diff options
Diffstat (limited to 'src/libdwfl/relocate.c')
| -rw-r--r-- | src/libdwfl/relocate.c | 122 |
1 files changed, 75 insertions, 47 deletions
diff --git a/src/libdwfl/relocate.c b/src/libdwfl/relocate.c index 95206f47..e102e1e4 100644 --- a/src/libdwfl/relocate.c +++ b/src/libdwfl/relocate.c @@ -1,51 +1,30 @@ /* Relocate debug information. - Copyright (C) 2005-2010 Red Hat, Inc. - This file is part of Red Hat elfutils. + Copyright (C) 2005-2011, 2014 Red Hat, Inc. + This file is part of elfutils. - Red Hat elfutils is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by the - Free Software Foundation; version 2 of the License. + This file is free software; you can redistribute it and/or modify + it under the terms of either - Red Hat elfutils is distributed in the hope that it will be useful, but + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at + your option) any later version + + or + + * the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at + your option) any later version + + or both in parallel, as here. + + elfutils is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. - You should have received a copy of the GNU General Public License along - with Red Hat elfutils; if not, write to the Free Software Foundation, - Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. - - In addition, as a special exception, Red Hat, Inc. gives You the - additional right to link the code of Red Hat elfutils with code licensed - under any Open Source Initiative certified open source license - (http://www.opensource.org/licenses/index.php) which requires the - distribution of source code with any binary distribution and to - distribute linked combinations of the two. Non-GPL Code permitted under - this exception must only link to the code of Red Hat elfutils through - those well defined interfaces identified in the file named EXCEPTION - found in the source code files (the "Approved Interfaces"). The files - of Non-GPL Code may instantiate templates or use macros or inline - functions from the Approved Interfaces without causing the resulting - work to be covered by the GNU General Public License. Only Red Hat, - Inc. may make changes or additions to the list of Approved Interfaces. - Red Hat's grant of this exception is conditioned upon your not adding - any new exceptions. If you wish to add a new Approved Interface or - exception, please contact Red Hat. You must obey the GNU General Public - License in all respects for all of the Red Hat elfutils code and other - code used in conjunction with Red Hat elfutils except the Non-GPL Code - covered by this exception. If you modify this file, you may extend this - exception to your version of the file, but you are not obligated to do - so. If you do not wish to provide this exception without modification, - you must delete this exception statement from your version and license - this file solely under the GPL without exception. - - Red Hat elfutils is an included package of the Open Invention Network. - An included package of the Open Invention Network is a package for which - Open Invention Network licensees cross-license their patents. No patent - license is granted, either expressly or impliedly, by designation as an - included package. Should you wish to participate in the Open Invention - Network licensing program, please visit www.openinventionnetwork.com - <http://www.openinventionnetwork.com>. */ + You should have received copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see <http://www.gnu.org/licenses/>. */ #include "libdwflP.h" @@ -59,7 +38,11 @@ internal_function __libdwfl_relocate_value (Dwfl_Module *mod, Elf *elf, size_t *shstrndx, Elf32_Word shndx, GElf_Addr *value) { - assert (mod->e_type == ET_REL); + /* No adjustment needed for section zero, it is never loaded. + Handle it first, just in case the ELF file has strange section + zero flags set. */ + if (shndx == 0) + return DWFL_E_NOERROR; Elf_Scn *refscn = elf_getscn (elf, shndx); GElf_Shdr refshdr_mem, *refshdr = gelf_getshdr (refscn, &refshdr_mem); @@ -223,7 +206,8 @@ resolve_symbol (Dwfl_Module *referer, struct reloc_symtab_cache *symtab, symtab->symstrdata = elf_getdata (elf_getscn (symtab->symelf, symtab->strtabndx), NULL); - if (unlikely (symtab->symstrdata == NULL)) + if (unlikely (symtab->symstrdata == NULL + || symtab->symstrdata->d_buf == NULL)) return DWFL_E_LIBELF; } if (unlikely (sym->st_name >= symtab->symstrdata->d_size)) @@ -275,7 +259,8 @@ resolve_symbol (Dwfl_Module *referer, struct reloc_symtab_cache *symtab, if (m->e_type != ET_REL) { - sym->st_value = dwfl_adjusted_st_value (m, sym->st_value); + sym->st_value = dwfl_adjusted_st_value (m, m->symfile->elf, + sym->st_value); return DWFL_E_NOERROR; } @@ -319,6 +304,46 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr, if (tdata == NULL) return DWFL_E_LIBELF; + /* If either the section that needs the relocation applied, or the + section that the relocations come from overlap one of the ehdrs, + shdrs or phdrs data then we refuse to do the relocations. It + isn't illegal for ELF section data to overlap the header data, + but updating the (relocation) data might corrupt the in-memory + libelf headers causing strange corruptions or errors. */ + size_t ehsize = gelf_fsize (relocated, ELF_T_EHDR, 1, EV_CURRENT); + if (unlikely (shdr->sh_offset < ehsize + || tshdr->sh_offset < ehsize)) + return DWFL_E_BADELF; + + GElf_Off shdrs_start = ehdr->e_shoff; + size_t shnums; + if (elf_getshdrnum (relocated, &shnums) < 0) + return DWFL_E_LIBELF; + /* Overflows will have been checked by elf_getshdrnum/get|rawdata. */ + size_t shentsize = gelf_fsize (relocated, ELF_T_SHDR, 1, EV_CURRENT); + GElf_Off shdrs_end = shdrs_start + shnums * shentsize; + if (unlikely ((shdrs_start < shdr->sh_offset + shdr->sh_size + && shdr->sh_offset < shdrs_end) + || (shdrs_start < tshdr->sh_offset + tshdr->sh_size + && tshdr->sh_offset < shdrs_end))) + return DWFL_E_BADELF; + + GElf_Off phdrs_start = ehdr->e_phoff; + size_t phnums; + if (elf_getphdrnum (relocated, &phnums) < 0) + return DWFL_E_LIBELF; + if (phdrs_start != 0 && phnums != 0) + { + /* Overflows will have been checked by elf_getphdrnum/get|rawdata. */ + size_t phentsize = gelf_fsize (relocated, ELF_T_PHDR, 1, EV_CURRENT); + GElf_Off phdrs_end = phdrs_start + phnums * phentsize; + if (unlikely ((phdrs_start < shdr->sh_offset + shdr->sh_size + && shdr->sh_offset < phdrs_end) + || (phdrs_start < tshdr->sh_offset + tshdr->sh_size + && tshdr->sh_offset < phdrs_end))) + return DWFL_E_BADELF; + } + /* Apply one relocation. Returns true for any invalid data. */ Dwfl_Error relocate (GElf_Addr offset, const GElf_Sxword *addend, int rtype, int symndx) @@ -387,7 +412,7 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr, return DWFL_E_BADRELTYPE; } - if (offset + size > tdata->d_size) + if (offset > tdata->d_size || tdata->d_size - offset < size) return DWFL_E_BADRELOFF; #define DO_TYPE(NAME, Name) GElf_##Name Name; @@ -478,7 +503,10 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr, } } - size_t nrels = shdr->sh_size / shdr->sh_entsize; + size_t sh_entsize + = gelf_fsize (relocated, shdr->sh_type == SHT_REL ? ELF_T_REL : ELF_T_RELA, + 1, EV_CURRENT); + size_t nrels = shdr->sh_size / sh_entsize; size_t complete = 0; if (shdr->sh_type == SHT_REL) for (size_t relidx = 0; !result && relidx < nrels; ++relidx) @@ -580,7 +608,7 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr, nrels = next; } - shdr->sh_size = reldata->d_size = nrels * shdr->sh_entsize; + shdr->sh_size = reldata->d_size = nrels * sh_entsize; gelf_update_shdr (scn, shdr); } |