From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <mjg59@coreos.com>
Date: Wed, 23 Mar 2016 17:03:43 -0700
Subject: [PATCH] Rework TPM measurements
Rework TPM measurements to use fewer PCRs. After discussion with upstream,
it's preferable to avoid using so many PCRs. Instead, measure into PCRs 8
and 9 but use a prefix in the event log to indicate which subsystem carried
out the measurements.
(cherry picked from commit bb3473d7c8741ad5ef7cf8aafbbcf094df08bfc9)
---
grub-core/kern/dl.c | 2 +-
grub-core/kern/tpm.c | 10 ++++++++--
grub-core/lib/cmdline.c | 4 ++--
grub-core/loader/i386/efi/linux.c | 4 ++--
grub-core/loader/i386/linux.c | 2 +-
grub-core/loader/i386/multiboot_mbi.c | 2 +-
grub-core/loader/i386/pc/linux.c | 2 +-
grub-core/loader/linux.c | 2 +-
grub-core/loader/multiboot.c | 2 +-
grub-core/loader/multiboot_mbi2.c | 2 +-
grub-core/script/execute.c | 4 ++--
include/grub/tpm.h | 9 +++------
12 files changed, 24 insertions(+), 21 deletions(-)
diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
index 387d1e6446d..d0989573866 100644
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -830,7 +830,7 @@ grub_dl_load_file (const char *filename)
opens of the same device. */
grub_file_close (file);
- grub_tpm_measure(core, size, GRUB_TPM_PCR, filename);
+ grub_tpm_measure(core, size, GRUB_BINARY_PCR, "grub_module", filename);
mod = grub_dl_load_core (core, size);
grub_free (core);
diff --git a/grub-core/kern/tpm.c b/grub-core/kern/tpm.c
index 1a991876c83..cb5a812035d 100644
--- a/grub-core/kern/tpm.c
+++ b/grub-core/kern/tpm.c
@@ -7,7 +7,13 @@
grub_err_t
grub_tpm_measure (unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
- const char *description)
+ const char *kind, const char *description)
{
- return grub_tpm_log_event(buf, size, pcr, description);
+ grub_err_t ret;
+ char *desc = grub_xasprintf("%s %s", kind, description);
+ if (!desc)
+ return GRUB_ERR_OUT_OF_MEMORY;
+ ret = grub_tpm_log_event(buf, size, pcr, description);
+ grub_free(desc);
+ return ret;
}
diff --git a/grub-core/lib/cmdline.c b/grub-core/lib/cmdline.c
index 6b56304d4a7..178f7382f07 100644
--- a/grub-core/lib/cmdline.c
+++ b/grub-core/lib/cmdline.c
@@ -126,8 +126,8 @@ int grub_create_loader_cmdline (int argc, char *argv[], char *buf,
*buf = 0;
- grub_tpm_measure ((void *)orig, grub_strlen (orig), GRUB_CMDLINE_PCR,
- "Kernel Commandline");
+ grub_tpm_measure ((void *)orig, grub_strlen (orig), GRUB_ASCII_PCR,
+ "grub_kernel_cmdline", orig);
return i;
}
diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c
index d837249b4a1..074dbd6513e 100644
--- a/grub-core/loader/i386/efi/linux.c
+++ b/grub-core/loader/i386/efi/linux.c
@@ -132,7 +132,7 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
argv[i]);
goto fail;
}
- grub_tpm_measure (ptr, cursize, GRUB_INITRD_PCR, "UEFI Linux initrd");
+ grub_tpm_measure (ptr, cursize, GRUB_BINARY_PCR, "grub_linuxefi", "Initrd");
ptr += cursize;
grub_memset (ptr, 0, ALIGN_UP_OVERHEAD (cursize, 4));
ptr += ALIGN_UP_OVERHEAD (cursize, 4);
@@ -197,7 +197,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
goto fail;
}
- grub_tpm_measure (kernel, filelen, GRUB_KERNEL_PCR, "UEFI Linux kernel");
+ grub_tpm_measure (kernel, filelen, GRUB_BINARY_PCR, "grub_linuxefi", "Kernel");
rc = grub_linuxefi_secure_validate (kernel, filelen);
if (rc < 0)
diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
index 94526966e8a..273f48a6c88 100644
--- a/grub-core/loader/i386/linux.c
+++ b/grub-core/loader/i386/linux.c
@@ -725,7 +725,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
goto fail;
}
- grub_tpm_measure (kernel, len, GRUB_KERNEL_PCR, "Linux Kernel");
+ grub_tpm_measure (kernel, len, GRUB_BINARY_PCR, "grub_linux", "Kernel");
grub_memcpy (&lh, kernel, sizeof (lh));
diff --git a/grub-core/loader/i386/multiboot_mbi.c b/grub-core/loader/i386/multiboot_mbi.c
index 1c5b0ac25ce..2ce424a997b 100644
--- a/grub-core/loader/i386/multiboot_mbi.c
+++ b/grub-core/loader/i386/multiboot_mbi.c
@@ -174,7 +174,7 @@ grub_multiboot_load (grub_file_t file, const char *filename)
return grub_errno;
}
- grub_tpm_measure((unsigned char*)buffer, len, GRUB_KERNEL_PCR, filename);
+ grub_tpm_measure((unsigned char*)buffer, len, GRUB_BINARY_PCR, "grub_multiboot", filename);
header = find_header (buffer, len);
diff --git a/grub-core/loader/i386/pc/linux.c b/grub-core/loader/i386/pc/linux.c
index 15544230763..4f8c02288ec 100644
--- a/grub-core/loader/i386/pc/linux.c
+++ b/grub-core/loader/i386/pc/linux.c
@@ -162,7 +162,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
goto fail;
}
- grub_tpm_measure (kernel, len, GRUB_KERNEL_PCR, "BIOS Linux Kernel");
+ grub_tpm_measure (kernel, len, GRUB_BINARY_PCR, "grub_linux16", "Kernel");
grub_memcpy (&lh, kernel, sizeof (lh));
kernel_offset = sizeof (lh);
diff --git a/grub-core/loader/linux.c b/grub-core/loader/linux.c
index 3005c0d19c9..78c41e33416 100644
--- a/grub-core/loader/linux.c
+++ b/grub-core/loader/linux.c
@@ -289,7 +289,7 @@ grub_initrd_load (struct grub_linux_initrd_context *initrd_ctx,
grub_initrd_close (initrd_ctx);
return grub_errno;
}
- grub_tpm_measure (ptr, cursize, GRUB_INITRD_PCR, "Linux Initrd");
+ grub_tpm_measure (ptr, cursize, GRUB_BINARY_PCR, "grub_initrd", "Initrd");
ptr += cursize;
}
if (newc)
diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c
index 93e026c53db..3b87dc4fab3 100644
--- a/grub-core/loader/multiboot.c
+++ b/grub-core/loader/multiboot.c
@@ -441,7 +441,7 @@ grub_cmd_module (grub_command_t cmd __attribute__ ((unused)),
}
grub_file_close (file);
- grub_tpm_measure (module, size, GRUB_KERNEL_PCR, argv[0]);
+ grub_tpm_measure (module, size, GRUB_BINARY_PCR, "grub_multiboot", argv[0]);
return GRUB_ERR_NONE;
}
diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index d5ad02a33a1..60ae4606fda 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -132,7 +132,7 @@ grub_multiboot2_load (grub_file_t file, const char *filename)
COMPILE_TIME_ASSERT (MULTIBOOT_HEADER_ALIGN % 4 == 0);
- grub_tpm_measure ((unsigned char *)buffer, len, GRUB_KERNEL_PCR, filename);
+ grub_tpm_measure ((unsigned char *)mld.buffer, len, GRUB_BINARY_PCR, "grub_multiboot", filename);
header = find_header (mld.buffer, len);
if (header == 0)
diff --git a/grub-core/script/execute.c b/grub-core/script/execute.c
index 9ae04a05160..976643c47b0 100644
--- a/grub-core/script/execute.c
+++ b/grub-core/script/execute.c
@@ -995,8 +995,8 @@ grub_script_execute_cmdline (struct grub_script_cmd *cmd)
argv.args[i]);
}
cmdstring[cmdlen-1]= '\0';
- grub_tpm_measure ((unsigned char *)cmdstring, cmdlen, GRUB_COMMAND_PCR,
- cmdstring);
+ grub_tpm_measure ((unsigned char *)cmdstring, cmdlen, GRUB_ASCII_PCR,
+ "grub_cmd", cmdstring);
grub_free(cmdstring);
invert = 0;
argc = argv.argc - 1;
diff --git a/include/grub/tpm.h b/include/grub/tpm.h
index 7fc9d77d277..ecb2d09ff5d 100644
--- a/include/grub/tpm.h
+++ b/include/grub/tpm.h
@@ -26,11 +26,8 @@
#define TPM_AUTHFAIL (TPM_BASE + 0x1)
#define TPM_BADINDEX (TPM_BASE + 0x2)
-#define GRUB_TPM_PCR 9
-#define GRUB_KERNEL_PCR 10
-#define GRUB_INITRD_PCR 11
-#define GRUB_CMDLINE_PCR 12
-#define GRUB_COMMAND_PCR 13
+#define GRUB_ASCII_PCR 8
+#define GRUB_BINARY_PCR 9
#define TPM_TAG_RQU_COMMAND 0x00C1
#define TPM_ORD_Extend 0x14
@@ -70,7 +67,7 @@ typedef struct {
} GRUB_PACKED ExtendOutgoing;
grub_err_t EXPORT_FUNC(grub_tpm_measure) (unsigned char *buf, grub_size_t size,
- grub_uint8_t pcr,
+ grub_uint8_t pcr, const char *kind,
const char *description);
#if defined (GRUB_MACHINE_EFI) || defined (GRUB_MACHINE_PCBIOS)
grub_err_t grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,