|
 |
893208 |
From fc0bca7bd2685b8f8e3c37f19ce74967870ef952 Mon Sep 17 00:00:00 2001
|
|
|
893208 |
From: Jon Maloy <jmaloy@redhat.com>
|
|
|
893208 |
Date: Thu, 21 Oct 2021 12:10:47 -0400
|
|
|
893208 |
Subject: [PATCH 2/2] e1000: fix tx re-entrancy problem
|
|
|
893208 |
MIME-Version: 1.0
|
|
|
893208 |
Content-Type: text/plain; charset=UTF-8
|
|
|
893208 |
Content-Transfer-Encoding: 8bit
|
|
|
893208 |
|
|
|
893208 |
RH-Author: Jon Maloy <jmaloy@redhat.com>
|
|
|
893208 |
RH-MergeRequest: 73: e1000: fix tx re-entrancy problem
|
|
|
893208 |
RH-Commit: [1/1] 3088ea275ddcee1ba0d47f7cff195af3e256f15f (jmaloy/qemu-kvm)
|
|
|
893208 |
RH-Bugzilla: 2025011
|
|
|
893208 |
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
|
|
|
893208 |
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
|
|
|
893208 |
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
|
|
|
893208 |
|
|
|
893208 |
The fact that the MMIO handler is not re-entrant causes an infinite
|
|
|
893208 |
loop under certain conditions:
|
|
|
893208 |
|
|
|
893208 |
Guest write to TDT -> Loopback -> RX (DMA to TDT) -> TX
|
|
|
893208 |
|
|
|
893208 |
We now eliminate the effect of this problem locally in e1000, by adding
|
|
|
893208 |
a boolean in struct E1000State indicating when the TX side is busy. This
|
|
|
893208 |
will cause any entering new call to return early instead of interfering
|
|
|
893208 |
with the ongoing work, and eliminates any risk of looping.
|
|
|
893208 |
|
|
|
893208 |
This is intended to address CVE-2021-20257.
|
|
|
893208 |
|
|
|
893208 |
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
|
|
|
893208 |
Signed-off-by: Jason Wang <jasowang@redhat.com>
|
|
|
893208 |
(cherry picked from commit 25ddb946e6301f42cff3094ea1c25fb78813e7e9)
|
|
|
893208 |
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
|
|
|
893208 |
---
|
|
|
893208 |
hw/net/e1000.c | 7 +++++++
|
|
|
893208 |
1 file changed, 7 insertions(+)
|
|
|
893208 |
|
|
|
893208 |
diff --git a/hw/net/e1000.c b/hw/net/e1000.c
|
|
|
893208 |
index 8680b7d46b..1963a5b243 100644
|
|
|
893208 |
--- a/hw/net/e1000.c
|
|
|
893208 |
+++ b/hw/net/e1000.c
|
|
|
893208 |
@@ -105,6 +105,7 @@ typedef struct E1000State_st {
|
|
|
893208 |
e1000x_txd_props props;
|
|
|
893208 |
e1000x_txd_props tso_props;
|
|
|
893208 |
uint16_t tso_frames;
|
|
|
893208 |
+ bool busy;
|
|
|
893208 |
} tx;
|
|
|
893208 |
|
|
|
893208 |
struct {
|
|
|
893208 |
@@ -749,6 +750,11 @@ start_xmit(E1000State *s)
|
|
|
893208 |
return;
|
|
|
893208 |
}
|
|
|
893208 |
|
|
|
893208 |
+ if (s->tx.busy) {
|
|
|
893208 |
+ return;
|
|
|
893208 |
+ }
|
|
|
893208 |
+ s->tx.busy = true;
|
|
|
893208 |
+
|
|
|
893208 |
while (s->mac_reg[TDH] != s->mac_reg[TDT]) {
|
|
|
893208 |
base = tx_desc_base(s) +
|
|
|
893208 |
sizeof(struct e1000_tx_desc) * s->mac_reg[TDH];
|
|
|
893208 |
@@ -775,6 +781,7 @@ start_xmit(E1000State *s)
|
|
|
893208 |
break;
|
|
|
893208 |
}
|
|
|
893208 |
}
|
|
|
893208 |
+ s->tx.busy = false;
|
|
|
893208 |
set_ics(s, 0, cause);
|
|
|
893208 |
}
|
|
|
893208 |
|
|
|
893208 |
--
|
|
|
893208 |
2.27.0
|
|
|
893208 |
|