FreeChainXenon/binutils-gdb
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

read_debug_line_header

Browse source 
This patch also better constrains the data read, and removes pointer UB.

	* dwarf.c (read_debug_line_header): Delete initial_length_size.
	Avoid pointer UB.  Keep within length specified by header.
	Delete dead code.
This commit is contained in:
Alan Modra 2021-05-15 14:48:48 +09:30
parent edba4e4aba
commit 37195e23e7
2 changed files with 11 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

23
binutils/dwarf.c
View file

@ -4053,7 +4053,6 @@ read_debug_line_header (struct dwarf_section * section,
unsigned char ** end_of_sequence)
{
unsigned char *hdrptr;
unsigned int initial_length_size;
/* Extract information from the Line Number Program Header.
(section 6.2.4 in the Dwarf3 doc). */
@ -4067,15 +4066,11 @@ read_debug_line_header (struct dwarf_section * section,
/* This section is 64-bit DWARF 3. */
SAFE_BYTE_GET_AND_INC (linfo->li_length, hdrptr, 8, end);
linfo->li_offset_size = 8;
initial_length_size = 12;
}
else
{
linfo->li_offset_size = 4;
initial_length_size = 4;
}
linfo->li_offset_size = 4;
if (linfo->li_length + initial_length_size > section->size)
if (linfo->li_length > (size_t) (end - hdrptr))
{
/* If the length field has a relocation against it, then we should
not complain if it is inaccurate (and probably negative). This
@ -4085,7 +4080,7 @@ read_debug_line_header (struct dwarf_section * section,
is used to compute the correct length once that is done. */
if (reloc_at (section, (hdrptr - section->start) - linfo->li_offset_size))
{
linfo->li_length = (end - data) - initial_length_size;
linfo->li_length = end - hdrptr;
}
else
{
@ -4094,6 +4089,7 @@ read_debug_line_header (struct dwarf_section * section,
return NULL;
}
}
end = hdrptr + linfo->li_length;
/* Get and check the version number. */
SAFE_BYTE_GET_AND_INC (linfo->li_version, hdrptr, 2, end);
@ -4144,16 +4140,7 @@ read_debug_line_header (struct dwarf_section * section,
SAFE_BYTE_GET_AND_INC (linfo->li_line_range, hdrptr, 1, end);
SAFE_BYTE_GET_AND_INC (linfo->li_opcode_base, hdrptr, 1, end);
* end_of_sequence = data + linfo->li_length + initial_length_size;
/* PR 17512: file:002-117414-0.004. */
if (* end_of_sequence > end)
{
warn (_("Line length %s extends beyond end of section\n"),
dwarf_vmatoa ("u", linfo->li_length));
* end_of_sequence = end;
return NULL;
}
*end_of_sequence = end;
return hdrptr;
}