[gexiv2] gexiv2_metadata_get_gps_altitude(): Fix leak

[Jens Georg <jensgeorg src gnome org>]

commit 6c7ebbd80a062d9fe699b3d956ac1dcaf9209668
Author: Roman Lebedev <lebedev ri gmail com>
Date:   Fri Aug 28 17:03:11 2015 +0300

    gexiv2_metadata_get_gps_altitude(): Fix leak
    
    free return from gexiv2_metadata_get_exif_tag_string()
    
    Fixes following AddressSanitizer issue:
    Direct leak of 2 byte(s) in 1 object(s) allocated from:
        #0 0x7f9de859c37a in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x9437a)
        #1 0x7f9de5e8f799 in g_malloc (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x4f799)
        #2 0x7f9de5ea812e in g_strdup (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x6812e)
        #3 0x7f9de963f7ce in gexiv2_metadata_get_exif_tag_string gexiv2/gexiv2-metadata-exif.cpp:113
        #4 0x7f9de9642cc6 in gexiv2_metadata_get_gps_altitude gexiv2/gexiv2-metadata-gps.cpp:178
        #5 0x7f9de9642f2a in gexiv2_metadata_get_gps_info gexiv2/gexiv2-metadata-gps.cpp:216
        #6 0x4172a1 in a_geotag_get_position /home/lebedevri/src/viking/src/geotag_exif.c:218
        #7 0x4170b0 in main /home/lebedevri/src/viking/test/geotag_read.c:14
        #8 0x7f9de26a1b44 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b44)
        #9 0x416fb8  (/home/lebedevri/src/viking/test/geotag_read+0x416fb8)
    
    https://bugzilla.gnome.org/show_bug.cgi?id=754241

 gexiv2/gexiv2-metadata-gps.cpp |   30 +++++++++++++++++++-----------
 1 files changed, 19 insertions(+), 11 deletions(-)
---
diff --git a/gexiv2/gexiv2-metadata-gps.cpp b/gexiv2/gexiv2-metadata-gps.cpp
index 3c81255..51f1495 100644
--- a/gexiv2/gexiv2-metadata-gps.cpp
+++ b/gexiv2/gexiv2-metadata-gps.cpp
@@ -170,33 +170,41 @@ gboolean gexiv2_metadata_get_gps_altitude (GExiv2Metadata *self, gdouble *altitu
     g_return_val_if_fail(GEXIV2_IS_METADATA (self), FALSE);
     g_return_val_if_fail(altitude != NULL, FALSE);
     g_return_val_if_fail(self->priv->image.get() != NULL, FALSE);
-    
+
     try {
         double num, den;
         *altitude = 0.0;
-        
+
         gchar* altitude_ref = gexiv2_metadata_get_exif_tag_string (self, "Exif.GPSInfo.GPSAltitudeRef");
-        if (altitude_ref == NULL || altitude_ref[0] == '\0')
+        if (altitude_ref == NULL || altitude_ref[0] == '\0') {
+            g_free(altitude_ref);
             return FALSE;
-        
+        }
+
         Exiv2::ExifData& exif_data = self->priv->image->exifData();
         Exiv2::ExifKey key ("Exif.GPSInfo.GPSAltitude");
         Exiv2::ExifData::iterator it = exif_data.findKey (key);
-        
+
         if (it != exif_data.end () && (*it).count() == 1) {
             num = (double)((*it).toRational(0).first);
             den = (double)((*it).toRational(0).second);
-            
-            if (den == 0)
+
+            if (den == 0) {
+                g_free(altitude_ref);
                 return FALSE;
-            
+            }
+
             *altitude = num/den;
-        } else
+        } else {
+            g_free(altitude_ref);
             return FALSE;
-        
+        }
+
         if (altitude_ref[0] == '1')
             *altitude *= -1.0;
-        
+
+        g_free(altitude_ref);
+
         return TRUE;
     } catch (Exiv2::Error &e) {
         LOG_ERROR(e);