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path: root/drivers/virt/coco
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-rw-r--r--drivers/virt/coco/Kconfig14
-rw-r--r--drivers/virt/coco/Makefile8
-rw-r--r--drivers/virt/coco/sev-guest/Kconfig1
-rw-r--r--drivers/virt/coco/sev-guest/sev-guest.c214
-rw-r--r--drivers/virt/coco/tdx-guest/Kconfig1
-rw-r--r--drivers/virt/coco/tdx-guest/tdx-guest.c229
-rw-r--r--drivers/virt/coco/tsm.c425
7 files changed, 864 insertions, 28 deletions
diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig
new file mode 100644
index 000000000000..87d142c1f932
--- /dev/null
+++ b/drivers/virt/coco/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# 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"
+
+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..18c1aba5edb7
--- /dev/null
+++ b/drivers/virt/coco/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# 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/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 97dbe715e96a..bc564adcf499 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -16,9 +16,13 @@
#include <linux/miscdevice.h>
#include <linux/set_memory.h>
#include <linux/fs.h>
+#include <linux/tsm.h>
#include <crypto/aead.h>
#include <linux/scatterlist.h>
#include <linux/psp-sev.h>
+#include <linux/sockptr.h>
+#include <linux/cleanup.h>
+#include <linux/uuid.h>
#include <uapi/linux/sev-guest.h>
#include <uapi/linux/psp-sev.h>
@@ -57,6 +61,11 @@ 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;
};
@@ -470,11 +479,16 @@ 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;
+ 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 +496,7 @@ 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 +510,7 @@ 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 +525,9 @@ 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 +546,11 @@ 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;
@@ -550,31 +564,39 @@ 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_ext_report_req req;
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 */
- if (!req.certs_len || !req.certs_address)
+ /* caller does not want certificate data */
+ 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))
- 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
@@ -582,8 +604,8 @@ 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
@@ -597,28 +619,26 @@ 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_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:
@@ -631,6 +651,7 @@ 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)))
@@ -659,7 +680,14 @@ 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;
@@ -743,6 +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;
@@ -816,6 +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;
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 <linux/mod_devicetable.h>
#include <linux/string.h>
#include <linux/uaccess.h>
+#include <linux/set_memory.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/tsm.h>
+#include <linux/sizes.h>
#include <uapi/linux/tdx-guest.h>
#include <asm/cpu_device_id.h>
#include <asm/tdx.h>
+/*
+ * 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<GetQuote>"
+ */
+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<GetQuote>",
+ * 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(&quote_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(&quote_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);
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 <linux/tsm.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/rwsem.h>
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/cleanup.h>
+#include <linux/configfs.h>
+
+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");
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-17 12:28:01 +0300