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e1000: fail early for evil descriptor

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During procss_tx_desc(), driver can try to chain data descriptor with
legacy descriptor, when will lead underflow for the following
calculation in process_tx_desc() for bytes:

            if (tp->size + bytes > msh)
                bytes = msh - tp->size;

This will lead a infinite loop. So check and fail early if tp->size if
greater or equal to msh.

Reported-by: Alexander Bulekov <alxndr@bu.edu>
Reported-by: Cheolwoo Myung <cwmyung@snu.ac.kr>
Reported-by: Ruhr-University Bochum <bugs-syssec@rub.de>
Cc: Prasad J Pandit <ppandit@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Jason Wang 2021-02-24 13:45:28 +08:00
parent e73b4317b7
commit 3de46e6fc4
1 changed files with 4 additions and 0 deletions
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4
hw/net/e1000.c
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@ -670,6 +670,9 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
msh = tp->tso_props.hdr_len + tp->tso_props.mss; msh = tp->tso_props.hdr_len + tp->tso_props.mss;
do { do {
bytes = split_size; bytes = split_size;
if (tp->size >= msh) {
goto eop;
}
if (tp->size + bytes > msh) if (tp->size + bytes > msh)
bytes = msh - tp->size; bytes = msh - tp->size;
@ -695,6 +698,7 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
tp->size += split_size; tp->size += split_size;
} }
eop:
if (!(txd_lower & E1000_TXD_CMD_EOP)) if (!(txd_lower & E1000_TXD_CMD_EOP))
return; return;
if (!(tp->cptse && tp->size < tp->tso_props.hdr_len)) { if (!(tp->cptse && tp->size < tp->tso_props.hdr_len)) {