From 1ed9669ab7ef35a592dd78636c60300466f9c71f Mon Sep 17 00:00:00 2001 From: Mauro Matteo Cascella Date: Thu, 4 Nov 2021 17:31:38 +0100 Subject: [PATCH 2/2] hw/scsi/scsi-disk: MODE_PAGE_ALLS not allowed in MODE SELECT commands MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Jon Maloy RH-MergeRequest: 69: hw/scsi/scsi-disk: MODE_PAGE_ALLS not allowed in MODE SELECT commands RH-Commit: [1/1] 929b23f9ac50b3b1e6712c85018feee384a0ca19 (jmaloy/qemu-kvm) RH-Bugzilla: 2020720 RH-Acked-by: Mauro Matteo Cascella RH-Acked-by: Hanna Reitz RH-Acked-by: Stefano Garzarella RH-Acked-by: Philippe Mathieu-Daudé 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 Fixes: a8f4bbe2900 ("scsi-disk: store valid mode pages in a table") Fixes: #546 Reported-by: Qiuhao Li Signed-off-by: Mauro Matteo Cascella Signed-off-by: Paolo Bonzini (cherry picked from commit b3af7fdf9cc537f8f0dd3e2423d83f5c99a457e8) Signed-off-by: Jon Maloy --- 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); -- 2.27.0