From: Miklos Szeredi <miklos@szeredi.hu>
Date: Fri, 22 Apr 2005 12:04:55 +0000 (+0000)
Subject: fix
X-Git-Tag: fuse_2_3_pre5~2
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0111f9dbe43a8c4ae516d3eb470186770894c5bf;p=qemu-gpiodev%2Flibfuse.git

fix
---

diff --git a/ChangeLog b/ChangeLog
index 94327f4..5415803 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,12 @@
 	* Fix buggy behavior of open(..., O_CREAT|O_EXCL) if interrupted.
 	Reported by David Shaw
 
+	* Remove "allow_root" option from kernel module, and implement
+	it's functionality in the library
+
+	* Fix Oops caused by premature release of fuse_conn.  Clean up
+	related code, to be more readable
+
 2005-04-08  Miklos Szeredi <miklos@szeredi.hu>
 
 	* Fix Oops in case of nfs export.  Spotted by David Shaw
diff --git a/kernel/dev.c b/kernel/dev.c
index 29a9b63..d64423e 100644
--- a/kernel/dev.c
+++ b/kernel/dev.c
@@ -24,7 +24,7 @@ static inline struct fuse_conn *fuse_get_conn(struct file *file)
 	struct fuse_conn *fc;
 	spin_lock(&fuse_lock);
 	fc = file->private_data;
-	if (fc && !fc->sb)
+	if (fc && !fc->mounted)
 		fc = NULL;
 	spin_unlock(&fuse_lock);
 	return fc;
@@ -214,7 +214,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 	spin_unlock(&fuse_lock);
 	if (req->background) {
 		down_read(&fc->sbput_sem);
-		if (fc->sb)
+		if (fc->mounted)
 			fuse_release_background(req);
 		up_read(&fc->sbput_sem);
 	}
@@ -371,7 +371,7 @@ static void request_send_wait(struct fuse_conn *fc, struct fuse_req *req,
 {
 	req->isreply = 1;
 	spin_lock(&fuse_lock);
-	if (!fc->file)
+	if (!fc->connected)
 		req->out.h.error = -ENOTCONN;
 	else if (fc->conn_error)
 		req->out.h.error = -ECONNREFUSED;
@@ -404,7 +404,7 @@ void request_send_nonint(struct fuse_conn *fc, struct fuse_req *req)
 static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
 {
 	spin_lock(&fuse_lock);
-	if (fc->file) {
+	if (fc->connected) {
 		queue_request(fc, req);
 		spin_unlock(&fuse_lock);
 	} else {
@@ -659,7 +659,7 @@ static void request_wait(struct fuse_conn *fc)
 	DECLARE_WAITQUEUE(wait, current);
 
 	add_wait_queue_exclusive(&fc->waitq, &wait);
-	while (fc->sb && list_empty(&fc->pending)) {
+	while (fc->mounted && list_empty(&fc->pending)) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (signal_pending(current))
 			break;
@@ -709,7 +709,7 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov,
 		goto err_unlock;
 	request_wait(fc);
 	err = -ENODEV;
-	if (!fc->sb)
+	if (!fc->mounted)
 		goto err_unlock;
 	err = -ERESTARTSYS;
 	if (list_empty(&fc->pending))
@@ -917,7 +917,7 @@ static int fuse_dev_release(struct inode *inode, struct file *file)
 	spin_lock(&fuse_lock);
 	fc = file->private_data;
 	if (fc) {
-		fc->file = NULL;
+		fc->connected = 0;
 		end_requests(fc, &fc->pending);
 		end_requests(fc, &fc->processing);
 		fuse_release_conn(fc);
diff --git a/kernel/dir.c b/kernel/dir.c
index 6ae498c..947d538 100644
--- a/kernel/dir.c
+++ b/kernel/dir.c
@@ -441,9 +441,7 @@ static int fuse_revalidate(struct dentry *entry)
 
 	if (get_node_id(inode) == FUSE_ROOT_ID) {
 		if (!(fc->flags & FUSE_ALLOW_OTHER) &&
-		    current->fsuid != fc->user_id &&
-		    (!(fc->flags & FUSE_ALLOW_ROOT) ||
-		     !capable(CAP_DAC_OVERRIDE)))
+		    current->fsuid != fc->user_id)
 			return -EACCES;
 	} else if (time_before_eq(jiffies, fi->i_time))
 		return 0;
@@ -455,8 +453,7 @@ static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
-	if (!(fc->flags & FUSE_ALLOW_OTHER) && current->fsuid != fc->user_id &&
-	    (!(fc->flags & FUSE_ALLOW_ROOT) || !capable(CAP_DAC_OVERRIDE)))
+	if (!(fc->flags & FUSE_ALLOW_OTHER) && current->fsuid != fc->user_id)
 		return -EACCES;
 	else if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
 #ifdef KERNEL_2_6_10_PLUS
diff --git a/kernel/fuse_i.h b/kernel/fuse_i.h
index 373f36d..164eaa7 100644
--- a/kernel/fuse_i.h
+++ b/kernel/fuse_i.h
@@ -101,10 +101,6 @@ static inline void set_page_dirty_lock(struct page *page)
 /** Bypass the page cache for read and write operations  */
 #define FUSE_DIRECT_IO           (1 << 3)
 
-/** Allow root and setuid-root programs to access fuse-mounted
-    filesystems */
-#define FUSE_ALLOW_ROOT		 (1 << 4)
-
 /** FUSE inode */
 struct fuse_inode {
 	/** Inode data */
@@ -260,11 +256,8 @@ struct fuse_req {
  * unmounted.
  */
 struct fuse_conn {
-	/** The superblock of the mounted filesystem */
-	struct super_block *sb;
-
-	/** The opened client device */
-	struct file *file;
+	/** Reference count */
+	int count;
 
 	/** The user id for this mount */
 	uid_t user_id;
@@ -307,6 +300,12 @@ struct fuse_conn {
 	/** The next unique request id */
 	int reqctr;
 
+	/** Mount is active */
+	unsigned mounted : 1;
+
+	/** Connection established */
+	unsigned connected : 1;
+
 	/** Connection failed (version mismatch) */
 	unsigned conn_error : 1;
 
diff --git a/kernel/inode.c b/kernel/inode.c
index 1feaba9..9b894f5 100644
--- a/kernel/inode.c
+++ b/kernel/inode.c
@@ -99,8 +99,8 @@ void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 
 static void fuse_clear_inode(struct inode *inode)
 {
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	if (fc && (inode->i_sb->s_flags & MS_ACTIVE)) {
+	if (inode->i_sb->s_flags & MS_ACTIVE) {
+		struct fuse_conn *fc = get_fuse_conn(inode);
 		struct fuse_inode *fi = get_fuse_inode(inode);
 		fuse_send_forget(fc, fi->forget_req, fi->nodeid, inode->i_version);
 		fi->forget_req = NULL;
@@ -260,14 +260,13 @@ static void fuse_put_super(struct super_block *sb)
 						   struct fuse_req, bg_entry));
 
 	spin_lock(&fuse_lock);
-	fc->sb = NULL;
+	fc->mounted = 0;
 	fc->user_id = 0;
 	fc->flags = 0;
 	/* Flush all readers on this fs */
 	wake_up_all(&fc->waitq);
 	up_write(&fc->sbput_sem);
 	fuse_release_conn(fc);
-	*get_fuse_conn_super_p(sb) = NULL;
 	spin_unlock(&fuse_lock);
 }
 
@@ -314,7 +313,6 @@ enum {
 	OPT_USER_ID,
 	OPT_DEFAULT_PERMISSIONS,
 	OPT_ALLOW_OTHER,
-	OPT_ALLOW_ROOT,
 	OPT_KERNEL_CACHE,
 #ifndef KERNEL_2_6
 	OPT_LARGE_READ,
@@ -330,7 +328,6 @@ static match_table_t tokens = {
 	{OPT_USER_ID,			"user_id=%u"},
 	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
 	{OPT_ALLOW_OTHER,		"allow_other"},
-	{OPT_ALLOW_ROOT,		"allow_root"},
 	{OPT_KERNEL_CACHE,		"kernel_cache"},
 #ifndef KERNEL_2_6
 	{OPT_LARGE_READ,		"large_read"},
@@ -382,10 +379,6 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
 			d->flags |= FUSE_ALLOW_OTHER;
 			break;
 
-		case OPT_ALLOW_ROOT:
-			d->flags |= FUSE_ALLOW_ROOT;
-			break;
-
 		case OPT_KERNEL_CACHE:
 			d->flags |= FUSE_KERNEL_CACHE;
 			break;
@@ -424,8 +417,6 @@ static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 		seq_puts(m, ",default_permissions");
 	if (fc->flags & FUSE_ALLOW_OTHER)
 		seq_puts(m, ",allow_other");
-	if (fc->flags & FUSE_ALLOW_ROOT)
-		seq_puts(m, ",allow_root");
 	if (fc->flags & FUSE_KERNEL_CACHE)
 		seq_puts(m, ",kernel_cache");
 #ifndef KERNEL_2_6
@@ -453,7 +444,8 @@ static void free_conn(struct fuse_conn *fc)
 /* Must be called with the fuse lock held */
 void fuse_release_conn(struct fuse_conn *fc)
 {
-	if (!fc->sb && !fc->file)
+	fc->count--;
+	if (!fc->count)
 		free_conn(fc);
 }
 
@@ -465,10 +457,6 @@ static struct fuse_conn *new_conn(void)
 	if (fc != NULL) {
 		int i;
 		memset(fc, 0, sizeof(*fc));
-		fc->sb = NULL;
-		fc->file = NULL;
-		fc->flags = 0;
-		fc->user_id = 0;
 		init_waitqueue_head(&fc->waitq);
 		INIT_LIST_HEAD(&fc->pending);
 		INIT_LIST_HEAD(&fc->processing);
@@ -508,8 +496,10 @@ static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
 		fc = ERR_PTR(-EINVAL);
 	} else {
 		file->private_data = fc;
-		fc->sb = sb;
-		fc->file = file;
+		*get_fuse_conn_super_p(sb) = fc;
+		fc->mounted = 1;
+		fc->connected = 1;
+		fc->count = 2;
 	}
 	spin_unlock(&fuse_lock);
 	return fc;
@@ -636,8 +626,6 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 #endif
 	fc->max_write = FUSE_MAX_IN / 2;
 
-	*get_fuse_conn_super_p(sb) = fc;
-
 	err = -ENOMEM;
 	root = get_root_inode(sb, d.rootmode);
 	if (root == NULL)
@@ -653,10 +641,8 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 
  err:
 	spin_lock(&fuse_lock);
-	fc->sb = NULL;
 	fuse_release_conn(fc);
 	spin_unlock(&fuse_lock);
-	*get_fuse_conn_super_p(sb) = NULL;
 	return err;
 }
 
diff --git a/lib/fuse.c b/lib/fuse.c
index 82adeb2..9659a0d 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -35,6 +35,9 @@
 /** Use st_ino field in getattr instead of generating inode numbers  */
 #define FUSE_USE_INO     (1 << 3)
 
+/** Only allow root or the owner to access the filesystem */
+#define FUSE_ALLOW_ROOT  (1 << 4)
+
 #define FUSE_KERNEL_MINOR_VERSION_NEED 1
 #define FUSE_VERSION_FILE_OLD "/proc/fs/fuse/version"
 #define FUSE_VERSION_FILE_NEW "/sys/fs/fuse/version"
@@ -1765,6 +1768,15 @@ void fuse_process_cmd(struct fuse *f, struct fuse_cmd *cmd)
         goto out;
     }
 
+    if ((f->flags & FUSE_ALLOW_ROOT) && in->uid != f->owner && in->uid != 0 &&
+        in->opcode != FUSE_INIT && in->opcode != FUSE_READ &&
+        in->opcode != FUSE_WRITE && in->opcode != FUSE_FSYNC && 
+        in->opcode != FUSE_RELEASE && in->opcode != FUSE_READDIR &&
+        in->opcode != FUSE_FSYNCDIR && in->opcode != FUSE_RELEASEDIR) {
+        send_reply(f, in, -EACCES, NULL, 0);
+        goto out;
+    }
+
     ctx->fuse = f;
     ctx->uid = in->uid;
     ctx->gid = in->gid;
@@ -2000,7 +2012,8 @@ int fuse_is_lib_option(const char *opt)
 {
     if (strcmp(opt, "debug") == 0 ||
         strcmp(opt, "hard_remove") == 0 ||
-        strcmp(opt, "use_ino") == 0)
+        strcmp(opt, "use_ino") == 0 ||
+        strcmp(opt, "allow_root") == 0)
         return 1;
     else
         return 0;
@@ -2025,6 +2038,8 @@ static int parse_lib_opts(struct fuse *f, const char *opts)
                 f->flags |= FUSE_HARD_REMOVE;
             else if (strcmp(opt, "use_ino") == 0)
                 f->flags |= FUSE_USE_INO;
+            else if (strcmp(opt, "allow_root") == 0)
+                f->flags |= FUSE_ALLOW_ROOT;
             else
                 fprintf(stderr, "fuse: warning: unknown option `%s'\n", opt);
         }
@@ -2100,6 +2115,8 @@ struct fuse *fuse_new_common(int fd, const char *opts,
     root->refctr = 1;
     hash_id(f, root);
 
+    f->owner = getuid();
+
     return f;
 
  out_free_root:
diff --git a/lib/fuse_i.h b/lib/fuse_i.h
index 4a9f04a..3bdfb00 100644
--- a/lib/fuse_i.h
+++ b/lib/fuse_i.h
@@ -32,6 +32,7 @@ struct fuse {
     void *user_data;
     int major;
     int minor;
+    uid_t owner;
 };
 
 struct fuse *fuse_new_common(int fd, const char *opts,
diff --git a/lib/helper.c b/lib/helper.c
index 42fe44c..d1a3d1f 100644
--- a/lib/helper.c
+++ b/lib/helper.c
@@ -138,8 +138,12 @@ static int add_options(char **lib_optp, char **kernel_optp, const char *opts)
 
     while((opt = strsep(&s, ",")) != NULL) {
         int res;
-        if (fuse_is_lib_option(opt))
+        if (fuse_is_lib_option(opt)) {
             res = add_option_to(opt, lib_optp);
+            /* Compatibility hack */
+            if (strcmp(opt, "allow_root") == 0 && res != -1)
+                res = add_option_to("allow_other", kernel_optp);
+        }
         else
             res = add_option_to(opt, kernel_optp);
         if (res == -1) {