diff options
-rw-r--r-- | Documentation/ABI/testing/configfs-tsm | 64 | ||||
-rw-r--r-- | arch/x86/include/asm/sev.h | 31 | ||||
-rw-r--r-- | arch/x86/kernel/sev.c | 50 | ||||
-rw-r--r-- | drivers/virt/coco/sev-guest/sev-guest.c | 179 | ||||
-rw-r--r-- | drivers/virt/coco/tsm.c | 93 | ||||
-rw-r--r-- | include/linux/tsm.h | 19 |
6 files changed, 433 insertions, 3 deletions
diff --git a/Documentation/ABI/testing/configfs-tsm b/Documentation/ABI/testing/configfs-tsm index dd24202b5ba5..1db2008f25f9 100644 --- a/Documentation/ABI/testing/configfs-tsm +++ b/Documentation/ABI/testing/configfs-tsm @@ -31,6 +31,18 @@ Description: Standardization v2.03 Section 4.1.8.1 MSG_REPORT_REQ. https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56421.pdf +What: /sys/kernel/config/tsm/report/$name/manifestblob +Date: January, 2024 +KernelVersion: v6.10 +Contact: linux-coco@lists.linux.dev +Description: + (RO) Optional supplemental data that a TSM may emit, visibility + of this attribute depends on TSM, and may be empty if no + manifest data is available. + + See 'service_provider' for information on the format of the + manifest blob. + What: /sys/kernel/config/tsm/report/$name/provider Date: September, 2023 KernelVersion: v6.7 @@ -80,3 +92,55 @@ Contact: linux-coco@lists.linux.dev Description: (RO) Indicates the minimum permissible value that can be written to @privlevel. + +What: /sys/kernel/config/tsm/report/$name/service_provider +Date: January, 2024 +KernelVersion: v6.10 +Contact: linux-coco@lists.linux.dev +Description: + (WO) Attribute is visible if a TSM implementation provider + supports the concept of attestation reports from a service + provider for TVMs, like SEV-SNP running under an SVSM. + Specifying the service provider via this attribute will create + an attestation report as specified by the service provider. + Currently supported service-providers are: + svsm + + For the "svsm" service provider, see the Secure VM Service Module + for SEV-SNP Guests v1.00 Section 7. For the doc, search for + "site:amd.com "Secure VM Service Module for SEV-SNP + Guests", docID: 58019" + +What: /sys/kernel/config/tsm/report/$name/service_guid +Date: January, 2024 +KernelVersion: v6.10 +Contact: linux-coco@lists.linux.dev +Description: + (WO) Attribute is visible if a TSM implementation provider + supports the concept of attestation reports from a service + provider for TVMs, like SEV-SNP running under an SVSM. + Specifying an empty/null GUID (00000000-0000-0000-0000-000000) + requests all active services within the service provider be + part of the attestation report. Specifying a GUID request + an attestation report of just the specified service using the + manifest form specified by the service_manifest_version + attribute. + + See 'service_provider' for information on the format of the + service guid. + +What: /sys/kernel/config/tsm/report/$name/service_manifest_version +Date: January, 2024 +KernelVersion: v6.10 +Contact: linux-coco@lists.linux.dev +Description: + (WO) Attribute is visible if a TSM implementation provider + supports the concept of attestation reports from a service + provider for TVMs, like SEV-SNP running under an SVSM. + Indicates the service manifest version requested for the + attestation report (default 0). If this field is not set by + the user, the default manifest version of the service (the + service's initial/first manifest version) is returned. + + See 'service_provider' for information on the format of the + service manifest version. diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 9c6f269d4bf5..ac5886ce252e 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -214,6 +214,27 @@ struct svsm_pvalidate_call { sizeof(struct svsm_pvalidate_entry)) /* + * The SVSM Attestation related structures + */ +struct svsm_loc_entry { + u64 pa; + u32 len; + u8 rsvd[4]; +}; + +struct svsm_attest_call { + struct svsm_loc_entry report_buf; + struct svsm_loc_entry nonce; + struct svsm_loc_entry manifest_buf; + struct svsm_loc_entry certificates_buf; + + /* For attesting a single service */ + u8 service_guid[16]; + u32 service_manifest_ver; + u8 rsvd[4]; +}; + +/* * SVSM protocol structure */ struct svsm_call { @@ -236,6 +257,10 @@ struct svsm_call { #define SVSM_CORE_CREATE_VCPU 2 #define SVSM_CORE_DELETE_VCPU 3 +#define SVSM_ATTEST_CALL(x) ((1ULL << 32) | (x)) +#define SVSM_ATTEST_SERVICES 0 +#define SVSM_ATTEST_SINGLE_SERVICE 1 + #ifdef CONFIG_AMD_MEM_ENCRYPT extern u8 snp_vmpl; @@ -317,6 +342,7 @@ bool snp_init(struct boot_params *bp); void __noreturn snp_abort(void); void snp_dmi_setup(void); int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio); +int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call, struct svsm_attest_call *input); void snp_accept_memory(phys_addr_t start, phys_addr_t end); u64 snp_get_unsupported_features(u64 status); u64 sev_get_status(void); @@ -349,7 +375,10 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in { return -ENOTTY; } - +static inline int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call, struct svsm_attest_call *input) +{ + return -ENOTTY; +} static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { } static inline u64 snp_get_unsupported_features(u64 status) { return 0; } static inline u64 sev_get_status(void) { return 0; } diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 4dc7ae33eac9..53ac3e0fc92a 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2387,6 +2387,56 @@ static int __init init_sev_config(char *str) } __setup("sev=", init_sev_config); +static void update_attest_input(struct svsm_call *call, struct svsm_attest_call *input) +{ + /* If (new) lengths have been returned, propagate them up */ + if (call->rcx_out != call->rcx) + input->manifest_buf.len = call->rcx_out; + + if (call->rdx_out != call->rdx) + input->certificates_buf.len = call->rdx_out; + + if (call->r8_out != call->r8) + input->report_buf.len = call->r8_out; +} + +int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call, + struct svsm_attest_call *input) +{ + struct svsm_attest_call *ac; + unsigned long flags; + u64 attest_call_pa; + int ret; + + if (!snp_vmpl) + return -EINVAL; + + local_irq_save(flags); + + call->caa = svsm_get_caa(); + + ac = (struct svsm_attest_call *)call->caa->svsm_buffer; + attest_call_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer); + + *ac = *input; + + /* + * Set input registers for the request and set RDX and R8 to known + * values in order to detect length values being returned in them. + */ + call->rax = call_id; + call->rcx = attest_call_pa; + call->rdx = -1; + call->r8 = -1; + ret = svsm_perform_call_protocol(call); + update_attest_input(call, input); + + local_irq_restore(flags); + + return ret; +} +EXPORT_SYMBOL_GPL(snp_issue_svsm_attest_req); + int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio) { struct ghcb_state state; diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 0c70a38c8cc0..37522886ae95 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -39,6 +39,8 @@ #define SNP_REQ_MAX_RETRY_DURATION (60*HZ) #define SNP_REQ_RETRY_DELAY (2*HZ) +#define SVSM_MAX_RETRIES 3 + struct snp_guest_crypto { struct crypto_aead *tfm; u8 *iv, *authtag; @@ -791,6 +793,143 @@ struct snp_msg_cert_entry { u32 length; }; +static int sev_svsm_report_new(struct tsm_report *report, void *data) +{ + unsigned int rep_len, man_len, certs_len; + struct tsm_desc *desc = &report->desc; + struct svsm_attest_call ac = {}; + unsigned int retry_count; + void *rep, *man, *certs; + struct svsm_call call; + unsigned int size; + bool try_again; + void *buffer; + u64 call_id; + int ret; + + /* + * Allocate pages for the request: + * - Report blob (4K) + * - Manifest blob (4K) + * - Certificate blob (16K) + * + * Above addresses must be 4K aligned + */ + rep_len = SZ_4K; + man_len = SZ_4K; + certs_len = SEV_FW_BLOB_MAX_SIZE; + + guard(mutex)(&snp_cmd_mutex); + + if (guid_is_null(&desc->service_guid)) { + call_id = SVSM_ATTEST_CALL(SVSM_ATTEST_SERVICES); + } else { + export_guid(ac.service_guid, &desc->service_guid); + ac.service_manifest_ver = desc->service_manifest_version; + + call_id = SVSM_ATTEST_CALL(SVSM_ATTEST_SINGLE_SERVICE); + } + + retry_count = 0; + +retry: + memset(&call, 0, sizeof(call)); + + size = rep_len + man_len + certs_len; + buffer = alloc_pages_exact(size, __GFP_ZERO); + if (!buffer) + return -ENOMEM; + + rep = buffer; + ac.report_buf.pa = __pa(rep); + ac.report_buf.len = rep_len; + + man = rep + rep_len; + ac.manifest_buf.pa = __pa(man); + ac.manifest_buf.len = man_len; + + certs = man + man_len; + ac.certificates_buf.pa = __pa(certs); + ac.certificates_buf.len = certs_len; + + ac.nonce.pa = __pa(desc->inblob); + ac.nonce.len = desc->inblob_len; + + ret = snp_issue_svsm_attest_req(call_id, &call, &ac); + if (ret) { + free_pages_exact(buffer, size); + + switch (call.rax_out) { + case SVSM_ERR_INVALID_PARAMETER: + try_again = false; + + if (ac.report_buf.len > rep_len) { + rep_len = PAGE_ALIGN(ac.report_buf.len); + try_again = true; + } + + if (ac.manifest_buf.len > man_len) { + man_len = PAGE_ALIGN(ac.manifest_buf.len); + try_again = true; + } + + if (ac.certificates_buf.len > certs_len) { + certs_len = PAGE_ALIGN(ac.certificates_buf.len); + try_again = true; + } + + /* If one of the buffers wasn't large enough, retry the request */ + if (try_again && retry_count < SVSM_MAX_RETRIES) { + retry_count++; + goto retry; + } + + return -EINVAL; + default: + pr_err_ratelimited("SVSM attestation request failed (%d / 0x%llx)\n", + ret, call.rax_out); + return -EINVAL; + } + } + + /* + * Allocate all the blob memory buffers at once so that the cleanup is + * done for errors that occur after the first allocation (i.e. before + * using no_free_ptr()). + */ + rep_len = ac.report_buf.len; + void *rbuf __free(kvfree) = kvzalloc(rep_len, GFP_KERNEL); + + man_len = ac.manifest_buf.len; + void *mbuf __free(kvfree) = kvzalloc(man_len, GFP_KERNEL); + + certs_len = ac.certificates_buf.len; + void *cbuf __free(kvfree) = certs_len ? kvzalloc(certs_len, GFP_KERNEL) : NULL; + + if (!rbuf || !mbuf || (certs_len && !cbuf)) { + free_pages_exact(buffer, size); + return -ENOMEM; + } + + memcpy(rbuf, rep, rep_len); + report->outblob = no_free_ptr(rbuf); + report->outblob_len = rep_len; + + memcpy(mbuf, man, man_len); + report->manifestblob = no_free_ptr(mbuf); + report->manifestblob_len = man_len; + + if (certs_len) { + memcpy(cbuf, certs, certs_len); + report->auxblob = no_free_ptr(cbuf); + report->auxblob_len = certs_len; + } + + free_pages_exact(buffer, size); + + return 0; +} + static int sev_report_new(struct tsm_report *report, void *data) { struct snp_msg_cert_entry *cert_table; @@ -805,6 +944,13 @@ static int sev_report_new(struct tsm_report *report, void *data) if (desc->inblob_len != SNP_REPORT_USER_DATA_SIZE) return -EINVAL; + if (desc->service_provider) { + if (strcmp(desc->service_provider, "svsm")) + return -EINVAL; + + return sev_svsm_report_new(report, data); + } + void *buf __free(kvfree) = kvzalloc(size, GFP_KERNEL); if (!buf) return -ENOMEM; @@ -893,9 +1039,42 @@ static int sev_report_new(struct tsm_report *report, void *data) return 0; } +static bool sev_report_attr_visible(int n) +{ + switch (n) { + case TSM_REPORT_GENERATION: + case TSM_REPORT_PROVIDER: + case TSM_REPORT_PRIVLEVEL: + case TSM_REPORT_PRIVLEVEL_FLOOR: + return true; + case TSM_REPORT_SERVICE_PROVIDER: + case TSM_REPORT_SERVICE_GUID: + case TSM_REPORT_SERVICE_MANIFEST_VER: + return snp_vmpl; + } + + return false; +} + +static bool sev_report_bin_attr_visible(int n) +{ + switch (n) { + case TSM_REPORT_INBLOB: + case TSM_REPORT_OUTBLOB: + case TSM_REPORT_AUXBLOB: + return true; + case TSM_REPORT_MANIFESTBLOB: + return snp_vmpl; + } + + return false; +} + static struct tsm_ops sev_tsm_ops = { .name = KBUILD_MODNAME, .report_new = sev_report_new, + .report_attr_visible = sev_report_attr_visible, + .report_bin_attr_visible = sev_report_bin_attr_visible, }; static void unregister_sev_tsm(void *data) diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm.c index 7db534b63c9f..9432d4e303f1 100644 --- a/drivers/virt/coco/tsm.c +++ b/drivers/virt/coco/tsm.c @@ -34,7 +34,7 @@ static DECLARE_RWSEM(tsm_rwsem); * 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'. + * 'auxblob' and 'manifestblob'. */ struct tsm_report_state { @@ -47,6 +47,7 @@ struct tsm_report_state { enum tsm_data_select { TSM_REPORT, TSM_CERTS, + TSM_MANIFEST, }; static struct tsm_report *to_tsm_report(struct config_item *cfg) @@ -118,6 +119,74 @@ static ssize_t tsm_report_privlevel_floor_show(struct config_item *cfg, } CONFIGFS_ATTR_RO(tsm_report_, privlevel_floor); +static ssize_t tsm_report_service_provider_store(struct config_item *cfg, + const char *buf, size_t len) +{ + struct tsm_report *report = to_tsm_report(cfg); + size_t sp_len; + char *sp; + int rc; + + guard(rwsem_write)(&tsm_rwsem); + rc = try_advance_write_generation(report); + if (rc) + return rc; + + sp_len = (buf[len - 1] != '\n') ? len : len - 1; + + sp = kstrndup(buf, sp_len, GFP_KERNEL); + if (!sp) + return -ENOMEM; + kfree(report->desc.service_provider); + + report->desc.service_provider = sp; + + return len; +} +CONFIGFS_ATTR_WO(tsm_report_, service_provider); + +static ssize_t tsm_report_service_guid_store(struct config_item *cfg, + const char *buf, size_t len) +{ + 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.service_guid = guid_null; + + rc = guid_parse(buf, &report->desc.service_guid); + if (rc) + return rc; + + return len; +} +CONFIGFS_ATTR_WO(tsm_report_, service_guid); + +static ssize_t tsm_report_service_manifest_version_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; + + guard(rwsem_write)(&tsm_rwsem); + rc = try_advance_write_generation(report); + if (rc) + return rc; + report->desc.service_manifest_version = val; + + return len; +} +CONFIGFS_ATTR_WO(tsm_report_, service_manifest_version); + static ssize_t tsm_report_inblob_write(struct config_item *cfg, const void *buf, size_t count) { @@ -162,6 +231,9 @@ static ssize_t __read_report(struct tsm_report *report, void *buf, size_t count, if (select == TSM_REPORT) { out = report->outblob; len = report->outblob_len; + } else if (select == TSM_MANIFEST) { + out = report->manifestblob; + len = report->manifestblob_len; } else { out = report->auxblob; len = report->auxblob_len; @@ -187,7 +259,7 @@ static ssize_t read_cached_report(struct tsm_report *report, void *buf, /* * A given TSM backend always fills in ->outblob regardless of - * whether the report includes an auxblob or not. + * whether the report includes an auxblob/manifestblob or not. */ if (!report->outblob || state->read_generation != state->write_generation) @@ -223,8 +295,10 @@ static ssize_t tsm_report_read(struct tsm_report *report, void *buf, kvfree(report->outblob); kvfree(report->auxblob); + kvfree(report->manifestblob); report->outblob = NULL; report->auxblob = NULL; + report->manifestblob = NULL; rc = ops->report_new(report, provider.data); if (rc < 0) return rc; @@ -251,11 +325,23 @@ static ssize_t tsm_report_auxblob_read(struct config_item *cfg, void *buf, } CONFIGFS_BIN_ATTR_RO(tsm_report_, auxblob, NULL, TSM_OUTBLOB_MAX); +static ssize_t tsm_report_manifestblob_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_MANIFEST); +} +CONFIGFS_BIN_ATTR_RO(tsm_report_, manifestblob, NULL, TSM_OUTBLOB_MAX); + static struct configfs_attribute *tsm_report_attrs[] = { [TSM_REPORT_GENERATION] = &tsm_report_attr_generation, [TSM_REPORT_PROVIDER] = &tsm_report_attr_provider, [TSM_REPORT_PRIVLEVEL] = &tsm_report_attr_privlevel, [TSM_REPORT_PRIVLEVEL_FLOOR] = &tsm_report_attr_privlevel_floor, + [TSM_REPORT_SERVICE_PROVIDER] = &tsm_report_attr_service_provider, + [TSM_REPORT_SERVICE_GUID] = &tsm_report_attr_service_guid, + [TSM_REPORT_SERVICE_MANIFEST_VER] = &tsm_report_attr_service_manifest_version, NULL, }; @@ -263,6 +349,7 @@ static struct configfs_bin_attribute *tsm_report_bin_attrs[] = { [TSM_REPORT_INBLOB] = &tsm_report_attr_inblob, [TSM_REPORT_OUTBLOB] = &tsm_report_attr_outblob, [TSM_REPORT_AUXBLOB] = &tsm_report_attr_auxblob, + [TSM_REPORT_MANIFESTBLOB] = &tsm_report_attr_manifestblob, NULL, }; @@ -271,8 +358,10 @@ 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->manifestblob); kvfree(report->auxblob); kvfree(report->outblob); + kfree(report->desc.service_provider); kfree(state); } diff --git a/include/linux/tsm.h b/include/linux/tsm.h index 30d9d270b446..11b0c525be30 100644 --- a/include/linux/tsm.h +++ b/include/linux/tsm.h @@ -4,6 +4,7 @@ #include <linux/sizes.h> #include <linux/types.h> +#include <linux/uuid.h> #define TSM_INBLOB_MAX 64 #define TSM_OUTBLOB_MAX SZ_32K @@ -19,11 +20,17 @@ * @privlevel: optional privilege level to associate with @outblob * @inblob_len: sizeof @inblob * @inblob: arbitrary input data + * @service_provider: optional name of where to obtain the tsm report blob + * @service_guid: optional service-provider service guid to attest + * @service_manifest_version: optional service-provider service manifest version requested */ struct tsm_desc { unsigned int privlevel; size_t inblob_len; u8 inblob[TSM_INBLOB_MAX]; + char *service_provider; + guid_t service_guid; + unsigned int service_manifest_version; }; /** @@ -33,6 +40,8 @@ struct tsm_desc { * @outblob: generated evidence to provider to the attestation agent * @auxblob_len: sizeof(@auxblob) * @auxblob: (optional) auxiliary data to the report (e.g. certificate data) + * @manifestblob_len: sizeof(@manifestblob) + * @manifestblob: (optional) manifest data associated with the report */ struct tsm_report { struct tsm_desc desc; @@ -40,6 +49,8 @@ struct tsm_report { u8 *outblob; size_t auxblob_len; u8 *auxblob; + size_t manifestblob_len; + u8 *manifestblob; }; /** @@ -48,12 +59,18 @@ struct tsm_report { * @TSM_REPORT_PROVIDER: index of the provider name attribute * @TSM_REPORT_PRIVLEVEL: index of the desired privilege level attribute * @TSM_REPORT_PRIVLEVEL_FLOOR: index of the minimum allowed privileg level attribute + * @TSM_REPORT_SERVICE_PROVIDER: index of the service provider identifier attribute + * @TSM_REPORT_SERVICE_GUID: index of the service GUID attribute + * @TSM_REPORT_SERVICE_MANIFEST_VER: index of the service manifest version attribute */ enum tsm_attr_index { TSM_REPORT_GENERATION, TSM_REPORT_PROVIDER, TSM_REPORT_PRIVLEVEL, TSM_REPORT_PRIVLEVEL_FLOOR, + TSM_REPORT_SERVICE_PROVIDER, + TSM_REPORT_SERVICE_GUID, + TSM_REPORT_SERVICE_MANIFEST_VER, }; /** @@ -61,11 +78,13 @@ enum tsm_attr_index { * @TSM_REPORT_INBLOB: index of the binary report input attribute * @TSM_REPORT_OUTBLOB: index of the binary report output attribute * @TSM_REPORT_AUXBLOB: index of the binary auxiliary data attribute + * @TSM_REPORT_MANIFESTBLOB: index of the binary manifest data attribute */ enum tsm_bin_attr_index { TSM_REPORT_INBLOB, TSM_REPORT_OUTBLOB, TSM_REPORT_AUXBLOB, + TSM_REPORT_MANIFESTBLOB, }; /** |