On Wed, 15 Jan 2025 at 22:02, Raymond Mao <[email protected]> wrote: > > Add PCR allocate wrapper APIs for using in tcg2 protocol. > The wrapper proceeds a PCR allocate command, followed by a > shutdown command.
We have lib/tpm_tcg2.c does any of the functions belong to that file? Unless we expect the non-TCG version to do something similar.... > A system boot is required after two commands since TPM device needs > a HW reset to activate the new algorithms config. > Also, a helper function is included to determine the new bank mask > for PCR allocation by combining the status of current active, > supported and eventlog bank masks. > A new kconfig is created. PCR allocate and system reboot only > happens when the kconfig is selected, otherwise just exit with > errors. > > Signed-off-by: Raymond Mao <[email protected]> > --- > include/tpm-v2.h | 20 ++++++++ > lib/Kconfig | 12 +++++ > lib/tpm-v2.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 153 insertions(+) > > diff --git a/include/tpm-v2.h b/include/tpm-v2.h > index af3158f6e4..79dc4a34e2 100644 > --- a/include/tpm-v2.h > +++ b/include/tpm-v2.h > @@ -703,6 +703,17 @@ u32 tpm2_report_state(struct udevice *dev, uint > vendor_cmd, uint vendor_subcmd, > u32 tpm2_enable_nvcommits(struct udevice *dev, uint vendor_cmd, > uint vendor_subcmd); > > +/** > + * tpm2_pcr_allocate_get_mask - Get algorithm bitmask for PCR allocate Naming nit. This is comparing the EventLog, U-Boot supported, and active algorithms. Can we rename it to tpm2_scan_masks() or something similar and update the description with that? > + * > + * @dev TPM device > + * @log_active Active algorithm bitmask > + * @mask Bitmask for PCR allocate > + * > + * Return: zero on success, negative errno otherwise > + */ > +int tpm2_pcr_allocate_get_mask(struct udevice *dev, u32 log_active, u32 > *mask); > + > /** > * tpm2_pcr_config_algo() - Allocate the active PCRs. Requires reboot > * > @@ -730,6 +741,15 @@ u32 tpm2_pcr_config_algo(struct udevice *dev, u32 > algo_mask, > u32 tpm2_send_pcr_allocate(struct udevice *dev, const char *pw, > const ssize_t pw_sz, struct tpml_pcr_selection > *pcr, > u32 pcr_len); > +/** > + * tpm2_pcr_allocate() - Allocate the PCRs > + * > + * @param dev TPM device > + * @log_active Bitmask of eventlog algorithms > + * > + * Return: code of the operation > + */ > +int tpm2_pcr_allocate(struct udevice *dev, u32 log_active); > > /** > * tpm2_auto_start() - start up the TPM and perform selftests. > diff --git a/lib/Kconfig b/lib/Kconfig > index baeb615626..0732333849 100644 > --- a/lib/Kconfig > +++ b/lib/Kconfig > @@ -514,6 +514,18 @@ config VPL_TPM > for the low-level TPM interface, but only one TPM is supported at > a time by the TPM library. > > +config TPM_PCR_ALLOCATE > + bool "Re-configurate TPM algorithms in run-time (PCR allocate)" > + depends on TPM_V2 && (MEASURED_BOOT || EFI_TCG2_PROTOCOL) > + help > + This enables a detection for the dismatches of algorithms among TPM > + device, eventlog from previous boot stage and U-Boot support. > + A PCR allocate command will be sent to reconfigurate the TPM device > + in run-time to make sure algorithms in TPM device, eventlog and > + U-Boot are aligned with each other. > + A system reboot will be proceeded after then to activate the new > + algorithms. > + > endmenu > > menu "Android Verified Boot" > diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c > index 045b5dd9eb..71abf070de 100644 > --- a/lib/tpm-v2.c > +++ b/lib/tpm-v2.c > @@ -44,6 +44,127 @@ static int tpm2_update_active_banks(struct udevice *dev) > return 0; > } > > +static void tpm2_print_selected_algorithm_name(u32 selected) > +{ > + size_t i; > + const char *str; > + > + for (i = 0; i < ARRAY_SIZE(hash_algo_list); i++) { > + const struct digest_info *algo = &hash_algo_list[i]; > + > + if (!(selected & algo->hash_mask)) > + continue; > + > + str = tpm2_algorithm_name(algo->hash_alg); > + if (str) > + log_info("%s\n", str); > + } > +} > + > +int tpm2_pcr_allocate_get_mask(struct udevice *dev, u32 log_active, u32 > *mask) > +{ > + struct tpml_pcr_selection pcrs; > + u32 active = 0; > + u32 supported = 0; > + int rc, i; > + > + *mask = 0; > + > + rc = tpm2_get_pcr_info(dev, &pcrs); > + if (rc) > + return rc; > + > + for (i = 0; i < pcrs.count; i++) { > + struct tpms_pcr_selection *sel = &pcrs.selection[i]; > + size_t j; > + u32 hash_mask = 0; > + > + for (j = 0; j < ARRAY_SIZE(hash_algo_list); j++) { > + if (hash_algo_list[j].hash_alg == sel->hash) > + hash_mask = hash_algo_list[j].hash_mask; > + } > + > + if (tpm2_algorithm_supported(sel->hash)) > + supported |= hash_mask; > + > + if (tpm2_is_active_bank(sel)) > + active |= hash_mask; We duplicate this in the tcg functions for getting active pcr banks, but I can live with it now and refactor it later. > + } > + > + /* All eventlog algorithm(s) must be supported */ > + if (log_active & ~supported) { > + log_err("EventLog contains U-Boot unsupported > algorithm(s)\n"); > + tpm2_print_selected_algorithm_name(log_active & ~supported); > + rc = -1; > + } > + if (log_active && active & ~log_active) { > + log_warning("TPM active algorithm(s) not exist in > eventlog\n"); > + tpm2_print_selected_algorithm_name(active & ~log_active); > + *mask = log_active; > + } > + > + /* Any active algorithm(s) which are not supported must be removed */ > + if (active & ~supported) { > + log_warning("TPM active algorithm(s) unsupported by > u-boot\n"); > + tpm2_print_selected_algorithm_name(active & ~supported); > + if (*mask) if (rc) is clearer here I think > + *mask = active & supported & *mask; > + else > + *mask = active & supported; > + } > + > + return rc; > +} > + > +static int tpm2_proceed_pcr_allocate(struct udevice *dev, u32 algo_mask) Naming this tpm2_pcr_allocate() is better > +{ > + struct tpml_pcr_selection pcr = { 0 }; > + u32 pcr_len = 0; > + int rc; > + > + rc = tpm2_get_pcr_info(dev, &pcr); > + if (rc) > + return rc; > + > + rc = tpm2_pcr_config_algo(dev, algo_mask, &pcr, &pcr_len); > + if (rc) > + return rc; > + > + /* Assume no password */ > + rc = tpm2_send_pcr_allocate(dev, NULL, 0, &pcr, pcr_len); > + if (rc) > + return rc; > + > + /* Send TPM2_Shutdown, assume mode = TPM2_SU_CLEAR */ > + return tpm2_startup(dev, false, TPM2_SU_CLEAR); > +} > + > +int tpm2_pcr_allocate(struct udevice *dev, u32 log_active) This assumes there's a log involved. So let's find a better name and keep the current one for the function above. > +{ > + u32 algo_mask = 0; > + int rc; > + > + rc = tpm2_pcr_allocate_get_mask(dev, log_active, &algo_mask); > + if (rc) > + return rc; > + > + if (algo_mask) { > + if (!IS_ENABLED(CONFIG_TPM_PCR_ALLOCATE)) > + return -1; > + > + rc = tpm2_proceed_pcr_allocate(dev, algo_mask); > + if (rc) > + return rc; > + > + log_info("PCR allocate done, shutdown TPM and reboot\n"); > + do_reset(NULL, 0, 0, NULL); > + log_err("reset does not work!\n"); > + return -1; > + } > + > + return 0; > +} > + > u32 tpm2_startup(struct udevice *dev, bool bon, enum tpm2_startup_types mode) > { > int op = bon ? TPM2_CC_STARTUP : TPM2_CC_SHUTDOWN; > -- > 2.25.1 > Thanks /Ilias
