From db10cb9b574675402bfd8fe1a31aafdd45b002df Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 10 Oct 2023 12:53:33 -0700 Subject: virt: sevguest: Fix passing a stack buffer as a scatterlist target CONFIG_DEBUG_SG highlights that get_{report,ext_report,derived_key)()} are passing stack buffers as the @req_buf argument to handle_guest_request(), generating a Call Trace of the following form: WARNING: CPU: 0 PID: 1175 at include/linux/scatterlist.h:187 enc_dec_message+0x518/0x5b0 [sev_guest] [..] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:enc_dec_message+0x518/0x5b0 [sev_guest] Call Trace: [..] handle_guest_request+0x135/0x520 [sev_guest] get_ext_report+0x1ec/0x3e0 [sev_guest] snp_guest_ioctl+0x157/0x200 [sev_guest] Note that the above Call Trace was with the DEBUG_SG BUG_ON()s converted to WARN_ON()s. This is benign as long as there are no hardware crypto accelerators loaded for the aead cipher, and no subsequent dma_map_sg() is performed on the scatterlist. However, sev-guest can not assume the presence of an aead accelerator nor can it assume that CONFIG_DEBUG_SG is disabled. Resolve this bug by allocating virt_addr_valid() memory, similar to the other buffers am @snp_dev instance carries, to marshal requests from user buffers to kernel buffers. Reported-by: Peter Gonda Closes: http://lore.kernel.org/r/CAMkAt6r2VPPMZ__SQfJse8qWsUyYW3AgYbOUVM0S_Vtk=KvkxQ@mail.gmail.com Fixes: fce96cf04430 ("virt: Add SEV-SNP guest driver") Cc: Borislav Petkov Cc: Tom Lendacky Cc: Dionna Glaze Cc: Jeremi Piotrowski Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams --- drivers/virt/coco/sev-guest/sev-guest.c | 45 ++++++++++++++++++--------------- 1 file changed, 25 insertions(+), 20 deletions(-) (limited to 'drivers/virt') diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 97dbe715e96a..5bee58ef5f1e 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -57,6 +57,11 @@ struct snp_guest_dev { struct snp_secrets_page_layout *layout; struct snp_req_data input; + union { + struct snp_report_req report; + struct snp_derived_key_req derived_key; + struct snp_ext_report_req ext_report; + } req; u32 *os_area_msg_seqno; u8 *vmpck; }; @@ -473,8 +478,8 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) { struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_report_req *req = &snp_dev->req.report; struct snp_report_resp *resp; - struct snp_report_req req; int rc, resp_len; lockdep_assert_held(&snp_cmd_mutex); @@ -482,7 +487,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io if (!arg->req_data || !arg->resp_data) return -EINVAL; - if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) + if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req))) return -EFAULT; /* @@ -496,7 +501,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io return -ENOMEM; rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, - SNP_MSG_REPORT_REQ, &req, sizeof(req), resp->data, + SNP_MSG_REPORT_REQ, req, sizeof(*req), resp->data, resp_len); if (rc) goto e_free; @@ -511,9 +516,9 @@ e_free: static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) { + struct snp_derived_key_req *req = &snp_dev->req.derived_key; struct snp_guest_crypto *crypto = snp_dev->crypto; struct snp_derived_key_resp resp = {0}; - struct snp_derived_key_req req; int rc, resp_len; /* Response data is 64 bytes and max authsize for GCM is 16 bytes. */ u8 buf[64 + 16]; @@ -532,11 +537,11 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque if (sizeof(buf) < resp_len) return -ENOMEM; - if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) + if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req))) return -EFAULT; rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, - SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len); + SNP_MSG_KEY_REQ, req, sizeof(*req), buf, resp_len); if (rc) return rc; @@ -552,8 +557,8 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) { + struct snp_ext_report_req *req = &snp_dev->req.ext_report; struct snp_guest_crypto *crypto = snp_dev->crypto; - struct snp_ext_report_req req; struct snp_report_resp *resp; int ret, npages = 0, resp_len; @@ -562,18 +567,18 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques if (!arg->req_data || !arg->resp_data) return -EINVAL; - if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) + if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req))) return -EFAULT; /* userspace does not want certificate data */ - if (!req.certs_len || !req.certs_address) + if (!req->certs_len || !req->certs_address) goto cmd; - if (req.certs_len > SEV_FW_BLOB_MAX_SIZE || - !IS_ALIGNED(req.certs_len, PAGE_SIZE)) + if (req->certs_len > SEV_FW_BLOB_MAX_SIZE || + !IS_ALIGNED(req->certs_len, PAGE_SIZE)) return -EINVAL; - if (!access_ok((const void __user *)req.certs_address, req.certs_len)) + if (!access_ok((const void __user *)req->certs_address, req->certs_len)) return -EFAULT; /* @@ -582,8 +587,8 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques * the host. If host does not supply any certs in it, then copy * zeros to indicate that certificate data was not provided. */ - memset(snp_dev->certs_data, 0, req.certs_len); - npages = req.certs_len >> PAGE_SHIFT; + memset(snp_dev->certs_data, 0, req->certs_len); + npages = req->certs_len >> PAGE_SHIFT; cmd: /* * The intermediate response buffer is used while decrypting the @@ -597,14 +602,14 @@ cmd: snp_dev->input.data_npages = npages; ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg, - SNP_MSG_REPORT_REQ, &req.data, - sizeof(req.data), resp->data, resp_len); + SNP_MSG_REPORT_REQ, &req->data, + sizeof(req->data), resp->data, resp_len); /* If certs length is invalid then copy the returned length */ if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) { - req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT; + req->certs_len = snp_dev->input.data_npages << PAGE_SHIFT; - if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req))) + if (copy_to_user((void __user *)arg->req_data, req, sizeof(*req))) ret = -EFAULT; } @@ -612,8 +617,8 @@ cmd: goto e_free; if (npages && - copy_to_user((void __user *)req.certs_address, snp_dev->certs_data, - req.certs_len)) { + copy_to_user((void __user *)req->certs_address, snp_dev->certs_data, + req->certs_len)) { ret = -EFAULT; goto e_free; } -- cgit From ec51ffcf263016111f090b9440a3c5a8338648e8 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Sat, 12 Aug 2023 17:21:00 -0700 Subject: virt: coco: Add a coco/Makefile and coco/Kconfig In preparation for adding another coco build target, relieve drivers/virt/Makefile of the responsibility to track new compilation unit additions to drivers/virt/coco/, and do the same for drivers/virt/Kconfig. Reviewed-by: Kuppuswamy Sathyanarayanan Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams --- drivers/virt/Kconfig | 6 +----- drivers/virt/Makefile | 4 +--- drivers/virt/coco/Kconfig | 9 +++++++++ drivers/virt/coco/Makefile | 7 +++++++ 4 files changed, 18 insertions(+), 8 deletions(-) create mode 100644 drivers/virt/coco/Kconfig create mode 100644 drivers/virt/coco/Makefile (limited to 'drivers/virt') diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig index f79ab13a5c28..40129b6f0eca 100644 --- a/drivers/virt/Kconfig +++ b/drivers/virt/Kconfig @@ -48,10 +48,6 @@ source "drivers/virt/nitro_enclaves/Kconfig" source "drivers/virt/acrn/Kconfig" -source "drivers/virt/coco/efi_secret/Kconfig" - -source "drivers/virt/coco/sev-guest/Kconfig" - -source "drivers/virt/coco/tdx-guest/Kconfig" +source "drivers/virt/coco/Kconfig" endif diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile index e9aa6fc96fab..f29901bd7820 100644 --- a/drivers/virt/Makefile +++ b/drivers/virt/Makefile @@ -9,6 +9,4 @@ obj-y += vboxguest/ obj-$(CONFIG_NITRO_ENCLAVES) += nitro_enclaves/ obj-$(CONFIG_ACRN_HSM) += acrn/ -obj-$(CONFIG_EFI_SECRET) += coco/efi_secret/ -obj-$(CONFIG_SEV_GUEST) += coco/sev-guest/ -obj-$(CONFIG_INTEL_TDX_GUEST) += coco/tdx-guest/ +obj-y += coco/ diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig new file mode 100644 index 000000000000..fc5c64f04c4a --- /dev/null +++ b/drivers/virt/coco/Kconfig @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Confidential computing related collateral +# +source "drivers/virt/coco/efi_secret/Kconfig" + +source "drivers/virt/coco/sev-guest/Kconfig" + +source "drivers/virt/coco/tdx-guest/Kconfig" diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile new file mode 100644 index 000000000000..55302ef719ad --- /dev/null +++ b/drivers/virt/coco/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Confidential computing related collateral +# +obj-$(CONFIG_EFI_SECRET) += efi_secret/ +obj-$(CONFIG_SEV_GUEST) += sev-guest/ +obj-$(CONFIG_INTEL_TDX_GUEST) += tdx-guest/ -- cgit From 70e6f7e2b98575621019aa40ac616be58ff984e0 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 25 Sep 2023 20:13:29 -0700 Subject: configfs-tsm: Introduce a shared ABI for attestation reports One of the common operations of a TSM (Trusted Security Module) is to provide a way for a TVM (confidential computing guest execution environment) to take a measurement of its launch state, sign it and submit it to a verifying party. Upon successful attestation that verifies the integrity of the TVM additional secrets may be deployed. The concept is common across TSMs, but the implementations are unfortunately vendor specific. While the industry grapples with a common definition of this attestation format [1], Linux need not make this problem worse by defining a new ABI per TSM that wants to perform a similar operation. The current momentum has been to invent new ioctl-ABI per TSM per function which at best is an abdication of the kernel's responsibility to make common infrastructure concepts share common ABI. The proposal, targeted to conceptually work with TDX, SEV-SNP, COVE if not more, is to define a configfs interface to retrieve the TSM-specific blob. report=/sys/kernel/config/tsm/report/report0 mkdir $report dd if=binary_userdata_plus_nonce > $report/inblob hexdump $report/outblob This approach later allows for the standardization of the attestation blob format without needing to invent a new ABI. Once standardization happens the standard format can be emitted by $report/outblob and indicated by $report/provider, or a new attribute like "$report/tcg_coco_report" can emit the standard format alongside the vendor format. Review of previous iterations of this interface identified that there is a need to scale report generation for multiple container environments [2]. Configfs enables a model where each container can bind mount one or more report generation item instances. Still, within a container only a single thread can be manipulating a given configuration instance at a time. A 'generation' count is provided to detect conflicts between multiple threads racing to configure a report instance. The SEV-SNP concepts of "extended reports" and "privilege levels" are optionally enabled by selecting 'tsm_report_ext_type' at register_tsm() time. The expectation is that those concepts are generic enough that they may be adopted by other TSM implementations. In other words, configfs-tsm aims to address a superset of TSM specific functionality with a common ABI where attributes may appear, or not appear, based on the set of concepts the implementation supports. Link: http://lore.kernel.org/r/64961c3baf8ce_142af829436@dwillia2-xfh.jf.intel.com.notmuch [1] Link: http://lore.kernel.org/r/57f3a05e-8fcd-4656-beea-56bb8365ae64@linux.microsoft.com [2] Cc: Kuppuswamy Sathyanarayanan Cc: Dionna Amalie Glaze Cc: James Bottomley Cc: Peter Gonda Cc: Greg Kroah-Hartman Cc: Samuel Ortiz Acked-by: Greg Kroah-Hartman Acked-by: Thomas Gleixner Reviewed-by: Kuppuswamy Sathyanarayanan Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams --- drivers/virt/coco/Kconfig | 5 + drivers/virt/coco/Makefile | 1 + drivers/virt/coco/tsm.c | 425 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 431 insertions(+) create mode 100644 drivers/virt/coco/tsm.c (limited to 'drivers/virt') diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig index fc5c64f04c4a..87d142c1f932 100644 --- a/drivers/virt/coco/Kconfig +++ b/drivers/virt/coco/Kconfig @@ -2,6 +2,11 @@ # # Confidential computing related collateral # + +config TSM_REPORTS + select CONFIGFS_FS + tristate + source "drivers/virt/coco/efi_secret/Kconfig" source "drivers/virt/coco/sev-guest/Kconfig" diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile index 55302ef719ad..18c1aba5edb7 100644 --- a/drivers/virt/coco/Makefile +++ b/drivers/virt/coco/Makefile @@ -2,6 +2,7 @@ # # Confidential computing related collateral # +obj-$(CONFIG_TSM_REPORTS) += tsm.o obj-$(CONFIG_EFI_SECRET) += efi_secret/ obj-$(CONFIG_SEV_GUEST) += sev-guest/ obj-$(CONFIG_INTEL_TDX_GUEST) += tdx-guest/ diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm.c new file mode 100644 index 000000000000..d1c2db83a8ca --- /dev/null +++ b/drivers/virt/coco/tsm.c @@ -0,0 +1,425 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2023 Intel Corporation. All rights reserved. */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +static struct tsm_provider { + const struct tsm_ops *ops; + const struct config_item_type *type; + void *data; +} provider; +static DECLARE_RWSEM(tsm_rwsem); + +/** + * DOC: Trusted Security Module (TSM) Attestation Report Interface + * + * The TSM report interface is a common provider of blobs that facilitate + * attestation of a TVM (confidential computing guest) by an attestation + * service. A TSM report combines a user-defined blob (likely a public-key with + * a nonce for a key-exchange protocol) with a signed attestation report. That + * combined blob is then used to obtain secrets provided by an agent that can + * validate the attestation report. The expectation is that this interface is + * invoked infrequently, however configfs allows for multiple agents to + * own their own report generation instances to generate reports as + * often as needed. + * + * The attestation report format is TSM provider specific, when / if a standard + * materializes that can be published instead of the vendor layout. Until then + * the 'provider' attribute indicates the format of 'outblob', and optionally + * 'auxblob'. + */ + +struct tsm_report_state { + struct tsm_report report; + unsigned long write_generation; + unsigned long read_generation; + struct config_item cfg; +}; + +enum tsm_data_select { + TSM_REPORT, + TSM_CERTS, +}; + +static struct tsm_report *to_tsm_report(struct config_item *cfg) +{ + struct tsm_report_state *state = + container_of(cfg, struct tsm_report_state, cfg); + + return &state->report; +} + +static struct tsm_report_state *to_state(struct tsm_report *report) +{ + return container_of(report, struct tsm_report_state, report); +} + +static int try_advance_write_generation(struct tsm_report *report) +{ + struct tsm_report_state *state = to_state(report); + + lockdep_assert_held_write(&tsm_rwsem); + + /* + * Malicious or broken userspace has written enough times for + * read_generation == write_generation by modular arithmetic without an + * interim read. Stop accepting updates until the current report + * configuration is read. + */ + if (state->write_generation == state->read_generation - 1) + return -EBUSY; + state->write_generation++; + return 0; +} + +static ssize_t tsm_report_privlevel_store(struct config_item *cfg, + const char *buf, size_t len) +{ + struct tsm_report *report = to_tsm_report(cfg); + unsigned int val; + int rc; + + rc = kstrtouint(buf, 0, &val); + if (rc) + return rc; + + /* + * The valid privilege levels that a TSM might accept, if it accepts a + * privilege level setting at all, are a max of TSM_PRIVLEVEL_MAX (see + * SEV-SNP GHCB) and a minimum of a TSM selected floor value no less + * than 0. + */ + if (provider.ops->privlevel_floor > val || val > TSM_PRIVLEVEL_MAX) + return -EINVAL; + + guard(rwsem_write)(&tsm_rwsem); + rc = try_advance_write_generation(report); + if (rc) + return rc; + report->desc.privlevel = val; + + return len; +} +CONFIGFS_ATTR_WO(tsm_report_, privlevel); + +static ssize_t tsm_report_privlevel_floor_show(struct config_item *cfg, + char *buf) +{ + guard(rwsem_read)(&tsm_rwsem); + return sysfs_emit(buf, "%u\n", provider.ops->privlevel_floor); +} +CONFIGFS_ATTR_RO(tsm_report_, privlevel_floor); + +static ssize_t tsm_report_inblob_write(struct config_item *cfg, + const void *buf, size_t count) +{ + struct tsm_report *report = to_tsm_report(cfg); + int rc; + + guard(rwsem_write)(&tsm_rwsem); + rc = try_advance_write_generation(report); + if (rc) + return rc; + + report->desc.inblob_len = count; + memcpy(report->desc.inblob, buf, count); + return count; +} +CONFIGFS_BIN_ATTR_WO(tsm_report_, inblob, NULL, TSM_INBLOB_MAX); + +static ssize_t tsm_report_generation_show(struct config_item *cfg, char *buf) +{ + struct tsm_report *report = to_tsm_report(cfg); + struct tsm_report_state *state = to_state(report); + + guard(rwsem_read)(&tsm_rwsem); + return sysfs_emit(buf, "%lu\n", state->write_generation); +} +CONFIGFS_ATTR_RO(tsm_report_, generation); + +static ssize_t tsm_report_provider_show(struct config_item *cfg, char *buf) +{ + guard(rwsem_read)(&tsm_rwsem); + return sysfs_emit(buf, "%s\n", provider.ops->name); +} +CONFIGFS_ATTR_RO(tsm_report_, provider); + +static ssize_t __read_report(struct tsm_report *report, void *buf, size_t count, + enum tsm_data_select select) +{ + loff_t offset = 0; + ssize_t len; + u8 *out; + + if (select == TSM_REPORT) { + out = report->outblob; + len = report->outblob_len; + } else { + out = report->auxblob; + len = report->auxblob_len; + } + + /* + * Recall that a NULL @buf is configfs requesting the size of + * the buffer. + */ + if (!buf) + return len; + return memory_read_from_buffer(buf, count, &offset, out, len); +} + +static ssize_t read_cached_report(struct tsm_report *report, void *buf, + size_t count, enum tsm_data_select select) +{ + struct tsm_report_state *state = to_state(report); + + guard(rwsem_read)(&tsm_rwsem); + if (!report->desc.inblob_len) + return -EINVAL; + + /* + * A given TSM backend always fills in ->outblob regardless of + * whether the report includes an auxblob or not. + */ + if (!report->outblob || + state->read_generation != state->write_generation) + return -EWOULDBLOCK; + + return __read_report(report, buf, count, select); +} + +static ssize_t tsm_report_read(struct tsm_report *report, void *buf, + size_t count, enum tsm_data_select select) +{ + struct tsm_report_state *state = to_state(report); + const struct tsm_ops *ops; + ssize_t rc; + + /* try to read from the existing report if present and valid... */ + rc = read_cached_report(report, buf, count, select); + if (rc >= 0 || rc != -EWOULDBLOCK) + return rc; + + /* slow path, report may need to be regenerated... */ + guard(rwsem_write)(&tsm_rwsem); + ops = provider.ops; + if (!ops) + return -ENOTTY; + if (!report->desc.inblob_len) + return -EINVAL; + + /* did another thread already generate this report? */ + if (report->outblob && + state->read_generation == state->write_generation) + goto out; + + kvfree(report->outblob); + kvfree(report->auxblob); + report->outblob = NULL; + report->auxblob = NULL; + rc = ops->report_new(report, provider.data); + if (rc < 0) + return rc; + state->read_generation = state->write_generation; +out: + return __read_report(report, buf, count, select); +} + +static ssize_t tsm_report_outblob_read(struct config_item *cfg, void *buf, + size_t count) +{ + struct tsm_report *report = to_tsm_report(cfg); + + return tsm_report_read(report, buf, count, TSM_REPORT); +} +CONFIGFS_BIN_ATTR_RO(tsm_report_, outblob, NULL, TSM_OUTBLOB_MAX); + +static ssize_t tsm_report_auxblob_read(struct config_item *cfg, void *buf, + size_t count) +{ + struct tsm_report *report = to_tsm_report(cfg); + + return tsm_report_read(report, buf, count, TSM_CERTS); +} +CONFIGFS_BIN_ATTR_RO(tsm_report_, auxblob, NULL, TSM_OUTBLOB_MAX); + +#define TSM_DEFAULT_ATTRS() \ + &tsm_report_attr_generation, \ + &tsm_report_attr_provider + +static struct configfs_attribute *tsm_report_attrs[] = { + TSM_DEFAULT_ATTRS(), + NULL, +}; + +static struct configfs_attribute *tsm_report_extra_attrs[] = { + TSM_DEFAULT_ATTRS(), + &tsm_report_attr_privlevel, + &tsm_report_attr_privlevel_floor, + NULL, +}; + +#define TSM_DEFAULT_BIN_ATTRS() \ + &tsm_report_attr_inblob, \ + &tsm_report_attr_outblob + +static struct configfs_bin_attribute *tsm_report_bin_attrs[] = { + TSM_DEFAULT_BIN_ATTRS(), + NULL, +}; + +static struct configfs_bin_attribute *tsm_report_bin_extra_attrs[] = { + TSM_DEFAULT_BIN_ATTRS(), + &tsm_report_attr_auxblob, + NULL, +}; + +static void tsm_report_item_release(struct config_item *cfg) +{ + struct tsm_report *report = to_tsm_report(cfg); + struct tsm_report_state *state = to_state(report); + + kvfree(report->auxblob); + kvfree(report->outblob); + kfree(state); +} + +static struct configfs_item_operations tsm_report_item_ops = { + .release = tsm_report_item_release, +}; + +const struct config_item_type tsm_report_default_type = { + .ct_owner = THIS_MODULE, + .ct_bin_attrs = tsm_report_bin_attrs, + .ct_attrs = tsm_report_attrs, + .ct_item_ops = &tsm_report_item_ops, +}; +EXPORT_SYMBOL_GPL(tsm_report_default_type); + +const struct config_item_type tsm_report_extra_type = { + .ct_owner = THIS_MODULE, + .ct_bin_attrs = tsm_report_bin_extra_attrs, + .ct_attrs = tsm_report_extra_attrs, + .ct_item_ops = &tsm_report_item_ops, +}; +EXPORT_SYMBOL_GPL(tsm_report_extra_type); + +static struct config_item *tsm_report_make_item(struct config_group *group, + const char *name) +{ + struct tsm_report_state *state; + + guard(rwsem_read)(&tsm_rwsem); + if (!provider.ops) + return ERR_PTR(-ENXIO); + + state = kzalloc(sizeof(*state), GFP_KERNEL); + if (!state) + return ERR_PTR(-ENOMEM); + + config_item_init_type_name(&state->cfg, name, provider.type); + return &state->cfg; +} + +static struct configfs_group_operations tsm_report_group_ops = { + .make_item = tsm_report_make_item, +}; + +static const struct config_item_type tsm_reports_type = { + .ct_owner = THIS_MODULE, + .ct_group_ops = &tsm_report_group_ops, +}; + +static const struct config_item_type tsm_root_group_type = { + .ct_owner = THIS_MODULE, +}; + +static struct configfs_subsystem tsm_configfs = { + .su_group = { + .cg_item = { + .ci_namebuf = "tsm", + .ci_type = &tsm_root_group_type, + }, + }, + .su_mutex = __MUTEX_INITIALIZER(tsm_configfs.su_mutex), +}; + +int tsm_register(const struct tsm_ops *ops, void *priv, + const struct config_item_type *type) +{ + const struct tsm_ops *conflict; + + if (!type) + type = &tsm_report_default_type; + if (!(type == &tsm_report_default_type || type == &tsm_report_extra_type)) + return -EINVAL; + + guard(rwsem_write)(&tsm_rwsem); + conflict = provider.ops; + if (conflict) { + pr_err("\"%s\" ops already registered\n", conflict->name); + return -EBUSY; + } + + provider.ops = ops; + provider.data = priv; + provider.type = type; + return 0; +} +EXPORT_SYMBOL_GPL(tsm_register); + +int tsm_unregister(const struct tsm_ops *ops) +{ + guard(rwsem_write)(&tsm_rwsem); + if (ops != provider.ops) + return -EBUSY; + provider.ops = NULL; + provider.data = NULL; + provider.type = NULL; + return 0; +} +EXPORT_SYMBOL_GPL(tsm_unregister); + +static struct config_group *tsm_report_group; + +static int __init tsm_init(void) +{ + struct config_group *root = &tsm_configfs.su_group; + struct config_group *tsm; + int rc; + + config_group_init(root); + rc = configfs_register_subsystem(&tsm_configfs); + if (rc) + return rc; + + tsm = configfs_register_default_group(root, "report", + &tsm_reports_type); + if (IS_ERR(tsm)) { + configfs_unregister_subsystem(&tsm_configfs); + return PTR_ERR(tsm); + } + tsm_report_group = tsm; + + return 0; +} +module_init(tsm_init); + +static void __exit tsm_exit(void) +{ + configfs_unregister_default_group(tsm_report_group); + configfs_unregister_subsystem(&tsm_configfs); +} +module_exit(tsm_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Provide Trusted Security Module attestation reports via configfs"); -- cgit From 2df2135366833c372f3a14ffcc655f9c5724d972 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 18 Jul 2023 17:55:50 -0700 Subject: virt: sevguest: Prep for kernel internal get_ext_report() In preparation for using the configs-tsm facility to convey attestation blobs to userspace, switch to using the 'sockptr' api for copying payloads to provided buffers where 'sockptr' handles user vs kernel buffers. While configfs-tsm is meant to replace existing confidential computing ioctl() implementations for attestation report retrieval the old ioctl() path needs to stick around for a deprecation period. No behavior change intended. Cc: Borislav Petkov Cc: Tom Lendacky Cc: Dionna Glaze Reviewed-by: Kuppuswamy Sathyanarayanan Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams --- drivers/virt/coco/sev-guest/sev-guest.c | 44 ++++++++++++++++++++++++--------- 1 file changed, 32 insertions(+), 12 deletions(-) (limited to 'drivers/virt') diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 5bee58ef5f1e..e5f8f115f4af 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -475,6 +476,11 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, return 0; } +struct snp_req_resp { + sockptr_t req_data; + sockptr_t resp_data; +}; + static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) { struct snp_guest_crypto *crypto = snp_dev->crypto; @@ -555,22 +561,25 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque return rc; } -static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) +static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg, + struct snp_req_resp *io) + { struct snp_ext_report_req *req = &snp_dev->req.ext_report; struct snp_guest_crypto *crypto = snp_dev->crypto; struct snp_report_resp *resp; int ret, npages = 0, resp_len; + sockptr_t certs_address; lockdep_assert_held(&snp_cmd_mutex); - if (!arg->req_data || !arg->resp_data) + if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data)) return -EINVAL; - if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req))) + if (copy_from_sockptr(req, io->req_data, sizeof(*req))) return -EFAULT; - /* userspace does not want certificate data */ + /* caller does not want certificate data */ if (!req->certs_len || !req->certs_address) goto cmd; @@ -578,8 +587,13 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques !IS_ALIGNED(req->certs_len, PAGE_SIZE)) return -EINVAL; - if (!access_ok((const void __user *)req->certs_address, req->certs_len)) - return -EFAULT; + if (sockptr_is_kernel(io->resp_data)) { + certs_address = KERNEL_SOCKPTR((void *)req->certs_address); + } else { + certs_address = USER_SOCKPTR((void __user *)req->certs_address); + if (!access_ok(certs_address.user, req->certs_len)) + return -EFAULT; + } /* * Initialize the intermediate buffer with all zeros. This buffer @@ -609,21 +623,19 @@ cmd: if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) { req->certs_len = snp_dev->input.data_npages << PAGE_SHIFT; - if (copy_to_user((void __user *)arg->req_data, req, sizeof(*req))) + if (copy_to_sockptr(io->req_data, req, sizeof(*req))) ret = -EFAULT; } if (ret) goto e_free; - if (npages && - copy_to_user((void __user *)req->certs_address, snp_dev->certs_data, - req->certs_len)) { + if (npages && copy_to_sockptr(certs_address, snp_dev->certs_data, req->certs_len)) { ret = -EFAULT; goto e_free; } - if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp))) + if (copy_to_sockptr(io->resp_data, resp, sizeof(*resp))) ret = -EFAULT; e_free: @@ -636,6 +648,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long struct snp_guest_dev *snp_dev = to_snp_dev(file); void __user *argp = (void __user *)arg; struct snp_guest_request_ioctl input; + struct snp_req_resp io; int ret = -ENOTTY; if (copy_from_user(&input, argp, sizeof(input))) @@ -664,7 +677,14 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long ret = get_derived_key(snp_dev, &input); break; case SNP_GET_EXT_REPORT: - ret = get_ext_report(snp_dev, &input); + /* + * As get_ext_report() may be called from the ioctl() path and a + * kernel internal path (configfs-tsm), decorate the passed + * buffers as user pointers. + */ + io.req_data = USER_SOCKPTR((void __user *)input.req_data); + io.resp_data = USER_SOCKPTR((void __user *)input.resp_data); + ret = get_ext_report(snp_dev, &input, &io); break; default: break; -- cgit From f47906782c76294b3468f7584f666bc114927aa1 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 10 Oct 2023 20:03:19 -0700 Subject: virt: sevguest: Add TSM_REPORTS support for SNP_GET_EXT_REPORT The sevguest driver was a first mover in the confidential computing space. As a first mover that afforded some leeway to build the driver without concern for common infrastructure. Now that sevguest is no longer a singleton [1] the common operation of building and transmitting attestation report blobs can / should be made common. In this model the so called "TSM-provider" implementations can share a common envelope ABI even if the contents of that envelope remain vendor-specific. When / if the industry agrees on an attestation record format, that definition can also fit in the same ABI. In the meantime the kernel's maintenance burden is reduced and collaboration on the commons is increased. Convert sevguest to use CONFIG_TSM_REPORTS to retrieve the data that the SNP_GET_EXT_REPORT ioctl produces. An example flow follows for retrieving the report blob via the TSM interface utility, assuming no nonce and VMPL==2: report=/sys/kernel/config/tsm/report/report0 mkdir $report echo 2 > $report/privlevel dd if=/dev/urandom bs=64 count=1 > $report/inblob hexdump -C $report/outblob # SNP report hexdump -C $report/auxblob # cert_table rmdir $report Given that the platform implementation is free to return empty certificate data if none is available it lets configfs-tsm be simplified as it only needs to worry about wrapping SNP_GET_EXT_REPORT, and leave SNP_GET_REPORT alone. The old ioctls can be lazily deprecated, the main motivation of this effort is to stop the proliferation of new ioctls, and to increase cross-vendor collaboration. Link: http://lore.kernel.org/r/64961c3baf8ce_142af829436@dwillia2-xfh.jf.intel.com.notmuch [1] Cc: Borislav Petkov Cc: Tom Lendacky Cc: Dionna Glaze Cc: Jeremi Piotrowski Tested-by: Kuppuswamy Sathyanarayanan Tested-by: Alexey Kardashevskiy Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams --- drivers/virt/coco/sev-guest/Kconfig | 1 + drivers/virt/coco/sev-guest/sev-guest.c | 135 ++++++++++++++++++++++++++++++++ 2 files changed, 136 insertions(+) (limited to 'drivers/virt') diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig index da2d7ca531f0..1cffc72c41cb 100644 --- a/drivers/virt/coco/sev-guest/Kconfig +++ b/drivers/virt/coco/sev-guest/Kconfig @@ -5,6 +5,7 @@ config SEV_GUEST select CRYPTO select CRYPTO_AEAD2 select CRYPTO_GCM + select TSM_REPORTS help SEV-SNP firmware provides the guest a mechanism to communicate with the PSP without risk from a malicious hypervisor who wishes to read, diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index e5f8f115f4af..bc564adcf499 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -16,10 +16,13 @@ #include #include #include +#include #include #include #include #include +#include +#include #include #include @@ -768,6 +771,130 @@ static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno return key; } +struct snp_msg_report_resp_hdr { + u32 status; + u32 report_size; + u8 rsvd[24]; +}; + +struct snp_msg_cert_entry { + guid_t guid; + u32 offset; + u32 length; +}; + +static int sev_report_new(struct tsm_report *report, void *data) +{ + struct snp_msg_cert_entry *cert_table; + struct tsm_desc *desc = &report->desc; + struct snp_guest_dev *snp_dev = data; + struct snp_msg_report_resp_hdr hdr; + const u32 report_size = SZ_4K; + const u32 ext_size = SEV_FW_BLOB_MAX_SIZE; + u32 certs_size, i, size = report_size + ext_size; + int ret; + + if (desc->inblob_len != SNP_REPORT_USER_DATA_SIZE) + return -EINVAL; + + void *buf __free(kvfree) = kvzalloc(size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + guard(mutex)(&snp_cmd_mutex); + + /* Check if the VMPCK is not empty */ + if (is_vmpck_empty(snp_dev)) { + dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n"); + return -ENOTTY; + } + + cert_table = buf + report_size; + struct snp_ext_report_req ext_req = { + .data = { .vmpl = desc->privlevel }, + .certs_address = (__u64)cert_table, + .certs_len = ext_size, + }; + memcpy(&ext_req.data.user_data, desc->inblob, desc->inblob_len); + + struct snp_guest_request_ioctl input = { + .msg_version = 1, + .req_data = (__u64)&ext_req, + .resp_data = (__u64)buf, + .exitinfo2 = 0xff, + }; + struct snp_req_resp io = { + .req_data = KERNEL_SOCKPTR(&ext_req), + .resp_data = KERNEL_SOCKPTR(buf), + }; + + ret = get_ext_report(snp_dev, &input, &io); + if (ret) + return ret; + + memcpy(&hdr, buf, sizeof(hdr)); + if (hdr.status == SEV_RET_INVALID_PARAM) + return -EINVAL; + if (hdr.status == SEV_RET_INVALID_KEY) + return -EINVAL; + if (hdr.status) + return -ENXIO; + if ((hdr.report_size + sizeof(hdr)) > report_size) + return -ENOMEM; + + void *rbuf __free(kvfree) = kvzalloc(hdr.report_size, GFP_KERNEL); + if (!rbuf) + return -ENOMEM; + + memcpy(rbuf, buf + sizeof(hdr), hdr.report_size); + report->outblob = no_free_ptr(rbuf); + report->outblob_len = hdr.report_size; + + certs_size = 0; + for (i = 0; i < ext_size / sizeof(struct snp_msg_cert_entry); i++) { + struct snp_msg_cert_entry *ent = &cert_table[i]; + + if (guid_is_null(&ent->guid) && !ent->offset && !ent->length) + break; + certs_size = max(certs_size, ent->offset + ent->length); + } + + /* Suspicious that the response populated entries without populating size */ + if (!certs_size && i) + dev_warn_ratelimited(snp_dev->dev, "certificate slots conveyed without size\n"); + + /* No certs to report */ + if (!certs_size) + return 0; + + /* Suspicious that the certificate blob size contract was violated + */ + if (certs_size > ext_size) { + dev_warn_ratelimited(snp_dev->dev, "certificate data truncated\n"); + certs_size = ext_size; + } + + void *cbuf __free(kvfree) = kvzalloc(certs_size, GFP_KERNEL); + if (!cbuf) + return -ENOMEM; + + memcpy(cbuf, cert_table, certs_size); + report->auxblob = no_free_ptr(cbuf); + report->auxblob_len = certs_size; + + return 0; +} + +static const struct tsm_ops sev_tsm_ops = { + .name = KBUILD_MODNAME, + .report_new = sev_report_new, +}; + +static void unregister_sev_tsm(void *data) +{ + tsm_unregister(&sev_tsm_ops); +} + static int __init sev_guest_probe(struct platform_device *pdev) { struct snp_secrets_page_layout *layout; @@ -841,6 +968,14 @@ static int __init sev_guest_probe(struct platform_device *pdev) snp_dev->input.resp_gpa = __pa(snp_dev->response); snp_dev->input.data_gpa = __pa(snp_dev->certs_data); + ret = tsm_register(&sev_tsm_ops, snp_dev, &tsm_report_extra_type); + if (ret) + goto e_free_cert_data; + + ret = devm_add_action_or_reset(&pdev->dev, unregister_sev_tsm, NULL); + if (ret) + goto e_free_cert_data; + ret = misc_register(misc); if (ret) goto e_free_cert_data; -- cgit From f4738f56d1dc62aaba69b33702a5ab098f1b8c63 Mon Sep 17 00:00:00 2001 From: Kuppuswamy Sathyanarayanan Date: Mon, 25 Sep 2023 20:10:10 -0700 Subject: virt: tdx-guest: Add Quote generation support using TSM_REPORTS In TDX guest, the attestation process is used to verify the TDX guest trustworthiness to other entities before provisioning secrets to the guest. The first step in the attestation process is TDREPORT generation, which involves getting the guest measurement data in the format of TDREPORT, which is further used to validate the authenticity of the TDX guest. TDREPORT by design is integrity-protected and can only be verified on the local machine. To support remote verification of the TDREPORT in a SGX-based attestation, the TDREPORT needs to be sent to the SGX Quoting Enclave (QE) to convert it to a remotely verifiable Quote. SGX QE by design can only run outside of the TDX guest (i.e. in a host process or in a normal VM) and guest can use communication channels like vsock or TCP/IP to send the TDREPORT to the QE. But for security concerns, the TDX guest may not support these communication channels. To handle such cases, TDX defines a GetQuote hypercall which can be used by the guest to request the host VMM to communicate with the SGX QE. More details about GetQuote hypercall can be found in TDX Guest-Host Communication Interface (GHCI) for Intel TDX 1.0, section titled "TDG.VP.VMCALL". Trusted Security Module (TSM) [1] exposes a common ABI for Confidential Computing Guest platforms to get the measurement data via ConfigFS. Extend the TSM framework and add support to allow an attestation agent to get the TDX Quote data (included usage example below). report=/sys/kernel/config/tsm/report/report0 mkdir $report dd if=/dev/urandom bs=64 count=1 > $report/inblob hexdump -C $report/outblob rmdir $report GetQuote TDVMCALL requires TD guest pass a 4K aligned shared buffer with TDREPORT data as input, which is further used by the VMM to copy the TD Quote result after successful Quote generation. To create the shared buffer, allocate a large enough memory and mark it shared using set_memory_decrypted() in tdx_guest_init(). This buffer will be re-used for GetQuote requests in the TDX TSM handler. Although this method reserves a fixed chunk of memory for GetQuote requests, such one time allocation can help avoid memory fragmentation related allocation failures later in the uptime of the guest. Since the Quote generation process is not time-critical or frequently used, the current version uses a polling model for Quote requests and it also does not support parallel GetQuote requests. Link: https://lore.kernel.org/lkml/169342399185.3934343.3035845348326944519.stgit@dwillia2-xfh.jf.intel.com/ [1] Signed-off-by: Kuppuswamy Sathyanarayanan Reviewed-by: Erdem Aktas Tested-by: Kuppuswamy Sathyanarayanan Tested-by: Peter Gonda Reviewed-by: Tom Lendacky Signed-off-by: Dan Williams --- drivers/virt/coco/tdx-guest/Kconfig | 1 + drivers/virt/coco/tdx-guest/tdx-guest.c | 229 +++++++++++++++++++++++++++++++- 2 files changed, 229 insertions(+), 1 deletion(-) (limited to 'drivers/virt') diff --git a/drivers/virt/coco/tdx-guest/Kconfig b/drivers/virt/coco/tdx-guest/Kconfig index 14246fc2fb02..22dd59e19431 100644 --- a/drivers/virt/coco/tdx-guest/Kconfig +++ b/drivers/virt/coco/tdx-guest/Kconfig @@ -1,6 +1,7 @@ config TDX_GUEST_DRIVER tristate "TDX Guest driver" depends on INTEL_TDX_GUEST + select TSM_REPORTS help The driver provides userspace interface to communicate with the TDX module to request the TDX guest details like attestation diff --git a/drivers/virt/coco/tdx-guest/tdx-guest.c b/drivers/virt/coco/tdx-guest/tdx-guest.c index 5e44a0fa69bd..1253bf76b570 100644 --- a/drivers/virt/coco/tdx-guest/tdx-guest.c +++ b/drivers/virt/coco/tdx-guest/tdx-guest.c @@ -12,12 +12,60 @@ #include #include #include +#include +#include +#include +#include +#include #include #include #include +/* + * Intel's SGX QE implementation generally uses Quote size less + * than 8K (2K Quote data + ~5K of certificate blob). + */ +#define GET_QUOTE_BUF_SIZE SZ_8K + +#define GET_QUOTE_CMD_VER 1 + +/* TDX GetQuote status codes */ +#define GET_QUOTE_SUCCESS 0 +#define GET_QUOTE_IN_FLIGHT 0xffffffffffffffff + +/* struct tdx_quote_buf: Format of Quote request buffer. + * @version: Quote format version, filled by TD. + * @status: Status code of Quote request, filled by VMM. + * @in_len: Length of TDREPORT, filled by TD. + * @out_len: Length of Quote data, filled by VMM. + * @data: Quote data on output or TDREPORT on input. + * + * More details of Quote request buffer can be found in TDX + * Guest-Host Communication Interface (GHCI) for Intel TDX 1.0, + * section titled "TDG.VP.VMCALL" + */ +struct tdx_quote_buf { + u64 version; + u64 status; + u32 in_len; + u32 out_len; + u8 data[]; +}; + +/* Quote data buffer */ +static void *quote_data; + +/* Lock to streamline quote requests */ +static DEFINE_MUTEX(quote_lock); + +/* + * GetQuote request timeout in seconds. Expect that 30 seconds + * is enough time for QE to respond to any Quote requests. + */ +static u32 getquote_timeout = 30; + static long tdx_get_report0(struct tdx_report_req __user *req) { u8 *reportdata, *tdreport; @@ -53,6 +101,154 @@ out: return ret; } +static void free_quote_buf(void *buf) +{ + size_t len = PAGE_ALIGN(GET_QUOTE_BUF_SIZE); + unsigned int count = len >> PAGE_SHIFT; + + if (set_memory_encrypted((unsigned long)buf, count)) { + pr_err("Failed to restore encryption mask for Quote buffer, leak it\n"); + return; + } + + free_pages_exact(buf, len); +} + +static void *alloc_quote_buf(void) +{ + size_t len = PAGE_ALIGN(GET_QUOTE_BUF_SIZE); + unsigned int count = len >> PAGE_SHIFT; + void *addr; + + addr = alloc_pages_exact(len, GFP_KERNEL | __GFP_ZERO); + if (!addr) + return NULL; + + if (set_memory_decrypted((unsigned long)addr, count)) { + free_pages_exact(addr, len); + return NULL; + } + + return addr; +} + +/* + * wait_for_quote_completion() - Wait for Quote request completion + * @quote_buf: Address of Quote buffer. + * @timeout: Timeout in seconds to wait for the Quote generation. + * + * As per TDX GHCI v1.0 specification, sec titled "TDG.VP.VMCALL", + * the status field in the Quote buffer will be set to GET_QUOTE_IN_FLIGHT + * while VMM processes the GetQuote request, and will change it to success + * or error code after processing is complete. So wait till the status + * changes from GET_QUOTE_IN_FLIGHT or the request being timed out. + */ +static int wait_for_quote_completion(struct tdx_quote_buf *quote_buf, u32 timeout) +{ + int i = 0; + + /* + * Quote requests usually take a few seconds to complete, so waking up + * once per second to recheck the status is fine for this use case. + */ + while (quote_buf->status == GET_QUOTE_IN_FLIGHT && i++ < timeout) { + if (msleep_interruptible(MSEC_PER_SEC)) + return -EINTR; + } + + return (i == timeout) ? -ETIMEDOUT : 0; +} + +static int tdx_report_new(struct tsm_report *report, void *data) +{ + u8 *buf, *reportdata = NULL, *tdreport = NULL; + struct tdx_quote_buf *quote_buf = quote_data; + struct tsm_desc *desc = &report->desc; + int ret; + u64 err; + + /* TODO: switch to guard(mutex_intr) */ + if (mutex_lock_interruptible("e_lock)) + return -EINTR; + + /* + * If the previous request is timedout or interrupted, and the + * Quote buf status is still in GET_QUOTE_IN_FLIGHT (owned by + * VMM), don't permit any new request. + */ + if (quote_buf->status == GET_QUOTE_IN_FLIGHT) { + ret = -EBUSY; + goto done; + } + + if (desc->inblob_len != TDX_REPORTDATA_LEN) { + ret = -EINVAL; + goto done; + } + + reportdata = kmalloc(TDX_REPORTDATA_LEN, GFP_KERNEL); + if (!reportdata) { + ret = -ENOMEM; + goto done; + } + + tdreport = kzalloc(TDX_REPORT_LEN, GFP_KERNEL); + if (!tdreport) { + ret = -ENOMEM; + goto done; + } + + memcpy(reportdata, desc->inblob, desc->inblob_len); + + /* Generate TDREPORT0 using "TDG.MR.REPORT" TDCALL */ + ret = tdx_mcall_get_report0(reportdata, tdreport); + if (ret) { + pr_err("GetReport call failed\n"); + goto done; + } + + memset(quote_data, 0, GET_QUOTE_BUF_SIZE); + + /* Update Quote buffer header */ + quote_buf->version = GET_QUOTE_CMD_VER; + quote_buf->in_len = TDX_REPORT_LEN; + + memcpy(quote_buf->data, tdreport, TDX_REPORT_LEN); + + err = tdx_hcall_get_quote(quote_data, GET_QUOTE_BUF_SIZE); + if (err) { + pr_err("GetQuote hypercall failed, status:%llx\n", err); + ret = -EIO; + goto done; + } + + ret = wait_for_quote_completion(quote_buf, getquote_timeout); + if (ret) { + pr_err("GetQuote request timedout\n"); + goto done; + } + + buf = kvmemdup(quote_buf->data, quote_buf->out_len, GFP_KERNEL); + if (!buf) { + ret = -ENOMEM; + goto done; + } + + report->outblob = buf; + report->outblob_len = quote_buf->out_len; + + /* + * TODO: parse the PEM-formatted cert chain out of the quote buffer when + * provided + */ +done: + mutex_unlock("e_lock); + kfree(reportdata); + kfree(tdreport); + + return ret; +} + static long tdx_guest_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -82,17 +278,48 @@ static const struct x86_cpu_id tdx_guest_ids[] = { }; MODULE_DEVICE_TABLE(x86cpu, tdx_guest_ids); +static const struct tsm_ops tdx_tsm_ops = { + .name = KBUILD_MODNAME, + .report_new = tdx_report_new, +}; + static int __init tdx_guest_init(void) { + int ret; + if (!x86_match_cpu(tdx_guest_ids)) return -ENODEV; - return misc_register(&tdx_misc_dev); + ret = misc_register(&tdx_misc_dev); + if (ret) + return ret; + + quote_data = alloc_quote_buf(); + if (!quote_data) { + pr_err("Failed to allocate Quote buffer\n"); + ret = -ENOMEM; + goto free_misc; + } + + ret = tsm_register(&tdx_tsm_ops, NULL, NULL); + if (ret) + goto free_quote; + + return 0; + +free_quote: + free_quote_buf(quote_data); +free_misc: + misc_deregister(&tdx_misc_dev); + + return ret; } module_init(tdx_guest_init); static void __exit tdx_guest_exit(void) { + tsm_unregister(&tdx_tsm_ops); + free_quote_buf(quote_data); misc_deregister(&tdx_misc_dev); } module_exit(tdx_guest_exit); -- cgit