[binutils-gdb] Fix a crash with a malformed PE header

[Jon TURNEY]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=a08c904d4e9688a869242d9cec1b64ca23b1214e

commit a08c904d4e9688a869242d9cec1b64ca23b1214e
Author: Jon Turney <jon.turney@dronecode.org.uk>
Date:   Thu Jan 2 00:25:56 2020 +0000

    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
    
    gdb/ChangeLog:
    
    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.

Diff:
---
 gdb/ChangeLog      | 5 +++++
 gdb/coff-pe-read.c | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 177b505..9a3cca2 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+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.
+
 2020-01-06  Eli Zaretskii  <eliz@gnu.org>
 
 	* windows-tdep.c: Fix a typo in WINDOWS_SIGABRT.
diff --git a/gdb/coff-pe-read.c b/gdb/coff-pe-read.c
index e1c51d4..d0c1e05 100644
--- 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;
+    }
+
   export_rva = export_opthdrrva;
   export_size = export_opthdrsize;