From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Matthew Garrett <mjg59@coreos.com>

Date: Thu, 13 Oct 2016 13:55:26 -0700

Subject: [PATCH] Make TPM errors less fatal

Handle TPM errors, and stop trying to use the TPM once we hit one.

---

 grub-core/kern/dl.c                   |  1 +

 grub-core/kern/i386/pc/tpm.c          | 21 +++++++++++++++++----

 grub-core/lib/cmdline.c               |  1 +

 grub-core/loader/i386/efi/linux.c     |  2 ++

 grub-core/loader/i386/linux.c         |  1 +

 grub-core/loader/i386/multiboot_mbi.c |  1 +

 grub-core/loader/i386/pc/linux.c      |  1 +

 grub-core/loader/linux.c              |  2 ++

 grub-core/loader/multiboot.c          |  1 +

 grub-core/loader/multiboot_mbi2.c     |  1 +

 grub-core/script/execute.c            |  1 +

 11 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c

index d0989573866..91105bc4677 100644

--- a/grub-core/kern/dl.c

+++ b/grub-core/kern/dl.c

@@ -831,6 +831,7 @@ grub_dl_load_file (const char *filename)

   grub_file_close (file);

   grub_tpm_measure(core, size, GRUB_BINARY_PCR, "grub_module", filename);

+  grub_print_error();

   mod = grub_dl_load_core (core, size);

   grub_free (core);

diff --git a/grub-core/kern/i386/pc/tpm.c b/grub-core/kern/i386/pc/tpm.c

index 8c6c1e6ece2..f6f264aff2e 100644

--- a/grub-core/kern/i386/pc/tpm.c

+++ b/grub-core/kern/i386/pc/tpm.c

@@ -7,21 +7,28 @@

 #define TCPA_MAGIC 0x41504354

+static int tpm_presence = -1;

+

 int tpm_present(void);

 int tpm_present(void)

 {

   struct grub_bios_int_registers regs;

+  if (tpm_presence != -1)

+    return tpm_presence;

+

   regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;

   regs.eax = 0xbb00;

   regs.ebx = TCPA_MAGIC;

   grub_bios_interrupt (0x1a, ®s;;

   if (regs.eax == 0)

-    return 1;

+    tpm_presence = 1;

+  else

+    tpm_presence = 0;

-  return 0;

+  return tpm_presence;

 }

 grub_err_t

@@ -49,7 +56,10 @@ grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,

   grub_bios_interrupt (0x1a, ®s;;

   if (regs.eax)

-    return grub_error (GRUB_ERR_IO, N_("TPM error %x\n"), regs.eax);

+    {

+	tpm_presence = 0;

+	return grub_error (GRUB_ERR_IO, N_("TPM error %x, disabling TPM"), regs.eax);

+    }

   return 0;

 }

@@ -126,7 +136,10 @@ grub_tpm_log_event(unsigned char *buf, grub_size_t size, grub_uint8_t pcr,

 	grub_free(event);

 	if (regs.eax)

-		return grub_error (GRUB_ERR_IO, N_("TPM error %x\n"), regs.eax);

+	  {

+		tpm_presence = 0;

+		return grub_error (GRUB_ERR_IO, N_("TPM error %x, disabling TPM"), regs.eax);

+	  }

 	return 0;

 }

diff --git a/grub-core/lib/cmdline.c b/grub-core/lib/cmdline.c

index 178f7382f07..d5c12957cad 100644

--- a/grub-core/lib/cmdline.c

+++ b/grub-core/lib/cmdline.c

@@ -128,6 +128,7 @@ int grub_create_loader_cmdline (int argc, char *argv[], char *buf,

   grub_tpm_measure ((void *)orig, grub_strlen (orig), GRUB_ASCII_PCR,

 		    "grub_kernel_cmdline", orig);

+  grub_print_error();

   return i;

 }

diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c

index 074dbd6513e..ea9f5134e67 100644

--- a/grub-core/loader/i386/efi/linux.c

+++ b/grub-core/loader/i386/efi/linux.c

@@ -133,6 +133,7 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),

           goto fail;

         }

       grub_tpm_measure (ptr, cursize, GRUB_BINARY_PCR, "grub_linuxefi", "Initrd");

+      grub_print_error();

       ptr += cursize;

       grub_memset (ptr, 0, ALIGN_UP_OVERHEAD (cursize, 4));

       ptr += ALIGN_UP_OVERHEAD (cursize, 4);

@@ -198,6 +199,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

     }

   grub_tpm_measure (kernel, filelen, GRUB_BINARY_PCR, "grub_linuxefi", "Kernel");

+  grub_print_error();

   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 273f48a6c88..76304f05700 100644

--- a/grub-core/loader/i386/linux.c

+++ b/grub-core/loader/i386/linux.c

@@ -726,6 +726,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

     }

   grub_tpm_measure (kernel, len, GRUB_BINARY_PCR, "grub_linux", "Kernel");

+  grub_print_error();

   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 2ce424a997b..ca85358f771 100644

--- a/grub-core/loader/i386/multiboot_mbi.c

+++ b/grub-core/loader/i386/multiboot_mbi.c

@@ -175,6 +175,7 @@ grub_multiboot_load (grub_file_t file, const char *filename)

     }

   grub_tpm_measure((unsigned char*)buffer, len, GRUB_BINARY_PCR, "grub_multiboot", filename);

+  grub_print_error();

   header = find_header (buffer, len);

diff --git a/grub-core/loader/i386/pc/linux.c b/grub-core/loader/i386/pc/linux.c

index 4f8c02288ec..cfff25c21b5 100644

--- a/grub-core/loader/i386/pc/linux.c

+++ b/grub-core/loader/i386/pc/linux.c

@@ -163,6 +163,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

     }

   grub_tpm_measure (kernel, len, GRUB_BINARY_PCR, "grub_linux16", "Kernel");

+  grub_print_error();

   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 78c41e33416..c2c7cfcd0fd 100644

--- a/grub-core/loader/linux.c

+++ b/grub-core/loader/linux.c

@@ -290,6 +290,8 @@ grub_initrd_load (struct grub_linux_initrd_context *initrd_ctx,

 	  return grub_errno;

 	}

       grub_tpm_measure (ptr, cursize, GRUB_BINARY_PCR, "grub_initrd", "Initrd");

+      grub_print_error();

+

       ptr += cursize;

     }

   if (newc)

diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c

index 3b87dc4fab3..9a8dae5565b 100644

--- a/grub-core/loader/multiboot.c

+++ b/grub-core/loader/multiboot.c

@@ -442,6 +442,7 @@ grub_cmd_module (grub_command_t cmd __attribute__ ((unused)),

   grub_file_close (file);

   grub_tpm_measure (module, size, GRUB_BINARY_PCR, "grub_multiboot", argv[0]);

+  grub_print_error();

   return GRUB_ERR_NONE;

 }

diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c

index 60ae4606fda..54078455e2f 100644

--- a/grub-core/loader/multiboot_mbi2.c

+++ b/grub-core/loader/multiboot_mbi2.c

@@ -133,6 +133,7 @@ grub_multiboot2_load (grub_file_t file, const char *filename)

   COMPILE_TIME_ASSERT (MULTIBOOT_HEADER_ALIGN % 4 == 0);

   grub_tpm_measure ((unsigned char *)mld.buffer, len, GRUB_BINARY_PCR, "grub_multiboot", filename);

+  grub_print_error();

   header = find_header (mld.buffer, len);

   if (header == 0)

diff --git a/grub-core/script/execute.c b/grub-core/script/execute.c

index 976643c47b0..93965777138 100644

--- a/grub-core/script/execute.c

+++ b/grub-core/script/execute.c

@@ -997,6 +997,7 @@ grub_script_execute_cmdline (struct grub_script_cmd *cmd)

   cmdstring[cmdlen-1]= '\0';

   grub_tpm_measure ((unsigned char *)cmdstring, cmdlen, GRUB_ASCII_PCR,

 		    "grub_cmd", cmdstring);

+  grub_print_error();

   grub_free(cmdstring);

   invert = 0;

   argc = argv.argc - 1;