| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20250523095322.88774-10-chao.gao@intel.com>
Date: Fri, 23 May 2025 02:52:32 -0700
From: Chao Gao <chao.gao@...el.com>
To: linux-coco@...ts.linux.dev,
x86@...nel.org,
kvm@...r.kernel.org
Cc: seanjc@...gle.com,
pbonzini@...hat.com,
eddie.dong@...el.com,
kirill.shutemov@...el.com,
dave.hansen@...el.com,
dan.j.williams@...el.com,
kai.huang@...el.com,
isaku.yamahata@...el.com,
elena.reshetova@...el.com,
rick.p.edgecombe@...el.com,
Chao Gao <chao.gao@...el.com>,
Farrah Chen <farrah.chen@...el.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>,
linux-kernel@...r.kernel.org
Subject: [RFC PATCH 09/20] x86/virt/seamldr: Allocate and populate a module update request
Allocate and populate a module update request, i.e., struct seamldr_params,
as defined in "SEAM Loader (SEAMLDR) Interface Specification" [1],
Revision 343755-004, Section 3.2.
struct seamldr_params includes a module binary, a sigstruct file, and an
update scenario. Parse the bitstream format, as defined by Intel, to
extract the binary and the sigstruct.
Currently, only the "UPDATE" scenario is supported.
Signed-off-by: Chao Gao <chao.gao@...el.com>
Tested-by: Farrah Chen <farrah.chen@...el.com>
Link: https://cdrdv2.intel.com/v1/dl/getContent/733584 [1]
---
arch/x86/virt/vmx/tdx/seamldr.c | 145 +++++++++++++++++++++++++++++++-
1 file changed, 144 insertions(+), 1 deletion(-)
diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c
index da862e71ebce..cdf85dff6d69 100644
--- a/arch/x86/virt/vmx/tdx/seamldr.c
+++ b/arch/x86/virt/vmx/tdx/seamldr.c
@@ -11,6 +11,8 @@
#include <linux/firmware.h>
#include <linux/gfp.h>
#include <linux/kobject.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
#include <linux/sysfs.h>
#include "tdx.h"
@@ -41,6 +43,26 @@ struct tdx_status {
DECLARE_BITMAP(fw_state, TDX_FW_STATE_BITS);
};
+/* SEAMLDR can accept up to 496 4KB pages for TDX module binary */
+#define SEAMLDR_MAX_NR_MODULE_4KB_PAGES 496
+
+/* scenario field in struct seamldr_params */
+#define SEAMLDR_SCENARIO_UPDATE 1
+
+/*
+ * Passed to P-SEAMLDR to describe information about the TDX module to install.
+ * Defined in "SEAM Loader (SEAMLDR) Interface Specification", Revision
+ * 343755-003, Section 3.2.
+ */
+struct seamldr_params {
+ u32 version;
+ u32 scenario;
+ u64 sigstruct_pa;
+ u8 reserved[104];
+ u64 num_module_pages;
+ u64 mod_pages_pa_list[SEAMLDR_MAX_NR_MODULE_4KB_PAGES];
+} __packed;
+
struct fw_upload *tdx_fwl;
static struct tdx_status tdx_status;
static struct seamldr_info seamldr_info __aligned(256);
@@ -113,9 +135,130 @@ int get_seamldr_info(void)
return seamldr_call(P_SEAMLDR_INFO, &args);
}
+static void free_seamldr_params(struct seamldr_params *params)
+{
+ free_page((unsigned long)params);
+}
+
+/* Allocate and populate a seamldr_params */
+static struct seamldr_params *alloc_seamldr_params(const void *module, int module_size,
+ const void *sig, int sig_size)
+{
+ struct seamldr_params *params;
+ const u8 *ptr;
+ int i;
+
+ BUILD_BUG_ON(sizeof(struct seamldr_params) != SZ_4K);
+ if (module_size > SEAMLDR_MAX_NR_MODULE_4KB_PAGES * SZ_4K)
+ return ERR_PTR(-EINVAL);
+
+ /* current seamldr_params accepts one 4KB-page for sigstruct */
+ if (sig_size != SZ_4K)
+ return ERR_PTR(-EINVAL);
+
+ params = (struct seamldr_params *)get_zeroed_page(GFP_KERNEL);
+ if (!params)
+ return ERR_PTR(-ENOMEM);
+
+ params->scenario = SEAMLDR_SCENARIO_UPDATE;
+ params->sigstruct_pa = (vmalloc_to_pfn(sig) << PAGE_SHIFT) +
+ ((unsigned long)sig & ~PAGE_MASK);
+ params->num_module_pages = DIV_ROUND_UP(module_size, SZ_4K);
+
+ ptr = module;
+ for (i = 0; i < params->num_module_pages; i++) {
+ params->mod_pages_pa_list[i] = (vmalloc_to_pfn(ptr) << PAGE_SHIFT) +
+ ((unsigned long)ptr & ~PAGE_MASK);
+ ptr += SZ_4K;
+ }
+
+ return params;
+}
+
+struct tdx_blob {
+ u16 version;
+ u16 checksum;
+ u32 offset_of_module;
+ u8 signature[8];
+ u32 len;
+ u32 resv1;
+ u64 resv2[509];
+ u8 data[];
+} __packed;
+
+/* Verify that the checksum of the entire blob is zero */
+static bool verify_checksum(const struct tdx_blob *blob)
+{
+ u32 size = blob->len;
+ u16 checksum = 0;
+ const u16 *p;
+ int i;
+
+ /* Handle the last byte if the size is odd */
+ if (size % 2) {
+ checksum += *((const u8 *)blob + size - 1);
+ size--;
+ }
+
+ p = (const u16 *)blob;
+ for (i = 0; i < size; i += 2) {
+ checksum += *p;
+ p++;
+ }
+
+ return !checksum;
+}
+
+static struct seamldr_params *init_seamldr_params(const u8 *data, u32 size)
+{
+ const struct tdx_blob *blob = (const void *)data;
+ const void *sig, *module;
+ int module_size, sig_size;
+
+ /* Split the given blob into a sigstruct and a module */
+ sig = blob->data;
+ sig_size = blob->offset_of_module - sizeof(struct tdx_blob);
+ module = data + blob->offset_of_module;
+ module_size = size - blob->offset_of_module;
+
+ if (sig_size <= 0 || module_size <= 0 || blob->len != size)
+ return ERR_PTR(-EINVAL);
+
+ if (memcmp(blob->signature, "TDX-BLOB", 8)) {
+ pr_err("invalid signature\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (!verify_checksum(blob)) {
+ pr_err("invalid checksum\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ return alloc_seamldr_params(module, module_size, sig, sig_size);
+}
+
+/*
+ * Temporary flag to guard TD-Preserving updates. This will be removed once
+ * all necessary components for its support are integrated.
+ */
+static bool td_preserving_ready;
+
+DEFINE_FREE(free_seamldr_params, struct seamldr_params *,
+ if (!IS_ERR_OR_NULL(_T)) free_seamldr_params(_T))
+
static int seamldr_install_module(const u8 *data, u32 size)
{
- return -EOPNOTSUPP;
+ if (!td_preserving_ready)
+ return -EOPNOTSUPP;
+
+ struct seamldr_params *params __free(free_seamldr_params) =
+ init_seamldr_params(data, size);
+ if (IS_ERR(params))
+ return PTR_ERR(params);
+
+ /* TODO: Install and initialize the new TDX module */
+
+ return 0;
}
static enum fw_upload_err tdx_fw_prepare(struct fw_upload *fwl,
--
2.47.1
Powered by blists - more mailing lists