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[PULL,2/2] hw/net/net_tx_pkt: fix assertion failure in net_tx_pkt_add_raw_fragment()

Message ID 1596523270-5492-3-git-send-email-jasowang@redhat.com
State New
Headers show
Series [PULL,1/2] colo-compare: Remove superfluous NULL-pointer checks for s->iothread | expand

Commit Message

Jason Wang Aug. 4, 2020, 6:41 a.m. UTC
From: Mauro Matteo Cascella <mcascell@redhat.com>

An assertion failure issue was found in the code that processes network packets
while adding data fragments into the packet context. It could be abused by a
malicious guest to abort the QEMU process on the host. This patch replaces the
affected assert() with a conditional statement, returning false if the current
data fragment exceeds max_raw_frags.

Reported-by: Alexander Bulekov <alxndr@bu.edu>
Reported-by: Ziming Zhang <ezrakiez@gmail.com>
Reviewed-by: Dmitry Fleytman <dmitry.fleytman@gmail.com>
Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
 hw/net/net_tx_pkt.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index 9560e4a..da262ed 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -379,7 +379,10 @@  bool net_tx_pkt_add_raw_fragment(struct NetTxPkt *pkt, hwaddr pa,
     hwaddr mapped_len = 0;
     struct iovec *ventry;
-    assert(pkt->max_raw_frags > pkt->raw_frags);
+    if (pkt->raw_frags >= pkt->max_raw_frags) {
+        return false;
+    }
     if (!len) {
         return true;