hw/net/net_tx_pkt: Fix overrun in update_sctp_checksum()
If a fragmented packet size is too short, do not try to
calculate its checksum.
Reproduced using:
$ cat << EOF | qemu-system-i386 -display none -nodefaults \
-machine q35,accel=qtest -m 32M \
-device igb,netdev=net0 \
-netdev user,id=net0 \
-qtest stdio
outl 0xcf8 0x80000810
outl 0xcfc 0xe0000000
outl 0xcf8 0x80000804
outw 0xcfc 0x06
write 0xe0000403 0x1 0x02
writel 0xe0003808 0xffffffff
write 0xe000381a 0x1 0x5b
write 0xe000381b 0x1 0x00
EOF
Assertion failed: (offset == 0), function iov_from_buf_full, file util/iov.c, line 39.
#1 0x5575e81e952a in iov_from_buf_full qemu/util/iov.c:39:5
#2 0x5575e6500768 in net_tx_pkt_update_sctp_checksum qemu/hw/net/net_tx_pkt.c:144:9
#3 0x5575e659f3e1 in igb_setup_tx_offloads qemu/hw/net/igb_core.c:478:11
#4 0x5575e659f3e1 in igb_tx_pkt_send qemu/hw/net/igb_core.c:552:10
#5 0x5575e659f3e1 in igb_process_tx_desc qemu/hw/net/igb_core.c:671:17
#6 0x5575e659f3e1 in igb_start_xmit qemu/hw/net/igb_core.c:903:9
#7 0x5575e659f3e1 in igb_set_tdt qemu/hw/net/igb_core.c:2812:5
#8 0x5575e657d6a4 in igb_core_write qemu/hw/net/igb_core.c:4248:9
Fixes: CVE-2024-3567
Cc: qemu-stable@nongnu.org
Reported-by: Zheyu Ma <zheyuma97@gmail.com>
Fixes: f199b13bc1 ("igb: Implement Tx SCTP CSO")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2273
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20240410070459.49112-1-philmd@linaro.org>
diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index 2134a18..b7b1de8 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -141,6 +141,10 @@
uint32_t csum = 0;
struct iovec *pl_start_frag = pkt->vec + NET_TX_PKT_PL_START_FRAG;
+ if (iov_size(pl_start_frag, pkt->payload_frags) < 8 + sizeof(csum)) {
+ return false;
+ }
+
if (iov_from_buf(pl_start_frag, pkt->payload_frags, 8, &csum, sizeof(csum)) < sizeof(csum)) {
return false;
}
