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envelope-from=borntraeger@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org If a guest submits an sccb with a tiny header length but a large number of event mask entries, the write_event_mask handler will 1. return the wrong RC (ok instead of error) 2. write to memory after the allocated sccb in qemu host memory. Add the necessary checks. Cc: qemu-stable@nongnu.org Reviewed-by: Hendrik Brueckner Signed-off-by: Christian Borntraeger --- hw/s390x/event-facility.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c index fee286ea63..184c469bd3 100644 --- a/hw/s390x/event-facility.c +++ b/hw/s390x/event-facility.c @@ -286,6 +286,7 @@ static void read_event_data(SCLPEventFacility *ef, SCCB *sccb) static void write_event_mask(SCLPEventFacility *ef, SCCB *sccb) { WriteEventMask *we_mask = (WriteEventMask *) sccb; + uint16_t sccb_length = be16_to_cpu(sccb->h.length); uint16_t mask_length = be16_to_cpu(we_mask->mask_length); sccb_mask_t tmp_mask; @@ -294,6 +295,11 @@ static void write_event_mask(SCLPEventFacility *ef, SCCB *sccb) return; } + if (sccb_length < sizeof(WriteEventMask) + 4 * mask_length) { + sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); + return; + } + /* * Note: We currently only support masks up to 8 byte length; * the remainder is filled up with zeroes. Older Linux -- 2.53.0