From d949ff5607b9f595e0eed2ff15fbe5eb84eb3a34 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Fri, 28 Apr 2017 10:28:04 +0100 Subject: [PATCH] Fix heap-buffer overflow bugs caused when dumping debug information from a corrupt binary. PR binutils/21438 * dwarf.c (process_extended_line_op): Do not assume that the string extracted from the section is NUL terminated. (fetch_indirect_string): If the string retrieved from the section is not NUL terminated, return an error message. (fetch_indirect_line_string): Likewise. (fetch_indexed_string): Likewise. Upstream-Status: Backport CVE: CVE-2017-8398 Signed-off-by: Armin Kuster --- binutils/ChangeLog | 10 +++++++++ binutils/dwarf.c | 66 +++++++++++++++++++++++++++++++++++++++++------------- 2 files changed, 60 insertions(+), 16 deletions(-) Index: git/binutils/dwarf.c =================================================================== --- git.orig/binutils/dwarf.c +++ git/binutils/dwarf.c @@ -472,15 +472,20 @@ process_extended_line_op (unsigned char printf (_(" Entry\tDir\tTime\tSize\tName\n")); printf (" %d\t", ++state_machine_regs.last_file_entry); - name = data; - data += strnlen ((char *) data, end - data) + 1; - printf ("%s\t", dwarf_vmatoa ("u", read_uleb128 (data, & bytes_read, end))); - data += bytes_read; - printf ("%s\t", dwarf_vmatoa ("u", read_uleb128 (data, & bytes_read, end))); - data += bytes_read; - printf ("%s\t", dwarf_vmatoa ("u", read_uleb128 (data, & bytes_read, end))); - data += bytes_read; - printf ("%s\n\n", name); + { + size_t l; + + name = data; + l = strnlen ((char *) data, end - data); + data += len + 1; + printf ("%s\t", dwarf_vmatoa ("u", read_uleb128 (data, & bytes_read, end))); + data += bytes_read; + printf ("%s\t", dwarf_vmatoa ("u", read_uleb128 (data, & bytes_read, end))); + data += bytes_read; + printf ("%s\t", dwarf_vmatoa ("u", read_uleb128 (data, & bytes_read, end))); + data += bytes_read; + printf ("%.*s\n\n", (int) l, name); + } if (((unsigned int) (data - orig_data) != len) || data == end) warn (_("DW_LNE_define_file: Bad opcode length\n")); @@ -597,18 +602,27 @@ static const unsigned char * fetch_indirect_string (dwarf_vma offset) { struct dwarf_section *section = &debug_displays [str].section; + const unsigned char * ret; if (section->start == NULL) return (const unsigned char *) _(""); - if (offset > section->size) + if (offset >= section->size) { warn (_("DW_FORM_strp offset too big: %s\n"), dwarf_vmatoa ("x", offset)); return (const unsigned char *) _(""); } + ret = section->start + offset; + /* Unfortunately we cannot rely upon the .debug_str section ending with a + NUL byte. Since our caller is expecting to receive a well formed C + string we test for the lack of a terminating byte here. */ + if (strnlen ((const char *) ret, section->size - offset) + == section->size - offset) + ret = (const unsigned char *) + _(""); - return (const unsigned char *) section->start + offset; + return ret; } static const char * @@ -621,6 +635,7 @@ fetch_indexed_string (dwarf_vma idx, str struct dwarf_section *str_section = &debug_displays [str_sec_idx].section; dwarf_vma index_offset = idx * offset_size; dwarf_vma str_offset; + const char * ret; if (index_section->start == NULL) return (dwo ? _("") @@ -628,7 +643,7 @@ fetch_indexed_string (dwarf_vma idx, str if (this_set != NULL) index_offset += this_set->section_offsets [DW_SECT_STR_OFFSETS]; - if (index_offset > index_section->size) + if (index_offset >= index_section->size) { warn (_("DW_FORM_GNU_str_index offset too big: %s\n"), dwarf_vmatoa ("x", index_offset)); @@ -641,14 +656,22 @@ fetch_indexed_string (dwarf_vma idx, str str_offset = byte_get (index_section->start + index_offset, offset_size); str_offset -= str_section->address; - if (str_offset > str_section->size) + if (str_offset >= str_section->size) { warn (_("DW_FORM_GNU_str_index indirect offset too big: %s\n"), dwarf_vmatoa ("x", str_offset)); return _(""); } - return (const char *) str_section->start + str_offset; + ret = (const char *) str_section->start + str_offset; + /* Unfortunately we cannot rely upon str_section ending with a NUL byte. + Since our caller is expecting to receive a well formed C string we test + for the lack of a terminating byte here. */ + if (strnlen (ret, str_section->size - str_offset) + == str_section->size - str_offset) + ret = (const char *) _(""); + + return ret; } static const char * Index: git/binutils/ChangeLog =================================================================== --- git.orig/binutils/ChangeLog +++ git/binutils/ChangeLog @@ -1,3 +1,13 @@ +2017-04-28 Nick Clifton + + PR binutils/21438 + * dwarf.c (process_extended_line_op): Do not assume that the + string extracted from the section is NUL terminated. + (fetch_indirect_string): If the string retrieved from the section + is not NUL terminated, return an error message. + (fetch_indirect_line_string): Likewise. + (fetch_indexed_string): Likewise. + 2017-02-14 Nick Clifton PR binutils/21157