| Message ID | 20210418053039.811996-1-philmd@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [PATCH-for-6.0?,v2] mptsas: Remove unused MPTSASState 'pending' field (CVE-2021-3392) | expand |
On 4/18/21 7:30 AM, Philippe Mathieu-Daudé 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> > --- > Supersedes: <20210416102243.1293871-1-mjt@msgid.tls.msk.ru> > > 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 | 4 ---- > 2 files changed, 5 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..5abbc742aaf 100644 > --- a/hw/scsi/mptsas.c > +++ b/hw/scsi/mptsas.c > @@ -257,7 +257,6 @@ static void mptsas_free_request(MPTSASRequest *req) > 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 +302,6 @@ 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 +1317,6 @@ 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); > } > >
On Sun, 18 Apr 2021 at 06:30, Philippe Mathieu-Daudé <philmd@redhat.com> 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> > 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> > --- > Supersedes: <20210416102243.1293871-1-mjt@msgid.tls.msk.ru> > > 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 | 4 ---- > 2 files changed, 5 deletions(-) This fails to compile: ../../hw/scsi/mptsas.c: In function ‘mptsas_free_request’: ../../hw/scsi/mptsas.c:254:18: error: unused variable ‘s’ [-Werror=unused-variable] MPTSASState *s = req->dev; ^ cc1: all warnings being treated as errors thanks -- PMM
On 4/19/21 3:32 PM, Peter Maydell wrote: > On Sun, 18 Apr 2021 at 06:30, Philippe Mathieu-Daudé <philmd@redhat.com> 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> >> 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> >> --- >> Supersedes: <20210416102243.1293871-1-mjt@msgid.tls.msk.ru> >> >> 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 | 4 ---- >> 2 files changed, 5 deletions(-) > > This fails to compile: > > ../../hw/scsi/mptsas.c: In function ‘mptsas_free_request’: > ../../hw/scsi/mptsas.c:254:18: error: unused variable ‘s’ > [-Werror=unused-variable] > MPTSASState *s = req->dev; > ^ > cc1: all warnings being treated as errors What a shame... Sorry, v3 coming.
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..5abbc742aaf 100644 --- a/hw/scsi/mptsas.c +++ b/hw/scsi/mptsas.c @@ -257,7 +257,6 @@ static void mptsas_free_request(MPTSASRequest *req) 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 +302,6 @@ 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 +1317,6 @@ 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); }