From: Michael Tokarev <mjt@tls.msk.ru>
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>
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: e351b826112 ("hw: Add support for LSI SAS1068 (mptsas) device")
[PMD: Reworded description, added more tags]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
v3: Remove now unused variable in mptsas_free_request (pm215)
MJT patch:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg799236.html
Since rc4 is soon, I'm directly respining his patch with my comments
addressed.
This is not a new regression (present since QEMU v2.6.0) but is a
CVE...
PJP first patch:
https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg02660.html
---
hw/scsi/mptsas.h | 1 -
hw/scsi/mptsas.c | 6 ------
2 files changed, 7 deletions(-)
diff --git a/hw/scsi/mptsas.h b/hw/scsi/mptsas.h
index b85ac1a5fcc..c046497db71 100644
--- a/hw/scsi/mptsas.h
+++ b/hw/scsi/mptsas.h
@@ -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);
diff --git a/hw/scsi/mptsas.c b/hw/scsi/mptsas.c
index 7416e787061..db3219e7d20 100644
--- a/hw/scsi/mptsas.c
+++ b/hw/scsi/mptsas.c
@@ -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);
}
--
2.26.3
On Mon, 19 Apr 2021 at 14:42, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote: > > From: Michael Tokarev <mjt@tls.msk.ru> > > 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> > 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: e351b826112 ("hw: Add support for LSI SAS1068 (mptsas) device") > [PMD: Reworded description, added more tags] > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > --- > v3: Remove now unused variable in mptsas_free_request (pm215) > > MJT patch: > https://www.mail-archive.com/qemu-devel@nongnu.org/msg799236.html > > Since rc4 is soon, I'm directly respining his patch with my comments > addressed. > > This is not a new regression (present since QEMU v2.6.0) but is a > CVE... > > PJP first patch: > https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg02660.html This is clearly-safe and since it's marked as a CVE and we're doing rc4 anyway we might as well put it in. Applied to master, thanks. -- PMM
On 4/19/21 6:47 PM, Peter Maydell wrote: > On Mon, 19 Apr 2021 at 14:42, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote: >> >> From: Michael Tokarev <mjt@tls.msk.ru> >> >> 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> >> 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: e351b826112 ("hw: Add support for LSI SAS1068 (mptsas) device") >> [PMD: Reworded description, added more tags] >> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> >> --- >> v3: Remove now unused variable in mptsas_free_request (pm215) >> >> MJT patch: >> https://www.mail-archive.com/qemu-devel@nongnu.org/msg799236.html >> >> Since rc4 is soon, I'm directly respining his patch with my comments >> addressed. >> >> This is not a new regression (present since QEMU v2.6.0) but is a >> CVE... >> >> PJP first patch: >> https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg02660.html > > This is clearly-safe and since it's marked as a CVE and we're doing > rc4 anyway we might as well put it in. Applied to master, thanks. Thank you! Phil.
© 2016 - 2024 Red Hat, Inc.