blob: 26e22b4c314da66f04f0ca28fcb63b04bb87b2c3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
[Ubuntu note: remove fuzz-lsi53c895a-test.c changes since the file does not
exist for this release]
From b987718bbb1d0eabf95499b976212dd5f0120d75 Mon Sep 17 00:00:00 2001
From: Thomas Huth <thuth@redhat.com>
Date: Mon, 22 May 2023 11:10:11 +0200
Subject: [PATCH] hw/scsi/lsi53c895a: Fix reentrancy issues in the LSI
controller (CVE-2023-0330)
We cannot use the generic reentrancy guard in the LSI code, so
we have to manually prevent endless reentrancy here. The problematic
lsi_execute_script() function has already a way to detect whether
too many instructions have been executed - we just have to slightly
change the logic here that it also takes into account if the function
has been called too often in a reentrant way.
The code in fuzz-lsi53c895a-test.c has been taken from an earlier
patch by Mauro Matteo Cascella.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1563
Message-Id: <20230522091011.1082574-1-thuth@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reference: https://launchpad.net/ubuntu/+source/qemu/1:4.2-3ubuntu6.27
Upstream-Status: Backport [import from ubuntu https://git.launchpad.net/ubuntu/+source/qemu/tree/debian/patches/CVE-2023-0330.patch?h=ubuntu/focal-security
Upstream commit https://gitlab.com/qemu-project/qemu/-/commit/b987718bbb1d0eabf95499b976212dd5f0120d75]
CVE: CVE-2023-0330
Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
---
hw/scsi/lsi53c895a.c | 23 +++++++++++++++------
tests/qtest/fuzz-lsi53c895a-test.c | 33 ++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+), 6 deletions(-)
--- qemu-4.2.orig/hw/scsi/lsi53c895a.c
+++ qemu-4.2/hw/scsi/lsi53c895a.c
@@ -1135,15 +1135,24 @@ static void lsi_execute_script(LSIState
uint32_t addr, addr_high;
int opcode;
int insn_processed = 0;
+ static int reentrancy_level;
+
+ reentrancy_level++;
s->istat1 |= LSI_ISTAT1_SRUN;
again:
- if (++insn_processed > LSI_MAX_INSN) {
- /* Some windows drivers make the device spin waiting for a memory
- location to change. If we have been executed a lot of code then
- assume this is the case and force an unexpected device disconnect.
- This is apparently sufficient to beat the drivers into submission.
- */
+ /*
+ * Some windows drivers make the device spin waiting for a memory location
+ * to change. If we have executed more than LSI_MAX_INSN instructions then
+ * assume this is the case and force an unexpected device disconnect. This
+ * is apparently sufficient to beat the drivers into submission.
+ *
+ * Another issue (CVE-2023-0330) can occur if the script is programmed to
+ * trigger itself again and again. Avoid this problem by stopping after
+ * being called multiple times in a reentrant way (8 is an arbitrary value
+ * which should be enough for all valid use cases).
+ */
+ if (++insn_processed > LSI_MAX_INSN || reentrancy_level > 8) {
if (!(s->sien0 & LSI_SIST0_UDC)) {
qemu_log_mask(LOG_GUEST_ERROR,
"lsi_scsi: inf. loop with UDC masked");
@@ -1597,6 +1606,8 @@ again:
}
}
trace_lsi_execute_script_stop();
+
+ reentrancy_level--;
}
static uint8_t lsi_reg_readb(LSIState *s, int offset)
|
