Fix heap-buffer-overflow error detected by address sanitization on a fuzzed binary.

	PR binutils/20794
	* readelf.c (process_section_headers): Fix off-by-one error when
	checking for invalid sh_link and sh_info fields.

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 09f76b9..d586e03 100644 (file)
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,9 @@
+2016-11-08  Nick Clifton  <nickc@redhat.com>
+
+       PR binutils/20794
+       * readelf.c (process_section_headers): Fix off-by-one error when
+       checking for invalid sh_link and sh_info fields.
+
 2016-11-04  Andrew Burgess  <andrew.burgess@embecosm.com>
 
        * objcopy.c (copy_section): Add extra calls to free for error

diff --git a/binutils/readelf.c b/binutils/readelf.c
index 114486c..e782e95 100644 (file)
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -5978,7 +5978,7 @@ process_section_headers (FILE * file)
        case SHT_REL:
        case SHT_RELA:
          if (section->sh_link < 1
-             || section->sh_link > elf_header.e_shnum
+             || section->sh_link >= elf_header.e_shnum
              || (section_headers[section->sh_link].sh_type != SHT_SYMTAB
                  && section_headers[section->sh_link].sh_type != SHT_DYNSYM))
            warn (_("[%2u]: Link field (%u) should index a symtab section.\n"),
@@ -5992,7 +5992,7 @@ process_section_headers (FILE * file)
        case SHT_GNU_verdef:
        case SHT_GNU_LIBLIST:
          if (section->sh_link < 1
-             || section->sh_link > elf_header.e_shnum
+             || section->sh_link >= elf_header.e_shnum
              || section_headers[section->sh_link].sh_type != SHT_STRTAB)
            warn (_("[%2u]: Link field (%u) should index a string section.\n"),
                  i, section->sh_link);
@@ -6025,7 +6025,7 @@ process_section_headers (FILE * file)
        case SHT_REL:
        case SHT_RELA:
          if (section->sh_info < 1
-             || section->sh_info > elf_header.e_shnum
+             || section->sh_info >= elf_header.e_shnum
              || (section_headers[section->sh_info].sh_type != SHT_PROGBITS
                  && section_headers[section->sh_info].sh_type != SHT_NOBITS
                  && section_headers[section->sh_info].sh_type != SHT_NOTE
@@ -6072,7 +6072,7 @@ process_section_headers (FILE * file)
            ;
          else if (section->sh_flags & SHF_INFO_LINK)
            {
-             if (section->sh_info < 1 || section->sh_info > elf_header.e_shnum)
+             if (section->sh_info < 1 || section->sh_info >= elf_header.e_shnum)
                warn (_("[%2u]: Expected link to another section in info field"), i);
            }
          else if (section->sh_type < SHT_LOOS && section->sh_info != 0)