* [PATCH] e1000: fail early for evil descriptor
@ 2021-02-24 5:45 Jason Wang
2021-02-26 7:05 ` Jason Wang
0 siblings, 1 reply; 2+ messages in thread
From: Jason Wang @ 2021-02-24 5:45 UTC (permalink / raw)
To: jasowang
Cc: Alexander Bulekov, Cheolwoo Myung, Ruhr-University Bochum,
qemu-devel, Prasad J Pandit
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>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
hw/net/e1000.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index d8da2f6528..4345d863e6 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -670,6 +670,9 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
msh = tp->tso_props.hdr_len + tp->tso_props.mss;
do {
bytes = split_size;
+ if (tp->size >= msh) {
+ goto eop;
+ }
if (tp->size + bytes > msh)
bytes = msh - tp->size;
@@ -695,6 +698,7 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
tp->size += split_size;
}
+eop:
if (!(txd_lower & E1000_TXD_CMD_EOP))
return;
if (!(tp->cptse && tp->size < tp->tso_props.hdr_len)) {
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] e1000: fail early for evil descriptor
2021-02-24 5:45 [PATCH] e1000: fail early for evil descriptor Jason Wang
@ 2021-02-26 7:05 ` Jason Wang
0 siblings, 0 replies; 2+ messages in thread
From: Jason Wang @ 2021-02-26 7:05 UTC (permalink / raw)
Cc: Alexander Bulekov, Cheolwoo Myung, Ruhr-University Bochum,
qemu-devel, Prasad J Pandit
On 2021/2/24 1:45 下午, Jason Wang wrote:
> 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>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> hw/net/e1000.c | 4 ++++
> 1 file changed, 4 insertions(+)
Applied.
Thanks
>
> diff --git a/hw/net/e1000.c b/hw/net/e1000.c
> index d8da2f6528..4345d863e6 100644
> --- a/hw/net/e1000.c
> +++ b/hw/net/e1000.c
> @@ -670,6 +670,9 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
> msh = tp->tso_props.hdr_len + tp->tso_props.mss;
> do {
> bytes = split_size;
> + if (tp->size >= msh) {
> + goto eop;
> + }
> if (tp->size + bytes > msh)
> bytes = msh - tp->size;
>
> @@ -695,6 +698,7 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
> tp->size += split_size;
> }
>
> +eop:
> if (!(txd_lower & E1000_TXD_CMD_EOP))
> return;
> if (!(tp->cptse && tp->size < tp->tso_props.hdr_len)) {
^ permalink raw reply [flat|nested] 2+ messages in thread
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