", 5, SHT_RELA, atleast, 0, SHF_ALLOC }, // XXX more tests + { ".rel", 4, SHT_REL, atleast, 0, SHF_ALLOC }, // XXX more tests + { ".rodata", 8, SHT_PROGBITS, exact, SHF_ALLOC, 0 }, + { ".rodata1", 9, SHT_PROGBITS, exact, SHF_ALLOC, 0 }, + { ".shstrtab", 10, SHT_STRTAB, exact, 0, 0 }, + { ".strtab", 8, SHT_STRTAB, atleast, 0, SHF_ALLOC }, // XXX more tests + { ".symtab", 8, SHT_SYMTAB, atleast, 0, SHF_ALLOC }, // XXX more tests + { ".symtab_shndx", 14, SHT_SYMTAB_SHNDX, atleast, 0, SHF_ALLOC }, // XXX more tests + { ".tbss", 6, SHT_NOBITS, exact, SHF_ALLOC | SHF_WRITE | SHF_TLS, 0 }, + { ".tdata", 7, SHT_PROGBITS, exact, SHF_ALLOC | SHF_WRITE | SHF_TLS, 0 }, + { ".tdata1", 8, SHT_PROGBITS, exact, SHF_ALLOC | SHF_WRITE | SHF_TLS, 0 }, + { ".text", 6, SHT_PROGBITS, exact, SHF_ALLOC | SHF_EXECINSTR, 0 } + }; +#define nspecial_sections \ + (sizeof (special_sections) / sizeof (special_sections[0])) + + +static const char * +section_flags_string (GElf_Word flags, char *buf, size_t len) +{ + static const struct + { + GElf_Word flag; + const char *name; + } known_flags[] = + { +#define NEWFLAG(name) { SHF_##name, #name } + NEWFLAG (WRITE), + NEWFLAG (ALLOC), + NEWFLAG (EXECINSTR), + NEWFLAG (MERGE), + NEWFLAG (STRINGS), + NEWFLAG (INFO_LINK), + NEWFLAG (LINK_ORDER), + NEWFLAG (OS_NONCONFORMING), + NEWFLAG (GROUP), + NEWFLAG (TLS) + }; +#undef NEWFLAG + const size_t nknown_flags = sizeof (known_flags) / sizeof (known_flags[0]); + + char *cp = buf; + size_t cnt; + + for (cnt = 0; cnt < nknown_flags; ++cnt) + if (flags & known_flags[cnt].flag) + { + if (cp != buf && len > 1) + { + *cp++ = '|'; + --len; + } + + size_t ncopy = MIN (len - 1, strlen (known_flags[cnt].name)); + cp = mempcpy (cp, known_flags[cnt].name, ncopy); + len -= ncopy; + + flags ^= known_flags[cnt].flag; + } + + if (flags != 0 || cp == buf) + snprintf (cp, len - 1, "%" PRIx64, (uint64_t) flags); + + *cp = '\0'; + + return buf; +} + + +static void +check_versym (Ebl *ebl, GElf_Shdr *shdr, int idx) +{ + /* The number of elements in the version symbol table must be the + same as the number of symbols. */ + GElf_Shdr symshdr_mem; + GElf_Shdr *symshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link), + &symshdr_mem); + if (symshdr == NULL) + /* The error has already been reported. */ + return; + + if (symshdr->sh_type != SHT_DYNSYM) + { + ERROR (gettext ("\ +section [%2d] '%s' refers in sh_link to section [%2d] '%s' which is no dynamic symbol table\n"), + idx, section_name (ebl, idx), + shdr->sh_link, section_name (ebl, shdr->sh_link)); + return; + } + + if (shdr->sh_size / shdr->sh_entsize + != symshdr->sh_size / symshdr->sh_entsize) + ERROR (gettext ("\ +section [%2d] '%s' has different number of entries than symbol table [%2d] '%s'\n"), + idx, section_name (ebl, idx), + shdr->sh_link, section_name (ebl, shdr->sh_link)); + + // XXX TODO A lot more tests + // check value of the fields. local symbols must have zero entries. + // nonlocal symbols refer to valid version. Check that version index + // in bound. +} + + +static void +check_sections (Ebl *ebl, GElf_Ehdr *ehdr) +{ + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + size_t cnt; + bool dot_interp_section = false; + + if (ehdr->e_shoff == 0) + /* No section header. */ + return; + + /* Allocate array to count references in section groups. */ + scnref = (int *) xcalloc (shnum, sizeof (int)); + + /* Check the zeroth section first. It must not have any contents + and the section header must contain nonzero value at most in the + sh_size and sh_link fields. */ + shdr = gelf_getshdr (elf_getscn (ebl->elf, 0), &shdr_mem); + if (shdr == NULL) + ERROR (gettext ("cannot get section header of zeroth section\n")); + else + { + if (shdr->sh_name != 0) + ERROR (gettext ("zeroth section has nonzero name\n")); + if (shdr->sh_type != 0) + ERROR (gettext ("zeroth section has nonzero type\n")); + if (shdr->sh_flags != 0) + ERROR (gettext ("zeroth section has nonzero flags\n")); + if (shdr->sh_addr != 0) + ERROR (gettext ("zeroth section has nonzero address\n")); + if (shdr->sh_offset != 0) + ERROR (gettext ("zeroth section has nonzero offset\n")); + if (shdr->sh_info != 0) + ERROR (gettext ("zeroth section has nonzero info field\n")); + if (shdr->sh_addralign != 0) + ERROR (gettext ("zeroth section has nonzero align value\n")); + if (shdr->sh_entsize != 0) + ERROR (gettext ("zeroth section has nonzero entry size value\n")); + + if (shdr->sh_size != 0 && ehdr->e_shnum != 0) + ERROR (gettext ("\ +zeroth section has nonzero size value while ELF header has nonzero shnum value\n")); + + if (shdr->sh_link != 0 && ehdr->e_shstrndx != SHN_XINDEX) + ERROR (gettext ("\ +zeroth section has nonzero link value while ELF header does not signal overflow in shstrndx\n")); + } + + for (cnt = 1; cnt < shnum; ++cnt) + { + Elf_Scn *scn; + + scn = elf_getscn (ebl->elf, cnt); + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + { + ERROR (gettext ("\ +cannot get section header for section [%2zu] '%s': %s\n"), + cnt, section_name (ebl, cnt), elf_errmsg (-1)); + continue; + } + + const char *scnname = elf_strptr (ebl->elf, shstrndx, shdr->sh_name); + + if (scnname == NULL) + ERROR (gettext ("section [%2zu]: invalid name\n"), cnt); + else + { + /* Check whether it is one of the special sections defined in + the gABI. */ + size_t s; + for (s = 0; s < nspecial_sections; ++s) + if (strncmp (scnname, special_sections[s].name, + special_sections[s].namelen) == 0) + { + char stbuf1[100]; + char stbuf2[100]; + char stbuf3[100]; + + if (shdr->sh_type != special_sections[s].type + && !(is_debuginfo && shdr->sh_type == SHT_NOBITS)) + ERROR (gettext ("\ +section [%2d] '%s' has wrong type: expected %s, is %s\n"), + (int) cnt, scnname, + ebl_section_type_name (ebl, special_sections[s].type, + stbuf1, sizeof (stbuf1)), + ebl_section_type_name (ebl, shdr->sh_type, + stbuf2, sizeof (stbuf2))); + + if (special_sections[s].attrflag == exact) + { + /* Except for the link order and group bit all the + other bits should match exactly. */ + if ((shdr->sh_flags & ~(SHF_LINK_ORDER | SHF_GROUP)) + != special_sections[s].attr) + ERROR (gettext ("\ +section [%2zu] '%s' has wrong flags: expected %s, is %s\n"), + cnt, scnname, + section_flags_string (special_sections[s].attr, + stbuf1, sizeof (stbuf1)), + section_flags_string (shdr->sh_flags + & ~SHF_LINK_ORDER, + stbuf2, sizeof (stbuf2))); + } + else if (special_sections[s].attrflag == atleast) + { + if ((shdr->sh_flags & special_sections[s].attr) + != special_sections[s].attr + || ((shdr->sh_flags & ~(SHF_LINK_ORDER | SHF_GROUP + | special_sections[s].attr + | special_sections[s].attr2)) + != 0)) + ERROR (gettext ("\ +section [%2zu] '%s' has wrong flags: expected %s and possibly %s, is %s\n"), + cnt, scnname, + section_flags_string (special_sections[s].attr, + stbuf1, sizeof (stbuf1)), + section_flags_string (special_sections[s].attr2, + stbuf2, sizeof (stbuf2)), + section_flags_string (shdr->sh_flags + & ~(SHF_LINK_ORDER + | SHF_GROUP), + stbuf3, sizeof (stbuf3))); + } + + if (strcmp (scnname, ".interp") == 0) + { + dot_interp_section = true; + + if (ehdr->e_type == ET_REL) + ERROR (gettext ("\ +section [%2zu] '%s' present in object file\n"), + cnt, scnname); + + if ((shdr->sh_flags & SHF_ALLOC) != 0 + && !has_loadable_segment) + ERROR (gettext ("\ +section [%2zu] '%s' has SHF_ALLOC flag set but there is no loadable segment\n"), + cnt, scnname); + else if ((shdr->sh_flags & SHF_ALLOC) == 0 + && has_loadable_segment) + ERROR (gettext ("\ +section [%2zu] '%s' has SHF_ALLOC flag not set but there are loadable segments\n"), + cnt, scnname); + } + else + { + if (strcmp (scnname, ".symtab_shndx") == 0 + && ehdr->e_type != ET_REL) + ERROR (gettext ("\ +section [%2zu] '%s' is extension section index table in non-object file\n"), + cnt, scnname); + + /* These sections must have the SHF_ALLOC flag set iff + a loadable segment is available. + + .relxxx + .strtab + .symtab + .symtab_shndx + + Check that if there is a reference from the + loaded section these sections also have the + ALLOC flag set. */ +#if 0 + // XXX TODO + if ((shdr->sh_flags & SHF_ALLOC) != 0 + && !has_loadable_segment) + ERROR (gettext ("\ +section [%2zu] '%s' has SHF_ALLOC flag set but there is no loadable segment\n"), + cnt, scnname); + else if ((shdr->sh_flags & SHF_ALLOC) == 0 + && has_loadable_segment) + ERROR (gettext ("\ +section [%2zu] '%s' has SHF_ALLOC flag not set but there are loadable segments\n"), + cnt, scnname); +#endif + } + + break; + } + } + + if (shdr->sh_entsize != 0 && shdr->sh_size % shdr->sh_entsize) + ERROR (gettext ("\ +section [%2zu] '%s': size not multiple of entry size\n"), + cnt, section_name (ebl, cnt)); + + if (elf_strptr (ebl->elf, shstrndx, shdr->sh_name) == NULL) + ERROR (gettext ("cannot get section header\n")); + + if (shdr->sh_type >= SHT_NUM + && shdr->sh_type != SHT_GNU_LIBLIST + && shdr->sh_type != SHT_CHECKSUM + && shdr->sh_type != SHT_GNU_verdef + && shdr->sh_type != SHT_GNU_verneed + && shdr->sh_type != SHT_GNU_versym) + ERROR (gettext ("unsupported section type %d\n"), (int) shdr->sh_type); + +#define ALL_SH_FLAGS (SHF_WRITE | SHF_ALLOC | SHF_EXECINSTR | SHF_MERGE \ + | SHF_STRINGS | SHF_INFO_LINK | SHF_LINK_ORDER \ + | SHF_OS_NONCONFORMING | SHF_GROUP | SHF_TLS) + if (shdr->sh_flags & ~ALL_SH_FLAGS) + ERROR (gettext ("section [%2zu] '%s' contain unknown flag(s) %d\n"), + cnt, section_name (ebl, cnt), + (int) shdr->sh_flags & ~ALL_SH_FLAGS); + else if (shdr->sh_flags & SHF_TLS) + { + // XXX Correct? + if (shdr->sh_addr != 0 && !gnuld) + ERROR (gettext ("\ +section [%2zu] '%s': thread-local data sections address not zero\n"), + cnt, section_name (ebl, cnt)); + + // XXX TODO more tests!? + } + + if (shdr->sh_link >= shnum) + ERROR (gettext ("\ +section [%2zu] '%s': invalid section reference in link value\n"), + cnt, section_name (ebl, cnt)); + + if (SH_INFO_LINK_P (shdr) && shdr->sh_info >= shnum) + ERROR (gettext ("\ +section [%2zu] '%s': invalid section reference in info value\n"), + cnt, section_name (ebl, cnt)); + + if ((shdr->sh_flags & SHF_MERGE) == 0 + && (shdr->sh_flags & SHF_STRINGS) != 0 + && be_strict) + ERROR (gettext ("\ +section [%2zu] '%s': strings flag set without merge flag\n"), + cnt, section_name (ebl, cnt)); + + if ((shdr->sh_flags & SHF_MERGE) != 0 && shdr->sh_entsize == 0) + ERROR (gettext ("\ +section [%2zu] '%s': merge flag set but entry size is zero\n"), + cnt, section_name (ebl, cnt)); + + if (shdr->sh_flags & SHF_GROUP) + check_scn_group (ebl, cnt); + + if (ehdr->e_type != ET_REL && (shdr->sh_flags & SHF_ALLOC) != 0) + { + /* Make sure the section is contained in a loaded segment + and that the initialization part matches NOBITS sections. */ + int pcnt; + GElf_Phdr phdr_mem; + GElf_Phdr *phdr; + + for (pcnt = 0; pcnt < ehdr->e_phnum; ++pcnt) + if ((phdr = gelf_getphdr (ebl->elf, pcnt, &phdr_mem)) != NULL + && ((phdr->p_type == PT_LOAD + && (shdr->sh_flags & SHF_TLS) == 0) + || (phdr->p_type == PT_TLS + && (shdr->sh_flags & SHF_TLS) != 0)) + && phdr->p_offset <= shdr->sh_offset + && phdr->p_offset + phdr->p_memsz > shdr->sh_offset) + { + /* Found the segment. */ + if (phdr->p_offset + phdr->p_memsz + < shdr->sh_offset + shdr->sh_size) + ERROR (gettext ("\ +section [%2zu] '%s' not fully contained in segment of program header entry %d\n"), + cnt, section_name (ebl, cnt), pcnt); + + if (shdr->sh_type == SHT_NOBITS) + { + if (shdr->sh_offset < phdr->p_offset + phdr->p_filesz + && !is_debuginfo) + ERROR (gettext ("\ +section [%2zu] '%s' has type NOBITS but is read from the file in segment of program header entry %d\n"), + cnt, section_name (ebl, cnt), pcnt); + } + else + { + if (shdr->sh_offset >= phdr->p_offset + phdr->p_filesz) + ERROR (gettext ("\ +section [%2zu] '%s' has not type NOBITS but is not read from the file in segment of program header entry %d\n"), + cnt, section_name (ebl, cnt), pcnt); + } + + break; + } + + if (pcnt == ehdr->e_phnum) + ERROR (gettext ("\ +section [%2zu] '%s': alloc flag set but section not in any loaded segment\n"), + cnt, section_name (ebl, cnt)); + } + + if (cnt == shstrndx && shdr->sh_type != SHT_STRTAB) + ERROR (gettext ("\ +section [%2zu] '%s': ELF header says this is the section header string table but type is not SHT_TYPE\n"), + cnt, section_name (ebl, cnt)); + + switch (shdr->sh_type) + { + case SHT_SYMTAB: + case SHT_DYNSYM: + check_symtab (ebl, ehdr, cnt); + break; + + case SHT_RELA: + check_rela (ebl, ehdr, cnt); + break; + + case SHT_REL: + check_rel (ebl, ehdr, cnt); + break; + + case SHT_DYNAMIC: + check_dynamic (ebl, cnt); + break; + + case SHT_SYMTAB_SHNDX: + check_symtab_shndx (ebl, cnt); + break; + + case SHT_HASH: + check_hash (ebl, cnt); + break; + + case SHT_NULL: + check_null (ebl, shdr, cnt); + break; + + case SHT_GROUP: + check_group (ebl, ehdr, shdr, cnt); + break; + + case SHT_GNU_versym: + check_versym (ebl, shdr, cnt); + break; + + default: + /* Nothing. */ + break; + } + } + + if (has_interp_segment && !dot_interp_section) + ERROR (gettext ("INTERP program header entry but no .interp section\n")); + + free (scnref); +} + + +static void +check_note (Ebl *ebl, GElf_Ehdr *ehdr, GElf_Phdr *phdr, int cnt) +{ + if (ehdr->e_type != ET_CORE && ehdr->e_type != ET_REL + && ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) + ERROR (gettext ("\ +phdr[%d]: no note entries defined for the type of file\n"), + cnt); + + if (is_debuginfo) + /* The p_offset values in a separate debug file are bogus. */ + return; + + char *notemem = gelf_rawchunk (ebl->elf, phdr->p_offset, phdr->p_filesz); + + /* ELF64 files often use note section entries in the 32-bit format. + The p_align field is set to 8 in case the 64-bit format is used. + In case the p_align value is 0 or 4 the 32-bit format is + used. */ + GElf_Xword align = phdr->p_align == 0 || phdr->p_align == 4 ? 4 : 8; +#define ALIGNED_LEN(len) (((len) + align - 1) & ~(align - 1)) + + GElf_Xword idx = 0; + while (idx < phdr->p_filesz) + { + uint64_t namesz; + uint64_t descsz; + uint64_t type; + uint32_t namesz32; + uint32_t descsz32; + + if (align == 4) + { + uint32_t *ptr = (uint32_t *) (notemem + idx); + + if ((__BYTE_ORDER == __LITTLE_ENDIAN + && ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + || (__BYTE_ORDER == __BIG_ENDIAN + && ehdr->e_ident[EI_DATA] == ELFDATA2LSB)) + { + namesz32 = namesz = bswap_32 (*ptr); + ++ptr; + descsz32 = descsz = bswap_32 (*ptr); + ++ptr; + type = bswap_32 (*ptr); + } + else + { + namesz32 = namesz = *ptr++; + descsz32 = descsz = *ptr++; + type = *ptr; + } + } + else + { + uint64_t *ptr = (uint64_t *) (notemem + idx); + uint32_t *ptr32 = (uint32_t *) (notemem + idx); + + if ((__BYTE_ORDER == __LITTLE_ENDIAN + && ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + || (__BYTE_ORDER == __BIG_ENDIAN + && ehdr->e_ident[EI_DATA] == ELFDATA2LSB)) + { + namesz = bswap_64 (*ptr); + ++ptr; + descsz = bswap_64 (*ptr); + ++ptr; + type = bswap_64 (*ptr); + + namesz32 = bswap_32 (*ptr32); + ++ptr32; + descsz32 = bswap_32 (*ptr32); + } + else + { + namesz = *ptr++; + descsz = *ptr++; + type = *ptr; + + namesz32 = *ptr32++; + descsz32 = *ptr32; + } + } + + if (idx + 3 * align > phdr->p_filesz + || (idx + 3 * align + ALIGNED_LEN (namesz) + ALIGNED_LEN (descsz) + > phdr->p_filesz)) + { + if (ehdr->e_ident[EI_CLASS] == ELFCLASS64 + && idx + 3 * 4 <= phdr->p_filesz + && (idx + 3 * 4 + ALIGNED_LEN (namesz32) + ALIGNED_LEN (descsz32) + <= phdr->p_filesz)) + ERROR (gettext ("\ +phdr[%d]: note entries probably in form of a 32-bit ELF file\n"), cnt); + else + ERROR (gettext ("phdr[%d]: extra %zu bytes after last note\n"), + cnt, (size_t) (phdr->p_filesz - idx)); + break; + } + + /* Make sure it is one of the note types we know about. */ + if (ehdr->e_type == ET_CORE) + { + switch (type) + { + case NT_PRSTATUS: + case NT_FPREGSET: + case NT_PRPSINFO: + case NT_TASKSTRUCT: /* NT_PRXREG on Solaris. */ + case NT_PLATFORM: + case NT_AUXV: + case NT_GWINDOWS: + case NT_ASRS: + case NT_PSTATUS: + case NT_PSINFO: + case NT_PRCRED: + case NT_UTSNAME: + case NT_LWPSTATUS: + case NT_LWPSINFO: + case NT_PRFPXREG: + /* Known type. */ + break; + + default: + ERROR (gettext ("\ +phdr[%d]: unknown core file note type %" PRIu64 " at offset %" PRIu64 "\n"), + cnt, type, idx); + } + } + else + { + if (type != NT_VERSION) + ERROR (gettext ("\ +phdr[%d]: unknown object file note type %" PRIu64 " at offset %" PRIu64 "\n"), + cnt, type, idx); + } + + /* Move to the next entry. */ + idx += 3 * align + ALIGNED_LEN (namesz) + ALIGNED_LEN (descsz); + + } + + gelf_freechunk (ebl->elf, notemem); +} + + +static void +check_program_header (Ebl *ebl, GElf_Ehdr *ehdr) +{ + if (ehdr->e_phoff == 0) + return; + + if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN + && ehdr->e_type != ET_CORE) + ERROR (gettext ("\ +only executables, shared objects, and core files can have program headers\n")); + + int num_pt_interp = 0; + int num_pt_tls = 0; + int num_pt_relro = 0; + + for (int cnt = 0; cnt < ehdr->e_phnum; ++cnt) + { + GElf_Phdr phdr_mem; + GElf_Phdr *phdr; + + phdr = gelf_getphdr (ebl->elf, cnt, &phdr_mem); + if (phdr == NULL) + { + ERROR (gettext ("cannot get program header entry %d: %s\n"), + cnt, elf_errmsg (-1)); + continue; + } + + if (phdr->p_type >= PT_NUM && phdr->p_type != PT_GNU_EH_FRAME + && phdr->p_type != PT_GNU_STACK && phdr->p_type != PT_GNU_RELRO) + ERROR (gettext ("\ +program header entry %d: unknown program header entry type\n"), + cnt); + + if (phdr->p_type == PT_LOAD) + has_loadable_segment = true; + else if (phdr->p_type == PT_INTERP) + { + if (++num_pt_interp != 1) + { + if (num_pt_interp == 2) + ERROR (gettext ("\ +more than one INTERP entry in program header\n")); + } + has_interp_segment = true; + } + else if (phdr->p_type == PT_TLS) + { + if (++num_pt_tls == 2) + ERROR (gettext ("more than one TLS entry in program header\n")); + } + else if (phdr->p_type == PT_NOTE) + check_note (ebl, ehdr, phdr, cnt); + else if (phdr->p_type == PT_DYNAMIC + && ehdr->e_type == ET_EXEC && ! has_interp_segment) + ERROR (gettext ("static executable cannot have dynamic sections\n")); + else if (phdr->p_type == PT_GNU_RELRO) + { + if (++num_pt_relro == 2) + ERROR (gettext ("\ +more than one GNU_RELRO entry in program header\n")); + else + { + /* Check that the region is in a writable segment. */ + int inner; + for (inner = 0; inner < ehdr->e_phnum; ++inner) + { + GElf_Phdr phdr2_mem; + GElf_Phdr *phdr2; + + phdr2 = gelf_getphdr (ebl->elf, inner, &phdr2_mem); + if (phdr2 == NULL) + continue; + + if (phdr2->p_type == PT_LOAD + && phdr->p_vaddr >= phdr2->p_vaddr + && (phdr->p_vaddr + phdr->p_memsz + <= phdr2->p_vaddr + phdr2->p_memsz)) + { + if ((phdr2->p_flags & PF_W) == 0) + ERROR (gettext ("\ +loadable segment GNU_RELRO applies to is not writable\n")); + if ((phdr2->p_flags & PF_X) != 0) + ERROR (gettext ("\ +loadable segment GNU_RELRO applies to is executable\n")); + break; + } + } + + if (inner >= ehdr->e_phnum) + ERROR (gettext ("\ +GNU_RELRO segment not contained in a loaded segment\n")); + } + } + + if (phdr->p_filesz > phdr->p_memsz) + ERROR (gettext ("\ +program header entry %d: file size greater than memory size\n"), + cnt); + + if (phdr->p_align > 1) + { + if (!powerof2 (phdr->p_align)) + ERROR (gettext ("\ +program header entry %d: alignment not a power of 2\n"), cnt); + else if ((phdr->p_vaddr - phdr->p_offset) % phdr->p_align != 0) + ERROR (gettext ("\ +program header entry %d: file offset and virtual address not module of alignment\n"), cnt); + } + } +} + + +/* Process one file. */ +static void +process_elf_file (Elf *elf, const char *prefix, const char *suffix, + const char *fname, size_t size, bool only_one) +{ + /* Reset variables. */ + ndynamic = 0; + + GElf_Ehdr ehdr_mem; + GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem); + Ebl *ebl; + + /* Print the file name. */ + if (!only_one) + { + if (prefix != NULL) + printf ("\n%s(%s)%s:\n", prefix, fname, suffix); + else + printf ("\n%s:\n", fname); + } + + if (ehdr == NULL) + { + ERROR (gettext ("cannot read ELF header: %s\n"), elf_errmsg (-1)); + return; + } + + ebl = ebl_openbackend (elf); + /* If there is no appropriate backend library we cannot test + architecture and OS specific features. Any encountered extension + is an error. */ + + /* Go straight by the gABI, check all the parts in turn. */ + check_elf_header (ebl, ehdr, size); + + /* Check the program header. */ + check_program_header (ebl, ehdr); + + /* Next the section headers. It is OK if there are no section + headers at all. */ + check_sections (ebl, ehdr); + + /* Free the resources. */ + ebl_closebackend (ebl); +} |