From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43540) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eC1k2-0003he-Bm for qemu-devel@nongnu.org; Tue, 07 Nov 2017 06:08:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eC1jw-0000fX-6l for qemu-devel@nongnu.org; Tue, 07 Nov 2017 06:08:26 -0500 Received: from mail-vk0-x244.google.com ([2607:f8b0:400c:c05::244]:53439) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eC1jw-0000fI-13 for qemu-devel@nongnu.org; Tue, 07 Nov 2017 06:08:20 -0500 Received: by mail-vk0-x244.google.com with SMTP id k195so7680134vke.10 for ; Tue, 07 Nov 2017 03:08:20 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <7aa51688-2a80-b934-2b21-4673f4a600cc@linux.vnet.ibm.com> References: <20171106183925.16747-1-marcandre.lureau@redhat.com> <20171106183925.16747-26-marcandre.lureau@redhat.com> <79f747d6-d739-d213-34db-17d304491e05@linux.vnet.ibm.com> <67468788.36927096.1510006298683.JavaMail.zimbra@redhat.com> <7aa51688-2a80-b934-2b21-4673f4a600cc@linux.vnet.ibm.com> From: =?UTF-8?B?TWFyYy1BbmRyw6kgTHVyZWF1?= Date: Tue, 7 Nov 2017 12:08:18 +0100 Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 25/28] tpm-emulator: protect concurrent ctrl_chr access List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Berger Cc: amarnath valluri , QEMU Hi On Tue, Nov 7, 2017 at 2:11 AM, Stefan Berger wrote: > On 11/06/2017 05:11 PM, Marc-Andr=C3=A9 Lureau wrote: >> >> Hi >> >> ----- Original Message ----- >>> >>> On 11/06/2017 01:39 PM, Marc-Andr=C3=A9 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_TPMESTABLISHE= D >>> 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-Andr=C3=A9 Lureau >>> >>> Reviewed-by: Stefan Berger >>> >>> >> 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 =3D &tpm->ctrl_chr; >>>> uint32_t cmd_no =3D cpu_to_be32(cmd); >>>> ssize_t n =3D sizeof(uint32_t) + msg_len_in; >>>> uint8_t *buf =3D NULL; >>>> + int ret =3D -1; >>>> + >>>> + qemu_mutex_lock(&tpm->mutex); >>>> >>>> buf =3D 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 =3D qemu_chr_fe_write_all(dev, buf, n); >>>> if (n <=3D 0) { >>>> - return -1; >>>> + goto end; >>>> } >>>> >>>> if (msg_len_out !=3D 0) { >>>> n =3D qemu_chr_fe_read_all(dev, msg, msg_len_out); >>>> if (n <=3D 0) { >>>> - return -1; >>>> + goto end; >>>> } >>>> } >>>> >>>> - return 0; >>>> + ret =3D 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 =3D 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 establish= ed >>>> flag: %s", >>>> strerror(errno)); >>>> @@ -300,7 +310,7 @@ static int >>>> tpm_emulator_reset_tpm_established_flag(TPMBackend *tb, >>>> } >>>> >>>> reset_est.u.req.loc =3D 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 establishme= nt >>>> 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 VCP= U >>>> */ >>>> - 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(TPMEmulato= r >>>> *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 !=3D 0) { >>>> + if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_DATAFD, &res, 0, >>>> + sizeof(res)) < 0 || res !=3D 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 =3D g_new0(TPMEmulatorOptions, 1); >>>> tpm_emu->cur_locty_number =3D ~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 !=3D 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) >>> >>> >>> > > --=20 Marc-Andr=C3=A9 Lureau