dr_56: add boundary checking

src/descriptors/dr_56.c

@@ -62,15 +62,16 @@ dvbpsi_teletext_dr_t * dvbpsi_DecodeTeletextDr(
     if(p_descriptor->i_length % 5)
         return NULL;
 
-    int i_pages_number;
-    i_pages_number = p_descriptor->i_length / 5;
-
     /* Allocate memory */
     dvbpsi_teletext_dr_t * p_decoded;
     p_decoded = (dvbpsi_teletext_dr_t*)malloc(sizeof(dvbpsi_teletext_dr_t));
     if (!p_decoded)
         return NULL;
 
+    int i_pages_number;
+    i_pages_number = p_descriptor->i_length / 5;
+    if (i_pages_number > DVBPSI_TELETEXT_DR_MAX)
+        i_pages_number = DVBPSI_TELETEXT_DR_MAX;
     p_decoded->i_pages_number = i_pages_number;
 
     for (int i = 0; i < i_pages_number; i++)
@@ -99,6 +100,9 @@ dvbpsi_teletext_dr_t * dvbpsi_DecodeTeletextDr(
 dvbpsi_descriptor_t * dvbpsi_GenTeletextDr(dvbpsi_teletext_dr_t * p_decoded,
                                            bool b_duplicate)
 {
+    if (p_decoded->i_pages_number > DVBPSI_TELETEXT_DR_MAX)
+        p_decoded->i_pages_number = DVBPSI_TELETEXT_DR_MAX;
+
     /* Create the descriptor */
     dvbpsi_descriptor_t * p_descriptor =
             dvbpsi_NewDescriptor(0x56, p_decoded->i_pages_number * 8 , NULL);

src/descriptors/dr_56.h

@@ -62,6 +62,12 @@ typedef struct dvbpsi_teletextpage_s
 
 } dvbpsi_teletextpage_t;
 
+/*!
+ * \def DVBPSI_TELETEXT_DR_MAX
+ * \brief Maximum number of dvbpsi_teletextpage_t entries present in
+ * @see dvbpsi_teletext_dr_t
+ */
+#define DVBPSI_TELETEXT_DR_MAX 64
 
 /*****************************************************************************
  * dvbpsi_teletext_dr_t
@@ -80,11 +86,10 @@ typedef struct dvbpsi_teletextpage_s
 typedef struct dvbpsi_teletext_dr_s
 {
   uint8_t      i_pages_number;                           /*!< number of pages */
-  dvbpsi_teletextpage_t p_pages[64];    /*!< teletext pages */
+  dvbpsi_teletextpage_t p_pages[DVBPSI_TELETEXT_DR_MAX]; /*!< teletext pages */
 
 } dvbpsi_teletext_dr_t;
 
-
 /*****************************************************************************
  * dvbpsi_DecodeTeletextDataDr
  *****************************************************************************/