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From 212c129b82f0a53725a4167303de2ee0a865f82d Mon Sep 17 00:00:00 2001
From: Thomas Huth <thuth@redhat.com>
Date: Wed, 11 Nov 2020 12:03:08 -0500
Subject: [PATCH 08/18] s390/sclp: read sccb from mem based on provided length
RH-Author: Thomas Huth <thuth@redhat.com>
Message-id: <20201111120316.707489-5-thuth@redhat.com>
Patchwork-id: 99501
O-Subject: [RHEL-8.4.0 qemu-kvm PATCH v2 04/12] s390/sclp: read sccb from mem based on provided length
Bugzilla: 1798506
RH-Acked-by: Jens Freimann <jfreimann@redhat.com>
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
RH-Acked-by: David Hildenbrand <david@redhat.com>
From: Collin Walling <walling@linux.ibm.com>
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>
(cherry picked from commit c1db53a5910f988eeb32f031c53a50f3373fd824)
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
hw/s390x/event-facility.c | 2 +-
hw/s390x/sclp.c | 55 ++++++++++++++++++++++-----------------
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 66205697ae7..8aa7017f06b 100644
--- a/hw/s390x/event-facility.c
+++ b/hw/s390x/event-facility.c
@@ -215,7 +215,7 @@ 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 38278497319..cf1292beb22 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 c0a3faa37d7..55f53a46540 100644
--- a/include/hw/s390x/sclp.h
+++ b/include/hw/s390x/sclp.h
@@ -177,7 +177,7 @@ typedef struct IoaCfgSccb {
typedef struct SCCB {
SCCBHeader h;
- char data[SCCB_DATA_LEN];
+ char data[];
} QEMU_PACKED SCCB;
#define TYPE_SCLP "sclp"
--
2.27.0
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