Handle locations with more than 30 chars for lat/lon.

For some locations more than 30 characters are needed for
representing the lat/lon information and the null character
at the end of the string is overwritten.
This causes the next member of the struct to be included when
reading the string which causes a NumberFormatException in
convertRationalLatLonToFloat() in ExifInterface.java and a
0f is returned.

The size of GpsLongRaw/GpsLatRaw is increased to 72 in
jhead.h since this is the maximum length of the string,
i.e. 11 * 6 + 3(‘/’) + 2(’,’) + 1(\0) = 72 . The length of
each component is 11 since it is a 32 bit signed number.
In gpsinfo.c strncpy will copy at most 71 characters since
this is the maximum length of the string.

Change-Id: Id24995ed08aa277681d9648054ebddc2c275f6b6

2 files changed, 10 insertions, 5 deletions

diff --git a/gpsinfo.c b/gpsinfo.c
index 896ad28..2661e52 100644
--- a/gpsinfo.c
+++ b/gpsinfo.c
@@ -187,7 +187,7 @@ void ProcessGpsInfo(unsigned char * DirStart, int ByteCountUnused, unsigned char
 
         switch(Tag){
             char FmtString[21];
-            char TempString[50];
+            char TempString[MAX_BUF_SIZE];
             double Values[3];
 
             case TAG_GPS_LAT_REF:
@@ -237,9 +237,9 @@ void ProcessGpsInfo(unsigned char * DirStart, int ByteCountUnused, unsigned char
                     Get32s(8+(char*)ValuePtr), Get32s(12+(char*)ValuePtr),
                     Get32s(16+(char*)ValuePtr), Get32s(20+(char*)ValuePtr));
                 if (Tag == TAG_GPS_LAT){
-                    strncpy(ImageInfo.GpsLatRaw, TempString, 31);
+                    strncpy(ImageInfo.GpsLatRaw, TempString, MAX_BUF_SIZE);
                 }else{
-                    strncpy(ImageInfo.GpsLongRaw, TempString, 31);
+                    strncpy(ImageInfo.GpsLongRaw, TempString, MAX_BUF_SIZE);
                 }
                 break;
 
diff --git a/jhead.h b/jhead.h
index 4347fe8..a73c578 100644
--- a/jhead.h
+++ b/jhead.h
@@ -61,6 +61,11 @@ extern int DumpExifMap;
 
 #define MAX_DATE_COPIES 10
 
+// Buffer size must large enough to hold maximum location string
+// containing six signed integers plus delimeters and terminator,
+// i.e.: 11 * 6 + 3(‘/’) + 2(’,’) + 1(\0) = 72
+#define MAX_BUF_SIZE    72
+
 typedef struct {
     uint32_t num;
     uint32_t denom;
@@ -114,10 +119,10 @@ typedef struct {
 
     int GpsInfoPresent;
     char GpsLat[31];
-    char GpsLatRaw[31];
+    char GpsLatRaw[MAX_BUF_SIZE];
     char GpsLatRef[2];
     char GpsLong[31];
-    char GpsLongRaw[31];
+    char GpsLongRaw[MAX_BUF_SIZE];
     char GpsLongRef[2];
     char GpsAlt[20];
     rat_t GpsAltRaw;