diff options
author | Collin Walling <walling@linux.ibm.com> | 2020-09-15 15:44:11 -0400 |
---|---|---|
committer | Cornelia Huck <cohuck@redhat.com> | 2020-10-02 13:52:49 +0200 |
commit | c1db53a5910f988eeb32f031c53a50f3373fd824 (patch) | |
tree | 5d92e07d347e833103135b2a58f6c9f91b9ea324 | |
parent | db13387ca01a69d870cc16dd232375c2603596f2 (diff) |
s390/sclp: read sccb from mem based on provided length
The header contained within the SCCB passed to the SCLP service call
contains the actual length of the SCCB. Instead of allocating a static
4K size for the work sccb, let's allow for a variable size determined
by the value in the header. The proper checks are already in place to
ensure the SCCB length is sufficent to store a full response and that
the length does not cross any explicitly-set boundaries.
Signed-off-by: Collin Walling <walling@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20200915194416.107460-4-walling@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
-rw-r--r-- | hw/s390x/event-facility.c | 2 | ||||
-rw-r--r-- | hw/s390x/sclp.c | 55 | ||||
-rw-r--r-- | include/hw/s390x/sclp.h | 2 |
3 files changed, 33 insertions, 26 deletions
diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c index 645b4080c5..ed92ce510d 100644 --- a/hw/s390x/event-facility.c +++ b/hw/s390x/event-facility.c @@ -213,7 +213,7 @@ static uint16_t handle_sccb_read_events(SCLPEventFacility *ef, SCCB *sccb, event_buf = &red->ebh; event_buf->length = 0; - slen = sizeof(sccb->data); + slen = sccb_data_len(sccb); rc = SCLP_RC_NO_EVENT_BUFFERS_STORED; diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c index a37cfbf534..4ae6fb400b 100644 --- a/hw/s390x/sclp.c +++ b/hw/s390x/sclp.c @@ -231,25 +231,29 @@ int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb, { SCLPDevice *sclp = get_sclp_device(); SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp); - SCCB work_sccb; - hwaddr sccb_len = sizeof(SCCB); + SCCBHeader header; + g_autofree SCCB *work_sccb = NULL; - s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, sccb_len); + s390_cpu_pv_mem_read(env_archcpu(env), 0, &header, sizeof(SCCBHeader)); + + work_sccb = g_malloc0(be16_to_cpu(header.length)); + s390_cpu_pv_mem_read(env_archcpu(env), 0, work_sccb, + be16_to_cpu(header.length)); if (!sclp_command_code_valid(code)) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); goto out_write; } - if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb.h.length))) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); + if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb->h.length))) { + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); goto out_write; } - sclp_c->execute(sclp, &work_sccb, code); + sclp_c->execute(sclp, work_sccb, code); out_write: - s390_cpu_pv_mem_write(env_archcpu(env), 0, &work_sccb, - be16_to_cpu(work_sccb.h.length)); + s390_cpu_pv_mem_write(env_archcpu(env), 0, work_sccb, + be16_to_cpu(work_sccb->h.length)); sclp_c->service_interrupt(sclp, SCLP_PV_DUMMY_ADDR); return 0; } @@ -258,9 +262,8 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code) { SCLPDevice *sclp = get_sclp_device(); SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp); - SCCB work_sccb; - - hwaddr sccb_len = sizeof(SCCB); + SCCBHeader header; + g_autofree SCCB *work_sccb = NULL; /* first some basic checks on program checks */ if (env->psw.mask & PSW_MASK_PSTATE) { @@ -274,32 +277,36 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code) return -PGM_SPECIFICATION; } + /* the header contains the actual length of the sccb */ + cpu_physical_memory_read(sccb, &header, sizeof(SCCBHeader)); + + /* Valid sccb sizes */ + if (be16_to_cpu(header.length) < sizeof(SCCBHeader)) { + return -PGM_SPECIFICATION; + } + /* * we want to work on a private copy of the sccb, to prevent guests * from playing dirty tricks by modifying the memory content after * the host has checked the values */ - cpu_physical_memory_read(sccb, &work_sccb, sccb_len); - - /* Valid sccb sizes */ - if (be16_to_cpu(work_sccb.h.length) < sizeof(SCCBHeader)) { - return -PGM_SPECIFICATION; - } + work_sccb = g_malloc0(be16_to_cpu(header.length)); + cpu_physical_memory_read(sccb, work_sccb, be16_to_cpu(header.length)); if (!sclp_command_code_valid(code)) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); goto out_write; } - if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb.h.length))) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); + if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb->h.length))) { + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); goto out_write; } - sclp_c->execute(sclp, &work_sccb, code); + sclp_c->execute(sclp, work_sccb, code); out_write: - cpu_physical_memory_write(sccb, &work_sccb, - be16_to_cpu(work_sccb.h.length)); + cpu_physical_memory_write(sccb, work_sccb, + be16_to_cpu(work_sccb->h.length)); sclp_c->service_interrupt(sclp, sccb); diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h index cd730772f9..374ea83e78 100644 --- a/include/hw/s390x/sclp.h +++ b/include/hw/s390x/sclp.h @@ -178,7 +178,7 @@ typedef struct IoaCfgSccb { typedef struct SCCB { SCCBHeader h; - char data[SCCB_DATA_LEN]; + char data[]; } QEMU_PACKED SCCB; #define TYPE_SCLP "sclp" |