[PATCH v3 3/3] net: emaclite: fix handling for IP packets with specific lengths

[samuel.obuch@codasip.com]

From: Samuel Obuch <samuel.obuch@codasip.com>

The maximum length is capped similarly to the emaclite_send function.
Avoid integer underflow for values of ip->ip_len < 30, the minimum
length of an IP packet is 21 bytes.

Signed-off-by: Samuel Obuch <samuel.obuch@codasip.com>
---
 drivers/net/xilinx_emaclite.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/xilinx_emaclite.c b/drivers/net/xilinx_emaclite.c
index a4851ad36f..16ba915fba 100644
--- a/drivers/net/xilinx_emaclite.c
+++ b/drivers/net/xilinx_emaclite.c
@@ -517,6 +517,8 @@ try_again:
 		length = ntohs(ip->ip_len);
 		length += ETHER_HDR_SIZE + ETH_FCS_LEN;
 		debug("IP Packet %x\n", length);
+		if (length > PKTSIZE)
+			length = PKTSIZE;
 		break;
 	default:
 		debug("Other Packet\n");
@@ -525,7 +527,7 @@ try_again:
 	}
 
 	/* Read the rest of the packet which is longer then first read */
-	if (length != first_read)
+	if (length > first_read)
 		xemaclite_alignedread(addr + first_read,
 				      etherrxbuff + first_read,
 				      length - first_read);
-- 
2.31.1