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authorAlan Modra <amodra@gmail.com>2021-05-15 14:48:48 +0930
committerAlan Modra <amodra@gmail.com>2021-05-15 14:54:05 +0930
commit37195e23e731744d2d61c97844e884634b592f77 (patch)
tree82de8ba02e9cf68c9be4cab1a00d70e043d16d66 /binutils
parentedba4e4abaf679d3ce4d61fcbfe77b2bebfd4537 (diff)
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read_debug_line_header
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.
Diffstat (limited to 'binutils')
-rw-r--r--binutils/ChangeLog6
-rw-r--r--binutils/dwarf.c23
2 files changed, 11 insertions, 18 deletions
diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 669cdbd..93a47cb 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,5 +1,11 @@
2021-05-15 Alan Modra <amodra@gmail.com>
+ * dwarf.c (read_debug_line_header): Delete initial_length_size.
+ Avoid pointer UB. Keep within length specified by header.
+ Delete dead code.
+
+2021-05-15 Alan Modra <amodra@gmail.com>
+
* dwarf.c (process_debug_info): Always do the first CU length
scan for sanity checks. Remove initial_length_size var and
instead calculate end_cu. Use end_cu to limit data reads.
diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index b7061a9..4f69dbb 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -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;
}