Merge tag 'for-linus-3.12-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

Pull 9p updates from Eric Van Hensbergen:
 "Minor 9p fixes and tweaks for 3.12 merge window

  The first fixes namespace issues which causes a kernel NULL pointer
  dereference, the second fixes uevent handling to work better with
  udev, and the third switches some code to use srlcpy instead of
  strncpy in order to be safer.

  All changes have been baking in for-next for at least 2 weeks"

* tag 'for-linus-3.12-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  fs/9p: avoid accessing utsname after namespace has been torn down
  9p: send uevent after adding/removing mount_tag attribute
  fs: 9p: use strlcpy instead of strncpy

5 files changed, 19 insertions, 4 deletions

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index d384a8b77ee8..aa5ecf479a57 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -183,7 +183,7 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
 	else
 		flock.length = fl->fl_end - fl->fl_start + 1;
 	flock.proc_id = fl->fl_pid;
-	flock.client_id = utsname()->nodename;
+	flock.client_id = fid->clnt->name;
 	if (IS_SETLKW(cmd))
 		flock.flags = P9_LOCK_FLAGS_BLOCK;
 
@@ -260,7 +260,7 @@ static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
 	else
 		glock.length = fl->fl_end - fl->fl_start + 1;
 	glock.proc_id = fl->fl_pid;
-	glock.client_id = utsname()->nodename;
+	glock.client_id = fid->clnt->name;
 
 	res = p9_client_getlock_dotl(fid, &glock);
 	if (res < 0)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 25b018efb8ab..94de6d1482e2 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -146,7 +146,7 @@ static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 		char type = 0, ext[32];
 		int major = -1, minor = -1;
 
-		strncpy(ext, stat->extension, sizeof(ext));
+		strlcpy(ext, stat->extension, sizeof(ext));
 		sscanf(ext, "%c %u %u", &type, &major, &minor);
 		switch (type) {
 		case 'c':
@@ -1186,7 +1186,7 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 			 * this even with .u extension. So check
 			 * for non NULL stat->extension
 			 */
-			strncpy(ext, stat->extension, sizeof(ext));
+			strlcpy(ext, stat->extension, sizeof(ext));
 			/* HARDLINKCOUNT %u */
 			sscanf(ext, "%13s %u", tag_name, &i_nlink);
 			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index 4c7c01a73911..c38a005bd0cf 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -26,6 +26,8 @@
 #ifndef NET_9P_CLIENT_H
 #define NET_9P_CLIENT_H
 
+#include <linux/utsname.h>
+
 /* Number of requests per row */
 #define P9_ROW_MAXTAG 255
 
@@ -134,6 +136,7 @@ struct p9_req_t {
  * @tagpool - transaction id accounting for session
  * @reqs - 2D array of requests
  * @max_tag - current maximum tag id allocated
+ * @name - node name used as client id
  *
  * The client structure is used to keep track of various per-client
  * state that has been instantiated.
@@ -164,6 +167,8 @@ struct p9_client {
 	struct p9_idpool *tagpool;
 	struct p9_req_t *reqs[P9_ROW_MAXTAG];
 	int max_tag;
+
+	char name[__NEW_UTS_LEN + 1];
 };
 
 /**
diff --git a/net/9p/client.c b/net/9p/client.c
index ba93bdab2701..ee8fd6bd4035 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -987,6 +987,7 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
 {
 	int err;
 	struct p9_client *clnt;
+	char *client_id;
 
 	err = 0;
 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
@@ -995,6 +996,10 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
 
 	clnt->trans_mod = NULL;
 	clnt->trans = NULL;
+
+	client_id = utsname()->nodename;
+	memcpy(clnt->name, client_id, strlen(client_id) + 1);
+
 	spin_lock_init(&clnt->lock);
 	INIT_LIST_HEAD(&clnt->fidlist);
 
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index e1c26b101830..990afab2be1b 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -577,6 +577,10 @@ static int p9_virtio_probe(struct virtio_device *vdev)
 	mutex_lock(&virtio_9p_lock);
 	list_add_tail(&chan->chan_list, &virtio_chan_list);
 	mutex_unlock(&virtio_9p_lock);
+
+	/* Let udev rules use the new mount_tag attribute. */
+	kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
+
 	return 0;
 
 out_free_tag:
@@ -654,6 +658,7 @@ static void p9_virtio_remove(struct virtio_device *vdev)
 	list_del(&chan->chan_list);
 	mutex_unlock(&virtio_9p_lock);
 	sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
+	kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
 	kfree(chan->tag);
 	kfree(chan->vc_wq);
 	kfree(chan);