[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 01/23] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op (v10)
The implementation does not actually do any patching. It just adds the framework for doing the hypercalls, keeping track of ELF payloads, and the basic operations: - query which payloads exist, - query for specific payloads, - check*1, apply*1, replace*1, and unload payloads. *1: Which of course in this patch are nops. Acked-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx> --- v2: Rebased on keyhandler: rework keyhandler infrastructure v3: Fixed XSM. v4: Removed REVERTED state. Split status and error code. Add REPLACE action. Separate payload data from the payload structure. s/XSPLICE_ID_../XSPLICE_NAME_../ v5: Add xsplice and CONFIG_XSPLICE build toption. Fix code per Jan's review. Update the sysctl.h (change bits to enum like) v6: Rebase on Kconfig changes. v7: Add missing pad checks. Re-order keyhandler.h to build on ARM. v8: Rebase on build: hook the schedulers into Kconfig v9: s/id/name/ s/payload_list_lock/payload_lock/ v10: Put #ifdef CONFIG_XSPLICE in header file. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> --- tools/flask/policy/policy/modules/xen/xen.te | 1 + xen/common/Kconfig | 10 + xen/common/Makefile | 2 + xen/common/sysctl.c | 7 + xen/common/xsplice.c | 386 +++++++++++++++++++++++++++ xen/include/public/sysctl.h | 156 +++++++++++ xen/include/xen/xsplice.h | 15 ++ xen/xsm/flask/hooks.c | 6 + xen/xsm/flask/policy/access_vectors | 2 + 9 files changed, 585 insertions(+) create mode 100644 xen/common/xsplice.c create mode 100644 xen/include/xen/xsplice.h diff --git a/tools/flask/policy/policy/modules/xen/xen.te b/tools/flask/policy/policy/modules/xen/xen.te index d35ae22..542c3e1 100644 --- a/tools/flask/policy/policy/modules/xen/xen.te +++ b/tools/flask/policy/policy/modules/xen/xen.te @@ -72,6 +72,7 @@ allow dom0_t xen_t:xen2 { allow dom0_t xen_t:xen2 { pmu_ctrl get_symbol + xsplice_op }; allow dom0_t xen_t:mmu memorymap; diff --git a/xen/common/Kconfig b/xen/common/Kconfig index 6f404b4..619aa9e 100644 --- a/xen/common/Kconfig +++ b/xen/common/Kconfig @@ -152,4 +152,14 @@ config SCHED_DEFAULT endmenu +# Enable/Disable xsplice support +config XSPLICE + bool "xsplice support" + default y + ---help--- + Allows a running Xen hypervisor to be patched without rebooting. + This is primarily used to patch an hypervisor with XSA fixes. + + If unsure, say Y. + endmenu diff --git a/xen/common/Makefile b/xen/common/Makefile index 6e82b33..43b3911 100644 --- a/xen/common/Makefile +++ b/xen/common/Makefile @@ -72,3 +72,5 @@ subdir-$(coverage) += gcov subdir-y += libelf subdir-$(CONFIG_HAS_DEVICE_TREE) += libfdt + +obj-$(CONFIG_XSPLICE) += xsplice.o diff --git a/xen/common/sysctl.c b/xen/common/sysctl.c index 1624024..68e3eb4 100644 --- a/xen/common/sysctl.c +++ b/xen/common/sysctl.c @@ -28,6 +28,7 @@ #include <xsm/xsm.h> #include <xen/pmstat.h> #include <xen/gcov.h> +#include <xen/xsplice.h> long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl) { @@ -460,6 +461,12 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl) ret = tmem_control(&op->u.tmem_op); break; + case XEN_SYSCTL_xsplice_op: + ret = xsplice_control(&op->u.xsplice); + if ( ret != -ENOSYS ) + copyback = 1; + break; + default: ret = arch_do_sysctl(op, u_sysctl); copyback = 0; diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c new file mode 100644 index 0000000..125d9b8 --- /dev/null +++ b/xen/common/xsplice.c @@ -0,0 +1,386 @@ +/* + * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved. + * + */ + +#include <xen/guest_access.h> +#include <xen/keyhandler.h> +#include <xen/lib.h> +#include <xen/list.h> +#include <xen/mm.h> +#include <xen/sched.h> +#include <xen/smp.h> +#include <xen/spinlock.h> +#include <xen/xsplice.h> + +#include <asm/event.h> +#include <public/sysctl.h> + +static DEFINE_SPINLOCK(payload_lock); +static LIST_HEAD(payload_list); + +static unsigned int payload_cnt; +static unsigned int payload_version = 1; + +struct payload { + int32_t state; /* One of the XSPLICE_STATE_*. */ + int32_t rc; /* 0 or -XEN_EXX. */ + struct list_head list; /* Linked to 'payload_list'. */ + char name[XEN_XSPLICE_NAME_SIZE + 1];/* Name of it. */ +}; + +static const char *state2str(int32_t state) +{ +#define STATE(x) [XSPLICE_STATE_##x] = #x + static const char *const names[] = { + STATE(LOADED), + STATE(CHECKED), + STATE(APPLIED), + }; +#undef STATE + + if (state >= ARRAY_SIZE(names)) + return "unknown"; + + if (state < 0) + return "-EXX"; + + if (!names[state]) + return "unknown"; + + return names[state]; +} + +static void xsplice_printall(unsigned char key) +{ + struct payload *data; + + spin_lock(&payload_lock); + + list_for_each_entry ( data, &payload_list, list ) + printk(" name=%s state=%s(%d)\n", data->name, + state2str(data->state), data->state); + + spin_unlock(&payload_lock); +} + +static int verify_name(xen_xsplice_name_t *name) +{ + if ( name->size == 0 || name->size > XEN_XSPLICE_NAME_SIZE ) + return -EINVAL; + + if ( name->pad[0] || name->pad[1] || name->pad[2] ) + return -EINVAL; + + if ( !guest_handle_okay(name->name, name->size) ) + return -EINVAL; + + return 0; +} + +static int find_payload(xen_xsplice_name_t *name, bool_t need_lock, + struct payload **f) +{ + struct payload *data; + XEN_GUEST_HANDLE_PARAM(char) str; + char n[XEN_XSPLICE_NAME_SIZE + 1] = { 0 }; + int rc = -EINVAL; + + rc = verify_name(name); + if ( rc ) + return rc; + + str = guest_handle_cast(name->name, char); + if ( copy_from_guest(n, str, name->size) ) + return -EFAULT; + + if ( need_lock ) + spin_lock(&payload_lock); + + rc = -ENOENT; + list_for_each_entry ( data, &payload_list, list ) + { + if ( !strcmp(data->name, n) ) + { + *f = data; + rc = 0; + break; + } + } + + if ( need_lock ) + spin_unlock(&payload_lock); + + return rc; +} + +static int verify_payload(xen_sysctl_xsplice_upload_t *upload) +{ + if ( verify_name(&upload->name) ) + return -EINVAL; + + if ( upload->size == 0 ) + return -EINVAL; + + if ( !guest_handle_okay(upload->payload, upload->size) ) + return -EFAULT; + + return 0; +} + +/* + * We MUST be holding the payload_lock spinlock. + */ +static void free_payload(struct payload *data) +{ + list_del(&data->list); + payload_cnt--; + payload_version++; + xfree(data); +} + +static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload) +{ + struct payload *data = NULL; + uint8_t *raw_data; + int rc; + + rc = verify_payload(upload); + if ( rc ) + return rc; + + rc = find_payload(&upload->name, 1 /* true. */, &data); + if ( rc == 0 /* Found. */ ) + return -EEXIST; + + if ( rc != -ENOENT ) + return rc; + + data = xzalloc(struct payload); + if ( !data ) + return -ENOMEM; + + memset(data, 0, sizeof *data); + rc = -EFAULT; + if ( copy_from_guest(data->name, upload->name.name, upload->name.size) ) + goto err_data; + + rc = -ENOMEM; + raw_data = alloc_xenheap_pages(get_order_from_bytes(upload->size), 0); + if ( !raw_data ) + goto err_data; + + rc = -EFAULT; + if ( copy_from_guest(raw_data, upload->payload, upload->size) ) + goto err_raw; + + data->state = XSPLICE_STATE_LOADED; + data->rc = 0; + INIT_LIST_HEAD(&data->list); + + spin_lock(&payload_lock); + list_add_tail(&data->list, &payload_list); + payload_cnt++; + payload_version++; + spin_unlock(&payload_lock); + + free_xenheap_pages(raw_data, get_order_from_bytes(upload->size)); + return 0; + + err_raw: + free_xenheap_pages(raw_data, get_order_from_bytes(upload->size)); + err_data: + xfree(data); + return rc; +} + +static int xsplice_get(xen_sysctl_xsplice_summary_t *summary) +{ + struct payload *data; + int rc; + + if ( summary->status.state ) + return -EINVAL; + + if ( summary->status.rc != 0 ) + return -EINVAL; + + rc = verify_name(&summary->name); + if ( rc ) + return rc; + + rc = find_payload(&summary->name, 1 /* true. */, &data); + if ( rc ) + return rc; + + summary->status.state = data->state; + summary->status.rc = data->rc; + + return 0; +} + +static int xsplice_list(xen_sysctl_xsplice_list_t *list) +{ + xen_xsplice_status_t status; + struct payload *data; + unsigned int idx = 0, i = 0; + int rc = 0; + + if ( list->nr > 1024 ) + return -E2BIG; + + if ( list->pad != 0 ) + return -EINVAL; + + if ( !guest_handle_okay(list->status, sizeof(status) * list->nr) || + !guest_handle_okay(list->name, XEN_XSPLICE_NAME_SIZE * list->nr) || + !guest_handle_okay(list->len, sizeof(uint32_t) * list->nr) ) + return -EINVAL; + + spin_lock(&payload_lock); + if ( list->idx > payload_cnt || !list->nr ) + { + spin_unlock(&payload_lock); + return -EINVAL; + } + + list_for_each_entry( data, &payload_list, list ) + { + uint32_t len; + + if ( list->idx > i++ ) + continue; + + status.state = data->state; + status.rc = data->rc; + len = strlen(data->name); + + /* N.B. 'idx' != 'i'. */ + if ( __copy_to_guest_offset(list->name, idx * XEN_XSPLICE_NAME_SIZE, + data->name, len) || + __copy_to_guest_offset(list->len, idx, &len, 1) || + __copy_to_guest_offset(list->status, idx, &status, 1) ) + { + rc = -EFAULT; + break; + } + idx++; + if ( hypercall_preempt_check() || (idx + 1 > list->nr) ) + break; + } + list->nr = payload_cnt - i; /* Remaining amount. */ + list->version = payload_version; + spin_unlock(&payload_lock); + + /* And how many we have processed. */ + return rc ? : idx; +} + +static int xsplice_action(xen_sysctl_xsplice_action_t *action) +{ + struct payload *data; + int rc; + + rc = verify_name(&action->name); + if ( rc ) + return rc; + + spin_lock(&payload_lock); + rc = find_payload(&action->name, 0 /* We are holding the lock. */, &data); + if ( rc ) + goto out; + + switch ( action->cmd ) + { + case XSPLICE_ACTION_CHECK: + if ( (data->state == XSPLICE_STATE_LOADED) || + (data->state == XSPLICE_STATE_CHECKED) ) + { + /* No implementation yet. */ + data->state = XSPLICE_STATE_CHECKED; + data->rc = 0; + rc = 0; + } + break; + case XSPLICE_ACTION_UNLOAD: + if ( (data->state == XSPLICE_STATE_LOADED) || + (data->state == XSPLICE_STATE_CHECKED) ) + { + free_payload(data); + /* No touching 'data' from here on! */ + rc = 0; + } + break; + case XSPLICE_ACTION_REVERT: + if ( data->state == XSPLICE_STATE_APPLIED ) + { + /* No implementation yet. */ + data->state = XSPLICE_STATE_CHECKED; + data->rc = 0; + rc = 0; + } + break; + case XSPLICE_ACTION_APPLY: + if ( (data->state == XSPLICE_STATE_CHECKED) ) + { + /* No implementation yet. */ + data->state = XSPLICE_STATE_APPLIED; + data->rc = 0; + rc = 0; + } + break; + case XSPLICE_ACTION_REPLACE: + if ( data->state == XSPLICE_STATE_CHECKED ) + { + /* No implementation yet. */ + data->state = XSPLICE_STATE_CHECKED; + data->rc = 0; + rc = 0; + } + break; + default: + rc = -EOPNOTSUPP; + break; + } + + out: + spin_unlock(&payload_lock); + + return rc; +} + +int xsplice_control(xen_sysctl_xsplice_op_t *xsplice) +{ + int rc; + + if ( xsplice->pad != 0 ) + return -EINVAL; + + switch ( xsplice->cmd ) + { + case XEN_SYSCTL_XSPLICE_UPLOAD: + rc = xsplice_upload(&xsplice->u.upload); + break; + case XEN_SYSCTL_XSPLICE_GET: + rc = xsplice_get(&xsplice->u.get); + break; + case XEN_SYSCTL_XSPLICE_LIST: + rc = xsplice_list(&xsplice->u.list); + break; + case XEN_SYSCTL_XSPLICE_ACTION: + rc = xsplice_action(&xsplice->u.action); + break; + default: + rc = -EOPNOTSUPP; + break; + } + + return rc; +} + +static int __init xsplice_init(void) +{ + register_keyhandler('x', xsplice_printall, "print xsplicing info", 1); + return 0; +} +__initcall(xsplice_init); diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h index 96680eb..d549e7a 100644 --- a/xen/include/public/sysctl.h +++ b/xen/include/public/sysctl.h @@ -766,6 +766,160 @@ struct xen_sysctl_tmem_op { typedef struct xen_sysctl_tmem_op xen_sysctl_tmem_op_t; DEFINE_XEN_GUEST_HANDLE(xen_sysctl_tmem_op_t); +/* + * XEN_SYSCTL_XSPLICE_op + * + * Refer to the http://xenbits.xenproject.org/docs/unstable/misc/xsplice.html + * for the design details of this hyprcall. + */ + +/* + * Structure describing an ELF payload. Uniquely identifies the + * payload. Should be human readable. + * Recommended length is upto XEN_XSPLICE_NAME_SIZE. + */ +#define XEN_XSPLICE_NAME_SIZE 128 +struct xen_xsplice_name { + XEN_GUEST_HANDLE_64(char) name; /* IN: pointer to name. */ + uint16_t size; /* IN: size of name. May be upto + XEN_XSPLICE_NAME_SIZE. */ + uint16_t pad[3]; /* IN: MUST be zero. */ +}; +typedef struct xen_xsplice_name xen_xsplice_name_t; +DEFINE_XEN_GUEST_HANDLE(xen_xsplice_name_t); + +/* + * Upload a payload to the hypervisor. The payload is verified + * against basic checks and if there are any issues the proper return code + * will be returned. The payload is not applied at this time - that is + * controlled by XEN_SYSCTL_XSPLICE_ACTION. + * + * The return value is zero if the payload was succesfully uploaded. + * Otherwise an EXX return value is provided. Duplicate `name` are not + * supported. + * + * The payload at this point is verified against the basic checks. + * + * The `payload` is the ELF payload as mentioned in the `Payload format` + * section in the xSplice design document. + */ +#define XEN_SYSCTL_XSPLICE_UPLOAD 0 +struct xen_sysctl_xsplice_upload { + xen_xsplice_name_t name; /* IN, name of the patch. */ + uint64_t size; /* IN, size of the ELF file. */ + XEN_GUEST_HANDLE_64(uint8) payload; /* IN, the ELF file. */ +}; +typedef struct xen_sysctl_xsplice_upload xen_sysctl_xsplice_upload_t; +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_upload_t); + +/* + * Retrieve an status of an specific payload. + * + * Upon completion the `struct xen_xsplice_status` is updated. + * + * The return value is zero on success and XEN_EXX on failure. This operation + * is synchronous and does not require preemption. + */ +#define XEN_SYSCTL_XSPLICE_GET 1 + +struct xen_xsplice_status { +#define XSPLICE_STATE_LOADED 1 +#define XSPLICE_STATE_CHECKED 2 +#define XSPLICE_STATE_APPLIED 3 + int32_t state; /* OUT: XSPLICE_STATE_*. IN: MUST be zero. */ + int32_t rc; /* OUT: 0 if no error, otherwise -XEN_EXX. */ + /* IN: MUST be zero. */ +}; +typedef struct xen_xsplice_status xen_xsplice_status_t; +DEFINE_XEN_GUEST_HANDLE(xen_xsplice_status_t); + +struct xen_sysctl_xsplice_summary { + xen_xsplice_name_t name; /* IN, name of the payload. */ + xen_xsplice_status_t status; /* IN/OUT, state of it. */ +}; +typedef struct xen_sysctl_xsplice_summary xen_sysctl_xsplice_summary_t; +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_summary_t); + +/* + * Retrieve an array of abbreviated status and names of payloads that are + * loaded in the hypervisor. + * + * If the hypercall returns an positive number, it is the number (up to `nr`) + * of the payloads returned, along with `nr` updated with the number of remaining + * payloads, `version` updated (it may be the same across hypercalls. If it + * varies the data is stale and further calls could fail). The `status`, + * `name`, and `len`' are updated at their designed index value (`idx`) with + * the returned value of data. + * + * If the hypercall returns E2BIG the `nr` is too big and should be + * lowered. + * + * This operation can be preempted by the hypercall returning EAGAIN. + * Retry. + * + * Note that due to the asynchronous nature of hypercalls the domain might have + * added or removed the number of payloads making this information stale. It is + * the responsibility of the toolstack to use the `version` field to check + * between each invocation. if the version differs it should discard the stale + * data and start from scratch. It is OK for the toolstack to use the new + * `version` field. + */ +#define XEN_SYSCTL_XSPLICE_LIST 2 +struct xen_sysctl_xsplice_list { + uint32_t version; /* IN/OUT: Initially *MUST* be zero. + On subsequent calls reuse value. + If varies between calls, we are + * getting stale data. */ + uint32_t idx; /* IN/OUT: Index into array. */ + uint32_t nr; /* IN: How many status, name, and len + should fill out. + OUT: How many payloads left. */ + uint32_t pad; /* IN: Must be zero. */ + XEN_GUEST_HANDLE_64(xen_xsplice_status_t) status; /* OUT. Must have enough + space allocate for nr of them. */ + XEN_GUEST_HANDLE_64(char) name; /* OUT: Array of names. Each member + MUST XEN_XSPLICE_NAME_SIZE in size. + Must have nr of them. */ + XEN_GUEST_HANDLE_64(uint32) len; /* OUT: Array of lengths of name's. + Must have nr of them. */ +}; +typedef struct xen_sysctl_xsplice_list xen_sysctl_xsplice_list_t; +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_list_t); + +/* + * Perform an operation on the payload structure referenced by the `name` field. + * The operation request is asynchronous and the status should be retrieved + * by using either XEN_SYSCTL_XSPLICE_GET or XEN_SYSCTL_XSPLICE_LIST hypercall. + */ +#define XEN_SYSCTL_XSPLICE_ACTION 3 +struct xen_sysctl_xsplice_action { + xen_xsplice_name_t name; /* IN, name of the patch. */ +#define XSPLICE_ACTION_CHECK 1 +#define XSPLICE_ACTION_UNLOAD 2 +#define XSPLICE_ACTION_REVERT 3 +#define XSPLICE_ACTION_APPLY 4 +#define XSPLICE_ACTION_REPLACE 5 + uint32_t cmd; /* IN: XSPLICE_ACTION_*. */ + uint32_t timeout; /* IN: Zero if no timeout. */ + /* Or upper bound of time (ms) */ + /* for operation to take. */ +}; +typedef struct xen_sysctl_xsplice_action xen_sysctl_xsplice_action_t; +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_action_t); + +struct xen_sysctl_xsplice_op { + uint32_t cmd; /* IN: XEN_SYSCTL_XSPLICE_*. */ + uint32_t pad; /* IN: Always zero. */ + union { + xen_sysctl_xsplice_upload_t upload; + xen_sysctl_xsplice_list_t list; + xen_sysctl_xsplice_summary_t get; + xen_sysctl_xsplice_action_t action; + } u; +}; +typedef struct xen_sysctl_xsplice_op xen_sysctl_xsplice_op_t; +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_op_t); + struct xen_sysctl { uint32_t cmd; #define XEN_SYSCTL_readconsole 1 @@ -791,6 +945,7 @@ struct xen_sysctl { #define XEN_SYSCTL_pcitopoinfo 22 #define XEN_SYSCTL_psr_cat_op 23 #define XEN_SYSCTL_tmem_op 24 +#define XEN_SYSCTL_xsplice_op 25 uint32_t interface_version; /* XEN_SYSCTL_INTERFACE_VERSION */ union { struct xen_sysctl_readconsole readconsole; @@ -816,6 +971,7 @@ struct xen_sysctl { struct xen_sysctl_psr_cmt_op psr_cmt_op; struct xen_sysctl_psr_cat_op psr_cat_op; struct xen_sysctl_tmem_op tmem_op; + struct xen_sysctl_xsplice_op xsplice; uint8_t pad[128]; } u; }; diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h new file mode 100644 index 0000000..cf465c4 --- /dev/null +++ b/xen/include/xen/xsplice.h @@ -0,0 +1,15 @@ +#ifndef __XEN_XSPLICE_H__ +#define __XEN_XSPLICE_H__ + +struct xen_sysctl_xsplice_op; + +#ifdef CONFIG_XSPLICE +int xsplice_control(struct xen_sysctl_xsplice_op *); +#else +#include <xen/errno.h> /* For -ENOSYS */ +static inline int xsplice_control(struct xen_sysctl_xsplice_op *op) +{ + return -ENOSYS; +} +#endif +#endif /* __XEN_XSPLICE_H__ */ diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c index f63c3e2..c856e1e 100644 --- a/xen/xsm/flask/hooks.c +++ b/xen/xsm/flask/hooks.c @@ -807,6 +807,12 @@ static int flask_sysctl(int cmd) case XEN_SYSCTL_tmem_op: return domain_has_xen(current->domain, XEN__TMEM_CONTROL); +#ifdef CONFIG_XSPLICE + case XEN_SYSCTL_xsplice_op: + return avc_current_has_perm(SECINITSID_XEN, SECCLASS_XEN2, + XEN2__XSPLICE_OP, NULL); +#endif + default: printk("flask_sysctl: Unknown op %d\n", cmd); return -EPERM; diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors index effb59f..5f08d05 100644 --- a/xen/xsm/flask/policy/access_vectors +++ b/xen/xsm/flask/policy/access_vectors @@ -93,6 +93,8 @@ class xen2 pmu_ctrl # PMU use (domains, including unprivileged ones, will be using this operation) pmu_use +# XEN_SYSCTL_xsplice_op + xsplice_op } # Classes domain and domain2 consist of operations that a domain performs on -- 2.1.0 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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