From patchwork Fri Feb 8 21:42:20 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Berger X-Patchwork-Id: 219337 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 9942F2C0089 for ; Sat, 9 Feb 2013 09:46:38 +1100 (EST) Received: from localhost ([::1]:44728 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U3vjh-0007rs-QB for incoming@patchwork.ozlabs.org; Fri, 08 Feb 2013 16:43:57 -0500 Received: from eggs.gnu.org ([208.118.235.92]:55987) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U3vjA-000717-2J for qemu-devel@nongnu.org; Fri, 08 Feb 2013 16:43:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U3vj6-0003Ze-8U for qemu-devel@nongnu.org; Fri, 08 Feb 2013 16:43:23 -0500 Received: from e34.co.us.ibm.com ([32.97.110.152]:35440) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U3vj5-0003ZX-Ug for qemu-devel@nongnu.org; Fri, 08 Feb 2013 16:43:20 -0500 Received: from /spool/local by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 8 Feb 2013 14:43:16 -0700 Received: from d03relay01.boulder.ibm.com (d03relay01.boulder.ibm.com [9.17.195.226]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id CDB753E4003E for ; Fri, 8 Feb 2013 14:43:07 -0700 (MST) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay01.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r18LhDSW594656 for ; Fri, 8 Feb 2013 14:43:13 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r18LhAj3005587 for ; Fri, 8 Feb 2013 14:43:13 -0700 Received: from k-d941f-5.watson.ibm.com (k-d941f-5.watson.ibm.com [9.2.141.165]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r18Lh3oR005140 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 8 Feb 2013 14:43:05 -0700 Received: from k-d941f-5.watson.ibm.com (localhost.localdomain [127.0.0.1]) by k-d941f-5.watson.ibm.com (8.14.5/8.14.3) with ESMTP id r18Lh1J9018262; Fri, 8 Feb 2013 16:43:02 -0500 Received: (from root@localhost) by k-d941f-5.watson.ibm.com (8.14.5/8.14.5/Submit) id r18Lh1de018247; Fri, 8 Feb 2013 16:43:01 -0500 From: Stefan Berger To: stefanb@linux.vnet.ibm.com, qemu-devel@nongnu.org, anthony@codemonkey.ws Date: Fri, 8 Feb 2013 16:42:20 -0500 Message-Id: <1360359741-18151-7-git-send-email-stefanb@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1360359741-18151-1-git-send-email-stefanb@linux.vnet.ibm.com> References: <1360359741-18151-1-git-send-email-stefanb@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13020821-2876-0000-0000-00000510E6FD X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 32.97.110.152 Cc: andreas.niederl@iaik.tugraz.at, mst@redhat.com Subject: [Qemu-devel] [PATCH V21 6/7] Add support for cancelling of a TPM command X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This patch adds support for cancelling an executing TPM command. In Linux for example a user can cancel a command through the TPM's sysfs 'cancel' entry using echo "1" > /sysfs/class/misc/tpm0/device/cancel This patch propagates the cancellation of a command inside a VM to the host TPM's sysfs entry. It also uses the possibility to cancel the command before QEMU VM shutdown or reboot, which helps in preventing QEMU from hanging while waiting for the completion of the command. To relieve higher layers or users from having to determine the TPM's cancel sysfs entry, the driver searches for the entry in well known locations. Signed-off-by: Stefan Berger --- qemu-options.hx | 9 ++- tpm/tpm_passthrough.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++---- vl.c | 5 ++ 3 files changed, 164 insertions(+), 15 deletions(-) diff --git a/qemu-options.hx b/qemu-options.hx index e7e868e..c533c29 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -2193,7 +2193,7 @@ DEFHEADING() DEFHEADING(TPM device options:) DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ - "-tpmdev passthrough,id=id[,path=path]\n" + "-tpmdev passthrough,id=id[,path=path][,cancel_path=path]\n" " use path to provide path to a character device; default is /dev/tpm0\n", QEMU_ARCH_ALL) STEXI @@ -2216,7 +2216,7 @@ Use ? to print all available TPM backend types. qemu -tpmdev ? @end example -@item -tpmdev passthrough, id=@var{id}, path=@var{path} +@item -tpmdev passthrough, id=@var{id}, path=@var{path}, path=@var{cancel_path} (Linux-host only) Enable access to the host's TPM using the passthrough driver. @@ -2225,6 +2225,11 @@ driver. a Linux host this would be @code{/dev/tpm0}. @option{path} is optional and by default @code{/dev/tpm0} is used. +@option{cancel_path} specifies the path to the host TPM device's sysfs +entry allowing for cancellation of an ongoing TPM command. +@option{cancel_path} is optional and by default QEMU will search for the +sysfs entry to use. + Some notes about using the host's TPM with the passthrough driver: The TPM device accessed by the passthrough driver must not be diff --git a/tpm/tpm_passthrough.c b/tpm/tpm_passthrough.c index 7d5de8e..baca21f 100644 --- a/tpm/tpm_passthrough.c +++ b/tpm/tpm_passthrough.c @@ -22,6 +22,8 @@ * License along with this library; if not, see */ +#include + #include "qemu-common.h" #include "qapi/error.h" #include "qemu/sockets.h" @@ -57,11 +59,18 @@ struct TPMPassthruState { char *tpm_dev; int tpm_fd; + bool tpm_executing; + bool tpm_op_canceled; + int cancel_fd; bool had_startup_error; }; #define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0" +/* functions */ + +static void tpm_passthrough_cancel_cmd(TPMBackend *tb); + static int tpm_passthrough_unix_write(int fd, const uint8_t *buf, uint32_t len) { return send_all(fd, buf, len); @@ -79,25 +88,36 @@ static uint32_t tpm_passthrough_get_size_from_buffer(const uint8_t *buf) return be32_to_cpu(resp->len); } -static int tpm_passthrough_unix_tx_bufs(int tpm_fd, +static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt, const uint8_t *in, uint32_t in_len, uint8_t *out, uint32_t out_len) { int ret; - ret = tpm_passthrough_unix_write(tpm_fd, in, in_len); + tpm_pt->tpm_op_canceled = false; + tpm_pt->tpm_executing = true; + + ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len); if (ret != in_len) { - error_report("tpm_passthrough: error while transmitting data " - "to TPM: %s (%i)\n", - strerror(errno), errno); + if (!tpm_pt->tpm_op_canceled || + (tpm_pt->tpm_op_canceled && errno != ECANCELED)) { + error_report("tpm_passthrough: error while transmitting data " + "to TPM: %s (%i)\n", + strerror(errno), errno); + } goto err_exit; } - ret = tpm_passthrough_unix_read(tpm_fd, out, out_len); + tpm_pt->tpm_executing = false; + + ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len); if (ret < 0) { - error_report("tpm_passthrough: error while reading data from " - "TPM: %s (%i)\n", - strerror(errno), errno); + if (!tpm_pt->tpm_op_canceled || + (tpm_pt->tpm_op_canceled && errno != ECANCELED)) { + error_report("tpm_passthrough: error while reading data from " + "TPM: %s (%i)\n", + strerror(errno), errno); + } } else if (ret < sizeof(struct tpm_resp_hdr) || tpm_passthrough_get_size_from_buffer(out) != ret) { ret = -1; @@ -110,13 +130,15 @@ err_exit: tpm_write_fatal_error_response(out, out_len); } + tpm_pt->tpm_executing = false; + return ret; } -static int tpm_passthrough_unix_transfer(int tpm_fd, +static int tpm_passthrough_unix_transfer(TPMPassthruState *tpm_pt, const TPMLocality *locty_data) { - return tpm_passthrough_unix_tx_bufs(tpm_fd, + return tpm_passthrough_unix_tx_bufs(tpm_pt, locty_data->w_buffer.buffer, locty_data->w_offset, locty_data->r_buffer.buffer, @@ -134,7 +156,7 @@ static void tpm_passthrough_worker_thread(gpointer data, switch (cmd) { case TPM_BACKEND_CMD_PROCESS_CMD: - tpm_passthrough_unix_transfer(tpm_pt->tpm_fd, + tpm_passthrough_unix_transfer(tpm_pt, thr_parms->tpm_state->locty_data); thr_parms->recv_data_callback(thr_parms->tpm_state, @@ -172,6 +194,8 @@ static void tpm_passthrough_reset(TPMBackend *tb) DPRINTF("tpm_passthrough: CALL TO TPM_RESET!\n"); + tpm_passthrough_cancel_cmd(tb); + tpm_backend_thread_end(&tpm_pt->tbt); tpm_pt->had_startup_error = false; @@ -221,7 +245,29 @@ static void tpm_passthrough_deliver_request(TPMBackend *tb) static void tpm_passthrough_cancel_cmd(TPMBackend *tb) { - /* cancelling an ongoing command is known not to work with some TPMs */ + TPMPassthruState *tpm_pt = tb->s.tpm_pt; + int n; + + /* + * As of Linux 3.7 the tpm_tis driver does not properly cancel + * commands on all TPM manufacturers' TPMs. + * Only cancel if we're busy so we don't cancel someone else's + * command, e.g., a command executed on the host. + */ + if (tpm_pt->tpm_executing) { + if (tpm_pt->cancel_fd >= 0) { + n = write(tpm_pt->cancel_fd, "-", 1); + if (n != 1) { + error_report("Canceling TPM command failed: %s\n", + strerror(errno)); + } else { + tpm_pt->tpm_op_canceled = true; + } + } else { + error_report("Cannot cancel TPM command due to missing " + "TPM sysfs cancel entry"); + } + } } static const char *tpm_passthrough_create_desc(void) @@ -281,10 +327,97 @@ static int tpm_passthrough_test_tpmdev(int fd) return 0; } +/* + * Check whether the given base path, e.g., /sys/class/misc/tpm0/device, + * is the sysfs directory of a TPM. A TPM sysfs directory should be uniquely + * recognizable by the file entries 'pcrs' and 'cancel'. + * Upon success 'true' is returned and the basebath buffer has '/cancel' + * appended. + */ +static bool tpm_passthrough_check_sysfs_cancel(char *basepath, size_t bufsz) +{ + char path[PATH_MAX]; + struct stat statbuf; + + snprintf(path, sizeof(path), "%s/pcrs", basepath); + if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) { + return false; + } + + snprintf(path, sizeof(path), "%s/cancel", basepath); + if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) { + return false; + } + + strncpy(basepath, path, bufsz); + + return true; +} + +/* + * Determine the sysfs cancel file following kernel documentation + * in Documentation/ABI/stable/sysfs-class-tpm + */ +static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb) +{ + int fd = -1; + unsigned int idx; + DIR *pnp_dir; + char path[PATH_MAX]; + struct dirent entry, *result; + int len; + + if (tb->cancel_path) { + fd = qemu_open(tb->cancel_path, O_WRONLY); + if (fd < 0) { + error_report("Could not open TPM cancel path : %s", + strerror(errno)); + } + return fd; + } + + snprintf(path, sizeof(path), "/sys/class/misc"); + pnp_dir = opendir(path); + if (pnp_dir != NULL) { + while (readdir_r(pnp_dir, &entry, &result) == 0 && + result != NULL) { + /* + * only allow /sys/class/misc/tpm%u type of paths + */ + if (sscanf(entry.d_name, "tpm%u%n", &idx, &len) < 1 || + len <= strlen("tpm") || + len != strlen(entry.d_name)) { + continue; + } + + snprintf(path, sizeof(path), "/sys/class/misc/%s/device", + entry.d_name); + if (!tpm_passthrough_check_sysfs_cancel(path, sizeof(path))) { + continue; + } + + fd = qemu_open(path, O_WRONLY); + break; + } + closedir(pnp_dir); + } + + if (fd >= 0) { + tb->cancel_path = g_strdup(path); + } + + return fd; +} + static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb) { const char *value; + value = qemu_opt_get(opts, "cancel_path"); + if (value) { + tb->cancel_path = g_strdup(value); + } + value = qemu_opt_get(opts, "path"); if (!value) { value = TPM_PASSTHROUGH_DEFAULT_DEVICE; @@ -337,6 +470,8 @@ static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id) goto err_exit; } + tb->s.tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb); + return tb; err_exit: @@ -351,12 +486,16 @@ static void tpm_passthrough_destroy(TPMBackend *tb) { TPMPassthruState *tpm_pt = tb->s.tpm_pt; + tpm_passthrough_cancel_cmd(tb); + tpm_backend_thread_end(&tpm_pt->tbt); qemu_close(tpm_pt->tpm_fd); + qemu_close(tb->s.tpm_pt->cancel_fd); g_free(tb->id); g_free(tb->path); + g_free(tb->cancel_path); g_free(tb->s.tpm_pt->tpm_dev); g_free(tb->s.tpm_pt); g_free(tb); diff --git a/vl.c b/vl.c index 5b7f085..63b81db 100644 --- a/vl.c +++ b/vl.c @@ -503,6 +503,11 @@ static QemuOptsList qemu_tpmdev_opts = { .help = "Type of TPM backend", }, { + .name = "cancel_path", + .type = QEMU_OPT_STRING, + .help = "Sysfs file entry for canceling TPM commands", + }, + { .name = "path", .type = QEMU_OPT_STRING, .help = "Path to TPM device on the host",