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hw/scsi/scsi-disk: MODE_PAGE_ALLS not allowed in MODE SELECT commands

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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: a8f4bbe290 ("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>
This commit is contained in:
Mauro Matteo Cascella 2021-11-04 17:31:38 +01:00 committed by Paolo Bonzini
parent b04dc92e01
commit b3af7fdf9c
1 changed files with 6 additions and 0 deletions
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6
hw/scsi/scsi-disk.c
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@ -1087,6 +1087,7 @@ static int mode_sense_page(SCSIDiskState *s, int page, uint8_t **p_outbuf,
uint8_t *p = *p_outbuf + 2; uint8_t *p = *p_outbuf + 2;
int length; int length;
assert(page < ARRAY_SIZE(mode_sense_valid));
if ((mode_sense_valid[page] & (1 << s->qdev.type)) == 0) { if ((mode_sense_valid[page] & (1 << s->qdev.type)) == 0) {
return -1; return -1;
} }
@ -1428,6 +1429,11 @@ static int scsi_disk_check_mode_select(SCSIDiskState *s, int page,
return -1; return -1;
} }
/* MODE_PAGE_ALLS is only valid for MODE SENSE commands */
if (page == MODE_PAGE_ALLS) {
return -1;
}
p = mode_current; p = mode_current;
memset(mode_current, 0, inlen + 2); memset(mode_current, 0, inlen + 2);
len = mode_sense_page(s, page, &p, 0); len = mode_sense_page(s, page, &p, 0);