diff options
Diffstat (limited to 'src/libdwfl/elf-from-memory.c')
| -rw-r--r-- | src/libdwfl/elf-from-memory.c | 122 |
1 files changed, 62 insertions, 60 deletions
diff --git a/src/libdwfl/elf-from-memory.c b/src/libdwfl/elf-from-memory.c index 0fb5f8a3..b35fac71 100644 --- a/src/libdwfl/elf-from-memory.c +++ b/src/libdwfl/elf-from-memory.c @@ -1,51 +1,30 @@ /* Reconstruct an ELF file by reading the segments out of remote memory. - Copyright (C) 2005-2011 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 <config.h> #include "../libelf/libelfP.h" @@ -69,10 +48,14 @@ MAXREAD bytes from the remote memory at target address ADDRESS into the local buffer at DATA; it should return -1 for errors (with code in `errno'), 0 if it failed to read at least MINREAD bytes due to EOF, or - the number of bytes read if >= MINREAD. ARG is passed through. */ + the number of bytes read if >= MINREAD. ARG is passed through. + + PAGESIZE is the minimum page size and alignment used for the PT_LOAD + segments. */ Elf * elf_from_remote_memory (GElf_Addr ehdr_vma, + GElf_Xword pagesize, GElf_Addr *loadbasep, ssize_t (*read_memory) (void *arg, void *data, GElf_Addr address, @@ -104,6 +87,7 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, if (memcmp (buffer, ELFMAG, SELFMAG) != 0) { bad_elf: + free (buffer); __libdwfl_seterrno (DWFL_E_BADELF); return NULL; } @@ -212,25 +196,37 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, /* Scan for PT_LOAD segments to find the total size of the file image. */ size_t contents_size = 0; GElf_Off segments_end = 0; + GElf_Off segments_end_mem = 0; GElf_Addr loadbase = ehdr_vma; bool found_base = false; switch (ehdr.e32.e_ident[EI_CLASS]) { - inline void handle_segment (GElf_Addr vaddr, GElf_Off offset, - GElf_Xword filesz, GElf_Xword align) + /* Sanity checks segments and calculates segment_end, + segments_end, segments_end_mem and loadbase (if not + found_base yet). Returns true if sanity checking failed, + false otherwise. */ + inline bool handle_segment (GElf_Addr vaddr, GElf_Off offset, + GElf_Xword filesz, GElf_Xword memsz) { - GElf_Off segment_end = ((offset + filesz + align - 1) & -align); + /* Sanity check the segment load aligns with the pagesize. */ + if (((vaddr - offset) & (pagesize - 1)) != 0) + return true; + + GElf_Off segment_end = ((offset + filesz + pagesize - 1) + & -pagesize); if (segment_end > (GElf_Off) contents_size) contents_size = segment_end; - if (!found_base && (offset & -align) == 0) + if (!found_base && (offset & -pagesize) == 0) { - loadbase = ehdr_vma - (vaddr & -align); + loadbase = ehdr_vma - (vaddr & -pagesize); found_base = true; } segments_end = offset + filesz; + segments_end_mem = offset + memsz; + return false; } case ELFCLASS32: @@ -239,8 +235,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, goto libelf_error; for (uint_fast16_t i = 0; i < phnum; ++i) if (phdrs.p32[i].p_type == PT_LOAD) - handle_segment (phdrs.p32[i].p_vaddr, phdrs.p32[i].p_offset, - phdrs.p32[i].p_filesz, phdrs.p32[i].p_align); + if (handle_segment (phdrs.p32[i].p_vaddr, phdrs.p32[i].p_offset, + phdrs.p32[i].p_filesz, phdrs.p32[i].p_memsz)) + goto bad_elf; break; case ELFCLASS64: @@ -249,8 +246,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, goto libelf_error; for (uint_fast16_t i = 0; i < phnum; ++i) if (phdrs.p64[i].p_type == PT_LOAD) - handle_segment (phdrs.p64[i].p_vaddr, phdrs.p64[i].p_offset, - phdrs.p64[i].p_filesz, phdrs.p64[i].p_align); + if (handle_segment (phdrs.p64[i].p_vaddr, phdrs.p64[i].p_offset, + phdrs.p64[i].p_filesz, phdrs.p64[i].p_memsz)) + goto bad_elf; break; default: @@ -260,9 +258,11 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, /* Trim the last segment so we don't bother with zeros in the last page that are off the end of the file. However, if the extra bit in that - page includes the section headers, keep them. */ + page includes the section headers and the memory isn't extended (which + might indicate it will have been reused otherwise), keep them. */ if ((GElf_Off) contents_size > segments_end - && (GElf_Off) contents_size >= shdrs_end) + && (GElf_Off) contents_size >= shdrs_end + && segments_end == segments_end_mem) { contents_size = segments_end; if ((GElf_Off) contents_size < shdrs_end) @@ -280,15 +280,17 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, switch (ehdr.e32.e_ident[EI_CLASS]) { + /* Reads the given segment. Returns true if reading fails, + false otherwise. */ inline bool handle_segment (GElf_Addr vaddr, GElf_Off offset, - GElf_Xword filesz, GElf_Xword align) + GElf_Xword filesz) { - GElf_Off start = offset & -align; - GElf_Off end = (offset + filesz + align - 1) & -align; + GElf_Off start = offset & -pagesize; + GElf_Off end = (offset + filesz + pagesize - 1) & -pagesize; if (end > (GElf_Off) contents_size) end = contents_size; nread = (*read_memory) (arg, buffer + start, - (loadbase + vaddr) & -align, + (loadbase + vaddr) & -pagesize, end - start, end - start); return nread <= 0; } @@ -297,7 +299,7 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, for (uint_fast16_t i = 0; i < phnum; ++i) if (phdrs.p32[i].p_type == PT_LOAD) if (handle_segment (phdrs.p32[i].p_vaddr, phdrs.p32[i].p_offset, - phdrs.p32[i].p_filesz, phdrs.p32[i].p_align)) + phdrs.p32[i].p_filesz)) goto read_error; /* If the segments visible in memory didn't include the section @@ -322,9 +324,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, case ELFCLASS64: for (uint_fast16_t i = 0; i < phnum; ++i) - if (phdrs.p32[i].p_type == PT_LOAD) + if (phdrs.p64[i].p_type == PT_LOAD) if (handle_segment (phdrs.p64[i].p_vaddr, phdrs.p64[i].p_offset, - phdrs.p64[i].p_filesz, phdrs.p64[i].p_align)) + phdrs.p64[i].p_filesz)) goto read_error; /* If the segments visible in memory didn't include the section |