Re: [PATCH v8 04/15] x86: Secure Launch Resource Table header file

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On 2/15/24 12:08 AM, Ard Biesheuvel wrote:
On Wed, 14 Feb 2024 at 23:31, Ross Philipson <ross.philipson@xxxxxxxxxx> wrote:

Introduce the Secure Launch Resource Table which forms the formal
interface between the pre and post launch code.

Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxxx>
---
  include/linux/slr_table.h | 270 ++++++++++++++++++++++++++++++++++++++
  1 file changed, 270 insertions(+)
  create mode 100644 include/linux/slr_table.h

diff --git a/include/linux/slr_table.h b/include/linux/slr_table.h
new file mode 100644
index 000000000000..42020988233a
--- /dev/null
+++ b/include/linux/slr_table.h
@@ -0,0 +1,270 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Secure Launch Resource Table
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#ifndef _LINUX_SLR_TABLE_H
+#define _LINUX_SLR_TABLE_H
+
+/* Put this in efi.h if it becomes a standard */
+#define SLR_TABLE_GUID                         EFI_GUID(0x877a9b2a, 0x0385, 0x45d1, 0xa0, 0x34, 0x9d, 0xac, 0x9c, 0x9e, 0x56, 0x5f)
+
+/* SLR table header values */
+#define SLR_TABLE_MAGIC                0x4452544d
+#define SLR_TABLE_REVISION     1
+
+/* Current revisions for the policy and UEFI config */
+#define SLR_POLICY_REVISION            1
+#define SLR_UEFI_CONFIG_REVISION       1
+
+/* SLR defined architectures */
+#define SLR_INTEL_TXT          1
+#define SLR_AMD_SKINIT         2
+
+/* SLR defined bootloaders */
+#define SLR_BOOTLOADER_INVALID 0
+#define SLR_BOOTLOADER_GRUB    1
+
+/* Log formats */
+#define SLR_DRTM_TPM12_LOG     1
+#define SLR_DRTM_TPM20_LOG     2
+
+/* DRTM Policy Entry Flags */
+#define SLR_POLICY_FLAG_MEASURED       0x1
+#define SLR_POLICY_IMPLICIT_SIZE       0x2
+
+/* Array Lengths */
+#define TPM_EVENT_INFO_LENGTH          32
+#define TXT_VARIABLE_MTRRS_LENGTH      32
+
+/* Tags */
+#define SLR_ENTRY_INVALID      0x0000
+#define SLR_ENTRY_DL_INFO      0x0001
+#define SLR_ENTRY_LOG_INFO     0x0002
+#define SLR_ENTRY_ENTRY_POLICY 0x0003
+#define SLR_ENTRY_INTEL_INFO   0x0004
+#define SLR_ENTRY_AMD_INFO     0x0005
+#define SLR_ENTRY_ARM_INFO     0x0006
+#define SLR_ENTRY_UEFI_INFO    0x0007
+#define SLR_ENTRY_UEFI_CONFIG  0x0008
+#define SLR_ENTRY_END          0xffff
+
+/* Entity Types */
+#define SLR_ET_UNSPECIFIED     0x0000
+#define SLR_ET_SLRT            0x0001
+#define SLR_ET_BOOT_PARAMS     0x0002
+#define SLR_ET_SETUP_DATA      0x0003
+#define SLR_ET_CMDLINE         0x0004
+#define SLR_ET_UEFI_MEMMAP     0x0005
+#define SLR_ET_RAMDISK         0x0006
+#define SLR_ET_TXT_OS2MLE      0x0010
+#define SLR_ET_UNUSED          0xffff
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Primary SLR Table Header
+ */
+struct slr_table {
+       u32 magic;
+       u16 revision;
+       u16 architecture;
+       u32 size;
+       u32 max_size;
+       /* entries[] */
+} __packed;

Packing this struct has no effect on the layout so better drop the
__packed here. If this table is part of a structure that can appear
misaligned in memory, better to pack the outer struct or deal with it
there in another way.

+
+/*
+ * Common SLRT Table Header
+ */
+struct slr_entry_hdr {
+       u16 tag;
+       u16 size;
+} __packed;

Same here

+
+/*
+ * Boot loader context
+ */
+struct slr_bl_context {
+       u16 bootloader;
+       u16 reserved;
+       u64 context;
+} __packed;
+
+/*
+ * DRTM Dynamic Launch Configuration
+ */
+struct slr_entry_dl_info {
+       struct slr_entry_hdr hdr;
+       struct slr_bl_context bl_context;
+       u64 dl_handler;

I noticed in the EFI patch that this is actually

void (*dl_handler)(struct slr_bl_context *bl_context);

so better declare it as such.

+       u64 dce_base;
+       u32 dce_size;
+       u64 dlme_entry;
+} __packed;
+
+/*
+ * TPM Log Information
+ */
+struct slr_entry_log_info {
+       struct slr_entry_hdr hdr;
+       u16 format;
+       u16 reserved;
+       u64 addr;
+       u32 size;
+} __packed;
+
+/*
+ * DRTM Measurement Policy
+ */
+struct slr_entry_policy {
+       struct slr_entry_hdr hdr;
+       u16 revision;
+       u16 nr_entries;
+       /* policy_entries[] */

Please use a flex array here:

   struct slr_policy_entry policy_entries[];

Yes we will use flex arrays everywhere it is relevant in here going forward.

Thanks
Ross


+} __packed;
+
+/*
+ * DRTM Measurement Entry
+ */
+struct slr_policy_entry {
+       u16 pcr;
+       u16 entity_type;
+       u16 flags;
+       u16 reserved;
+       u64 entity;
+       u64 size;
+       char evt_info[TPM_EVENT_INFO_LENGTH];
+} __packed;
+
+/*
+ * Secure Launch defined MTRR saving structures
+ */
+struct slr_txt_mtrr_pair {
+       u64 mtrr_physbase;
+       u64 mtrr_physmask;
+} __packed;
+
+struct slr_txt_mtrr_state {
+       u64 default_mem_type;
+       u64 mtrr_vcnt;
+       struct slr_txt_mtrr_pair mtrr_pair[TXT_VARIABLE_MTRRS_LENGTH];
+} __packed;
+
+/*
+ * Intel TXT Info table
+ */
+struct slr_entry_intel_info {
+       struct slr_entry_hdr hdr;
+       u64 saved_misc_enable_msr;
+       struct slr_txt_mtrr_state saved_bsp_mtrrs;
+} __packed;
+
+/*
+ * AMD SKINIT Info table
+ */
+struct slr_entry_amd_info {
+       struct slr_entry_hdr hdr;
+} __packed;
+
+/*
+ * ARM DRTM Info table
+ */
+struct slr_entry_arm_info {
+       struct slr_entry_hdr hdr;
+} __packed;
+

These two look preliminary, so better to drop them now and introduce
only once you know what they will look like.

+struct slr_entry_uefi_config {
+       struct slr_entry_hdr hdr;
+       u16 revision;
+       u16 nr_entries;
+       /* uefi_cfg_entries[] */

Use a flex array

+} __packed;
+
+struct slr_uefi_cfg_entry {
+       u16 pcr;
+       u16 reserved;
+       u64 cfg; /* address or value */
+       u32 size;
+       char evt_info[TPM_EVENT_INFO_LENGTH];
+} __packed;
+
+static inline void *slr_end_of_entrys(struct slr_table *table)

typo 'entrys' ?

+{
+       return (((void *)table) + table->size);

You can drop two sets of parens here

+}
+
+static inline struct slr_entry_hdr *
+slr_next_entry(struct slr_table *table,
+              struct slr_entry_hdr *curr)
+{
+       struct slr_entry_hdr *next = (struct slr_entry_hdr *)
+                               ((u8 *)curr + curr->size);
+
+       if ((void *)next >= slr_end_of_entrys(table))
+               return NULL;
+       if (next->tag == SLR_ENTRY_END)
+               return NULL;
+
+       return next;
+}
+
+static inline struct slr_entry_hdr *
+slr_next_entry_by_tag(struct slr_table *table,
+                     struct slr_entry_hdr *entry,
+                     u16 tag)
+{
+       if (!entry) /* Start from the beginning */
+               entry = (struct slr_entry_hdr *)(((u8 *)table) + sizeof(*table));
+
+       for ( ; ; ) {
+               if (entry->tag == tag)
+                       return entry;
+
+               entry = slr_next_entry(table, entry);
+               if (!entry)
+                       return NULL;
+       }
+
+       return NULL;
+}
+
+static inline int
+slr_add_entry(struct slr_table *table,
+             struct slr_entry_hdr *entry)
+{
+       struct slr_entry_hdr *end;
+
+       if ((table->size + entry->size) > table->max_size)
+               return -1;
+
+       memcpy((u8 *)table + table->size - sizeof(*end), entry, entry->size);
+       table->size += entry->size;
+
+       end  = (struct slr_entry_hdr *)((u8 *)table + table->size - sizeof(*end));
+       end->tag = SLR_ENTRY_END;
+       end->size = sizeof(*end);
+
+       return 0;
+}
+
+static inline void
+slr_init_table(struct slr_table *slrt, u16 architecture, u32 max_size)
+{
+       struct slr_entry_hdr *end;
+
+       slrt->magic = SLR_TABLE_MAGIC;
+       slrt->revision = SLR_TABLE_REVISION;
+       slrt->architecture = architecture;
+       slrt->size = sizeof(*slrt) + sizeof(*end);
+       slrt->max_size = max_size;
+       end = (struct slr_entry_hdr *)((u8 *)slrt + sizeof(*slrt));
+       end->tag = SLR_ENTRY_END;
+       end->size = sizeof(*end);
+}
+
+#endif /* !__ASSEMBLY */
+
+#endif /* _LINUX_SLR_TABLE_H */
--
2.39.3






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