From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40268) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eBmL0-0007xt-Gu for qemu-devel@nongnu.org; Mon, 06 Nov 2017 13:41:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eBmKv-0005c7-Qr for qemu-devel@nongnu.org; Mon, 06 Nov 2017 13:41:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46708) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eBmKv-0005bI-Hm for qemu-devel@nongnu.org; Mon, 06 Nov 2017 13:41:29 -0500 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Mon, 6 Nov 2017 19:39:22 +0100 Message-Id: <20171106183925.16747-26-marcandre.lureau@redhat.com> In-Reply-To: <20171106183925.16747-1-marcandre.lureau@redhat.com> References: <20171106183925.16747-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [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: qemu-devel@nongnu.org Cc: amarnath.valluri@intel.com, stefanb@linux.vnet.ibm.com, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= 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. Add a mutex to protect from concurrent control commands. Signed-off-by: Marc-Andr=C3=A9 Lureau --- 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; =20 =20 -static int tpm_emulator_ctrlcmd(CharBackend *dev, unsigned long cmd, voi= d *msg, +static int tpm_emulator_ctrlcmd(TPMEmulator *tpm, unsigned long cmd, voi= d *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); =20 buf =3D g_alloca(n); memcpy(buf, &cmd_no, sizeof(cmd_no)); @@ -87,17 +93,21 @@ static int tpm_emulator_ctrlcmd(CharBackend *dev, uns= igned long cmd, void *msg, =20 n =3D qemu_chr_fe_write_all(dev, buf, n); if (n <=3D 0) { - return -1; + goto end; } =20 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; } } =20 - return 0; + ret =3D 0; + +end: + qemu_mutex_unlock(&tpm->mutex); + return ret; } =20 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, =20 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; =20 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(TPM= Backend *tb) ptm_est est; =20 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 fl= ag: %s", strerror(errno)); @@ -300,7 +310,7 @@ static int tpm_emulator_reset_tpm_established_flag(TP= MBackend *tb, } =20 reset_est.u.req.loc =3D tpm_emu->cur_locty_number; - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_RESET_TPMESTABLISHE= D, + 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 bi= t: %s", @@ -329,7 +339,7 @@ static void tpm_emulator_cancel_cmd(TPMBackend *tb) } =20 /* FIXME: make the function non-blocking, or it may block a VCPU */ - if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_CANCEL_TPM_CMD, &re= s, 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) =20 qemu_chr_fe_set_msgfds(&tpm_emu->ctrl_chr, fds + 1, 1); =20 - 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); } =20 /* @@ -503,8 +514,7 @@ static void tpm_emulator_shutdown(TPMEmulator *tpm_em= u) { ptm_res res; =20 - 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); } =20 static void tpm_emulator_class_init(ObjectClass *klass, void *data) --=20 2.15.0.rc0.40.gaefcc5f6f