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mptsas: Remove unused MPTSASState 'pending' field (CVE-2021-3392) 

While processing SCSI i/o requests in mptsas_process_scsi_io_request(),
the Megaraid emulator appends new MPTSASRequest object 'req' to
the 's->pending' queue. In case of an error, this same object gets
dequeued in mptsas_free_request() only if SCSIRequest object
'req->sreq' is initialised. This may lead to a use-after-free issue.

Since s->pending is actually not used, simply remove it from
MPTSASState.

Cc: qemu-stable@nongnu.org
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reported-by: Cheolwoo Myung <cwmyung@snu.ac.kr>
Message-id: 20210419134247.1467982-1-f4bug@amsat.org
Message-Id: <20210416102243.1293871-1-mjt@msgid.tls.msk.ru>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Cheolwoo Myung <cwmyung@snu.ac.kr>
BugLink: https://bugs.launchpad.net/qemu/+bug/1914236 (CVE-2021-3392)
Fixes: e351b82611 ("hw: Add support for LSI SAS1068 (mptsas) device")
[PMD: Reworded description, added more tags]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Michael Tokarev 2021-04-19 15:42:47 +02:00 committed by Peter Maydell
parent 0c5393a134
commit 3791642c8d
2 changed files with 0 additions and 7 deletions
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6
hw/scsi/mptsas.c
View File

@ -251,13 +251,10 @@ static int mptsas_build_sgl(MPTSASState *s, MPTSASRequest *req, hwaddr addr)
static void mptsas_free_request(MPTSASRequest *req)
{
MPTSASState *s = req->dev;
if (req->sreq != NULL) {
req->sreq->hba_private = NULL;
scsi_req_unref(req->sreq);
req->sreq = NULL;
QTAILQ_REMOVE(&s->pending, req, next);
}
qemu_sglist_destroy(&req->qsg);
g_free(req);
@ -303,7 +300,6 @@ static int mptsas_process_scsi_io_request(MPTSASState *s,
}
req = g_new0(MPTSASRequest, 1);
QTAILQ_INSERT_TAIL(&s->pending, req, next);
req->scsi_io = *scsi_io;
req->dev = s;
@ -1319,8 +1315,6 @@ static void mptsas_scsi_realize(PCIDevice *dev, Error **errp)
s->request_bh = qemu_bh_new(mptsas_fetch_requests, s);
QTAILQ_INIT(&s->pending);
scsi_bus_new(&s->bus, sizeof(s->bus), &dev->qdev, &mptsas_scsi_info, NULL);
}

1
hw/scsi/mptsas.h
View File

@ -79,7 +79,6 @@ struct MPTSASState {
uint16_t reply_frame_size;
SCSIBus bus;
QTAILQ_HEAD(, MPTSASRequest) pending;
};
void mptsas_fix_scsi_io_endianness(MPIMsgSCSIIORequest *req);