From dd32b5ea7eeea367058ec8e0f9eb41de41a8d106 Mon Sep 17 00:00:00 2001 From: Akihiko Odaki Date: Thu, 23 Feb 2023 19:20:10 +0900 Subject: hw/net/net_tx_pkt: Check the payload length Check the payload length if checksumming to ensure the payload contains the space for the resulting value. This bug was found by Alexander Bulekov with the fuzzer: https://patchew.org/QEMU/20230129053316.1071513-1-alxndr@bu.edu/ The fixed test case is: fuzz/crash_6aeaa33e7211ecd603726c53e834df4c6d1e08bc Fixes: e263cd49c7 ("Packet abstraction for VMWARE network devices") Signed-off-by: Akihiko Odaki Signed-off-by: Jason Wang --- hw/net/net_tx_pkt.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'hw') diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c index 4a35e84..986a3ad 100644 --- a/hw/net/net_tx_pkt.c +++ b/hw/net/net_tx_pkt.c @@ -342,11 +342,17 @@ bool net_tx_pkt_build_vheader(struct NetTxPkt *pkt, bool tso_enable, if (csum_enable) { switch (pkt->l4proto) { case IP_PROTO_TCP: + if (pkt->payload_len < sizeof(struct tcp_hdr)) { + return false; + } pkt->virt_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; pkt->virt_hdr.csum_start = pkt->hdr_len; pkt->virt_hdr.csum_offset = offsetof(struct tcp_hdr, th_sum); break; case IP_PROTO_UDP: + if (pkt->payload_len < sizeof(struct udp_hdr)) { + return false; + } pkt->virt_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; pkt->virt_hdr.csum_start = pkt->hdr_len; pkt->virt_hdr.csum_offset = offsetof(struct udp_hdr, uh_sum); -- cgit v1.1