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[PATCH] gdb/dwarf2read.c: Sanity check DW_AT_sibling values.
- From: Will Newton <will dot newton at linaro dot org>
- To: gdb-patches at sourceware dot org
- Cc: Patch Tracking <patches at linaro dot org>
- Date: Fri, 01 Nov 2013 14:21:30 -0700
- Subject: [PATCH] gdb/dwarf2read.c: Sanity check DW_AT_sibling values.
- Authentication-results: sourceware.org; auth=none
When reading objects with corrupt debug information it is possible that
the sibling chain can form a loop, which leads to an infinite loop and
memory exhaustion.
Avoid this situation by disregarding and DW_AT_sibling values that point
to a lower address than the current entry.
gdb/ChangeLog:
2013-11-01 Will Newton <will.newton@linaro.org>
PR gdb/12866
* dwarf2read.c (skip_one_die): Sanity check DW_AT_sibling
values. (read_partial_die): Likewise.
---
gdb/dwarf2read.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 3974d0b..d4dfd45 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -7016,7 +7016,14 @@ skip_one_die (const struct die_reader_specs *reader, const gdb_byte *info_ptr,
complaint (&symfile_complaints,
_("ignoring absolute DW_AT_sibling"));
else
- return buffer + dwarf2_get_ref_die_offset (&attr).sect_off;
+ {
+ const gdb_byte *sibling_ptr = buffer + dwarf2_get_ref_die_offset (&attr).sect_off;
+ if (sibling_ptr < info_ptr)
+ complaint (&symfile_complaints,
+ _("DW_AT_sibling points backwards"));
+ else
+ return buffer + dwarf2_get_ref_die_offset (&attr).sect_off;
+ }
}
/* If it isn't DW_AT_sibling, skip this attribute. */
@@ -15134,7 +15141,14 @@ read_partial_die (const struct die_reader_specs *reader,
complaint (&symfile_complaints,
_("ignoring absolute DW_AT_sibling"));
else
- part_die->sibling = buffer + dwarf2_get_ref_die_offset (&attr).sect_off;
+ {
+ const gdb_byte *sibling_ptr = buffer + dwarf2_get_ref_die_offset (&attr).sect_off;
+ if (sibling_ptr < info_ptr)
+ complaint (&symfile_complaints,
+ _("DW_AT_sibling points backwards"));
+ else
+ part_die->sibling = sibling_ptr;
+ }
break;
case DW_AT_byte_size:
part_die->has_byte_size = 1;
--
1.8.1.4