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From b3af7fdf9cc537f8f0dd3e2423d83f5c99a457e8 Mon Sep 17 00:00:00 2001
From: Mauro Matteo Cascella <mcascell@redhat.com>
Date: Thu, 4 Nov 2021 17:31:38 +0100
Subject: [PATCH] hw/scsi/scsi-disk: MODE_PAGE_ALLS not allowed in MODE SELECT
commands
This avoids an off-by-one read of 'mode_sense_valid' buffer in
hw/scsi/scsi-disk.c:mode_sense_page().
Fixes: CVE-2021-3930
Cc: qemu-stable@nongnu.org
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Fixes: a8f4bbe2900 ("scsi-disk: store valid mode pages in a table")
Fixes: #546
Reported-by: Qiuhao Li <Qiuhao.Li@outlook.com>
Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
https://gitlab.com/qemu-project/qemu/-/commit/b3af7fdf9cc537f8f0dd3e2423d83f5c99a457e8
CVE: CVE-2021-3930
Upstream-Status: Backport
Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com>
---
hw/scsi/scsi-disk.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index e8a547dbb7..d4914178ea 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -1087,6 +1087,7 @@ static int mode_sense_page(SCSIDiskState *s, int page, uint8_t **p_outbuf,
uint8_t *p = *p_outbuf + 2;
int length;
+ assert(page < ARRAY_SIZE(mode_sense_valid));
if ((mode_sense_valid[page] & (1 << s->qdev.type)) == 0) {
return -1;
}
@@ -1428,6 +1429,11 @@ static int scsi_disk_check_mode_select(SCSIDiskState *s, int page,
return -1;
}
+ /* MODE_PAGE_ALLS is only valid for MODE SENSE commands */
+ if (page == MODE_PAGE_ALLS) {
+ return -1;
+ }
+
p = mode_current;
memset(mode_current, 0, inlen + 2);
len = mode_sense_page(s, page, &p, 0);
--
GitLab
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