[binutils-gdb] Fix potential NULL pointer dereference

[Luis Machado <luisgpm at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b5e1db87897cabfd9beb8b1bd49f7d965c0f2607

commit b5e1db87897cabfd9beb8b1bd49f7d965c0f2607
Author: Luis Machado <lgustavo@codesourcery.com>
Date:   Mon Oct 24 17:51:33 2016 -0500

    Fix potential NULL pointer dereference
    
    This patch addresses a potential NULL pointer dereference when we try to
    duplicate a string. The input pointer can be NULL and that may lead to
    crashes. We simply add a check for that case.
    
    gdb/ChangeLog:
    2016-10-24  Luis Machado  <lgustavo@codesourcery.com>
    
    	* exec.c (exec_file_locate_attach): Prevent NULL pointer dereference
    	when duplicating a string.

Diff:
---
 gdb/ChangeLog | 5 +++++
 gdb/exec.c    | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 388cc1f..43175ff 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2016-10-24  Luis Machado  <lgustavo@codesourcery.com>
 
+	* exec.c (exec_file_locate_attach): Prevent NULL pointer dereference
+	when duplicating a string.
+
+2016-10-24  Luis Machado  <lgustavo@codesourcery.com>
+
 	* exec.c (exception_print_same): Fix string comparison to use
 	statically-allocated ones.
 
diff --git a/gdb/exec.c b/gdb/exec.c
index 67ecc63..6e2a296 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -227,7 +227,8 @@ exec_file_locate_attach (int pid, int defer_bp_reset, int from_tty)
       prev_err = err;
 
       /* Save message so it doesn't get trashed by the catch below.  */
-      prev_err.message = xstrdup (err.message);
+      if (err.message != NULL)
+	prev_err.message = xstrdup (err.message);
     }
   END_CATCH