On 220705 2205, Mauro Matteo Cascella wrote: > Set current_req->req to NULL to prevent reusing a free'd buffer in case of > repeated SCSI cancel requests. Thanks to Thomas Huth for suggesting the patch. > > Fixes: CVE-2022-0216 > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/972 > Signed-off-by: Mauro Matteo Cascella <mcasc...@redhat.com> > --- > hw/scsi/lsi53c895a.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c > index c8773f73f7..99ea42d49b 100644 > --- a/hw/scsi/lsi53c895a.c > +++ b/hw/scsi/lsi53c895a.c > @@ -1028,8 +1028,9 @@ static void lsi_do_msgout(LSIState *s) > case 0x0d: > /* The ABORT TAG message clears the current I/O process only. */ > trace_lsi_do_msgout_abort(current_tag); > - if (current_req) { > + if (current_req && current_req->req) { > scsi_req_cancel(current_req->req); > + current_req->req = NULL; > } > lsi_disconnect(s); > break; > -- > 2.35.3 > >
Hi Mauro, https://gitlab.com/qemu-project/qemu/-/issues/972#note_1019851430 This reproducer crashes, with this patch applied. Maybe it is some different bug though - I'm not sure. With -trace lsi* lsi_reg_write Write reg DSP1 0x2d = 0x00 lsi_reg_write Write reg DSP2 0x2e = 0x40 lsi_reg_write Write reg DSP3 0x2f = 0x36 lsi_execute_script SCRIPTS dsp=0x364001d0 opcode 0x58000008 arg 0x0 lsi_execute_script_io_set Set ATN lsi_execute_script SCRIPTS dsp=0x364001d8 opcode 0x26010000 arg 0x5a41ae0d lsi_do_msgout MSG out len=65536 lsi_do_msgout_busdevicereset MSG: BUS DEVICE RESET tag=0x0 lsi_do_msgout_select Select LUN 0 lsi_do_msgout_abort MSG: ABORT TAG tag=0x0 In busdevicereset, there are also scsi_req_cancel calls. Do they need similar changes? -Alex
