[PATCH v4] hv_utils: Add validation for untrusted Hyper-V values

From: Andrea Parri (Microsoft)
Date: Mon Nov 09 2020 - 05:07:21 EST

From: Andres Beltran <lkmlabelt@xxxxxxxxx>

For additional robustness in the face of Hyper-V errors or malicious
behavior, validate all values that originate from packets that Hyper-V
has sent to the guest in the host-to-guest ring buffer. Ensure that
invalid values cannot cause indexing off the end of the icversion_data
array in vmbus_prep_negotiate_resp().

Signed-off-by: Andres Beltran <lkmlabelt@xxxxxxxxx>
Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
---
Changes in v3:
- Add size check for icframe_vercnt and icmsg_vercnt

Changes in v2:
- Use ratelimited form of kernel logging to print error messages

drivers/hv/channel_mgmt.c | 24 ++++-
drivers/hv/hv_fcopy.c | 36 +++++--
drivers/hv/hv_kvp.c | 122 ++++++++++++---------
drivers/hv/hv_snapshot.c | 89 ++++++++-------
drivers/hv/hv_util.c | 222 +++++++++++++++++++++++---------------
include/linux/hyperv.h | 9 +-
6 files changed, 314 insertions(+), 188 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 1d44bb635bb84..5bc5eef5da159 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -190,6 +190,7 @@ static u16 hv_get_dev_type(const struct vmbus_channel *channel)
* vmbus_prep_negotiate_resp() - Create default response for Negotiate message
* @icmsghdrp: Pointer to msg header structure
* @buf: Raw buffer channel data
+ * @buflen: Length of the raw buffer channel data.
* @fw_version: The framework versions we can support.
* @fw_vercnt: The size of @fw_version.
* @srv_version: The service versions we can support.
@@ -202,8 +203,8 @@ static u16 hv_get_dev_type(const struct vmbus_channel *channel)
* Set up and fill in default negotiate response message.
* Mainly used by Hyper-V drivers.
*/
-bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
- u8 *buf, const int *fw_version, int fw_vercnt,
+bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf,
+ u32 buflen, const int *fw_version, int fw_vercnt,
const int *srv_version, int srv_vercnt,
int *nego_fw_version, int *nego_srv_version)
{
@@ -215,10 +216,14 @@ bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
bool found_match = false;
struct icmsg_negotiate *negop;

+ /* Check that there's enough space for icframe_vercnt, icmsg_vercnt */
+ if (buflen < ICMSG_HDR + offsetof(struct icmsg_negotiate, reserved)) {
+ pr_err_ratelimited("Invalid icmsg negotiate\n");
+ return false;
+ }
+
icmsghdrp->icmsgsize = 0x10;
- negop = (struct icmsg_negotiate *)&buf[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
+ negop = (struct icmsg_negotiate *)&buf[ICMSG_HDR];

icframe_major = negop->icframe_vercnt;
icframe_minor = 0;
@@ -226,6 +231,15 @@ bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
icmsg_major = negop->icmsg_vercnt;
icmsg_minor = 0;

+ /* Validate negop packet */
+ if (icframe_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
+ icmsg_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
+ ICMSG_NEGOTIATE_PKT_SIZE(icframe_major, icmsg_major) > buflen) {
+ pr_err_ratelimited("Invalid icmsg negotiate - icframe_major: %u, icmsg_major: %u\n",
+ icframe_major, icmsg_major);
+ goto fw_error;
+ }
+
/*
* Select the framework version number we will
* support.
diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
index 5040d7e0cd9e9..59ce85e00a028 100644
--- a/drivers/hv/hv_fcopy.c
+++ b/drivers/hv/hv_fcopy.c
@@ -235,15 +235,27 @@ void hv_fcopy_onchannelcallback(void *context)
if (fcopy_transaction.state > HVUTIL_READY)
return;

- vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen,
- &requestid);
- if (recvlen <= 0)
+ if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen, &requestid)) {
+ pr_err_ratelimited("Fcopy request received. Could not read into recv buf\n");
return;
+ }
+
+ if (!recvlen)
+ return;
+
+ /* Ensure recvlen is big enough to read header data */
+ if (recvlen < ICMSG_HDR) {
+ pr_err_ratelimited("Fcopy request received. Packet length too small: %d\n",
+ recvlen);
+ return;
+ }

icmsghdr = (struct icmsg_hdr *)&recv_buffer[
sizeof(struct vmbuspipe_hdr)];
+
if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
- if (vmbus_prep_negotiate_resp(icmsghdr, recv_buffer,
+ if (vmbus_prep_negotiate_resp(icmsghdr,
+ recv_buffer, recvlen,
fw_versions, FW_VER_COUNT,
fcopy_versions, FCOPY_VER_COUNT,
NULL, &fcopy_srv_version)) {
@@ -252,10 +264,14 @@ void hv_fcopy_onchannelcallback(void *context)
fcopy_srv_version >> 16,
fcopy_srv_version & 0xFFFF);
}
- } else {
- fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
+ } else if (icmsghdr->icmsgtype == ICMSGTYPE_FCOPY) {
+ /* Ensure recvlen is big enough to contain hv_fcopy_hdr */
+ if (recvlen < ICMSG_HDR + sizeof(struct hv_fcopy_hdr)) {
+ pr_err_ratelimited("Invalid Fcopy hdr. Packet length too small: %u\n",
+ recvlen);
+ return;
+ }
+ fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[ICMSG_HDR];

/*
* Stash away this global state for completing the
@@ -280,6 +296,10 @@ void hv_fcopy_onchannelcallback(void *context)
schedule_delayed_work(&fcopy_timeout_work,
HV_UTIL_TIMEOUT * HZ);
return;
+ } else {
+ pr_err_ratelimited("Fcopy request received. Invalid msg type: %d\n",
+ icmsghdr->icmsgtype);
+ return;
}
icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 754d35a25a1cc..b49962d312cef 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -662,71 +662,87 @@ void hv_kvp_onchannelcallback(void *context)
if (kvp_transaction.state > HVUTIL_READY)
return;

- vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 4, &recvlen,
- &requestid);
-
- if (recvlen > 0) {
- icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
- sizeof(struct vmbuspipe_hdr)];
-
- if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
- if (vmbus_prep_negotiate_resp(icmsghdrp,
- recv_buffer, fw_versions, FW_VER_COUNT,
- kvp_versions, KVP_VER_COUNT,
- NULL, &kvp_srv_version)) {
- pr_info("KVP IC version %d.%d\n",
- kvp_srv_version >> 16,
- kvp_srv_version & 0xFFFF);
- }
- } else {
- kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
+ if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 4, &recvlen, &requestid)) {
+ pr_err_ratelimited("KVP request received. Could not read into recv buf\n");
+ return;
+ }

- /*
- * Stash away this global state for completing the
- * transaction; note transactions are serialized.
- */
+ if (!recvlen)
+ return;

- kvp_transaction.recv_len = recvlen;
- kvp_transaction.recv_req_id = requestid;
- kvp_transaction.kvp_msg = kvp_msg;
+ /* Ensure recvlen is big enough to read header data */
+ if (recvlen < ICMSG_HDR) {
+ pr_err_ratelimited("KVP request received. Packet length too small: %d\n",
+ recvlen);
+ return;
+ }

- if (kvp_transaction.state < HVUTIL_READY) {
- /* Userspace is not registered yet */
- kvp_respond_to_host(NULL, HV_E_FAIL);
- return;
- }
- kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
+ icmsghdrp = (struct icmsg_hdr *)&recv_buffer[sizeof(struct vmbuspipe_hdr)];
+
+ if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+ if (vmbus_prep_negotiate_resp(icmsghdrp,
+ recv_buffer, recvlen,
+ fw_versions, FW_VER_COUNT,
+ kvp_versions, KVP_VER_COUNT,
+ NULL, &kvp_srv_version)) {
+ pr_info("KVP IC version %d.%d\n",
+ kvp_srv_version >> 16,
+ kvp_srv_version & 0xFFFF);
+ }
+ } else if (icmsghdrp->icmsgtype == ICMSGTYPE_KVPEXCHANGE) {
+ /*
+ * recvlen is not checked against sizeof(struct kvp_msg) because kvp_msg contains
+ * a union of structs and the msg type received is not known. Code using this
+ * struct should provide validation when accessing its fields.
+ */
+ kvp_msg = (struct hv_kvp_msg *)&recv_buffer[ICMSG_HDR];

- /*
- * Get the information from the
- * user-mode component.
- * component. This transaction will be
- * completed when we get the value from
- * the user-mode component.
- * Set a timeout to deal with
- * user-mode not responding.
- */
- schedule_work(&kvp_sendkey_work);
- schedule_delayed_work(&kvp_timeout_work,
- HV_UTIL_TIMEOUT * HZ);
+ /*
+ * Stash away this global state for completing the
+ * transaction; note transactions are serialized.
+ */

- return;
+ kvp_transaction.recv_len = recvlen;
+ kvp_transaction.recv_req_id = requestid;
+ kvp_transaction.kvp_msg = kvp_msg;

+ if (kvp_transaction.state < HVUTIL_READY) {
+ /* Userspace is not registered yet */
+ kvp_respond_to_host(NULL, HV_E_FAIL);
+ return;
}
+ kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;

- icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
- | ICMSGHDRFLAG_RESPONSE;
+ /*
+ * Get the information from the
+ * user-mode component.
+ * component. This transaction will be
+ * completed when we get the value from
+ * the user-mode component.
+ * Set a timeout to deal with
+ * user-mode not responding.
+ */
+ schedule_work(&kvp_sendkey_work);
+ schedule_delayed_work(&kvp_timeout_work,
+ HV_UTIL_TIMEOUT * HZ);

- vmbus_sendpacket(channel, recv_buffer,
- recvlen, requestid,
- VM_PKT_DATA_INBAND, 0);
+ return;

- host_negotiatied = NEGO_FINISHED;
- hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
+ } else {
+ pr_err_ratelimited("KVP request received. Invalid msg type: %d\n",
+ icmsghdrp->icmsgtype);
+ return;
}

+ icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+ | ICMSGHDRFLAG_RESPONSE;
+
+ vmbus_sendpacket(channel, recv_buffer,
+ recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
+
+ host_negotiatied = NEGO_FINISHED;
+ hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
}

static void kvp_on_reset(void)
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 783779e4cc1a5..2267bd4c34725 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -298,49 +298,64 @@ void hv_vss_onchannelcallback(void *context)
if (vss_transaction.state > HVUTIL_READY)
return;

- vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen,
- &requestid);
-
- if (recvlen > 0) {
- icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
- sizeof(struct vmbuspipe_hdr)];
-
- if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
- if (vmbus_prep_negotiate_resp(icmsghdrp,
- recv_buffer, fw_versions, FW_VER_COUNT,
- vss_versions, VSS_VER_COUNT,
- NULL, &vss_srv_version)) {
-
- pr_info("VSS IC version %d.%d\n",
- vss_srv_version >> 16,
- vss_srv_version & 0xFFFF);
- }
- } else {
- vss_msg = (struct hv_vss_msg *)&recv_buffer[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
-
- /*
- * Stash away this global state for completing the
- * transaction; note transactions are serialized.
- */
-
- vss_transaction.recv_len = recvlen;
- vss_transaction.recv_req_id = requestid;
- vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
-
- schedule_work(&vss_handle_request_work);
+ if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen, &requestid)) {
+ pr_err_ratelimited("VSS request received. Could not read into recv buf\n");
+ return;
+ }
+
+ if (!recvlen)
+ return;
+
+ /* Ensure recvlen is big enough to read header data */
+ if (recvlen < ICMSG_HDR) {
+ pr_err_ratelimited("VSS request received. Packet length too small: %d\n",
+ recvlen);
+ return;
+ }
+
+ icmsghdrp = (struct icmsg_hdr *)&recv_buffer[sizeof(struct vmbuspipe_hdr)];
+
+ if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+ if (vmbus_prep_negotiate_resp(icmsghdrp,
+ recv_buffer, recvlen,
+ fw_versions, FW_VER_COUNT,
+ vss_versions, VSS_VER_COUNT,
+ NULL, &vss_srv_version)) {
+
+ pr_info("VSS IC version %d.%d\n",
+ vss_srv_version >> 16,
+ vss_srv_version & 0xFFFF);
+ }
+ } else if (icmsghdrp->icmsgtype == ICMSGTYPE_VSS) {
+ /* Ensure recvlen is big enough to contain hv_vss_msg */
+ if (recvlen < ICMSG_HDR + sizeof(struct hv_vss_msg)) {
+ pr_err_ratelimited("Invalid VSS msg. Packet length too small: %u\n",
+ recvlen);
return;
}
+ vss_msg = (struct hv_vss_msg *)&recv_buffer[ICMSG_HDR];
+
+ /*
+ * Stash away this global state for completing the
+ * transaction; note transactions are serialized.
+ */

- icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
- | ICMSGHDRFLAG_RESPONSE;
+ vss_transaction.recv_len = recvlen;
+ vss_transaction.recv_req_id = requestid;
+ vss_transaction.msg = (struct hv_vss_msg *)vss_msg;

- vmbus_sendpacket(channel, recv_buffer,
- recvlen, requestid,
- VM_PKT_DATA_INBAND, 0);
+ schedule_work(&vss_handle_request_work);
+ return;
+ } else {
+ pr_err_ratelimited("VSS request received. Invalid msg type: %d\n",
+ icmsghdrp->icmsgtype);
+ return;
}

+ icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION |
+ ICMSGHDRFLAG_RESPONSE;
+ vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
}

static void vss_on_reset(void)
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 05566ecdbe4b4..34f3e789cc9a2 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -195,73 +195,88 @@ static void shutdown_onchannelcallback(void *context)

struct icmsg_hdr *icmsghdrp;

- vmbus_recvpacket(channel, shut_txf_buf,
- HV_HYP_PAGE_SIZE, &recvlen, &requestid);
+ if (vmbus_recvpacket(channel, shut_txf_buf, HV_HYP_PAGE_SIZE, &recvlen, &requestid)) {
+ pr_err_ratelimited("Shutdown request received. Could not read into shut txf buf\n");
+ return;
+ }

- if (recvlen > 0) {
- icmsghdrp = (struct icmsg_hdr *)&shut_txf_buf[
- sizeof(struct vmbuspipe_hdr)];
+ if (!recvlen)
+ return;

- if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
- if (vmbus_prep_negotiate_resp(icmsghdrp, shut_txf_buf,
- fw_versions, FW_VER_COUNT,
- sd_versions, SD_VER_COUNT,
- NULL, &sd_srv_version)) {
- pr_info("Shutdown IC version %d.%d\n",
- sd_srv_version >> 16,
- sd_srv_version & 0xFFFF);
- }
- } else {
- shutdown_msg =
- (struct shutdown_msg_data *)&shut_txf_buf[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
+ /* Ensure recvlen is big enough to read header data */
+ if (recvlen < ICMSG_HDR) {
+ pr_err_ratelimited("Shutdown request received. Packet length too small: %d\n",
+ recvlen);
+ return;
+ }

- /*
- * shutdown_msg->flags can be 0(shut down), 2(reboot),
- * or 4(hibernate). It may bitwise-OR 1, which means
- * performing the request by force. Linux always tries
- * to perform the request by force.
- */
- switch (shutdown_msg->flags) {
- case 0:
- case 1:
- icmsghdrp->status = HV_S_OK;
- work = &shutdown_work;
- pr_info("Shutdown request received -"
- " graceful shutdown initiated\n");
- break;
- case 2:
- case 3:
- icmsghdrp->status = HV_S_OK;
- work = &restart_work;
- pr_info("Restart request received -"
- " graceful restart initiated\n");
- break;
- case 4:
- case 5:
- pr_info("Hibernation request received\n");
- icmsghdrp->status = hibernation_supported ?
- HV_S_OK : HV_E_FAIL;
- if (hibernation_supported)
- work = &hibernate_context.work;
- break;
- default:
- icmsghdrp->status = HV_E_FAIL;
- pr_info("Shutdown request received -"
- " Invalid request\n");
- break;
- }
+ icmsghdrp = (struct icmsg_hdr *)&shut_txf_buf[sizeof(struct vmbuspipe_hdr)];
+
+ if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+ if (vmbus_prep_negotiate_resp(icmsghdrp,
+ shut_txf_buf, recvlen,
+ fw_versions, FW_VER_COUNT,
+ sd_versions, SD_VER_COUNT,
+ NULL, &sd_srv_version)) {
+ pr_info("Shutdown IC version %d.%d\n",
+ sd_srv_version >> 16,
+ sd_srv_version & 0xFFFF);
+ }
+ } else if (icmsghdrp->icmsgtype == ICMSGTYPE_SHUTDOWN) {
+ /* Ensure recvlen is big enough to contain shutdown_msg_data struct */
+ if (recvlen < ICMSG_HDR + sizeof(struct shutdown_msg_data)) {
+ pr_err_ratelimited("Invalid shutdown msg data. Packet length too small: %u\n",
+ recvlen);
+ return;
}

- icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
- | ICMSGHDRFLAG_RESPONSE;
-
- vmbus_sendpacket(channel, shut_txf_buf,
- recvlen, requestid,
- VM_PKT_DATA_INBAND, 0);
+ shutdown_msg = (struct shutdown_msg_data *)&shut_txf_buf[ICMSG_HDR];
+
+ /*
+ * shutdown_msg->flags can be 0(shut down), 2(reboot),
+ * or 4(hibernate). It may bitwise-OR 1, which means
+ * performing the request by force. Linux always tries
+ * to perform the request by force.
+ */
+ switch (shutdown_msg->flags) {
+ case 0:
+ case 1:
+ icmsghdrp->status = HV_S_OK;
+ work = &shutdown_work;
+ pr_info("Shutdown request received - graceful shutdown initiated\n");
+ break;
+ case 2:
+ case 3:
+ icmsghdrp->status = HV_S_OK;
+ work = &restart_work;
+ pr_info("Restart request received - graceful restart initiated\n");
+ break;
+ case 4:
+ case 5:
+ pr_info("Hibernation request received\n");
+ icmsghdrp->status = hibernation_supported ?
+ HV_S_OK : HV_E_FAIL;
+ if (hibernation_supported)
+ work = &hibernate_context.work;
+ break;
+ default:
+ icmsghdrp->status = HV_E_FAIL;
+ pr_info("Shutdown request received - Invalid request\n");
+ break;
+ }
+ } else {
+ icmsghdrp->status = HV_E_FAIL;
+ pr_err_ratelimited("Shutdown request received. Invalid msg type: %d\n",
+ icmsghdrp->icmsgtype);
}

+ icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+ | ICMSGHDRFLAG_RESPONSE;
+
+ vmbus_sendpacket(channel, shut_txf_buf,
+ recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
+
if (work)
schedule_work(work);
}
@@ -396,19 +411,27 @@ static void timesync_onchannelcallback(void *context)
HV_HYP_PAGE_SIZE, &recvlen,
&requestid);
if (ret) {
- pr_warn_once("TimeSync IC pkt recv failed (Err: %d)\n",
- ret);
+ pr_err_ratelimited("TimeSync IC pkt recv failed (Err: %d)\n",
+ ret);
break;
}

if (!recvlen)
break;

+ /* Ensure recvlen is big enough to read header data */
+ if (recvlen < ICMSG_HDR) {
+ pr_err_ratelimited("Timesync request received. Packet length too small: %d\n",
+ recvlen);
+ break;
+ }
+
icmsghdrp = (struct icmsg_hdr *)&time_txf_buf[
sizeof(struct vmbuspipe_hdr)];

if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
- if (vmbus_prep_negotiate_resp(icmsghdrp, time_txf_buf,
+ if (vmbus_prep_negotiate_resp(icmsghdrp,
+ time_txf_buf, recvlen,
fw_versions, FW_VER_COUNT,
ts_versions, TS_VER_COUNT,
NULL, &ts_srv_version)) {
@@ -416,33 +439,44 @@ static void timesync_onchannelcallback(void *context)
ts_srv_version >> 16,
ts_srv_version & 0xFFFF);
}
- } else {
+ } else if (icmsghdrp->icmsgtype == ICMSGTYPE_TIMESYNC) {
if (ts_srv_version > TS_VERSION_3) {
- refdata = (struct ictimesync_ref_data *)
- &time_txf_buf[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
+ /* Ensure recvlen is big enough to read ictimesync_ref_data */
+ if (recvlen < ICMSG_HDR + sizeof(struct ictimesync_ref_data)) {
+ pr_err_ratelimited("Invalid ictimesync ref data. Length too small: %u\n",
+ recvlen);
+ break;
+ }
+ refdata = (struct ictimesync_ref_data *)&time_txf_buf[ICMSG_HDR];

adj_guesttime(refdata->parenttime,
refdata->vmreferencetime,
refdata->flags);
} else {
- timedatap = (struct ictimesync_data *)
- &time_txf_buf[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
+ /* Ensure recvlen is big enough to read ictimesync_data */
+ if (recvlen < ICMSG_HDR + sizeof(struct ictimesync_data)) {
+ pr_err_ratelimited("Invalid ictimesync data. Length too small: %u\n",
+ recvlen);
+ break;
+ }
+ timedatap = (struct ictimesync_data *)&time_txf_buf[ICMSG_HDR];
+
adj_guesttime(timedatap->parenttime,
hv_read_reference_counter(),
timedatap->flags);
}
+ } else {
+ icmsghdrp->status = HV_E_FAIL;
+ pr_err_ratelimited("Timesync request received. Invalid msg type: %d\n",
+ icmsghdrp->icmsgtype);
}

icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
| ICMSGHDRFLAG_RESPONSE;

vmbus_sendpacket(channel, time_txf_buf,
- recvlen, requestid,
- VM_PKT_DATA_INBAND, 0);
+ recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
}
}

@@ -462,18 +496,28 @@ static void heartbeat_onchannelcallback(void *context)

while (1) {

- vmbus_recvpacket(channel, hbeat_txf_buf,
- HV_HYP_PAGE_SIZE, &recvlen, &requestid);
+ if (vmbus_recvpacket(channel, hbeat_txf_buf, HV_HYP_PAGE_SIZE,
+ &recvlen, &requestid)) {
+ pr_err_ratelimited("Heartbeat request received. Could not read into hbeat txf buf\n");
+ return;
+ }

if (!recvlen)
break;

+ /* Ensure recvlen is big enough to read header data */
+ if (recvlen < ICMSG_HDR) {
+ pr_err_ratelimited("Hearbeat request received. Packet length too small: %d\n",
+ recvlen);
+ break;
+ }
+
icmsghdrp = (struct icmsg_hdr *)&hbeat_txf_buf[
sizeof(struct vmbuspipe_hdr)];

if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
if (vmbus_prep_negotiate_resp(icmsghdrp,
- hbeat_txf_buf,
+ hbeat_txf_buf, recvlen,
fw_versions, FW_VER_COUNT,
hb_versions, HB_VER_COUNT,
NULL, &hb_srv_version)) {
@@ -482,21 +526,31 @@ static void heartbeat_onchannelcallback(void *context)
hb_srv_version >> 16,
hb_srv_version & 0xFFFF);
}
- } else {
- heartbeat_msg =
- (struct heartbeat_msg_data *)&hbeat_txf_buf[
- sizeof(struct vmbuspipe_hdr) +
- sizeof(struct icmsg_hdr)];
+ } else if (icmsghdrp->icmsgtype == ICMSGTYPE_HEARTBEAT) {
+ /*
+ * Ensure recvlen is big enough to read seq_num. Reserved area is not
+ * included in the check as the host may not fill it up entirely
+ */
+ if (recvlen < ICMSG_HDR + sizeof(u64)) {
+ pr_err_ratelimited("Invalid heartbeat msg data. Length too small: %u\n",
+ recvlen);
+ break;
+ }
+ heartbeat_msg = (struct heartbeat_msg_data *)&hbeat_txf_buf[ICMSG_HDR];

heartbeat_msg->seq_num += 1;
+ } else {
+ icmsghdrp->status = HV_E_FAIL;
+ pr_err_ratelimited("Heartbeat request received. Invalid msg type: %d\n",
+ icmsghdrp->icmsgtype);
}

icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
| ICMSGHDRFLAG_RESPONSE;

vmbus_sendpacket(channel, hbeat_txf_buf,
- recvlen, requestid,
- VM_PKT_DATA_INBAND, 0);
+ recvlen, requestid,
+ VM_PKT_DATA_INBAND, 0);
}
}

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 5ddb479c4d4cb..696857aa038c0 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1471,6 +1471,7 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size);
#define ICMSGTYPE_SHUTDOWN 3
#define ICMSGTYPE_TIMESYNC 4
#define ICMSGTYPE_VSS 5
+#define ICMSGTYPE_FCOPY 7

#define ICMSGHDRFLAG_TRANSACTION 1
#define ICMSGHDRFLAG_REQUEST 2
@@ -1514,6 +1515,12 @@ struct icmsg_hdr {
u8 reserved[2];
} __packed;

+#define IC_VERSION_NEGOTIATION_MAX_VER_COUNT 100
+#define ICMSG_HDR (sizeof(struct vmbuspipe_hdr) + sizeof(struct icmsg_hdr))
+#define ICMSG_NEGOTIATE_PKT_SIZE(icframe_vercnt, icmsg_vercnt) \
+ (ICMSG_HDR + offsetof(struct icmsg_negotiate, icversion_data) + \
+ (((icframe_vercnt) + (icmsg_vercnt)) * sizeof(struct ic_version)))
+
struct icmsg_negotiate {
u16 icframe_vercnt;
u16 icmsg_vercnt;
@@ -1569,7 +1576,7 @@ struct hyperv_service_callback {
};

#define MAX_SRV_VER 0x7ffffff
-extern bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf,
+extern bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf, u32 buflen,
const int *fw_version, int fw_vercnt,
const int *srv_version, int srv_vercnt,
int *nego_fw_version, int *nego_srv_version);
--
2.25.1