145 lines
3.2 KiB
C
145 lines
3.2 KiB
C
#include <grub/err.h>
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#include <grub/i18n.h>
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#include <grub/mm.h>
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#include <grub/tpm.h>
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#include <grub/misc.h>
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#include <grub/i386/pc/int.h>
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#define TCPA_MAGIC 0x41504354
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static int tpm_presence = -1;
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int tpm_present(void);
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int tpm_present(void)
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{
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struct grub_bios_int_registers regs;
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if (tpm_presence != -1)
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return tpm_presence;
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regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
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regs.eax = 0xbb00;
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regs.ebx = TCPA_MAGIC;
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grub_bios_interrupt (0x1a, ®s);
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if (regs.eax == 0)
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tpm_presence = 1;
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else
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tpm_presence = 0;
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return tpm_presence;
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}
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grub_err_t
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grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,
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PassThroughToTPM_OutputParamBlock *outbuf)
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{
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struct grub_bios_int_registers regs;
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grub_addr_t inaddr, outaddr;
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if (!tpm_present())
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return 0;
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inaddr = (grub_addr_t) inbuf;
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outaddr = (grub_addr_t) outbuf;
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regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
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regs.eax = 0xbb02;
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regs.ebx = TCPA_MAGIC;
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regs.ecx = 0;
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regs.edx = 0;
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regs.es = (inaddr & 0xffff0000) >> 4;
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regs.edi = inaddr & 0xffff;
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regs.ds = outaddr >> 4;
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regs.esi = outaddr & 0xf;
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grub_bios_interrupt (0x1a, ®s);
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if (regs.eax)
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{
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tpm_presence = 0;
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return grub_error (GRUB_ERR_IO, N_("TPM error %x, disabling TPM"), regs.eax);
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}
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return 0;
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}
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typedef struct {
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grub_uint32_t pcrindex;
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grub_uint32_t eventtype;
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grub_uint8_t digest[20];
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grub_uint32_t eventdatasize;
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grub_uint8_t event[0];
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} GRUB_PACKED Event;
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typedef struct {
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grub_uint16_t ipblength;
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grub_uint16_t reserved;
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grub_uint32_t hashdataptr;
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grub_uint32_t hashdatalen;
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grub_uint32_t pcr;
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grub_uint32_t reserved2;
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grub_uint32_t logdataptr;
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grub_uint32_t logdatalen;
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} GRUB_PACKED EventIncoming;
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typedef struct {
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grub_uint16_t opblength;
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grub_uint16_t reserved;
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grub_uint32_t eventnum;
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grub_uint8_t hashvalue[20];
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} GRUB_PACKED EventOutgoing;
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grub_err_t
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grub_tpm_log_event(unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
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const char *description)
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{
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struct grub_bios_int_registers regs;
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EventIncoming incoming;
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EventOutgoing outgoing;
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Event *event;
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grub_uint32_t datalength;
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if (!tpm_present())
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return 0;
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datalength = grub_strlen(description);
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event = grub_zalloc(datalength + sizeof(Event));
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if (!event)
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return grub_error (GRUB_ERR_OUT_OF_MEMORY,
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N_("cannot allocate TPM event buffer"));
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event->pcrindex = pcr;
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event->eventtype = 0x0d;
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event->eventdatasize = grub_strlen(description);
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grub_memcpy(event->event, description, datalength);
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incoming.ipblength = sizeof(incoming);
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incoming.hashdataptr = (grub_uint32_t)buf;
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incoming.hashdatalen = size;
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incoming.pcr = pcr;
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incoming.logdataptr = (grub_uint32_t)event;
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incoming.logdatalen = datalength + sizeof(Event);
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regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
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regs.eax = 0xbb01;
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regs.ebx = TCPA_MAGIC;
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regs.ecx = 0;
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regs.edx = 0;
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regs.es = (((grub_addr_t) &incoming) & 0xffff0000) >> 4;
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regs.edi = ((grub_addr_t) &incoming) & 0xffff;
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regs.ds = (((grub_addr_t) &outgoing) & 0xffff0000) >> 4;
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regs.esi = ((grub_addr_t) &outgoing) & 0xffff;
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grub_bios_interrupt (0x1a, ®s);
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grub_free(event);
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if (regs.eax)
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{
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tpm_presence = 0;
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return grub_error (GRUB_ERR_IO, N_("TPM error %x, disabling TPM"), regs.eax);
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}
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return 0;
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}
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