[binutils-gdb] Fix heap-buffer overflow bugs caused when dumping debug information from a corrupt binary.
Nick Clifton
nickc@sourceware.org
Fri Apr 28 09:28:00 GMT 2017
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d949ff5607b9f595e0eed2ff15fbe5eb84eb3a34
commit d949ff5607b9f595e0eed2ff15fbe5eb84eb3a34
Author: Nick Clifton <nickc@redhat.com>
Date: Fri Apr 28 10:28:04 2017 +0100
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.
Diff:
---
binutils/ChangeLog | 10 +++++++++
binutils/dwarf.c | 66 +++++++++++++++++++++++++++++++++++++++++-------------
2 files changed, 60 insertions(+), 16 deletions(-)
diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index e072a20..951673b 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,13 @@
+2017-04-28 Nick Clifton <nickc@redhat.com>
+
+ 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.
+
2017-04-26 Nick Clifton <nickc@redhat.com>
PR binutils/21433
diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index bb141e4..cdedbb2 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -472,15 +472,20 @@ process_extended_line_op (unsigned char * data,
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"));
@@ -597,36 +602,56 @@ 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 *) _("<no .debug_str section>");
- 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 *) _("<offset is too big>");
}
- return (const unsigned char *) section->start + offset;
+ 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 *)
+ _("<no NUL byte at end of .debug_str section>");
+
+ return ret;
}
static const unsigned char *
fetch_indirect_line_string (dwarf_vma offset)
{
struct dwarf_section *section = &debug_displays [line_str].section;
+ const unsigned char * ret;
if (section->start == NULL)
return (const unsigned char *) _("<no .debug_line_str section>");
- if (offset > section->size)
+ if (offset >= section->size)
{
warn (_("DW_FORM_line_strp offset too big: %s\n"),
dwarf_vmatoa ("x", offset));
return (const unsigned char *) _("<offset is too big>");
}
- return (const unsigned char *) section->start + offset;
+ ret = section->start + offset;
+ /* Unfortunately we cannot rely upon the .debug_line_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 *)
+ _("<no NUL byte at end of .debug_line_str section>");
+
+ return ret;
}
static const char *
@@ -639,6 +664,7 @@ fetch_indexed_string (dwarf_vma idx, struct cu_tu_set *this_set,
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 ? _("<no .debug_str_offsets.dwo section>")
@@ -646,7 +672,7 @@ fetch_indexed_string (dwarf_vma idx, struct cu_tu_set *this_set,
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));
@@ -659,14 +685,22 @@ fetch_indexed_string (dwarf_vma idx, struct cu_tu_set *this_set,
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 _("<indirect index offset is too big>");
}
- 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 *) _("<no NUL byte at end of section>");
+
+ return ret;
}
static const char *
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