[PATCH 06/20] fsnotify: call fsnotify_parent in perm events

From: Eric Paris
Date: Thu Oct 28 2010 - 17:32:41 EST


fsnotify perm events do not call fsnotify parent. That means you cannot
register a perm event on a directory and enforce permissions on all inodes in
that directory. This patch fixes that situation.

Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
---

fs/notify/fsnotify.c | 15 +++++++++------
include/linux/fsnotify.h | 9 +++++++--
include/linux/fsnotify_backend.h | 8 +++++---
3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 57ecadd..20dc218 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -84,16 +84,17 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
}

/* Notify this dentry's parent about a child's events. */
-void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
{
struct dentry *parent;
struct inode *p_inode;
+ int ret = 0;

if (!dentry)
dentry = path->dentry;

if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
- return;
+ return 0;

parent = dget_parent(dentry);
p_inode = parent->d_inode;
@@ -106,14 +107,16 @@ void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
mask |= FS_EVENT_ON_CHILD;

if (path)
- fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
- dentry->d_name.name, 0);
+ ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
+ dentry->d_name.name, 0);
else
- fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
- dentry->d_name.name, 0);
+ ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
+ dentry->d_name.name, 0);
}

dput(parent);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(__fsnotify_parent);

diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 59d0df4..5059faa 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -26,12 +26,12 @@ static inline void fsnotify_d_instantiate(struct dentry *dentry,
}

/* Notify this dentry's parent about a child's events. */
-static inline void fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+static inline int fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
{
if (!dentry)
dentry = path->dentry;

- __fsnotify_parent(path, dentry, mask);
+ return __fsnotify_parent(path, dentry, mask);
}

/* simple call site for access decisions */
@@ -40,6 +40,7 @@ static inline int fsnotify_perm(struct file *file, int mask)
struct path *path = &file->f_path;
struct inode *inode = path->dentry->d_inode;
__u32 fsnotify_mask = 0;
+ int ret;

if (file->f_mode & FMODE_NONOTIFY)
return 0;
@@ -52,6 +53,10 @@ static inline int fsnotify_perm(struct file *file, int mask)
else
BUG();

+ ret = fsnotify_parent(path, NULL, fsnotify_mask);
+ if (ret)
+ return ret;
+
return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
}

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 0268921..b37f3a7 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -304,7 +304,7 @@ struct fsnotify_mark {
/* main fsnotify call to send events */
extern int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
const unsigned char *name, u32 cookie);
-extern void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask);
+extern int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask);
extern void __fsnotify_inode_delete(struct inode *inode);
extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
extern u32 fsnotify_get_cookie(void);
@@ -433,8 +433,10 @@ static inline int fsnotify(struct inode *to_tell, __u32 mask, void *data, int da
return 0;
}

-static inline void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
-{}
+static inline int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+{
+ return 0;
+}

static inline void __fsnotify_inode_delete(struct inode *inode)
{}

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