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Re: [Qemu-devel] [PATCH v2 25/28] tpm-emulator: protect concurrent ctrl_
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH v2 25/28] tpm-emulator: protect concurrent ctrl_chr access |
Date: |
Tue, 7 Nov 2017 12:08:18 +0100 |
Hi
On Tue, Nov 7, 2017 at 2:11 AM, Stefan Berger
<address@hidden> wrote:
> On 11/06/2017 05:11 PM, Marc-André Lureau wrote:
>>
>> Hi
>>
>> ----- Original Message -----
>>>
>>> On 11/06/2017 01:39 PM, Marc-André Lureau wrote:
>>>>
>>>> The control chardev is being used from the data thread to set the
>>>> locality of the next request. Altough the chr has a write mutex, we
>>>> may potentially read the reply from another thread request.
>>>
>>> Right, so there may be concurrency with the CMD_RESET/GET_TPMESTABLISHED
>>> commands. All the other ones shouldn't be affected. It sound like a bug
>>> in existing code.
>>>
>> I think so too, I'll rebase on master for 2.11, unless you can trivially
>> cherry-pick it.
>
>
> I could trivially cherry-pick it. Now can I send it as a pull request ?
>
Sure, thanks!
> Stefan
>
>
>>
>>>> Add a mutex to protect from concurrent control commands.
>>>>
>>>> Signed-off-by: Marc-André Lureau <address@hidden>
>>>
>>> Reviewed-by: Stefan Berger <address@hidden>
>>>
>>>
>> thanks
>>
>>>> ---
>>>> hw/tpm/tpm_emulator.c | 44
>>>> ++++++++++++++++++++++++++++----------------
>>>> 1 file changed, 28 insertions(+), 16 deletions(-)
>>>>
>>>> diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
>>>> index b77c0238c7..24cb61162f 100644
>>>> --- a/hw/tpm/tpm_emulator.c
>>>> +++ b/hw/tpm/tpm_emulator.c
>>>> @@ -71,15 +71,21 @@ typedef struct TPMEmulator {
>>>> ptm_cap caps; /* capabilities of the TPM */
>>>> uint8_t cur_locty_number; /* last set locality */
>>>> Error *migration_blocker;
>>>> +
>>>> + QemuMutex mutex;
>>>> } TPMEmulator;
>>>>
>>>>
>>>> -static int tpm_emulator_ctrlcmd(CharBackend *dev, unsigned long cmd,
>>>> void
>>>> *msg,
>>>> +static int tpm_emulator_ctrlcmd(TPMEmulator *tpm, unsigned long cmd,
>>>> void
>>>> *msg,
>>>> size_t msg_len_in, size_t
>>>> msg_len_out)
>>>> {
>>>> + CharBackend *dev = &tpm->ctrl_chr;
>>>> uint32_t cmd_no = cpu_to_be32(cmd);
>>>> ssize_t n = sizeof(uint32_t) + msg_len_in;
>>>> uint8_t *buf = NULL;
>>>> + int ret = -1;
>>>> +
>>>> + qemu_mutex_lock(&tpm->mutex);
>>>>
>>>> buf = g_alloca(n);
>>>> memcpy(buf, &cmd_no, sizeof(cmd_no));
>>>> @@ -87,17 +93,21 @@ static int tpm_emulator_ctrlcmd(CharBackend *dev,
>>>> unsigned long cmd, void *msg,
>>>>
>>>> n = qemu_chr_fe_write_all(dev, buf, n);
>>>> if (n <= 0) {
>>>> - return -1;
>>>> + goto end;
>>>> }
>>>>
>>>> if (msg_len_out != 0) {
>>>> n = qemu_chr_fe_read_all(dev, msg, msg_len_out);
>>>> if (n <= 0) {
>>>> - return -1;
>>>> + goto end;
>>>> }
>>>> }
>>>>
>>>> - return 0;
>>>> + ret = 0;
>>>> +
>>>> +end:
>>>> + qemu_mutex_unlock(&tpm->mutex);
>>>> + return ret;
>>>> }
>>>>
>>>> static int tpm_emulator_unix_tx_bufs(TPMEmulator *tpm_emu,
>>>> @@ -154,7 +164,7 @@ static int tpm_emulator_set_locality(TPMEmulator
>>>> *tpm_emu, uint8_t locty_number,
>>>>
>>>> DPRINTF("setting locality : 0x%x", locty_number);
>>>> loc.u.req.loc = locty_number;
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SET_LOCALITY,
>>>> &loc,
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_LOCALITY, &loc,
>>>> sizeof(loc), sizeof(loc)) < 0) {
>>>> error_setg(errp, "tpm-emulator: could not set locality : %s",
>>>> strerror(errno));
>>>> @@ -200,8 +210,8 @@ error:
>>>> static int tpm_emulator_probe_caps(TPMEmulator *tpm_emu)
>>>> {
>>>> DPRINTF("%s", __func__);
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_GET_CAPABILITY,
>>>> - &tpm_emu->caps, 0, sizeof(tpm_emu->caps)) < 0)
>>>> {
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_GET_CAPABILITY,
>>>> + &tpm_emu->caps, 0, sizeof(tpm_emu->caps))
>>>> <
>>>> 0) {
>>>> error_report("tpm-emulator: probing failed : %s",
>>>> strerror(errno));
>>>> return -1;
>>>> }
>>>> @@ -252,8 +262,8 @@ static int tpm_emulator_startup_tpm(TPMBackend *tb)
>>>> ptm_res res;
>>>>
>>>> DPRINTF("%s", __func__);
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_INIT, &init,
>>>> sizeof(init),
>>>> - sizeof(init)) < 0) {
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_INIT, &init, sizeof(init),
>>>> + sizeof(init)) < 0) {
>>>> error_report("tpm-emulator: could not send INIT: %s",
>>>> strerror(errno));
>>>> goto err_exit;
>>>> @@ -276,7 +286,7 @@ static bool
>>>> tpm_emulator_get_tpm_established_flag(TPMBackend *tb)
>>>> ptm_est est;
>>>>
>>>> DPRINTF("%s", __func__);
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr,
>>>> CMD_GET_TPMESTABLISHED,
>>>> &est,
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_GET_TPMESTABLISHED, &est,
>>>> 0, sizeof(est)) < 0) {
>>>> error_report("tpm-emulator: Could not get the TPM established
>>>> flag: %s",
>>>> strerror(errno));
>>>> @@ -300,7 +310,7 @@ static int
>>>> tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
>>>> }
>>>>
>>>> reset_est.u.req.loc = tpm_emu->cur_locty_number;
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr,
>>>> CMD_RESET_TPMESTABLISHED,
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_RESET_TPMESTABLISHED,
>>>> &reset_est, sizeof(reset_est),
>>>> sizeof(reset_est)) < 0) {
>>>> error_report("tpm-emulator: Could not reset the establishment
>>>> bit: %s",
>>>> @@ -329,7 +339,7 @@ static void tpm_emulator_cancel_cmd(TPMBackend *tb)
>>>> }
>>>>
>>>> /* FIXME: make the function non-blocking, or it may block a VCPU
>>>> */
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_CANCEL_TPM_CMD,
>>>> &res,
>>>> 0,
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_CANCEL_TPM_CMD, &res, 0,
>>>> sizeof(res)) < 0) {
>>>> error_report("tpm-emulator: Could not cancel command: %s",
>>>> strerror(errno));
>>>> @@ -377,8 +387,8 @@ static int tpm_emulator_prepare_data_fd(TPMEmulator
>>>> *tpm_emu)
>>>>
>>>> qemu_chr_fe_set_msgfds(&tpm_emu->ctrl_chr, fds + 1, 1);
>>>>
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SET_DATAFD, &res,
>>>> 0,
>>>> - sizeof(res)) || res != 0) {
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_DATAFD, &res, 0,
>>>> + sizeof(res)) < 0 || res != 0) {
>>>> error_report("tpm-emulator: Failed to send CMD_SET_DATAFD:
>>>> %s",
>>>> strerror(errno));
>>>> goto err_exit;
>>>> @@ -494,6 +504,7 @@ static void tpm_emulator_inst_init(Object *obj)
>>>> DPRINTF("%s", __func__);
>>>> tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
>>>> tpm_emu->cur_locty_number = ~0;
>>>> + qemu_mutex_init(&tpm_emu->mutex);
>>>> }
>>>>
>>>> /*
>>>> @@ -503,8 +514,7 @@ static void tpm_emulator_shutdown(TPMEmulator
>>>> *tpm_emu)
>>>> {
>>>> ptm_res res;
>>>>
>>>> - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SHUTDOWN, &res, 0,
>>>> - sizeof(res)) < 0) {
>>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SHUTDOWN, &res, 0,
>>>> sizeof(res))
>>>> < 0) {
>>>> error_report("tpm-emulator: Could not cleanly shutdown the
>>>> TPM:
>>>> %s",
>>>> strerror(errno));
>>>> } else if (res != 0) {
>>>> @@ -529,6 +539,8 @@ static void tpm_emulator_inst_finalize(Object *obj)
>>>> migrate_del_blocker(tpm_emu->migration_blocker);
>>>> error_free(tpm_emu->migration_blocker);
>>>> }
>>>> +
>>>> + qemu_mutex_destroy(&tpm_emu->mutex);
>>>> }
>>>>
>>>> static void tpm_emulator_class_init(ObjectClass *klass, void *data)
>>>
>>>
>>>
>
>
--
Marc-André Lureau
- [Qemu-devel] [PATCH v2 21/28] acpi: change TPM TIS data conditions, (continued)
- [Qemu-devel] [PATCH v2 21/28] acpi: change TPM TIS data conditions, Marc-André Lureau, 2017/11/06
- [Qemu-devel] [PATCH v2 22/28] tpm-emulator: add a FIXME comment about blocking cancel, Marc-André Lureau, 2017/11/06
- [Qemu-devel] [PATCH v2 23/28] tpm-tis: remove redundant 'tpm_tis:' in error messages, Marc-André Lureau, 2017/11/06
- [Qemu-devel] [PATCH v2 24/28] tpm-tis: check that at most one TPM device exists, Marc-André Lureau, 2017/11/06
- [Qemu-devel] [PATCH v2 25/28] tpm-emulator: protect concurrent ctrl_chr access, Marc-André Lureau, 2017/11/06
[Qemu-devel] [PATCH v2 26/28] qdev: add DEFINE_PROP_TPMBE, Marc-André Lureau, 2017/11/06
[Qemu-devel] [PATCH v2 27/28] tpm-tis: use DEFINE_PROP_TPMBE, Marc-André Lureau, 2017/11/06
[Qemu-devel] [PATCH v2 28/28] tpm: remove tpm_register_model(), Marc-André Lureau, 2017/11/06
Re: [Qemu-devel] [PATCH v2 00/28] TPM: code cleanup (not 2.11), Stefan Berger, 2017/11/06