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Fixes an infinite loop in readelf parsing a corrupt binary, and other minor corrections. 

PR binutils/17531
	* readelf.c (get_data): Move excessive length check to earlier on
	in the function and allow for wraparound in the arithmetic.
	(get_32bit_elf_symbols): Terminate early if the section size is
	zero.  Check for an invalid sh_entsize.  Check for an index
	section with an invalid size.
	(get_64bit_elf_symbols): Likewise.
	(process_section_groups): Check for an invalid sh_entsize.
This commit is contained in:
Espen Grindhaug 2014-11-27 15:49:23 +00:00 committed by Nick Clifton
parent 3a1cfc456f
commit c9c1d67440
2 changed files with 84 additions and 24 deletions
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12
binutils/ChangeLog
View File

@ -1,3 +1,15 @@
2014-11-27 Espen Grindhaug <espen@grindhaug.org>
Nick Clifton <nickc@redhat.com>
PR binutils/17531
* readelf.c (get_data): Move excessive length check to earlier on
in the function and allow for wraparound in the arithmetic.
(get_32bit_elf_symbols): Terminate early if the section size is
zero. Check for an invalid sh_entsize. Check for an index
section with an invalid size.
(get_64bit_elf_symbols): Likewise.
(process_section_groups): Check for an invalid sh_entsize.
2014-11-24 Mark Wielaard <mjw@redhat.com>
* dwarf.c (read_and_display_attr_value): Handle DW_LANG_C11,

96
binutils/readelf.c
View File

@ -165,7 +165,7 @@
#endif
char * program_name = "readelf";
static long archive_file_offset;
static unsigned long archive_file_offset;
static unsigned long archive_file_size;
static bfd_size_type current_file_size;
static unsigned long dynamic_addr;
@ -313,21 +313,35 @@ static const char *get_symbol_version_string
} \
while (0)
/* Retrieve NMEMB structures, each SIZE bytes long from FILE starting at OFFSET.
/* Retrieve NMEMB structures, each SIZE bytes long from FILE starting at OFFSET +
the offset of the current archive member, if we are examining an archive.
Put the retrieved data into VAR, if it is not NULL. Otherwise allocate a buffer
using malloc and fill that. In either case return the pointer to the start of
the retrieved data or NULL if something went wrong. If something does go wrong
emit an error message using REASON as part of the context. */
and REASON is not NULL then emit an error message using REASON as part of the
context. */
static void *
get_data (void * var, FILE * file, long offset, size_t size, size_t nmemb,
get_data (void * var, FILE * file, unsigned long offset, size_t size, size_t nmemb,
const char * reason)
{
void * mvar;
size_t amt = size * nmemb;
if (size == 0 || nmemb == 0)
return NULL;
/* Be kind to memory chekers (eg valgrind, address sanitizer) by not
attempting to allocate memory when the read is bound to fail. */
if (amt > current_file_size
|| offset + archive_file_offset + amt > current_file_size)
{
if (reason)
error (_("Reading 0x%lx bytes extends past end of file for %s\n"),
(unsigned long) amt, reason);
return NULL;
}
if (fseek (file, archive_file_offset + offset, SEEK_SET))
{
if (reason)
@ -336,16 +350,6 @@ get_data (void * var, FILE * file, long offset, size_t size, size_t nmemb,
return NULL;
}
/* Be kind to memory chekers (eg valgrind, address sanitizer) by not
attempting to allocate memory when the read is bound to fail. */
if (offset + archive_file_offset + size * nmemb > current_file_size)
{
if (reason)
error (_("Reading 0x%lx bytes extends past end of file for %s\n"),
(unsigned long) (size * nmemb), reason);
return NULL;
}
mvar = var;
if (mvar == NULL)
{
@ -362,14 +366,14 @@ get_data (void * var, FILE * file, long offset, size_t size, size_t nmemb,
return NULL;
}
((char *) mvar)[size * nmemb] = '\0';
((char *) mvar)[amt] = '\0';
}
if (fread (mvar, size, nmemb, file) != nmemb)
{
if (reason)
error (_("Unable to read in 0x%lx bytes of %s\n"),
(unsigned long)(size * nmemb), reason);
(unsigned long) amt, reason);
if (mvar != var)
free (mvar);
return NULL;
@ -4756,10 +4760,18 @@ get_32bit_elf_symbols (FILE * file,
Elf_Internal_Sym * psym;
unsigned int j;
/* Run some sanity checks first. */
if (section->sh_entsize == 0)
if (section->sh_size == 0)
{
error (_("sh_entsize is zero\n"));
if (num_syms_return != NULL)
* num_syms_return = 0;
return NULL;
}
/* Run some sanity checks first. */
if (section->sh_entsize == 0 || section->sh_entsize > section->sh_size)
{
error (_("Section %s has an invalid sh_entsize of 0x%lx\n"),
printable_section_name (section), (unsigned long) section->sh_entsize);
goto exit_point;
}
@ -4774,7 +4786,8 @@ get_32bit_elf_symbols (FILE * file,
if (number * sizeof (Elf32_External_Sym) > section->sh_size + 1)
{
error (_("Invalid sh_entsize\n"));
error (_("Size (0x%lx) of section %s is not a multiple of its sh_entsize (0x%lx)\n"),
section->sh_size, printable_section_name (section), section->sh_entsize);
goto exit_point;
}
@ -4794,6 +4807,15 @@ get_32bit_elf_symbols (FILE * file,
_("symbol table section indicies"));
if (shndx == NULL)
goto exit_point;
/* PR17531: file: heap-buffer-overflow */
else if (symtab_shndx_hdr->sh_size / sizeof (Elf_External_Sym_Shndx) < number)
{
error (_("Index section %s has an sh_size of 0x%lx - expected 0x%lx\n"),
printable_section_name (symtab_shndx_hdr),
(unsigned long) symtab_shndx_hdr->sh_size,
(unsigned long) section->sh_size);
goto exit_point;
}
}
isyms = (Elf_Internal_Sym *) cmalloc (number, sizeof (Elf_Internal_Sym));
@ -4844,10 +4866,18 @@ get_64bit_elf_symbols (FILE * file,
Elf_Internal_Sym * psym;
unsigned int j;
/* Run some sanity checks first. */
if (section->sh_entsize == 0)
if (section->sh_size == 0)
{
error (_("sh_entsize is zero\n"));
if (num_syms_return != NULL)
* num_syms_return = 0;
return NULL;
}
/* Run some sanity checks first. */
if (section->sh_entsize == 0 || section->sh_entsize > section->sh_size)
{
error (_("Section %s has an invalid sh_entsize of 0x%lx\n"),
printable_section_name (section), (unsigned long) section->sh_entsize);
goto exit_point;
}
@ -4862,7 +4892,8 @@ get_64bit_elf_symbols (FILE * file,
if (number * sizeof (Elf64_External_Sym) > section->sh_size + 1)
{
error (_("Invalid sh_entsize\n"));
error (_("Size (0x%lx) of section %s is not a multiple of its sh_entsize (0x%lx)\n"),
section->sh_size, printable_section_name (section), section->sh_entsize);
goto exit_point;
}
@ -4881,6 +4912,14 @@ get_64bit_elf_symbols (FILE * file,
_("symbol table section indicies"));
if (shndx == NULL)
goto exit_point;
else if (symtab_shndx_hdr->sh_size / sizeof (Elf_External_Sym_Shndx) < number)
{
error (_("Index section %s has an sh_size of 0x%lx - expected 0x%lx\n"),
printable_section_name (symtab_shndx_hdr),
(unsigned long) symtab_shndx_hdr->sh_size,
(unsigned long) section->sh_size);
goto exit_point;
}
}
isyms = (Elf_Internal_Sym *) cmalloc (number, sizeof (Elf_Internal_Sym));
@ -5796,6 +5835,15 @@ process_section_groups (FILE * file)
? strtab + sym->st_name : _("<corrupt>");
}
/* PR 17531: file: loop. */
if (section->sh_entsize > section->sh_size)
{
error (_("Section %s has sh_entsize (0x%lx) which is larger than its size (0x%lx)\n"),
printable_section_name (section),
section->sh_entsize, section->sh_size);
break;
}
start = (unsigned char *) get_data (NULL, file, section->sh_offset,
1, section->sh_size,
_("section data"));