gdb/SOURCES/gdb-rhbz1708192-parse_macro_definition-crash.patch
2021-09-09 17:02:55 +00:00

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2.5 KiB
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From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
From: Sergio Durigan Junior <sergiodj@redhat.com>
Date: Fri, 10 May 2019 16:57:26 -0400
Subject: gdb-rhbz1708192-parse_macro_definition-crash.patch
;; "Fix" segfault that happens on parse_macro_definition because
;; debugedit corrupts the .debug_macro section.
;; Sergio Durigan Junior, RH BZ 1708192.
Don't crash if dwarf_decode_macro_bytes's 'body' is NULL
Hi,
Ref.: https://bugzilla.redhat.com/show_bug.cgi?id=1708192
https://bugzilla.redhat.com/show_bug.cgi?id=1708786
During the Fedora RPM build process, gdb-add-index is invoked to
extract the DWARF index from the binary, and GDB will segfault because
dwarf2read.c:parse_definition_macro's 'body' variable is NULL.
The underlying problem is that Fedora's rpm-build's "debugedit"
program will silently corrupt .debug_macro strings when a binary is
compiled with -g3. This is being taken care of by Mark Wielaard,
here:
https://bugzilla.redhat.com/show_bug.cgi?id=1708786
However, I still feel it's important to make GDB more resilient
against invalid DWARF input, so I'm proposing this rather simple patch
to catch the situation when "body == NULL" (i.e., it's probably been
corrupted) and issue a complaint. This is not a real fix to the
problem, of course, but at least GDB is able to finish without
segfaulting.
OK for master?
gdb/ChangeLog:
2019-05-15 Sergio Durigan Junior <sergiodj@redhat.com>
Ref.: https://bugzilla.redhat.com/show_bug.cgi?id=1708192
* dwarf2read.c (dwarf_decode_macro_bytes): Check whether 'body' is
NULL, and complain if that's the case.
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -24355,7 +24355,21 @@ dwarf_decode_macro_bytes (struct dwarf2_per_objfile *dwarf2_per_objfile,
is_define ? _("definition") : _("undefinition"),
line == 0 ? _("zero") : _("non-zero"), line, body);
- if (is_define)
+ if (body == NULL)
+ {
+ /* Fedora's rpm-build's "debugedit" binary
+ corrupted .debug_macro sections.
+
+ For more info, see
+ https://bugzilla.redhat.com/show_bug.cgi?id=1708786 */
+ complaint (_("debug info gives %s invalid macro %s "
+ "without body (corrupted?) at line %d "
+ "on file %s"),
+ at_commandline ? _("command-line") : _("in-file"),
+ is_define ? _("definition") : _("undefinition"),
+ line, current_file->filename);
+ }
+ else if (is_define)
parse_macro_definition (current_file, line, body);
else
{