Re: [RFC PATCH] tpm: only set efi_tpm_final_log_size after successful event log parsing
From: Laura Abbott
Date: Mon Sep 23 2019 - 10:52:47 EST
On 9/18/19 8:23 PM, Jerry Snitselaar wrote:
On Wed Sep 18 19, 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 following:
[ 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 ]---
Fixes: c46f3405692de ("tpm: Reserve the TPM final events table")
Cc: Matthew Garrett <mjg59@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
---
drivers/firmware/efi/tpm.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
index 1d3f5ca3eaaf..5cd00a7833c2 100644
--- a/drivers/firmware/efi/tpm.c
+++ b/drivers/firmware/efi/tpm.c
@@ -40,8 +40,7 @@ int __init efi_tpm_eventlog_init(void)
{
struct linux_efi_tpm_eventlog *log_tbl;
struct efi_tcg2_final_events_table *final_tbl;
- unsigned int tbl_size;
- int ret = 0;
+ int tbl_size, ret = 0;
if (efi.tpm_log == EFI_INVALID_TABLE_ADDR) {
/*
@@ -80,11 +79,17 @@ int __init efi_tpm_eventlog_init(void)
+ sizeof(final_tbl->nr_events),
final_tbl->nr_events,
log_tbl->log);
+ if (tbl_size < 0) {
+ pr_err("Failed to parse event in TPM Final Event log\n");
+ goto calc_out;
+ }
+
memblock_reserve((unsigned long)final_tbl,
tbl_size + sizeof(*final_tbl));
- early_memunmap(final_tbl, sizeof(*final_tbl));
efi_tpm_final_log_size = tbl_size;
+calc_out:
+ early_memunmap(final_tbl, sizeof(*final_tbl));
out:
early_memunmap(log_tbl, sizeof(*log_tbl));
return ret;
--
2.23.0
I'm not sure what to set ret to, which currently isn't checked, or if anything
should be done with efi.tpm_final_log.
fwiw, this is being hit by a number of Fedora users
https://bugzilla.redhat.com/show_bug.cgi?id=1752961
I'd like to bring this patch to Fedora if there's general agreement
this is the correct approach.
Thanks,
Laura