[PATCH 2/6] robustify: elflint.
Mark Wielaard
mjw at redhat.com
Fri Jan 17 20:20:40 UTC 2014
From: Jakub Jelinek <jakub at redhat.com>
Signed-off-by: Mark Wielaard <mjw at redhat.com>
---
src/ChangeLog | 9 +++++
src/elflint.c | 96 +++++++++++++++++++++++++++++++++++++++++++-------------
2 files changed, 82 insertions(+), 23 deletions(-)
diff --git a/src/ChangeLog b/src/ChangeLog
index a3f56fb..9fdc9f9 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2014-01-17 Jakub Jelinek <jakub at redhat.com>
+
+ * elflint.c (section_name): Return "<invalid>" instead of
+ crashing on invalid section name.
+ (check_symtab, is_rel_dyn, check_rela, check_rel, check_dynamic,
+ check_symtab_shndx, check_hash, check_versym): Robustify.
+ (check_hash): Don't check entries beyond end of section.
+ (check_note): Don't crash if gelf_rawchunk fails.
+
2014-01-17 Petr Machata <pmachata at redhat.com>
* readelf.c (handle_dynamic, handle_relocs_rel)
diff --git a/src/elflint.c b/src/elflint.c
index e42072b..84051d2 100644
--- a/src/elflint.c
+++ b/src/elflint.c
@@ -1,5 +1,5 @@
/* Pedantic checking of ELF files compliance with gABI/psABI spec.
- Copyright (C) 2001-2013 Red Hat, Inc.
+ Copyright (C) 2001-2014 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <drepper at redhat.com>, 2001.
@@ -311,10 +311,19 @@ section_name (Ebl *ebl, int idx)
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr;
+ const char *ret;
+
+ if ((unsigned int) idx > shnum)
+ return "<invalid>";
shdr = gelf_getshdr (elf_getscn (ebl->elf, idx), &shdr_mem);
+ if (shdr == NULL)
+ return "<invalid>";
- return elf_strptr (ebl->elf, shstrndx, shdr->sh_name);
+ ret = elf_strptr (ebl->elf, shstrndx, shdr->sh_name);
+ if (ret == NULL)
+ return "<invalid>";
+ return ret;
}
@@ -625,7 +634,8 @@ section [%2d] '%s': symbol table cannot have more than one extended index sectio
}
}
- if (shdr->sh_entsize != gelf_fsize (ebl->elf, ELF_T_SYM, 1, EV_CURRENT))
+ size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_SYM, 1, EV_CURRENT);
+ if (shdr->sh_entsize != sh_entsize)
ERROR (gettext ("\
section [%2u] '%s': entry size is does not match ElfXX_Sym\n"),
idx, section_name (ebl, idx));
@@ -663,7 +673,7 @@ section [%2d] '%s': XINDEX for zeroth entry not zero\n"),
xndxscnidx, section_name (ebl, xndxscnidx));
}
- for (size_t cnt = 1; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt)
+ for (size_t cnt = 1; cnt < shdr->sh_size / sh_entsize; ++cnt)
{
sym = gelf_getsymshndx (data, xndxdata, cnt, &sym_mem, &xndx);
if (sym == NULL)
@@ -683,7 +693,8 @@ section [%2d] '%s': symbol %zu: invalid name value\n"),
else
{
name = elf_strptr (ebl->elf, shdr->sh_link, sym->st_name);
- assert (name != NULL);
+ assert (name != NULL
+ || strshdr->sh_type != SHT_STRTAB);
}
if (sym->st_shndx == SHN_XINDEX)
@@ -1040,9 +1051,11 @@ is_rel_dyn (Ebl *ebl, const GElf_Ehdr *ehdr, int idx, const GElf_Shdr *shdr,
{
GElf_Shdr rcshdr_mem;
const GElf_Shdr *rcshdr = gelf_getshdr (scn, &rcshdr_mem);
- assert (rcshdr != NULL);
- if (rcshdr->sh_type == SHT_DYNAMIC)
+ if (rcshdr == NULL)
+ break;
+
+ if (rcshdr->sh_type == SHT_DYNAMIC && rcshdr->sh_entsize)
{
/* Found the dynamic section. Look through it. */
Elf_Data *d = elf_getdata (scn, NULL);
@@ -1052,7 +1065,9 @@ is_rel_dyn (Ebl *ebl, const GElf_Ehdr *ehdr, int idx, const GElf_Shdr *shdr,
{
GElf_Dyn dyn_mem;
GElf_Dyn *dyn = gelf_getdyn (d, cnt, &dyn_mem);
- assert (dyn != NULL);
+
+ if (dyn == NULL)
+ break;
if (dyn->d_tag == DT_RELCOUNT)
{
@@ -1066,7 +1081,9 @@ section [%2d] '%s': DT_RELCOUNT used for this RELA section\n"),
/* 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)
+ if (shdr->sh_entsize != 0
+ && 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),
@@ -1226,7 +1243,8 @@ section [%2d] '%s': no relocations for merge-able sections possible\n"),
}
}
- if (shdr->sh_entsize != gelf_fsize (ebl->elf, reltype, 1, EV_CURRENT))
+ size_t sh_entsize = gelf_fsize (ebl->elf, reltype, 1, EV_CURRENT);
+ if (shdr->sh_entsize != sh_entsize)
ERROR (gettext (reltype == ELF_T_RELA ? "\
section [%2d] '%s': section entry size does not match ElfXX_Rela\n" : "\
section [%2d] '%s': section entry size does not match ElfXX_Rel\n"),
@@ -1449,7 +1467,8 @@ check_rela (Ebl *ebl, GElf_Ehdr *ehdr, GElf_Shdr *shdr, int idx)
Elf_Data *symdata = elf_getdata (symscn, NULL);
enum load_state state = state_undecided;
- for (size_t cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt)
+ size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_RELA, 1, EV_CURRENT);
+ for (size_t cnt = 0; cnt < shdr->sh_size / sh_entsize; ++cnt)
{
GElf_Rela rela_mem;
GElf_Rela *rela = gelf_getrela (data, cnt, &rela_mem);
@@ -1499,7 +1518,8 @@ check_rel (Ebl *ebl, GElf_Ehdr *ehdr, GElf_Shdr *shdr, int idx)
Elf_Data *symdata = elf_getdata (symscn, NULL);
enum load_state state = state_undecided;
- for (size_t cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt)
+ size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_REL, 1, EV_CURRENT);
+ for (size_t cnt = 0; cnt < shdr->sh_size / sh_entsize; ++cnt)
{
GElf_Rel rel_mem;
GElf_Rel *rel = gelf_getrel (data, cnt, &rel_mem);
@@ -1598,7 +1618,8 @@ section [%2d] '%s': referenced as string table for section [%2d] '%s' but type i
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))
+ size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_DYN, 1, EV_CURRENT);
+ if (shdr->sh_entsize != sh_entsize)
ERROR (gettext ("\
section [%2d] '%s': section entry size does not match ElfXX_Dyn\n"),
idx, section_name (ebl, idx));
@@ -1608,7 +1629,7 @@ section [%2d] '%s': section entry size does not match ElfXX_Dyn\n"),
idx, section_name (ebl, idx));
bool non_null_warned = false;
- for (cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt)
+ for (cnt = 0; cnt < shdr->sh_size / sh_entsize; ++cnt)
{
GElf_Dyn dyn_mem;
GElf_Dyn *dyn = gelf_getdyn (data, cnt, &dyn_mem);
@@ -1880,6 +1901,8 @@ section [%2d] '%s': entry size does not match Elf32_Word\n"),
idx, section_name (ebl, idx));
if (symshdr != NULL
+ && shdr->sh_entsize
+ && symshdr->sh_entsize
&& (shdr->sh_size / shdr->sh_entsize
< symshdr->sh_size / symshdr->sh_entsize))
ERROR (gettext ("\
@@ -1906,6 +1929,12 @@ section [%2d] '%s': extended section index in section [%2zu] '%s' refers to same
}
Elf_Data *data = elf_getdata (elf_getscn (ebl->elf, idx), NULL);
+ if (data == NULL)
+ {
+ ERROR (gettext ("section [%2d] '%s': cannot get section data\n"),
+ idx, section_name (ebl, idx));
+ return;
+ }
if (*((Elf32_Word *) data->d_buf) != 0)
ERROR (gettext ("symbol 0 should have zero extended section index\n"));
@@ -1948,7 +1977,7 @@ section [%2d] '%s': hash table section is too small (is %ld, expected %ld)\n"),
size_t maxidx = nchain;
- if (symshdr != NULL)
+ if (symshdr != NULL && symshdr->sh_entsize != 0)
{
size_t symsize = symshdr->sh_size / symshdr->sh_entsize;
@@ -1959,18 +1988,28 @@ section [%2d] '%s': hash table section is too small (is %ld, expected %ld)\n"),
maxidx = symsize;
}
+ Elf32_Word *buf = (Elf32_Word *) data->d_buf;
+ Elf32_Word *end = (Elf32_Word *) ((char *) data->d_buf + shdr->sh_size);
size_t cnt;
for (cnt = 2; cnt < 2 + nbucket; ++cnt)
- if (((Elf32_Word *) data->d_buf)[cnt] >= maxidx)
+ {
+ if (buf + cnt >= end)
+ break;
+ else if (buf[cnt] >= maxidx)
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] >= maxidx)
+ {
+ if (buf + cnt >= end)
+ break;
+ else if (buf[cnt] >= maxidx)
ERROR (gettext ("\
section [%2d] '%s': hash chain reference %zu out of bounds\n"),
idx, section_name (ebl, idx), cnt - 2 - nbucket);
+ }
}
@@ -2000,18 +2039,28 @@ section [%2d] '%s': hash table section is too small (is %ld, expected %ld)\n"),
maxidx = symsize;
}
+ Elf64_Xword *buf = (Elf64_Xword *) data->d_buf;
+ Elf64_Xword *end = (Elf64_Xword *) ((char *) data->d_buf + shdr->sh_size);
size_t cnt;
for (cnt = 2; cnt < 2 + nbucket; ++cnt)
- if (((Elf64_Xword *) data->d_buf)[cnt] >= maxidx)
+ {
+ if (buf + cnt >= end)
+ break;
+ else if (buf[cnt] >= maxidx)
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 (((Elf64_Xword *) data->d_buf)[cnt] >= maxidx)
+ {
+ if (buf + cnt >= end)
+ break;
+ else if (buf[cnt] >= maxidx)
ERROR (gettext ("\
section [%2d] '%s': hash chain reference %" PRIu64 " out of bounds\n"),
- idx, section_name (ebl, idx), (uint64_t) (cnt - 2 - nbucket));
+ idx, section_name (ebl, idx), (uint64_t) cnt - 2 - nbucket);
+ }
}
@@ -2036,7 +2085,7 @@ section [%2d] '%s': bitmask size not power of 2: %u\n"),
if (shdr->sh_size < (4 + bitmask_words + nbuckets) * sizeof (Elf32_Word))
{
ERROR (gettext ("\
-section [%2d] '%s': hash table section is too small (is %ld, expected at least%ld)\n"),
+section [%2d] '%s': hash table section is too small (is %ld, expected at least %ld)\n"),
idx, section_name (ebl, idx), (long int) shdr->sh_size,
(long int) ((4 + bitmask_words + nbuckets) * sizeof (Elf32_Word)));
return;
@@ -2708,8 +2757,9 @@ section [%2d] '%s' refers in sh_link to section [%2d] '%s' which is no dynamic s
/* The number of elements in the version symbol table must be the
same as the number of symbols. */
- if (shdr->sh_size / shdr->sh_entsize
- != symshdr->sh_size / symshdr->sh_entsize)
+ if (shdr->sh_entsize && symshdr->sh_entsize
+ && (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),
--
1.7.1
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