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; -- 2.23.0I'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
