Hi Jonathan, > * # Be careful, this email looks suspicious; * Out of Character: The sender > is exhibiting a significant deviation from their usual behavior, this may > indicate that their account has been compromised. Be extra cautious before > opening links or attachments. * > On Thu, Apr 23, 2026 at 02:55:14PM +0100, Yeoreum Yun wrote: > > > On Thu, 2026-04-23 at 13:53 +0100, Jonathan McDowell wrote: > > > > On Thu, Apr 23, 2026 at 01:34:13PM +0100, Yeoreum Yun wrote: > > > > > > > On Thu, 2026-04-23 at 06:55 +0100, Yeoreum Yun wrote: > > > > > > > > > On Wed, 2026-04-22 at 20:41 +0100, Yeoreum Yun wrote: > > > > > > > > > > > Hi Mimi, > > > > > > > > > > > > > > > > > > > > > > > On Wed, 2026-04-22 at 17:24 +0100, Yeoreum Yun wrote: > > > > > > > > > > > > > To generate the boot_aggregate log in the IMA > > > > > > > > > > > > > subsystem with TPM PCR values, > > > > > > > > > > > > > the TPM driver must be built as built-in and > > > > > > > > > > > > > must be probed before the IMA subsystem is > > > > > > > > > > > > > initialized. > > > > > > > > > > > > > > > > > > > > > > > > > > However, when the TPM device operates over the FF-A > > > > > > > > > > > > > protocol using > > > > > > > > > > > > > the CRB interface, probing fails and returns > > > > > > > > > > > > > -EPROBE_DEFER if > > > > > > > > > > > > > the tpm_crb_ffa device — an FF-A device that provides > > > > > > > > > > > > > the communication > > > > > > > > > > > > > interface to the tpm_crb driver — has not yet been > > > > > > > > > > > > > probed. > > > > > > > > > > > > > > > > > > > > > > > > > > To ensure the TPM device operating over the FF-A > > > > > > > > > > > > > protocol with > > > > > > > > > > > > > the CRB interface is probed before IMA initialization, > > > > > > > > > > > > > the following conditions must be met: > > > > > > > > > > > > > > > > > > > > > > > > > > 1. The corresponding ffa_device must be registered, > > > > > > > > > > > > > which is done via ffa_init(). > > > > > > > > > > > > > > > > > > > > > > > > > > 2. The tpm_crb_driver must successfully probe this > > > > > > > > > > > > > device via > > > > > > > > > > > > > tpm_crb_ffa_init(). > > > > > > > > > > > > > > > > > > > > > > > > > > 3. The tpm_crb driver using CRB over FF-A can then > > > > > > > > > > > > > be probed successfully. (See crb_acpi_add() and > > > > > > > > > > > > > tpm_crb_ffa_init() for reference.) > > > > > > > > > > > > > > > > > > > > > > > > > > Unfortunately, ffa_init(), tpm_crb_ffa_init(), and > > > > > > > > > > > > > crb_acpi_driver_init() are > > > > > > > > > > > > > all registered with device_initcall, which means > > > > > > > > > > > > > crb_acpi_driver_init() may > > > > > > > > > > > > > be invoked before ffa_init() and tpm_crb_ffa_init() > > > > > > > > > > > > > are completed. > > > > > > > > > > > > > > > > > > > > > > > > > > When this occurs, probing the TPM device is deferred. > > > > > > > > > > > > > However, the deferred probe can happen after the IMA > > > > > > > > > > > > > subsystem > > > > > > > > > > > > > has already been initialized, since IMA > > > > > > > > > > > > > initialization is performed > > > > > > > > > > > > > during late_initcall, and deferred_probe_initcall() > > > > > > > > > > > > > is performed > > > > > > > > > > > > > at the same level. > > > > > > > > > > > > > > > > > > > > > > > > > > To resolve this, call ima_init() again at > > > > > > > > > > > > > late_inicall_sync level > > > > > > > > > > > > > so that let IMA not miss TPM PCR value when > > > > > > > > > > > > > generating boot_aggregate > > > > > > > > > > > > > log though TPM device presents in the system. > > > > > > > > > > > > > > > > > > > > > > > > > > Signed-off-by: Yeoreum Yun <[email protected]> > > > > > > > > > > > > > > > > > > > > > > > > A lot of change for just detecting whether ima_init() > > > > > > > > > > > > is being called on > > > > > > > > > > > > late_initcall or late_initcall_sync(), without any > > > > > > > > > > > > explanation for all the other > > > > > > > > > > > > changes (e.g. ima_init_core). > > > > > > > > > > > > > > > > > > > > > > > > Please just limit the change to just calling ima_init() > > > > > > > > > > > > twice. > > > > > > > > > > > > > > > > > > > > > > My concern is that ima_update_policy_flags() will be > > > > > > > > > > > called > > > > > > > > > > > when ima_init() is deferred -- not initialised anything. > > > > > > > > > > > though functionally, it might be okay however, > > > > > > > > > > > I think ima_update_policy_flags() and notifier should > > > > > > > > > > > work after ima_init() > > > > > > > > > > > works logically. > > > > > > > > > > > > > > > > > > > > > > This change I think not much quite a lot. just wrapper > > > > > > > > > > > ima_init() with > > > > > > > > > > > ima_init_core() with some error handling. > > > > > > > > > > > > > > > > > > > > > > Am I missing something? > > > > > > > > > > > > > > > > > > > > Also, if we handle in ima_init() only, but it failed with > > > > > > > > > > other reason, > > > > > > > > > > we shouldn't call again ima_init() in the > > > > > > > > > > late_initcall_sync. > > > > > > > > > > > > > > > > > > > > To handle this, It wouldn't do in the ima_init() but we > > > > > > > > > > need to handle > > > > > > > > > > it by caller of ima_init(). > > > > > > > > > > > > > > > > > > Only tpm_default_chip() is being called to set the > > > > > > > > > ima_tpm_chip. On failure, > > > > > > > > > instead of going into TPM-bypass mode, return immediately. > > > > > > > > > There are no calls > > > > > > > > > to anything else. Just call ima_init() a second time. > > > > > > > > > > > > > > > > I’m not fully convinced this is sufficient. > > > > > > > > > > > > > > > > What I meant is the case where ima_init() fails due to other > > > > > > > > initialisation steps, not only tpm_default_chip() (e.g. > > > > > > > > ima_fs_init()). > > > > > > > > > > > > > > The purpose of THIS patch is to add late_initcall_sync, when the > > > > > > > TPM is not > > > > > > > available at late_initcall. This would be classified as a bug > > > > > > > fix and would be > > > > > > > backported. No other changes should be included in this patch. > > > > > > > > > > > > Okay. > > > > > > > > > > > > > > > > > > > > > > I’d also like to ask again whether it is fine to call > > > > > > > > ima_update_policy_flags() and keep the notifier registered in > > > > > > > > the > > > > > > > > deferred TPM case. While this may be functionally acceptable, > > > > > > > > it seems > > > > > > > > logically questionable to do so when ima_init() has not > > > > > > > > completed. > > > > > > > > > > > > > > Other than extending the TPM, IMA should behave exactly the same > > > > > > > whether there > > > > > > > is a TPM or goes into TPM-bypass mode. > > > > > > > > > > > > > > > > > > > > > > > There is also a possibility that a deferred case ultimately > > > > > > > > fails (e.g. > > > > > > > > deferred at late_initcall, but then failing at > > > > > > > > late_initcall_sync > > > > > > > > for another reason, even while entering TPM bypass mode). In > > > > > > > > that case, > > > > > > > > it seems more appropriate to handle this state in the caller of > > > > > > > > ima_init(), rather than inside ima_init() itself. > > > > > > > > > > > > > > If the TPM isn't found at late_initcall_sync(), then IMA should > > > > > > > go into TPM- > > > > > > > bypass mode. Please don't make any other changes to the existing > > > > > > > IMA behavior > > > > > > > and hide it here behind the late_initcall_sync change. > > > > > > > > > > > > Okay. you're talking called ima_update_policy_flags() at > > > > > > late_initcall > > > > > > wouldn't be not a problem even in case of late_initcall_sync's > > > > > > ima_init() > > > > > > get failed with "TPM-bypass mode". > > > > > > > > > > > > I see then, I'll make a patch simpler then. > > > > > > > > > > But I think in case of below situation: > > > > > - late_initcall's first ima_init() is deferred. > > > > > - late_initcall_sync try again but failed and try again with > > > > > CONFIG_IMA_DEFAULT_HASH. > > > > > > > > > > I would like to sustain init_ima_core to reduce the same code repeat > > > > > in late_initcall_sync. > > > > > > > > I think what Mimi's proposing is: > > > > > > > > If we're in late_initcall, and the TPM isn't available, return > > > > immediately with an error (the EPROBE_DEFER?), don't do any init. > > > > > > > > If we're in late_initcall_sync, either we're already initialised, so do > > > > return and nothing, or run through the entire flow, even if the TPM > > > > isn't unavailable. > > > > > > > > So ima_init() just needs to know a) if it's in the sync or non-sync mode > > > > and b) for the sync mode, if we've already done the init at > > > > non-sync. > > > > > > Thanks, Jonathan. That is exactly what I'm suggesting. Any other changes > > > should not be included in this patch. Since Yeoreum is not hearing me, > > > feel > > > free to post a patch. > > > > I see. so what you need to is this only > > If it looks good to you. I'll send it at v3. > > FWIW, I pulled the tpm_default_chip check out a level to account for the > extra init you mentioned, and have the following (completely untested or > compiled, but gives the approach): > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index d48bf0ad26f4..88fe105b7f00 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -166,6 +166,7 @@ enum lsm_order { > * @initcall_fs: LSM callback for fs_initcall setup, optional > * @initcall_device: LSM callback for device_initcall() setup, optional > * @initcall_late: LSM callback for late_initcall() setup, optional > + * @initcall_late_sync: LSM callback for late_initcall_sync() setup, optional > */ > struct lsm_info { > const struct lsm_id *id; > @@ -181,6 +182,7 @@ struct lsm_info { > int (*initcall_fs)(void); > int (*initcall_device)(void); > int (*initcall_late)(void); > + int (*initcall_late_sync)(void); > }; > #define DEFINE_LSM(lsm) > \ > diff --git a/security/integrity/ima/ima_init.c > b/security/integrity/ima/ima_init.c > index a2f34f2d8ad7..a60dfb8316d8 100644 > --- a/security/integrity/ima/ima_init.c > +++ b/security/integrity/ima/ima_init.c > @@ -119,10 +119,6 @@ int __init ima_init(void) > { > int rc; > - ima_tpm_chip = tpm_default_chip(); > - if (!ima_tpm_chip) > - pr_info("No TPM chip found, activating TPM-bypass!\n"); > - > rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA); > if (rc) > return rc; > diff --git a/security/integrity/ima/ima_main.c > b/security/integrity/ima/ima_main.c > index 1d6229b156fb..b60a85fa803a 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -1237,7 +1237,7 @@ static int ima_kernel_module_request(char *kmod_name) > #endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */ > -static int __init init_ima(void) > +static int __init init_ima(bool sync) > { > int error; > @@ -1247,6 +1247,19 @@ static int __init init_ima(void) > return 0; > } > + /* If we found the TPM during our first attempt, nothing further to do > */ > + if (sync && ima_tpm_chip) > + return 0; > + > + ima_tpm_chip = tpm_default_chip(); > + if (!ima_tpm_chip && !sync) { > + pr_debug("TPM not available, will try later\n"); > + return -EPROBE_DEFER; > + } > + > + if (!ima_tpm_chip) > + pr_info("No TPM chip found, activating TPM-bypass!\n"); > + > ima_appraise_parse_cmdline(); > ima_init_template_list(); > hash_setup(CONFIG_IMA_DEFAULT_HASH); > @@ -1274,6 +1287,16 @@ static int __init init_ima(void) > return error; > } > +static int __init init_ima_late(void) > +{ > + return init_ima(false); > +} > + > +static int __init init_ima_late_sync(void) > +{ > + return init_ima(true); > +} > + > static struct security_hook_list ima_hooks[] __ro_after_init = { > LSM_HOOK_INIT(bprm_check_security, ima_bprm_check), > LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec), > @@ -1319,6 +1342,7 @@ DEFINE_LSM(ima) = { > .init = init_ima_lsm, > .order = LSM_ORDER_LAST, > .blobs = &ima_blob_sizes, > - /* Start IMA after the TPM is available */ > - .initcall_late = init_ima, > + /* Ensure we start IMA after the TPM is available */ > + .initcall_late = init_ima_late, > + .initcall_late_sync = init_ima_late_sync, > }; > diff --git a/security/lsm_init.c b/security/lsm_init.c > index 573e2a7250c4..4e5c59beb82a 100644 > --- a/security/lsm_init.c > +++ b/security/lsm_init.c > @@ -547,13 +547,22 @@ device_initcall(security_initcall_device); > * security_initcall_late - Run the LSM late initcalls > */ > static int __init security_initcall_late(void) > +{ > + return lsm_initcall(late); > +} > +late_initcall(security_initcall_late); > + > +/** > + * security_initcall_late_sync - Run the LSM late initcalls sync > + */ > +static int __init security_initcall_late_sync(void) > { > int rc; > - rc = lsm_initcall(late); > + rc = lsm_initcall(late_sync); > lsm_pr_dbg("all enabled LSMs fully activated\n"); > call_blocking_lsm_notifier(LSM_STARTED_ALL, NULL); > return rc; > } > -late_initcall(security_initcall_late); > +late_initcall_sync(security_initcall_late_sync);
I'm fine this. but are we talking about "ima_init()" not "init_ima()"? Because of this, I've fixuated and make a long stupid speaking myself. If this seems good to Mimi, I don't care who send it. But If you're going to send this, could you includes 2 and 3 too? Thanks. -- Sincerely, Yeoreum Yun
