File xen.850e89b3ef1a7be6b71fa7ae22333c884e08431a.patch of Package xen

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File xen.850e89b3ef1a7be6b71fa7ae22333c884e08431a.patch of Package xen (Revision 09b40d2c58da0f26b857dc45786f38d9)

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From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Thu, 5 Apr 2018 03:50:52 +0200
Subject: 850e89b3ef1a7be6b71fa7ae22333c884e08431a
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

tools/blktap2: fix possible '\0' truncation

gcc-8 complains:

tapdisk-vbd.c: In function 'tapdisk_vbd_resume_ring':
    tapdisk-vbd.c:1671:53: error: 'snprintf' output may be truncated before the last format character [-Werror=format-truncation=]
       snprintf(params.name, sizeof(params.name) - 1, "%s", message);
                                                         ^
    tapdisk-vbd.c:1671:3: note: 'snprintf' output between 1 and 256 bytes into a destination of size 255
       snprintf(params.name, sizeof(params.name) - 1, "%s", message);
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The "- 1" in buffer size should be actually applied to message, to leave
place for terminating '\0', not the other way around (truncate '\0' even
if it would fit).

In function 'tapdisk_control_open_image',
        inlined from 'tapdisk_control_handle_request' at tapdisk-control.c:660:10:
    tapdisk-control.c:465:2: error: 'strncpy' specified bound 256 equals destination size [-Werror=stringop-truncation]
      strncpy(params.name, vbd->name, BLKTAP2_MAX_MESSAGE_LEN);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In function 'tapdisk_control_create_socket',
        inlined from 'tapdisk_control_open' at tapdisk-control.c:836:9:
    tapdisk-control.c:793:2: error: 'strncpy' specified bound 108 equals destination size [-Werror=stringop-truncation]
      strncpy(saddr.sun_path, td_control.path, sizeof(saddr.sun_path));
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

block-qcow.c: In function 'qcow_create':
    block-qcow.c:1216:5: error: 'strncpy' specified bound 4096 equals destination size [-Werror=stringop-truncation]
         strncpy(backing_filename, backing_file,
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          sizeof(backing_filename));
          ~~~~~~~~~~~~~~~~~~~~~~~~~

I those cases, reduce size of copied string and make sure final '\0' is
added.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-Acked-by: Juergen Gross <jgross@suse.com>
---
 tools/blktap2/drivers/block-qcow.c      | 3 ++-
 tools/blktap2/drivers/tapdisk-control.c | 5 +++--
 tools/blktap2/drivers/tapdisk-vbd.c     | 3 ++-
 3 files changed, 7 insertions(+), 4 deletions(-)

--- a/tools/blktap2/drivers/block-qcow.c
+++ b/tools/blktap2/drivers/block-qcow.c
@@ -1205,25 +1205,26 @@ int qcow_create(const char *filename, uint64_t total_size,
 	header_size = sizeof(header) + sizeof(QCowHeader_ext);
 	backing_filename_len = 0;
 	size = (total_size >> SECTOR_SHIFT);
 	if (backing_file) {
 		if (strcmp(backing_file, "fat:")) {
 			const char *p;
 			/* XXX: this is a hack: we do not attempt to 
 			 *check for URL like syntax */
 			p = strchr(backing_file, ':');
 			if (p && (p - backing_file) >= 2) {
 				/* URL like but exclude "c:" like filenames */
 				strncpy(backing_filename, backing_file,
-					sizeof(backing_filename));
+					sizeof(backing_filename) - 1);
+				backing_filename[sizeof(backing_filename) - 1] = '\0';
 			} else {
 				if (realpath(backing_file, backing_filename) == NULL ||
 				    stat(backing_filename, &st) != 0) {
 					return -1;
 				}
 			}
 			header.backing_file_offset = cpu_to_be64(header_size);
 			backing_filename_len = strlen(backing_filename);
 			header.backing_file_size = cpu_to_be32(
 				backing_filename_len);
 			header_size += backing_filename_len;
 			
--- a/tools/blktap2/drivers/tapdisk-control.c
+++ b/tools/blktap2/drivers/tapdisk-control.c
@@ -453,25 +453,26 @@ tapdisk_control_open_image(struct tapdisk_control_connection *connection,
 		goto out;
 
 	err = tapdisk_vbd_open_stack(vbd, request->u.params.storage, flags);
 	if (err)
 		goto out;
 
 	err = tapdisk_vbd_get_image_info(vbd, &image);
 	if (err)
 		goto fail_close;
 
 	params.capacity = image.size;
 	params.sector_size = image.secsize;
-	strncpy(params.name, vbd->name, BLKTAP2_MAX_MESSAGE_LEN);
+	strncpy(params.name, vbd->name, BLKTAP2_MAX_MESSAGE_LEN - 1);
+	params.name[BLKTAP2_MAX_MESSAGE_LEN - 1] = '\0';
 
 	err = ioctl(vbd->ring.fd, BLKTAP2_IOCTL_CREATE_DEVICE, &params);
 	if (err && errno != EEXIST) {
 		err = -errno;
 		EPRINTF("create device failed: %d\n", err);
 		goto fail_close;
 	}
 
 	err = 0;
 
 out:
 	memset(&response, 0, sizeof(response));
@@ -781,25 +782,25 @@ tapdisk_control_create_socket(char **socket_path)
 		EPRINTF("failed to unlink %s: %d\n", td_control.path, errno);
 		goto fail;
 	}
 
 	td_control.socket = socket(AF_UNIX, SOCK_STREAM, 0);
 	if (td_control.socket == -1) {
 		err = errno;
 		EPRINTF("failed to create control socket: %d\n", err);
 		goto fail;
 	}
 
 	memset(&saddr, 0, sizeof(saddr));
-	strncpy(saddr.sun_path, td_control.path, sizeof(saddr.sun_path));
+	strncpy(saddr.sun_path, td_control.path, sizeof(saddr.sun_path) - 1);
 	saddr.sun_family = AF_UNIX;
 
 	err = bind(td_control.socket,
 		   (const struct sockaddr *)&saddr, sizeof(saddr));
 	if (err == -1) {
 		err = errno;
 		EPRINTF("failed to bind to %s: %d\n", saddr.sun_path, err);
 		goto fail;
 	}
 
 	err = listen(td_control.socket, 10);
 	if (err == -1) {
--- a/tools/blktap2/drivers/tapdisk-vbd.c
+++ b/tools/blktap2/drivers/tapdisk-vbd.c
@@ -1659,25 +1659,26 @@ tapdisk_vbd_resume_ring(td_vbd_t *vbd)
 	}
 
 out:
 	if (!err) {
 		image_t image;
 		struct blktap2_params params;
 
 		memset(&params, 0, sizeof(params));
 		tapdisk_vbd_get_image_info(vbd, &image);
 
 		params.sector_size = image.secsize;
 		params.capacity    = image.size;
-		snprintf(params.name, sizeof(params.name) - 1, "%s", message);
+		snprintf(params.name, sizeof(params.name),
+			 "%.*s", (int)sizeof(params.name) - 1, message);
 
 		ioctl(vbd->ring.fd, BLKTAP2_IOCTL_SET_PARAMS, &params);
 		td_flag_clear(vbd->state, TD_VBD_PAUSED);
 	}
 
 	ioctl(vbd->ring.fd, BLKTAP2_IOCTL_RESUME, err);
 	return err;
 }
 
 static int
 tapdisk_vbd_check_ring_message(td_vbd_t *vbd)
 {

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File xen.850e89b3ef1a7be6b71fa7ae22333c884e08431a.patch of Package xen (Revision 09b40d2c58da0f26b857dc45786f38d9)

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