Re: [PATCH] libiberty: Fix memory leak in ada_demangle when symbol cannot be demangled.

[Ian Lance Taylor]

On Mon, Oct 31, 2016 at 2:57 AM, Mark Wielaard  wrote:
>
> libiberty/ChangeLog:
>
> * cplus-dem.c (ada_demangle): Initialize demangled to NULL and
> XDELETEVEC demangled when unknown.

This is OK.

Thanks.

Ian

[PATCH] libiberty: Fix memory leak in ada_demangle when symbol cannot be demangled.

[Mark Wielaard]

When a symbol cannot be demangled in ada_demangle a new demangled VEC
will be allocated without deleting the demangled VEC already in use.

Running testsuite/test-demangle under valgrind will show the leak for
this entry in testsuite/demangle-expected:

# Elaborated flag (not demangled)
--format=gnat
x_E


 11 bytes in 1 blocks are definitely lost in loss record 1 of 1
at 0x4C27BE3: malloc (vg_replace_malloc.c:299)
by 0x413FE7: xmalloc (xmalloc.c:148)
by 0x4025EC: ada_demangle (cplus-dem.c:930)
by 0x402C59: cplus_demangle (cplus-dem.c:892)
by 0x400FEC: main (test-demangle.c:317)

libiberty/ChangeLog:

* cplus-dem.c (ada_demangle): Initialize demangled to NULL and
XDELETEVEC demangled when unknown.
---
 libiberty/ChangeLog   | 5 +
 libiberty/cplus-dem.c | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index 5934bc1..73cbcc4 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,8 @@
+2016-10-31  Mark Wielaard  
+
+   * cplus-dem.c (ada_demangle): Initialize demangled to NULL and
+   XDELETEVEC demangled when unknown.
+
 2016-09-19  Andrew Stubbs  
 
* pex-win32.c (argv_to_cmdline): Quote zero-length parameters.
diff --git a/libiberty/cplus-dem.c b/libiberty/cplus-dem.c
index f954050..7f63397 100644
--- a/libiberty/cplus-dem.c
+++ b/libiberty/cplus-dem.c
@@ -911,7 +911,7 @@ ada_demangle (const char *mangled, int option 
ATTRIBUTE_UNUSED)
   int len0;
   const char* p;
   char *d;
-  char *demangled;
+  char *demangled = NULL;
   
   /* Discard leading _ada_, which is used for library level subprograms.  */
   if (strncmp (mangled, "_ada_", 5) == 0)
@@ -1156,6 +1156,7 @@ ada_demangle (const char *mangled, int option 
ATTRIBUTE_UNUSED)
   return demangled;
 
  unknown:
+  XDELETEVEC (demangled);
   len0 = strlen (mangled);
   demangled = XNEWVEC (char, len0 + 3);
 
-- 
1.8.3.1