Fix a crash with a malformed PE header
Commit Message
On 02/01/2020 13:56, Eli Zaretskii wrote:
>> From: Jon Turney <jon.turney@dronecode.org.uk>
>> Cc: Jon Turney <jon.turney@dronecode.org.uk>
>> Date: Thu, 2 Jan 2020 12:54:05 +0000
>>
>> --- a/gdb/coff-pe-read.c
>> +++ b/gdb/coff-pe-read.c
>> @@ -441,6 +441,12 @@ read_pe_exported_syms (minimal_symbol_reader &reader,
>> }
>> }
>>
>> + if (expptr == 0)
>> + {
>> + /* no section contains export table rva */
>> + return;
>> + }
>> +
>
> Thanks. Would it make sense to produce some diagnostic output here,
> when an appropriate debug-FOO option is set?
Yes, I suppose that's better than just a comment.
How about the attached?
From b78ee5736d93d7fa3476a69cc11229c047f477ec Mon Sep 17 00:00:00 2001
From: Jon Turney <jon.turney@dronecode.org.uk>
Date: Thu, 2 Jan 2020 00:25:56 +0000
Subject: [PATCH] Fix a crash with a malformed PE header
Don't try to read the PE export table when no section contains the RVA
for it.
(I have a PE executable [1] packed with UPX, where the export table data
directory entry contains a RVA which doesn't correspond to any section.
Mistakenly trying to debug this with gdb makes it crash.)
[1] https://cygwin.com/setup/setup-2.898.x86_64.exe
2020-01-02 Jon Turney <jon.turney@dronecode.org.uk>
* coff-pe-read.c (read_pe_exported_syms): Don't try to read the
export table if no section contains it's RVA.
---
gdb/ChangeLog | 5 +++++
gdb/coff-pe-read.c | 9 +++++++++
2 files changed, 14 insertions(+)
Comments
> Cc: Eli Zaretskii <eliz@gnu.org>
> From: Jon Turney <jon.turney@dronecode.org.uk>
> Date: Fri, 3 Jan 2020 13:11:24 +0000
>
> > Thanks. Would it make sense to produce some diagnostic output here,
> > when an appropriate debug-FOO option is set?
>
> Yes, I suppose that's better than just a comment.
>
> How about the attached?
LGTM, but please wait for someone else to approve this formally.
Thanks.
>>>>> "Jon" == Jon Turney <jon.turney@dronecode.org.uk> writes:
Jon> 2020-01-02 Jon Turney <jon.turney@dronecode.org.uk>
Jon> * coff-pe-read.c (read_pe_exported_syms): Don't try to read the
Jon> export table if no section contains it's RVA.
Thanks. This is ok.
Tom
@@ -441,6 +441,15 @@ read_pe_exported_syms (minimal_symbol_reader &reader,
}
}
+ if (expptr == 0)
+ {
+ if (debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog, _("No section contains export RVA for "
+ "dll \"%s\"\n"),
+ dll_name);
+ return;
+ }
+
export_rva = export_opthdrrva;
export_size = export_opthdrsize;