[PATCH v3 3/7] bfd: Improve nm and objdump without section header
Alan Modra
amodra@gmail.com
Tue Jun 6 06:44:49 GMT 2023
On Mon, Jun 05, 2023 at 08:32:18AM -0700, H.J. Lu wrote:
> --- a/bfd/elf.c
> +++ b/bfd/elf.c
> @@ -397,6 +397,17 @@ bfd_elf_get_elf_syms (bfd *ibfd,
> if (symcount == 0)
> return intsym_buf;
>
> + if (elf_use_dt_symtab_p (ibfd))
> + {
> + /* Use dynamic symbol table. */
> + if (elf_tdata (ibfd)->dt_symtab_count != (symcount + symoffset))
Nitpick: excess parentheses.
> + {
> + bfd_set_error (bfd_error_invalid_operation);
> + return NULL;
> + }
> + return elf_tdata (ibfd)->dt_symtab + symoffset;
> + }
> +
> /* Normal syms might have section extension entries. */
> shndx_hdr = NULL;
> if (elf_symtab_shndx_list (ibfd) != NULL)
> @@ -1873,6 +1884,564 @@ _bfd_elf_print_private_bfd_data (bfd *abfd, void *farg)
> return false;
> }
>
> +/* Find the file offset corresponding to VMA by using the program
> + headers. */
> +
> +static file_ptr
> +offset_from_vma (Elf_Internal_Phdr *phdrs, size_t phnum, bfd_vma vma,
> + size_t size, size_t *max_size_p)
> +{
> + Elf_Internal_Phdr *seg;
> + size_t i;
> +
> + for (seg = phdrs, i = 0; i < phnum; ++seg, ++i)
> + if (seg->p_type == PT_LOAD
> + && vma >= (seg->p_vaddr & -seg->p_align)
> + && vma + size <= seg->p_vaddr + seg->p_filesz)
> + {
> + if (max_size_p)
> + *max_size_p = seg->p_vaddr + seg->p_filesz - vma;
> + return (file_ptr) (vma - seg->p_vaddr + seg->p_offset);
No need for the cast here (and then no need for parens).
> + }
> +
> + bfd_set_error (bfd_error_invalid_operation);
> + return (file_ptr) -1;
> +}
> +
> +/* Convert hash table to internal form. */
> +
> +static bfd_vma *
> +get_hash_table_data (bfd *abfd, bfd_size_type number,
> + unsigned int ent_size, bfd_size_type filesize)
> +{
> + unsigned char *e_data = NULL;
> + bfd_vma *i_data = NULL;
> + bfd_size_type size;
> +
> + if (ent_size != 4 && ent_size != 8)
> + return NULL;
> +
> + /* If the size_t type is smaller than the bfd_size_type, eg because
> + you are building a 32-bit tool on a 64-bit host, then make sure
> + that when (number) is cast to (size_t) no information is lost. */
> + if (sizeof (size_t) < sizeof (bfd_size_type)
> + && (bfd_size_type) ((size_t) number) != number)
> + {
Just "if ((size_t) number != number)" will do.
> + bfd_set_error (bfd_error_file_too_big);
> + return NULL;
> + }
> +
> + size = ent_size * number;
> + /* Be kind to memory checkers (eg valgrind, address sanitizer) by not
> + attempting to allocate memory when the read is bound to fail. */
> + if (size > filesize
> + || number >= ~(size_t) 0 / ent_size
> + || number >= ~(size_t) 0 / sizeof (*i_data))
> + {
> + bfd_set_error (bfd_error_file_too_big);
> + return NULL;
> + }
> +
> + e_data = _bfd_malloc_and_read (abfd, size, size);
> + if (e_data == NULL)
> + return NULL;
> +
> + i_data = (bfd_vma *) bfd_malloc (number * sizeof (*i_data));
> + if (i_data == NULL)
> + {
> + free (e_data);
> + return NULL;
> + }
> +
> + if (ent_size == 4)
> + while (number--)
> + i_data[number] = bfd_get_32 (abfd, e_data + number * ent_size);
> + else
> + while (number--)
> + i_data[number] = bfd_get_64 (abfd, e_data + number * ent_size);
> +
> + free (e_data);
> + return i_data;
> +}
> +
> +/* Address of .MIPS.xhash section. FIXME: What is the best way to
> + support DT_MIPS_XHASH? */
> +#define DT_MIPS_XHASH 0x70000036
> +
> +/* Reconstruct dynamic symbol table from PT_DYNAMIC segment. */
> +
> +bool
> +_bfd_elf_get_dynamic_symbols (bfd *abfd, Elf_Internal_Phdr *phdr,
> + Elf_Internal_Phdr *phdrs, size_t phnum,
> + bfd_size_type filesize)
> +{
> + bfd_byte *extdyn, *extdynend;
> + size_t extdynsize;
> + void (*swap_dyn_in) (bfd *, const void *, Elf_Internal_Dyn *);
> + bool (*swap_symbol_in) (bfd *, const void *, const void *,
> + Elf_Internal_Sym *);
> + Elf_Internal_Dyn dyn;
> + bfd_vma dt_hash = 0;
> + bfd_vma dt_gnu_hash = 0;
> + bfd_vma dt_mips_xhash = 0;
> + bfd_vma dt_strtab = 0;
> + bfd_vma dt_symtab = 0;
> + size_t dt_strsz = 0;
> + bfd_vma dt_versym = 0;
> + bfd_vma dt_verdef = 0;
> + bfd_vma dt_verneed = 0;
> + bfd_byte *dynbuf = NULL;
> + char *strbuf = NULL;
> + bfd_vma *gnubuckets = NULL;
> + bfd_vma *gnuchains = NULL;
> + bfd_vma *mipsxlat = NULL;
> + file_ptr saved_filepos, filepos;
> + bool res = false;
> + size_t amt;
> + bfd_byte *esymbuf = NULL, *esym;
> + bfd_size_type symcount;
> + Elf_Internal_Sym *isymbuf = NULL;
> + Elf_Internal_Sym *isym, *isymend;
> + bfd_byte *versym = NULL;
> + bfd_byte *verdef = NULL;
> + bfd_byte *verneed = NULL;
> + size_t verdef_size;
> + size_t verneed_size;
> + size_t extsym_size;
> + const struct elf_backend_data *bed;
> +
> + /* Return TRUE if symbol table is bad. */
> + if (elf_bad_symtab (abfd))
> + return true;
> +
> + /* Return TRUE if DT_HASH/DT_GNU_HASH have bee processed before. */
> + if (elf_tdata (abfd)->dt_strtab != NULL)
> + return true;
> +
> + bed = get_elf_backend_data (abfd);
> +
> + /* Save file position for elf_object_p. */
> + saved_filepos = bfd_tell (abfd);
> +
> + if (bfd_seek (abfd, phdr->p_offset, SEEK_SET) != 0)
> + goto error_return;
> +
> + dynbuf = _bfd_malloc_and_read (abfd, phdr->p_filesz, phdr->p_filesz);
> + if (dynbuf == NULL)
> + goto error_return;
> +
> + extsym_size = bed->s->sizeof_sym;
> + extdynsize = bed->s->sizeof_dyn;
> + swap_dyn_in = bed->s->swap_dyn_in;
> +
> + extdyn = dynbuf;
> + if (phdr->p_filesz < extdynsize)
> + goto error_return;
> + extdynend = extdyn + phdr->p_filesz;
> + for (; extdyn <= (extdynend - extdynsize); extdyn += extdynsize)
> + {
> + swap_dyn_in (abfd, extdyn, &dyn);
> +
> + if (dyn.d_tag == DT_NULL)
> + break;
> +
> + switch (dyn.d_tag)
> + {
> + case DT_HASH:
> + dt_hash = dyn.d_un.d_val;
> + break;
> + case DT_GNU_HASH:
> + if (bed->elf_machine_code != EM_MIPS
> + && bed->elf_machine_code != EM_MIPS_RS3_LE)
> + dt_gnu_hash = dyn.d_un.d_val;
> + break;
> + case DT_STRTAB:
> + dt_strtab = dyn.d_un.d_val;
> + break;
> + case DT_SYMTAB:
> + dt_symtab = dyn.d_un.d_val;
> + break;
> + case DT_STRSZ:
> + dt_strsz = dyn.d_un.d_val;
> + break;
> + case DT_SYMENT:
> + if (dyn.d_un.d_val != extsym_size)
> + goto error_return;
> + break;
> + case DT_VERSYM:
> + dt_versym = dyn.d_un.d_val;
> + break;
> + case DT_VERDEF:
> + dt_verdef = dyn.d_un.d_val;
> + break;
> + case DT_VERNEED:
> + dt_verneed = dyn.d_un.d_val;
> + break;
> + default:
> + if (dyn.d_tag == DT_MIPS_XHASH
> + && (bed->elf_machine_code == EM_MIPS
> + || bed->elf_machine_code == EM_MIPS_RS3_LE))
> + {
> + dt_gnu_hash = dyn.d_un.d_val;
> + dt_mips_xhash = dyn.d_un.d_val;
> + }
> + break;
> + }
> + }
> +
> + /* Check if we can reconstruct dynamic symbol table from PT_DYNAMIC
> + segment. */
> + if ((!dt_hash && !dt_gnu_hash)
> + || !dt_strtab
> + || !dt_symtab
> + || !dt_strsz)
> + goto error_return;
> +
> + /* Get dynamic string table. */
> + filepos = offset_from_vma (phdrs, phnum, dt_strtab, dt_strsz, NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + /* Dynamic string table must be valid until ABFD is closed. */
> + strbuf = (char *) _bfd_alloc_and_read (abfd, dt_strsz, dt_strsz);
> + if (strbuf == NULL)
> + goto error_return;
> +
> + /* Get the real symbol count from DT_HASH or DT_GNU_HASH. Prefer
> + DT_HASH since it is simpler than DT_GNU_HASH. */
> + if (dt_hash)
> + {
> + unsigned char nb[16];
> + unsigned int hash_ent_size;
> +
> + switch (bed->elf_machine_code)
> + {
> + case EM_ALPHA:
> + case EM_S390:
> + case EM_S390_OLD:
> + if (bed->s->elfclass == ELFCLASS64)
> + {
> + hash_ent_size = 8;
> + break;
> + }
> + /* FALLTHROUGH */
> + default:
> + hash_ent_size = 4;
> + break;
> + }
> +
> + filepos = offset_from_vma (phdrs, phnum, dt_hash, sizeof (nb),
> + NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0
> + || (bfd_bread (nb, 2 * hash_ent_size, abfd)
> + != (2 * hash_ent_size)))
> + goto error_return;
> +
> + /* The number of dynamic symbol table entries equals the number
> + of chains. */
> + if (hash_ent_size == 8)
> + symcount = bfd_get_64 (abfd, nb + hash_ent_size);
> + else
> + symcount = bfd_get_32 (abfd, nb + hash_ent_size);
> + }
> + else
> + {
> + /* For DT_GNU_HASH, only defined symbols with non-STB_LOCAL
> + bindings are in hash table. Since in dynamic symbol table,
> + all symbols with STB_LOCAL binding are placed before symbols
> + with other bindings and all undefined symbols are placed
> + before defined ones, the highest symbol index in DT_GNU_HASH
> + is the highest dynamic symbol table index. */
> + unsigned char nb[16];
> + bfd_vma ngnubuckets;
> + bfd_vma gnusymidx;
> + size_t i, ngnuchains;
> + bfd_vma maxchain = 0xffffffff, bitmaskwords;
> + bfd_vma buckets_vma;
> +
> + filepos = offset_from_vma (phdrs, phnum, dt_gnu_hash,
> + sizeof (nb), NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0
> + || bfd_bread (nb, sizeof (nb), abfd) != sizeof (nb))
> + goto error_return;
> +
> + ngnubuckets = bfd_get_32 (abfd, nb);
> + gnusymidx = bfd_get_32 (abfd, nb + 4);
> + bitmaskwords = bfd_get_32 (abfd, nb + 8);
> + buckets_vma = dt_gnu_hash + 16;
> + if (bed->s->elfclass == ELFCLASS32)
> + buckets_vma += bitmaskwords * 4;
> + else
> + buckets_vma += bitmaskwords * 8;
> + filepos = offset_from_vma (phdrs, phnum, buckets_vma, 4, NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + gnubuckets = get_hash_table_data (abfd, ngnubuckets, 4, filesize);
> + if (gnubuckets == NULL)
> + goto error_return;
> +
> + for (i = 0; i < ngnubuckets; i++)
> + if (gnubuckets[i] != 0)
> + {
> + if (gnubuckets[i] < gnusymidx)
> + goto error_return;
> +
> + if (maxchain == 0xffffffff || gnubuckets[i] > maxchain)
> + maxchain = gnubuckets[i];
> + }
> +
> + if (maxchain == 0xffffffff)
> + {
> + symcount = 0;
> + goto empty_gnu_hash;
> + }
> +
> + maxchain -= gnusymidx;
> + filepos = offset_from_vma (phdrs, phnum,
> + (buckets_vma +
> + 4 * (ngnubuckets + maxchain)),
> + 4, NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + do
> + {
> + if (bfd_bread (nb, 4, abfd) != 4)
> + goto error_return;
> + ++maxchain;
> + if (maxchain == 0)
> + goto error_return;
> + }
> + while ((bfd_get_32 (abfd, nb) & 1) == 0);
> +
> + filepos = offset_from_vma (phdrs, phnum,
> + (buckets_vma + 4 * ngnubuckets),
> + 4, NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + gnuchains = get_hash_table_data (abfd, maxchain, 4, filesize);
> + if (gnubuckets == NULL)
> + goto error_return;
> + ngnuchains = maxchain;
> +
> + if (dt_mips_xhash)
> + {
> + filepos = offset_from_vma (phdrs, phnum,
> + (buckets_vma
> + + 4 * (ngnubuckets + maxchain)),
> + 4, NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + mipsxlat = get_hash_table_data (abfd, maxchain, 4, filesize);
> + if (mipsxlat == NULL)
> + goto error_return;
> + }
> +
> + symcount = 0;
> + for (i = 0; i < ngnubuckets; ++i)
> + if (gnubuckets[i] != 0)
> + {
> + bfd_vma si = gnubuckets[i];
> + bfd_vma off = si - gnusymidx;
> + do
> + {
> + if (mipsxlat)
> + {
> + if (mipsxlat[off] >= symcount)
> + symcount = mipsxlat[off] + 1;
> + }
> + else
> + {
> + if (si >= symcount)
> + symcount = si + 1;
> + }
> + si++;
> + }
> + while (off < ngnuchains && (gnuchains[off++] & 1) == 0);
> + }
> + }
> +
> + /* Swap in dynamic symbol table. */
> + if (_bfd_mul_overflow (symcount, extsym_size, &amt))
> + {
> + bfd_set_error (bfd_error_file_too_big);
> + goto error_return;
> + }
> +
> + filepos = offset_from_vma (phdrs, phnum, dt_symtab, amt, NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> + esymbuf = _bfd_malloc_and_read (abfd, amt, amt);
> + if (esymbuf == NULL)
> + goto error_return;
> +
> + if (_bfd_mul_overflow (symcount, sizeof (Elf_Internal_Sym), &amt))
> + {
> + bfd_set_error (bfd_error_file_too_big);
> + goto error_return;
> + }
> +
> + /* Dynamic symbol table must be valid until ABFD is closed. */
> + isymbuf = (Elf_Internal_Sym *) bfd_alloc (abfd, amt);
> + if (isymbuf == NULL)
> + goto error_return;
> +
> + swap_symbol_in = bed->s->swap_symbol_in;
> +
> + /* Convert the symbols to internal form. */
> + isymend = isymbuf + symcount;
> + for (esym = esymbuf, isym = isymbuf;
> + isym < isymend;
> + esym += extsym_size, isym++)
> + if (!swap_symbol_in (abfd, esym, NULL, isym)
> + || isym->st_name >= dt_strsz)
> + {
> + bfd_set_error (bfd_error_invalid_operation);
> + goto error_return;
> + }
> +
> + if (dt_versym)
> + {
> + /* Swap in DT_VERSYM. */
> + if (_bfd_mul_overflow (symcount, 2, &amt))
> + {
> + bfd_set_error (bfd_error_file_too_big);
> + goto error_return;
> + }
> +
> + filepos = offset_from_vma (phdrs, phnum, dt_versym, amt, NULL);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + /* DT_VERSYM info must be valid until ABFD is closed. */
> + versym = _bfd_alloc_and_read (abfd, amt, amt);
> +
> + if (dt_verdef)
> + {
> + /* Read in DT_VERDEF. */
> + filepos = offset_from_vma (phdrs, phnum, dt_verdef,
> + 0, &verdef_size);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + /* DT_VERDEF info must be valid until ABFD is closed. */
> + verdef = _bfd_alloc_and_read (abfd, verdef_size,
> + verdef_size);
> + }
> +
> + if (dt_verneed)
> + {
> + /* Read in DT_VERNEED. */
> + filepos = offset_from_vma (phdrs, phnum, dt_verneed,
> + 0, &verneed_size);
> + if (filepos == (file_ptr) -1
> + || bfd_seek (abfd, filepos, SEEK_SET) != 0)
> + goto error_return;
> +
> + /* DT_VERNEED info must be valid until ABFD is closed. */
> + verneed = _bfd_alloc_and_read (abfd, verneed_size,
> + verneed_size);
> + }
> + }
> +
> + empty_gnu_hash:
> + elf_tdata (abfd)->dt_strtab = strbuf;
> + elf_tdata (abfd)->dt_symtab = isymbuf;
> + elf_tdata (abfd)->dt_symtab_count = symcount;
> + elf_tdata (abfd)->dt_versym = versym;
> + elf_tdata (abfd)->dt_verdef = verdef;
> + elf_tdata (abfd)->dt_verneed = verneed;
> + elf_tdata (abfd)->dt_verdef_count
> + = verdef_size / sizeof (Elf_External_Verdef);
> + elf_tdata (abfd)->dt_verneed_count
> + = verneed_size / sizeof (Elf_External_Verneed);
These are all bfd_alloc by the look of it, and we'll have file size
sanity checks done before any alloc. Good!
> +
> + res = true;
> +
> + error_return:
> + /* Restore file position for elf_object_p. */
> + if (bfd_seek (abfd, saved_filepos, SEEK_SET) != 0)
> + res = false;
> + if (dynbuf != NULL)
> + free (dynbuf);
> + if (esymbuf != NULL)
> + free (esymbuf);
> + if (gnubuckets != NULL)
> + free (gnubuckets);
> + if (gnuchains != NULL)
> + free (gnuchains);
> + if (mipsxlat != NULL)
> + free (mipsxlat);
These days we just write free (x) without if (x != NULL).
> + return res;
> +}
> +
> +/* Reconstruct section from dynamic symbol. */
> +
> +asection *
> +_bfd_elf_get_section_from_dynamic_symbol (bfd *abfd,
> + Elf_Internal_Sym *isym)
> +{
> + asection *sec;
> + flagword flags;
> +
> + if (!elf_use_dt_symtab_p (abfd))
> + return NULL;
> +
> + flags = SEC_ALLOC | SEC_LOAD;
> + switch (ELF_ST_TYPE (isym->st_info))
> + {
> + case STT_FUNC:
> + case STT_GNU_IFUNC:
> + sec = bfd_get_section_by_name (abfd, ".text");
> + if (sec == NULL)
> + sec = bfd_make_section_with_flags (abfd,
> + ".text",
> + flags | SEC_CODE);
> + break;
> + case STT_COMMON:
> + sec = bfd_com_section_ptr;
> + break;
> + case STT_OBJECT:
> + sec = bfd_get_section_by_name (abfd, ".data");
> + if (sec == NULL)
> + sec = bfd_make_section_with_flags (abfd,
> + ".data",
> + flags | SEC_DATA);
> + break;
> + case STT_TLS:
> + sec = bfd_get_section_by_name (abfd, ".tdata");
> + if (sec == NULL)
> + sec = bfd_make_section_with_flags (abfd,
> + ".tdata",
> + (flags
> + | SEC_DATA
> + | SEC_THREAD_LOCAL));
> + break;
> + default:
> + sec = bfd_abs_section_ptr;
> + break;
> + }
> +
> + /* NB: Don't place this section in output. */
> + if (sec && 0)
> + sec->output_section = bfd_abs_section_ptr;
Please delete this rather than leaving it disabled, and delete the comment.
> +
> + return sec;
> +}
> +
> /* Get version name. If BASE_P is TRUE, return "Base" for VER_FLG_BASE
> and return symbol version for symbol version itself. */
>
> @@ -1882,8 +2451,11 @@ _bfd_elf_get_symbol_version_string (bfd *abfd, asymbol *symbol,
> bool *hidden)
> {
> const char *version_string = NULL;
> - if (elf_dynversym (abfd) != 0
> - && (elf_dynverdef (abfd) != 0 || elf_dynverref (abfd) != 0))
> + if ((elf_dynversym (abfd) != 0
> + && (elf_dynverdef (abfd) != 0 || elf_dynverref (abfd) != 0))
> + || (elf_tdata (abfd)->dt_versym != NULL
> + && (elf_tdata (abfd)->dt_verdef != NULL
> + || elf_tdata (abfd)->dt_verneed != NULL)))
> {
> unsigned int vernum = ((elf_symbol_type *) symbol)->version;
>
> @@ -8609,6 +9181,11 @@ _bfd_elf_get_dynamic_symtab_upper_bound (bfd *abfd)
>
> if (elf_dynsymtab (abfd) == 0)
> {
> + /* Check if there is dynamic symbol table. */
> + symcount = elf_tdata (abfd)->dt_symtab_count;
> + if (symcount)
> + goto compute_symtab_size;
> +
> bfd_set_error (bfd_error_invalid_operation);
> return -1;
> }
> @@ -8619,6 +9196,8 @@ _bfd_elf_get_dynamic_symtab_upper_bound (bfd *abfd)
> bfd_set_error (bfd_error_file_too_big);
> return -1;
> }
> +
> + compute_symtab_size:
> symtab_size = symcount * (sizeof (asymbol *));
> if (symcount == 0)
> symtab_size = sizeof (asymbol *);
> @@ -8826,35 +9405,51 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
> unsigned int freeidx = 0;
> size_t amt;
>
> - if (elf_dynverref (abfd) != 0)
> + if (elf_dynverref (abfd) != 0 || elf_tdata (abfd)->dt_verneed != NULL)
> {
> Elf_Internal_Shdr *hdr;
> Elf_External_Verneed *everneed;
> Elf_Internal_Verneed *iverneed;
> unsigned int i;
> bfd_byte *contents_end;
> + size_t verneed_count;
> + size_t verneed_size;
>
> - hdr = &elf_tdata (abfd)->dynverref_hdr;
> -
> - if (hdr->sh_info > hdr->sh_size / sizeof (Elf_External_Verneed))
> + if (elf_tdata (abfd)->dt_verneed != NULL)
> {
> - error_return_bad_verref:
> - _bfd_error_handler
> - (_("%pB: .gnu.version_r invalid entry"), abfd);
> - bfd_set_error (bfd_error_bad_value);
> - error_return_verref:
> - elf_tdata (abfd)->verref = NULL;
> - elf_tdata (abfd)->cverrefs = 0;
> - goto error_return;
> + hdr = NULL;
> + contents = elf_tdata (abfd)->dt_verneed;
> + verneed_count = elf_tdata (abfd)->dt_verneed_count;
> + verneed_size = verneed_count * sizeof (Elf_External_Verneed);
> }
> + else
> + {
> + hdr = &elf_tdata (abfd)->dynverref_hdr;
>
> - if (bfd_seek (abfd, hdr->sh_offset, SEEK_SET) != 0)
> - goto error_return_verref;
> - contents = _bfd_malloc_and_read (abfd, hdr->sh_size, hdr->sh_size);
> - if (contents == NULL)
> - goto error_return_verref;
> + if (hdr->sh_info > hdr->sh_size / sizeof (Elf_External_Verneed))
> + {
> + error_return_bad_verref:
> + _bfd_error_handler
> + (_("%pB: .gnu.version_r invalid entry"), abfd);
> + bfd_set_error (bfd_error_bad_value);
> + error_return_verref:
> + elf_tdata (abfd)->verref = NULL;
> + elf_tdata (abfd)->cverrefs = 0;
> + goto error_return;
> + }
> +
> + if (bfd_seek (abfd, hdr->sh_offset, SEEK_SET) != 0)
> + goto error_return_verref;
> + contents = _bfd_malloc_and_read (abfd, hdr->sh_size, hdr->sh_size);
> + if (contents == NULL)
> + goto error_return_verref;
> +
> + verneed_size = hdr->sh_size;
> + verneed_count = hdr->sh_info;
> + }
>
> - if (_bfd_mul_overflow (hdr->sh_info, sizeof (Elf_Internal_Verneed), &amt))
> + if (_bfd_mul_overflow (verneed_count,
> + sizeof (Elf_Internal_Verneed), &amt))
> {
> bfd_set_error (bfd_error_file_too_big);
> goto error_return_verref;
> @@ -8867,10 +9462,11 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
>
> BFD_ASSERT (sizeof (Elf_External_Verneed)
> == sizeof (Elf_External_Vernaux));
> - contents_end = contents + hdr->sh_size - sizeof (Elf_External_Verneed);
> + contents_end = (contents + verneed_size
> + - sizeof (Elf_External_Verneed));
> everneed = (Elf_External_Verneed *) contents;
> iverneed = elf_tdata (abfd)->verref;
> - for (i = 0; i < hdr->sh_info; i++, iverneed++)
> + for (i = 0; i < verneed_count; i++, iverneed++)
> {
> Elf_External_Vernaux *evernaux;
> Elf_Internal_Vernaux *ivernaux;
> @@ -8880,9 +9476,13 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
>
> iverneed->vn_bfd = abfd;
>
> - iverneed->vn_filename =
> - bfd_elf_string_from_elf_section (abfd, hdr->sh_link,
> - iverneed->vn_file);
> + if (elf_use_dt_symtab_p (abfd))
> + iverneed->vn_filename
> + = elf_tdata (abfd)->dt_strtab + iverneed->vn_file;
> + else
> + iverneed->vn_filename
> + = bfd_elf_string_from_elf_section (abfd, hdr->sh_link,
> + iverneed->vn_file);
> if (iverneed->vn_filename == NULL)
> goto error_return_bad_verref;
>
> @@ -8913,9 +9513,13 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
> {
> _bfd_elf_swap_vernaux_in (abfd, evernaux, ivernaux);
>
> - ivernaux->vna_nodename =
> - bfd_elf_string_from_elf_section (abfd, hdr->sh_link,
> - ivernaux->vna_name);
> + if (elf_use_dt_symtab_p (abfd))
> + ivernaux->vna_nodename
> + = elf_tdata (abfd)->dt_strtab + ivernaux->vna_name;
> + else
> + ivernaux->vna_nodename
> + = bfd_elf_string_from_elf_section (abfd, hdr->sh_link,
> + ivernaux->vna_name);
> if (ivernaux->vna_nodename == NULL)
> goto error_return_bad_verref;
>
> @@ -8954,11 +9558,12 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
> }
> elf_tdata (abfd)->cverrefs = i;
>
> - free (contents);
> + if (elf_tdata (abfd)->dt_verneed == NULL)
> + free (contents);
> contents = NULL;
> }
>
> - if (elf_dynverdef (abfd) != 0)
> + if (elf_dynverdef (abfd) != 0 || elf_tdata (abfd)->dt_verdef != NULL)
> {
> Elf_Internal_Shdr *hdr;
> Elf_External_Verdef *everdef;
> @@ -8968,40 +9573,56 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
> unsigned int i;
> unsigned int maxidx;
> bfd_byte *contents_end_def, *contents_end_aux;
> + size_t verdef_count;
> + size_t verdef_size;
>
> - hdr = &elf_tdata (abfd)->dynverdef_hdr;
> -
> - if (hdr->sh_size < sizeof (Elf_External_Verdef))
> + if (elf_tdata (abfd)->dt_verdef != NULL)
> {
> - error_return_bad_verdef:
> - _bfd_error_handler
> - (_("%pB: .gnu.version_d invalid entry"), abfd);
> - bfd_set_error (bfd_error_bad_value);
> - error_return_verdef:
> - elf_tdata (abfd)->verdef = NULL;
> - elf_tdata (abfd)->cverdefs = 0;
> - goto error_return;
> + hdr = NULL;
> + contents = elf_tdata (abfd)->dt_verdef;
> + verdef_count = elf_tdata (abfd)->dt_verdef_count;
> + verdef_size = verdef_count * sizeof (Elf_External_Verdef);
> }
> + else
> + {
> + hdr = &elf_tdata (abfd)->dynverdef_hdr;
>
> - if (bfd_seek (abfd, hdr->sh_offset, SEEK_SET) != 0)
> - goto error_return_verdef;
> - contents = _bfd_malloc_and_read (abfd, hdr->sh_size, hdr->sh_size);
> - if (contents == NULL)
> - goto error_return_verdef;
> + if (hdr->sh_size < sizeof (Elf_External_Verdef))
> + {
> + error_return_bad_verdef:
> + _bfd_error_handler
> + (_("%pB: .gnu.version_d invalid entry"), abfd);
> + bfd_set_error (bfd_error_bad_value);
> + error_return_verdef:
> + elf_tdata (abfd)->verdef = NULL;
> + elf_tdata (abfd)->cverdefs = 0;
> + goto error_return;
> + }
> +
> + if (bfd_seek (abfd, hdr->sh_offset, SEEK_SET) != 0)
> + goto error_return_verdef;
> + contents = _bfd_malloc_and_read (abfd, hdr->sh_size, hdr->sh_size);
> + if (contents == NULL)
> + goto error_return_verdef;
>
> - BFD_ASSERT (sizeof (Elf_External_Verdef)
> - >= sizeof (Elf_External_Verdaux));
> - contents_end_def = contents + hdr->sh_size
> - - sizeof (Elf_External_Verdef);
> - contents_end_aux = contents + hdr->sh_size
> - - sizeof (Elf_External_Verdaux);
> + BFD_ASSERT (sizeof (Elf_External_Verdef)
> + >= sizeof (Elf_External_Verdaux));
> +
> + verdef_count = hdr->sh_info;
> + verdef_size = hdr->sh_size;
> + }
> +
> + contents_end_def = (contents + verdef_size
> + - sizeof (Elf_External_Verdef));
> + contents_end_aux = (contents + verdef_size
> + - sizeof (Elf_External_Verdaux));
>
> /* We know the number of entries in the section but not the maximum
> index. Therefore we have to run through all entries and find
> the maximum. */
> everdef = (Elf_External_Verdef *) contents;
> maxidx = 0;
> - for (i = 0; i < hdr->sh_info; ++i)
> + for (i = 0; i < verdef_count; ++i)
> {
> _bfd_elf_swap_verdef_in (abfd, everdef, &iverdefmem);
>
> @@ -9044,7 +9665,7 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
>
> everdef = (Elf_External_Verdef *) contents;
> iverdefarr = elf_tdata (abfd)->verdef;
> - for (i = 0; i < hdr->sh_info; i++)
> + for (i = 0; i < verdef_count; ++i)
> {
> Elf_External_Verdaux *everdaux;
> Elf_Internal_Verdaux *iverdaux;
> @@ -9087,9 +9708,13 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
> {
> _bfd_elf_swap_verdaux_in (abfd, everdaux, iverdaux);
>
> - iverdaux->vda_nodename =
> - bfd_elf_string_from_elf_section (abfd, hdr->sh_link,
> - iverdaux->vda_name);
> + if (elf_use_dt_symtab_p (abfd))
> + iverdaux->vda_nodename
> + = elf_tdata (abfd)->dt_strtab + iverdaux->vda_name;
> + else
> + iverdaux->vda_nodename
> + = bfd_elf_string_from_elf_section (abfd, hdr->sh_link,
> + iverdaux->vda_name);
> if (iverdaux->vda_nodename == NULL)
> goto error_return_bad_verdef;
>
> @@ -9124,7 +9749,8 @@ _bfd_elf_slurp_version_tables (bfd *abfd, bool default_imported_symver)
> ((bfd_byte *) everdef + iverdef->vd_next));
> }
>
> - free (contents);
> + if (elf_tdata (abfd)->dt_verdef == NULL)
> + free (contents);
> contents = NULL;
> }
> else if (default_imported_symver)
> diff --git a/bfd/elfcode.h b/bfd/elfcode.h
> index 495e498838d..aae66bcebf8 100644
> --- a/bfd/elfcode.h
> +++ b/bfd/elfcode.h
> @@ -839,6 +839,21 @@ elf_object_p (bfd *abfd)
> abfd->read_only = 1;
> }
> }
> + if (i_phdr->p_filesz != 0)
> + {
> + if ((i_phdr->p_offset + i_phdr->p_filesz) > filesize)
> + goto got_no_match;
> + /* Try to reconstruct dynamic symbol table from PT_DYNAMIC
> + segment if there is no section header. */
> + if (i_phdr->p_type == PT_DYNAMIC
> + && i_ehdrp->e_shstrndx == 0
> + && i_ehdrp->e_shoff == 0
> + && !_bfd_elf_get_dynamic_symbols (abfd, i_phdr,
> + elf_tdata (abfd)->phdr,
> + i_ehdrp->e_phnum,
> + filesize))
> + goto got_no_match;
> + }
> }
> }
>
> @@ -1245,7 +1260,9 @@ elf_slurp_symbol_table (bfd *abfd, asymbol **symptrs, bool dynamic)
> if ((elf_dynverdef (abfd) != 0
> && elf_tdata (abfd)->verdef == NULL)
> || (elf_dynverref (abfd) != 0
> - && elf_tdata (abfd)->verref == NULL))
> + && elf_tdata (abfd)->verref == NULL)
> + || elf_tdata (abfd)->dt_verdef != NULL
> + || elf_tdata (abfd)->dt_verneed != NULL)
> {
> if (!_bfd_elf_slurp_version_tables (abfd, false))
> return -1;
> @@ -1253,11 +1270,15 @@ elf_slurp_symbol_table (bfd *abfd, asymbol **symptrs, bool dynamic)
> }
>
> ebd = get_elf_backend_data (abfd);
> - symcount = hdr->sh_size / sizeof (Elf_External_Sym);
> + symcount = elf_tdata (abfd)->dt_symtab_count;
> + if (symcount == 0)
> + symcount = hdr->sh_size / sizeof (Elf_External_Sym);
> if (symcount == 0)
> sym = symbase = NULL;
> else
> {
> + size_t i;
> +
> isymbuf = bfd_elf_get_elf_syms (abfd, hdr, symcount, 0,
> NULL, NULL, NULL);
> if (isymbuf == NULL)
> @@ -1304,12 +1325,18 @@ elf_slurp_symbol_table (bfd *abfd, asymbol **symptrs, bool dynamic)
> if (xver != NULL)
> ++xver;
> isymend = isymbuf + symcount;
> - for (isym = isymbuf + 1, sym = symbase; isym < isymend; isym++, sym++)
> + for (isym = isymbuf + 1, sym = symbase, i = 1;
> + isym < isymend;
> + isym++, sym++, i++)
> {
> memcpy (&sym->internal_elf_sym, isym, sizeof (Elf_Internal_Sym));
>
> sym->symbol.the_bfd = abfd;
> - sym->symbol.name = bfd_elf_sym_name (abfd, hdr, isym, NULL);
> + if (elf_use_dt_symtab_p (abfd))
> + sym->symbol.name = (elf_tdata (abfd)->dt_strtab
> + + isym->st_name);
> + else
> + sym->symbol.name = bfd_elf_sym_name (abfd, hdr, isym, NULL);
> sym->symbol.value = isym->st_value;
>
> if (isym->st_shndx == SHN_UNDEF)
> @@ -1343,6 +1370,15 @@ elf_slurp_symbol_table (bfd *abfd, asymbol **symptrs, bool dynamic)
> moment) about the alignment. */
> sym->symbol.value = isym->st_size;
> }
> + else if (elf_use_dt_symtab_p (abfd))
> + {
> + asection *sec;
> + sec = _bfd_elf_get_section_from_dynamic_symbol (abfd,
> + isym);
> + if (sec == NULL)
> + goto error_return;
> + sym->symbol.section = sec;
> + }
> else
> {
> sym->symbol.section
> @@ -1423,7 +1459,10 @@ elf_slurp_symbol_table (bfd *abfd, asymbol **symptrs, bool dynamic)
> if (dynamic)
> sym->symbol.flags |= BSF_DYNAMIC;
>
> - if (xver != NULL)
> + if (elf_tdata (abfd)->dt_versym)
> + sym->version = bfd_get_16 (abfd,
> + elf_tdata (abfd)->dt_versym + 2 * i);
> + else if (xver != NULL)
> {
> Elf_Internal_Versym iversym;
>
> @@ -1461,13 +1500,15 @@ elf_slurp_symbol_table (bfd *abfd, asymbol **symptrs, bool dynamic)
> }
>
> free (xverbuf);
> - if (hdr->contents != (unsigned char *) isymbuf)
> + if (hdr->contents != (unsigned char *) isymbuf
> + && !elf_use_dt_symtab_p (abfd))
> free (isymbuf);
> return symcount;
>
> error_return:
> free (xverbuf);
> - if (hdr->contents != (unsigned char *) isymbuf)
> + if (hdr->contents != (unsigned char *) isymbuf
> + && !elf_use_dt_symtab_p (abfd))
> free (isymbuf);
> return -1;
> }
> diff --git a/bfd/elflink.c b/bfd/elflink.c
> index f10faa5f8bd..422c7b25c81 100644
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -3571,6 +3571,12 @@ elf_link_is_defined_archive_symbol (bfd * abfd, carsym * symdef)
> if (! bfd_check_format (abfd, bfd_object))
> return false;
>
> + if (elf_use_dt_symtab_p (abfd))
> + {
> + bfd_set_error (bfd_error_wrong_format);
> + return false;
> + }
> +
> /* Select the appropriate symbol table. If we don't know if the
> object file is an IR object, give linker LTO plugin a chance to
> get the correct symbol table. */
> @@ -4233,6 +4239,12 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
> htab = elf_hash_table (info);
> bed = get_elf_backend_data (abfd);
>
> + if (elf_use_dt_symtab_p (abfd))
> + {
> + bfd_set_error (bfd_error_wrong_format);
> + return false;
> + }
> +
> if ((abfd->flags & DYNAMIC) == 0)
> dynamic = false;
> else
> --
> 2.40.1
--
Alan Modra
Australia Development Lab, IBM
More information about the Binutils
mailing list