From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: Re: Regression from efi: call get_event_log before ExitBootServices Date: Mon, 12 Mar 2018 17:30:35 +0000 Message-ID: References: <01000161fc0b4755-df0621f4-ab5d-479a-b425-adf98427a308-000000@email.amazonses.com> <0100016206a68850-bd5c96b3-f275-46ea-98b1-1317e02a5d6e-000000@email.amazonses.com> <29c1640a-cf19-ca19-7de9-96f202edfb5a@redhat.com> <010001620bafa06b-41525407-603e-40a9-ba11-6033b2f5dcc7-000000@email.amazonses.com> <010001621a9e5069-0b1a6328-97e4-4396-9438-b90f5b8c82a4-000000@email.amazonses.com> <010001621b287e42-58955302-cc14-4212-b7b0-e6e358633dab-000000@email.amazonses.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <010001621b287e42-58955302-cc14-4212-b7b0-e6e358633dab-000000@email.amazonses.com> Sender: linux-kernel-owner@vger.kernel.org To: Jeremy Cline Cc: Thiebaud Weksteen , Hans de Goede , Javier Martinez Canillas , Jarkko Sakkinen , linux-efi@vger.kernel.org, linux-integrity@vger.kernel.org, tpmdd-devel@lists.sourceforge.net, Linux Kernel Mailing List List-Id: tpmdd-devel@lists.sourceforge.net On 12 March 2018 at 17:01, Jeremy Cline wrote: > On 03/12/2018 10:56 AM, Ard Biesheuvel wrote: >> On 12 March 2018 at 14:30, Jeremy Cline wrote: >>> On 03/12/2018 07:08 AM, Ard Biesheuvel wrote: >>>> On 10 March 2018 at 10:45, Thiebaud Weksteen wrote: >>>>> On Fri, Mar 9, 2018 at 5:54 PM Jeremy Cline wrote: >>>>> >>>>>> On Fri, Mar 09, 2018 at 10:43:50AM +0000, Thiebaud Weksteen wrote: >>>>>>> Thanks a lot for trying out the patch! >>>>>>> >>>>>>> Please don't modify your install at this stage, I think we are hitting a >>>>>>> firmware bug and that would be awesome if we can fix how we are >>>>> handling it. >>>>>>> So, if we reach that stage in the function it could either be that: >>>>>>> * The allocation did not succeed, somehow, but the firmware still >>>>> returned >>>>>>> EFI_SUCCEED. >>>>>>> * The size requested is incorrect (I'm thinking something like a 1G of >>>>>>> log). This would be due to either a miscalculation of log_size >>>>> (possible) >>>>>>> or; the returned values of GetEventLog are not correct. >>>>>>> I'm sending a patch to add checks for these. Could you please apply and >>>>>>> retest? >>>>>>> Again, thanks for helping debugging this. >>>>> >>>>>> No problem, thanks for the help :) >>>>> >>>>>> With the new patch: >>>>> >>>>>> Locating the TCG2Protocol >>>>>> Calling GetEventLog on TCG2Protocol >>>>>> Log returned >>>>>> log_location is not empty >>>>>> log_size != 0 >>>>>> log_size < 1M >>>>>> Allocating memory for storing the logs >>>>>> Returned from memory allocation >>>>>> Copying log to new location >>>>> >>>>>> And then it hangs. I added a couple more print statements: >>>>> >>>>>> diff --git a/drivers/firmware/efi/libstub/tpm.c >>>>> b/drivers/firmware/efi/libstub/tpm.c >>>>>> index ee3fac109078..1ab5638bc50e 100644 >>>>>> --- a/drivers/firmware/efi/libstub/tpm.c >>>>>> +++ b/drivers/firmware/efi/libstub/tpm.c >>>>>> @@ -148,8 +148,11 @@ void >>>>> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg) >>>>>> efi_printk(sys_table_arg, "Copying log to new location\n"); >>>>> >>>>>> memset(log_tbl, 0, sizeof(*log_tbl) + log_size); >>>>>> + efi_printk(sys_table_arg, "Successfully memset log_tbl to 0\n"); >>>>>> log_tbl->size = log_size; >>>>>> + efi_printk(sys_table_arg, "Set log_tbl->size\n"); >>>>>> log_tbl->version = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2; >>>>>> + efi_printk(sys_table_arg, "Set log_tbl-version\n"); >>>>>> memcpy(log_tbl->log, (void *) first_entry_addr, log_size); >>>>> >>>>>> efi_printk(sys_table_arg, "Installing the log into the >>>>> configuration table\n"); >>>>> >>>>>> and it's hanging at "memset(log_tbl, 0, sizeof(*log_tbl) + log_size);" >>>>> >>>>> Thanks. Well, it looks like the memory that is supposedly allocated is not >>>>> usable. I'm thinking this is a firmware bug. >>>>> Ard, would you agree on this assumption? Thoughts on how to proceed? >>>>> >>>> >>>> I am rather puzzled why the allocate_pool() should succeed and the >>>> subsequent memset() should fail. This does not look like an issue that >>>> is intimately related to TPM2 support, rather an issue in the firmware >>>> that happens to get tickled after the change. >>>> >>>> Would you mind trying replacing EFI_LOADER_DATA with >>>> EFI_BOOT_SERVICES_DATA in the allocate_pool() call? >>> >>> Replacing EFI_LOADER_DATA with EFI_BOOT_SERVICES_DATA still hangs at the >>> memset() call. >>> >> >> Could you try the following please? (attached as well in case gmail mangles it) >> >> diff --git a/drivers/firmware/efi/libstub/tpm.c >> b/drivers/firmware/efi/libstub/tpm.c >> index 2298560cea72..30d960a344b7 100644 >> --- a/drivers/firmware/efi/libstub/tpm.c >> +++ b/drivers/firmware/efi/libstub/tpm.c >> @@ -70,6 +70,8 @@ void >> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg) >> size_t log_size, last_entry_size; >> efi_bool_t truncated; >> void *tcg2_protocol; >> + unsigned long num_pages; >> + efi_physical_addr_t log_tbl_alloc; >> >> status = efi_call_early(locate_protocol, &tcg2_guid, NULL, >> &tcg2_protocol); >> @@ -104,9 +106,12 @@ void >> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg) >> } >> >> /* Allocate space for the logs and copy them. */ >> - status = efi_call_early(allocate_pool, EFI_LOADER_DATA, >> - sizeof(*log_tbl) + log_size, >> - (void **) &log_tbl); >> + num_pages = DIV_ROUND_UP(sizeof(*log_tbl) + log_size, EFI_PAGE_SIZE); >> + status = efi_call_early(allocate_pages, >> + EFI_ALLOCATE_ANY_PAGES, >> + EFI_LOADER_DATA, >> + num_pages, >> + &log_tbl_alloc); >> >> if (status != EFI_SUCCESS) { >> efi_printk(sys_table_arg, >> @@ -114,6 +119,7 @@ void >> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg) >> return; >> } >> >> + log_tbl = (struct linux_efi_tpm_eventlog *)(unsigned long)log_tbl_alloc; >> memset(log_tbl, 0, sizeof(*log_tbl) + log_size); >> log_tbl->size = log_size; >> log_tbl->version = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2; >> @@ -126,7 +132,7 @@ void >> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg) >> return; >> >> err_free: >> - efi_call_early(free_pool, log_tbl); >> + efi_call_early(free_pages, log_tbl_alloc, num_pages); >> } >> >> void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table_arg) >> > > Hi Ard, > > When I apply this, it starts hanging at > > status = efi_call_proto(efi_tcg2_protocol, get_event_log, tcg2_protocol, > EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2, > &log_location, &log_last_entry, &truncated); > > rather than at the memset() call. > That is *very* surprising, given that the change only affects code that executes after that. I understand how annoying this is for you, and I think we should try to fix this, but reverting the patches outright isn't the solution either. Which UEFI vendor and version does your system report?