On 09.05.20 01:08, Collin Walling wrote:
The header of the SCCB contains the actual length of the
SCCB. Instead of using a static 4K size, let's allow
for a variable size determined by the value set 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 <address@hidden>
---
hw/s390x/sclp.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index 470d5da7a2..748d04a0e2 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -244,15 +244,16 @@ 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);
- s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, sccb_len);
+ s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, sizeof(SCCBHeader));
if (!sclp_command_code_valid(code)) {
work_sccb.h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
goto out_write;
}
+ s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, work_sccb.h.length);
be16_to_cpu() necessary.
+
if (!check_sccb_boundary_valid(sccb, code, &work_sccb)) {
goto out_write;
}
@@ -271,8 +272,6 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb,
uint32_t code)
SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp);
SCCB work_sccb;
- hwaddr sccb_len = sizeof(SCCB);
-
/* first some basic checks on program checks */
if (env->psw.mask & PSW_MASK_PSTATE) {
return -PGM_PRIVILEGED;
@@ -290,13 +289,16 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb,
uint32_t code)
* 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);
+ cpu_physical_memory_read(sccb, &work_sccb, sizeof(SCCBHeader));
/* Valid sccb sizes */
if (be16_to_cpu(work_sccb.h.length) < sizeof(SCCBHeader)) {
return -PGM_SPECIFICATION;
}
+ /* the header contains the actual length of the sccb */
+ cpu_physical_memory_read(sccb, &work_sccb, work_sccb.h.length);
be16_to_cpu() necessary.
+
if (!sclp_command_code_valid(code)) {
work_sccb.h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
goto out_write;