Have macros to handle the range check and byte swapping.

Combine the check for whether the field is within the packet data and
the swapping of the field into macros that do both, and use them.

Change-Id: I1db4c5fd76172edd44abc9fb111d79a2537c6c9d
Reviewed-on: https://code.wireshark.org/review/130
Reviewed-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>

1 files changed, 44 insertions, 56 deletions

diff --git a/wiretap/pcap-common.c b/wiretap/pcap-common.c
index f262e2be9d..e0e0b1a653 100644
--- a/wiretap/pcap-common.c
+++ b/wiretap/pcap-common.c
@@ -1184,6 +1184,33 @@ struct usb_device_setup_hdr {
 	(((char *)(void *)(fieldp)) - ((char *)(void *)(basep)) + \
 	    sizeof(*fieldp))
 
+/*
+ * Is that offset within the bounds of the packet?
+ */
+#define WITHIN_PACKET(basep, fieldp) \
+	(packet_size >= END_OFFSETOF((basep), (fieldp)))
+
+#define CHECK_AND_SWAP16(fieldp) \
+	{ \
+		if (!WITHIN_PACKET(usb_phdr, fieldp)) \
+			return; \
+		PBSWAP16((guint8 *)fieldp); \
+	}
+
+#define CHECK_AND_SWAP32(fieldp) \
+	{ \
+		if (!WITHIN_PACKET(usb_phdr, fieldp)) \
+			return; \
+		PBSWAP32((guint8 *)fieldp); \
+	}
+
+#define CHECK_AND_SWAP64(fieldp) \
+	{ \
+		if (!WITHIN_PACKET(usb_phdr, fieldp)) \
+			return; \
+		PBSWAP64((guint8 *)fieldp); \
+	}
+
 static void
 pcap_byteswap_linux_usb_pseudoheader(struct wtap_pkthdr *phdr, guint8 *pd,
     gboolean header_len_64_bytes)
@@ -1210,36 +1237,17 @@ pcap_byteswap_linux_usb_pseudoheader(struct wtap_pkthdr *phdr, guint8 *pd,
 	 */
 	usb_phdr = (struct linux_usb_phdr *)(void *)pd;
 
-	if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->id))
-		return;
-	PBSWAP64((guint8 *)&usb_phdr->id);
-	if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->bus_id))
-		return;
-	PBSWAP16((guint8 *)&usb_phdr->bus_id);
-	if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->ts_sec))
-		return;
-	PBSWAP64((guint8 *)&usb_phdr->ts_sec);
-	if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->ts_usec))
-		return;
-	PBSWAP32((guint8 *)&usb_phdr->ts_usec);
-	if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->status))
-		return;
-	PBSWAP32((guint8 *)&usb_phdr->status);
-	if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->urb_len))
-		return;
-	PBSWAP32((guint8 *)&usb_phdr->urb_len);
-	if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->data_len))
-		return;
-	PBSWAP32((guint8 *)&usb_phdr->data_len);
+	CHECK_AND_SWAP64(&usb_phdr->id);
+	CHECK_AND_SWAP16(&usb_phdr->bus_id);
+	CHECK_AND_SWAP64(&usb_phdr->ts_sec);
+	CHECK_AND_SWAP32(&usb_phdr->ts_usec);
+	CHECK_AND_SWAP32(&usb_phdr->status);
+	CHECK_AND_SWAP32(&usb_phdr->urb_len);
+	CHECK_AND_SWAP32(&usb_phdr->data_len);
 
 	if (usb_phdr->transfer_type == URB_ISOCHRONOUS) {
-		if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->s.iso.error_count))
-			return;
-		PBSWAP32((guint8 *)&usb_phdr->s.iso.error_count);
-
-		if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->s.iso.numdesc))
-			return;
-		PBSWAP32((guint8 *)&usb_phdr->s.iso.numdesc);
+		CHECK_AND_SWAP32(&usb_phdr->s.iso.error_count);
+		CHECK_AND_SWAP32(&usb_phdr->s.iso.numdesc);
 	}
 
 	if (header_len_64_bytes) {
@@ -1256,18 +1264,10 @@ pcap_byteswap_linux_usb_pseudoheader(struct wtap_pkthdr *phdr, guint8 *pd,
 		 * the additional fields from the beginning of
 		 * the packet.
 		 */
-		if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->interval))
-			return;
-		PBSWAP32((guint8 *)&usb_phdr->interval);
-		if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->start_frame))
-			return;
-		PBSWAP32((guint8 *)&usb_phdr->start_frame);
-		if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->xfer_flags))
-			return;
-		PBSWAP32((guint8 *)&usb_phdr->xfer_flags);
-		if (packet_size < END_OFFSETOF(usb_phdr, &usb_phdr->ndesc))
-			return;
-		PBSWAP32((guint8 *)&usb_phdr->ndesc);
+		CHECK_AND_SWAP32(&usb_phdr->interval);
+		CHECK_AND_SWAP32(&usb_phdr->start_frame);
+		CHECK_AND_SWAP32(&usb_phdr->xfer_flags);
+		CHECK_AND_SWAP32(&usb_phdr->ndesc);
 	}
 
 	if (usb_phdr->transfer_type == URB_ISOCHRONOUS) {
@@ -1283,22 +1283,10 @@ pcap_byteswap_linux_usb_pseudoheader(struct wtap_pkthdr *phdr, guint8 *pd,
 		}
 		iso_numdesc = usb_phdr->s.iso.numdesc;
 		for (i = 0; i < iso_numdesc; i++) {
-			/*
-			 * Always check if we have enough data from the
-			 * beginning of the packet (usb_phdr).
-			 */
-			if (packet_size < END_OFFSETOF(usb_phdr, &pisodesc->iso_status))
-				return;
-			PBSWAP32((guint8 *)&pisodesc->iso_status);
-			if (packet_size < END_OFFSETOF(usb_phdr, &pisodesc->iso_off))
-				return;
-			PBSWAP32((guint8 *)&pisodesc->iso_off);
-			if (packet_size < END_OFFSETOF(usb_phdr, &pisodesc->iso_len))
-				return;
-			PBSWAP32((guint8 *)&pisodesc->iso_len);
-			if (packet_size < END_OFFSETOF(usb_phdr, &pisodesc->_pad))
-				return;
-			PBSWAP32((guint8 *)&pisodesc->_pad);
+			CHECK_AND_SWAP32(&pisodesc->iso_status);
+			CHECK_AND_SWAP32(&pisodesc->iso_off);
+			CHECK_AND_SWAP32(&pisodesc->iso_len);
+			CHECK_AND_SWAP32(&pisodesc->_pad);
 
 			pisodesc++;
 		}