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Date:   Fri, 27 Sep 2019 18:31:12 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Jerry Snitselaar <jsnitsel@redhat.com>
Cc:     linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-integrity@vger.kernel.org, stable@vger.kernel.org,
        Matthew Garrett <mjg59@google.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH v3] tpm: only set efi_tpm_final_log_size after successful
 event log parsing
Message-ID: <20190927153112.GC10545@linux.intel.com>
References: <20190925172705.17358-1-jsnitsel@redhat.com>
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In-Reply-To: <20190925172705.17358-1-jsnitsel@redhat.com>
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On Wed, Sep 25, 2019 at 10:27:05AM -0700, Jerry Snitselaar wrote:
> If __calc_tpm2_event_size fails to parse an event it will return 0,
> resulting tpm2_calc_event_log_size returning -1. Currently there is
> no check of this return value, and efi_tpm_final_log_size can end up
> being set to this negative value resulting in a panic like the
> the one given below.
> 
> Also __calc_tpm2_event_size returns a size of 0 when it fails
> to parse an event, so update function documentation to reflect this.
> 
> [    0.774340] BUG: unable to handle page fault for address: ffffbc8fc00866ad
> [    0.774788] #PF: supervisor read access in kernel mode
> [    0.774788] #PF: error_code(0x0000) - not-present page
> [    0.774788] PGD 107d36067 P4D 107d36067 PUD 107d37067 PMD 107d38067 PTE 0
> [    0.774788] Oops: 0000 [#1] SMP PTI
> [    0.774788] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.3.0-0.rc2.1.elrdy.x86_64 #1
> [    0.774788] Hardware name: LENOVO 20HGS22D0W/20HGS22D0W, BIOS N1WET51W (1.30 ) 09/14/2018
> [    0.774788] RIP: 0010:memcpy_erms+0x6/0x10
> [    0.774788] Code: 90 90 90 90 eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 <f3> a4 c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe
> [    0.774788] RSP: 0000:ffffbc8fc0073b30 EFLAGS: 00010286
> [    0.774788] RAX: ffff9b1fc7c5b367 RBX: ffff9b1fc8390000 RCX: ffffffffffffe962
> [    0.774788] RDX: ffffffffffffe962 RSI: ffffbc8fc00866ad RDI: ffff9b1fc7c5b367
> [    0.774788] RBP: ffff9b1c10ca7018 R08: ffffbc8fc0085fff R09: 8000000000000063
> [    0.774788] R10: 0000000000001000 R11: 000fffffffe00000 R12: 0000000000003367
> [    0.774788] R13: ffff9b1fcc47c010 R14: ffffbc8fc0085000 R15: 0000000000000002
> [    0.774788] FS:  0000000000000000(0000) GS:ffff9b1fce200000(0000) knlGS:0000000000000000
> [    0.774788] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [    0.774788] CR2: ffffbc8fc00866ad CR3: 000000029f60a001 CR4: 00000000003606f0
> [    0.774788] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [    0.774788] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [    0.774788] Call Trace:
> [    0.774788]  tpm_read_log_efi+0x156/0x1a0
> [    0.774788]  tpm_bios_log_setup+0xc8/0x190
> [    0.774788]  tpm_chip_register+0x50/0x1c0
> [    0.774788]  tpm_tis_core_init.cold.9+0x28c/0x466
> [    0.774788]  tpm_tis_plat_probe+0xcc/0xea
> [    0.774788]  platform_drv_probe+0x35/0x80
> [    0.774788]  really_probe+0xef/0x390
> [    0.774788]  driver_probe_device+0xb4/0x100
> [    0.774788]  device_driver_attach+0x4f/0x60
> [    0.774788]  __driver_attach+0x86/0x140
> [    0.774788]  ? device_driver_attach+0x60/0x60
> [    0.774788]  bus_for_each_dev+0x76/0xc0
> [    0.774788]  ? klist_add_tail+0x3b/0x70
> [    0.774788]  bus_add_driver+0x14a/0x1e0
> [    0.774788]  ? tpm_init+0xea/0xea
> [    0.774788]  ? do_early_param+0x8e/0x8e
> [    0.774788]  driver_register+0x6b/0xb0
> [    0.774788]  ? tpm_init+0xea/0xea
> [    0.774788]  init_tis+0x86/0xd8
> [    0.774788]  ? do_early_param+0x8e/0x8e
> [    0.774788]  ? driver_register+0x94/0xb0
> [    0.774788]  do_one_initcall+0x46/0x1e4
> [    0.774788]  ? do_early_param+0x8e/0x8e
> [    0.774788]  kernel_init_freeable+0x199/0x242
> [    0.774788]  ? rest_init+0xaa/0xaa
> [    0.774788]  kernel_init+0xa/0x106
> [    0.774788]  ret_from_fork+0x35/0x40
> [    0.774788] Modules linked in:
> [    0.774788] CR2: ffffbc8fc00866ad
> [    0.774788] ---[ end trace 42930799f8d6eaea ]---
> [    0.774788] RIP: 0010:memcpy_erms+0x6/0x10
> [    0.774788] Code: 90 90 90 90 eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 <f3> a4 c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe
> [    0.774788] RSP: 0000:ffffbc8fc0073b30 EFLAGS: 00010286
> [    0.774788] RAX: ffff9b1fc7c5b367 RBX: ffff9b1fc8390000 RCX: ffffffffffffe962
> [    0.774788] RDX: ffffffffffffe962 RSI: ffffbc8fc00866ad RDI: ffff9b1fc7c5b367
> [    0.774788] RBP: ffff9b1c10ca7018 R08: ffffbc8fc0085fff R09: 8000000000000063
> [    0.774788] R10: 0000000000001000 R11: 000fffffffe00000 R12: 0000000000003367
> [    0.774788] R13: ffff9b1fcc47c010 R14: ffffbc8fc0085000 R15: 0000000000000002
> [    0.774788] FS:  0000000000000000(0000) GS:ffff9b1fce200000(0000) knlGS:0000000000000000
> [    0.774788] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [    0.774788] CR2: ffffbc8fc00866ad CR3: 000000029f60a001 CR4: 00000000003606f0
> [    0.774788] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [    0.774788] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [    0.774788] Kernel panic - not syncing: Fatal exception
> [    0.774788] Kernel Offset: 0x1d000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
> [    0.774788] ---[ end Kernel panic - not syncing: Fatal exception ]---
> 
> The root cause of the issue that caused the failure of event parsing
> in this case is resolved by Peter Jone's patchset dealing with large
> event logs where crossing over a page boundary causes the page with
> the event count to be unmapped.
> 
> Fixes: c46f3405692de ("tpm: Reserve the TPM final events table")
> Cc: linux-efi@vger.kernel.org
> Cc: linux-integrity@vger.kernel.org
> Cc: stable@vger.kernel.org
> Cc: Matthew Garrett <mjg59@google.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Reviewed-by:  <jarkko.sakkinen@linux.intel.com>

/Jarkko