Note some cases where we don't need to check the packet length.

These file formats have 16-bit packet lengths, so, even with some extra
metadata added, the packet data length will never be bigger than
WTAP_MAX_PACKET_SIZE.  (No, we won't ever reduce WTAP_MAX_PACKET_SIZE.)

Change-Id: I9e1b1d90971f91cc6e5d66d0aa93841445b2bc22
Reviewed-on: https://code.wireshark.org/review/15186
Reviewed-by: Guy Harris <guy@alum.mit.edu>

wiretap/camins.c

@@ -244,6 +244,12 @@ camins_read_packet(FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf,
 
     if (!find_next_pkt_dat_type_len(fh, &dat_trans_type, &dat_len, err, err_info))
         return FALSE;
+    /*
+     * The maximum value of length is 65535, which, even after
+     * DVB_CI_PSEUDO_HDR_LEN is added to it, is less than
+     * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check
+     * it.
+     */
 
     ws_buffer_assure_space(buf, DVB_CI_PSEUDO_HDR_LEN+dat_len);
     p = ws_buffer_start_ptr(buf);

wiretap/commview.c

@@ -146,6 +146,11 @@ commview_read_packet(FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf,
 
 	if(!commview_read_header(&cv_hdr, fh, err, err_info))
 		return FALSE;
+	/*
+	 * The maximum value of cv_hdr.data_len is 65535, which is less
+	 * than WTAP_MAX_PACKET_SIZE will ever be, so we don't need to
+	 * check it.
+	 */
 
 	switch(cv_hdr.flags & FLAGS_MEDIUM) {
 

wiretap/csids.c

@@ -179,6 +179,11 @@ csids_read_packet(FILE_T fh, csids_t *csids, struct wtap_pkthdr *phdr,
     return FALSE;
   hdr.seconds = pntoh32(&hdr.seconds);
   hdr.caplen = pntoh16(&hdr.caplen);
+  /*
+   * The maximum value of hdr.caplen is 65535, which is less than
+   * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check
+   * it.
+   */
 
   phdr->rec_type = REC_TYPE_PACKET;
   phdr->presence_flags = WTAP_HAS_TS;

wiretap/ipfix.c

@@ -157,6 +157,11 @@ ipfix_read_message(FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf, int *err, g
 
     if (!ipfix_read_message_header(&msg_hdr, fh, err, err_info))
         return FALSE;
+    /*
+     * The maximum value of msg_hdr.message_length is 65535, which is
+     * less than WTAP_MAX_PACKET_SIZE will ever be, so we don't need
+     * to check it.
+     */
 
     phdr->rec_type = REC_TYPE_PACKET;
     phdr->presence_flags = WTAP_HAS_TS;

wiretap/lanalyzer.c

@@ -482,6 +482,11 @@ static gboolean lanalyzer_read_trace_record(wtap *wth, FILE_T fh,
 
       true_size = pletoh16(&descriptor[4]);
       packet_size = pletoh16(&descriptor[6]);
+      /*
+       * The maximum value of packet_size is 65535, which is less than
+       * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check
+       * it.
+       */
 
       /*
        * OK, is the frame data size greater than than what's left of the

wiretap/logcat.c

@@ -186,6 +186,12 @@ static gboolean logcat_read_packet(struct logcat_phdr *logcat, FILE_T fh,
     } else {
         return FALSE;
     }
+    /*
+     * The maximum value of payload_length is 65535, which, even after
+     * the size of the logger entry structure is added to it, is less
+     * than WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check
+     * it.
+     */
 
     ws_buffer_assure_space(buf, packet_size);
     pd = ws_buffer_start_ptr(buf);

wiretap/netscaler.c

@@ -938,6 +938,9 @@ static gboolean nstrace_set_start_time(wtap *wth)
 
 /*
 ** Netscaler trace format read routines.
+**
+** The maximum value of the record data size is 65535, which is less than
+** WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check it.
 */
 #define TIMEDEFV10(phdr,fp,type) \
     do {\
@@ -1075,6 +1078,10 @@ static gboolean nstrace_read_v10(wtap *wth, int *err, gchar **err_info, gint64 *
 #define TIMEDEFV25(phdr,fp,type) TIMEDEFV24(phdr,fp,type)
 #define TIMEDEFV26(phdr,fp,type) TIMEDEFV24(phdr,fp,type)
 
+/*
+** The maximum value of the record data size is 65535, which is less than
+** WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check it.
+*/
 #define PARTSIZEDEFV20(phdr,pp,ver) \
     do {\
         (phdr)->presence_flags |= WTAP_HAS_CAP_LEN;\
@@ -1244,6 +1251,10 @@ static gboolean nstrace_read_v20(wtap *wth, int *err, gchar **err_info, gint64 *
 
 #define TIMEDEFV35 TIMEDEFV30
 
+/*
+** The maximum value of the record data size is 65535, which is less than
+** WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check it.
+*/
 #define FULLSIZEDEFV30(phdr,fp,ver)\
     do {\
         (phdr)->presence_flags |= WTAP_HAS_CAP_LEN;\
@@ -1665,6 +1676,8 @@ static gboolean nstrace_seek_read_v30(wtap *wth, gint64 seek_off,
 
     /*
     ** Get the record length.
+    ** The maximum value of the record data size is 65535, which is less
+    ** than WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check it.
     */
     record_length = nspr_getv20recordsize(&hdr);
 

wiretap/network_instruments.c

@@ -471,6 +471,11 @@ process_packet_header(wtap *wth, packet_entry_header *packet_header,
         phdr->len = packet_header->network_size - 4;
         phdr->caplen = MIN(packet_header->captured_size, phdr->len);
     }
+    /*
+     * The maximum value of packet_header->captured_size is 65535, which
+     * is less than WTAP_MAX_PACKET_SIZE will ever be, so we don't need
+     * to check it.
+     */
 
     /* set the wiretap timestamp, assuming for the moment that Observer encoded it in GMT */
     phdr->ts.secs = (time_t) ((packet_header->nano_seconds_since_2000 / 1000000000) + ansi_to_observer_epoch_offset);

wiretap/ngsniffer.c

@@ -1298,6 +1298,11 @@ ngsniffer_process_record(wtap *wth, gboolean is_random, guint *padding,
 		*err_info = g_strdup("ngsniffer: Record length is less than packet size");
 		return -1;
 	}
+	/*
+	 * The maximum value of length is 65535, which is less than
+	 * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check
+	 * it.
+	 */
 
 	if (padding != NULL) {
 		/*

wiretap/peekclassic.c

@@ -434,6 +434,11 @@ static int peekclassic_read_packet_v7(wtap *wth, FILE_T fh,
 	if (0 == sliceLength) {
 		sliceLength = length;
 	}
+	/*
+	 * The maximum value of sliceLength and length are 65535, which
+	 * are less than WTAP_MAX_PACKET_SIZE will ever be, so we don't
+	 * need to check them.
+	 */
 
 	/* fill in packet header values */
 	phdr->rec_type = REC_TYPE_PACKET;
@@ -613,6 +618,11 @@ static gboolean peekclassic_read_packet_v56(wtap *wth, FILE_T fh,
 	if (0 == sliceLength) {
 		sliceLength = length;
 	}
+	/*
+	 * The maximum value of sliceLength and length are 65535, which
+	 * are less than WTAP_MAX_PACKET_SIZE will ever be, so we don't
+	 * need to check them.
+	 */
 
 	/* fill in packet header values */
 	phdr->rec_type = REC_TYPE_PACKET;

wiretap/radcom.c

@@ -306,6 +306,11 @@ radcom_read_rec(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf,
 	}
 	length = pletoh16(&hdr.length);
 	real_length = pletoh16(&hdr.real_length);
+	/*
+	 * The maximum value of length is 65535, which is less than
+	 * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check
+	 * it.
+	 */
 
 	phdr->rec_type = REC_TYPE_PACKET;
 	phdr->presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN;