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Make TPM errors less fatal

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Handle TPM errors, and stop trying to use the TPM once we hit one.
This commit is contained in:
Matthew Garrett 2016-10-13 13:55:26 -07:00
parent 5962f7d5e7
commit bf25cda14e
11 changed files with 29 additions and 4 deletions
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21
grub-core/kern/i386/pc/tpm.c
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@ -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, &regs);
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, &regs);
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;
}