From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
Subject: [PATCH] debugfs: debugfs_create_* shouldn't be checking permissions
Debugfs files and and directories are created by kernel subsystems not
directly by users, so we shouldn't be using lookup_one_len, which checks
permissions.
This was causing krb5 mounts to fail to Fedora servers using gss-proxy
if selinux was enabled, on kernels since 388f0c776781 "sunrpc: add a
debugfs rpc_xprt directory with an info file in it", which creates a new
debugfs directory for each new rpc client.
Reported-by: Anthony Messina <amessina@xxxxxxxxxxxx>
Reported-by: Jason Tibbits <tibbs@xxxxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
---
fs/debugfs/inode.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
I swiped this code fragment from net/sunrpc/rpc_pipe.c, and it's gotten
only minimal testing. (It does fix krb5 mounts, though.)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 96400ab42d13..75e5daa6a63f 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -251,6 +251,7 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
{
struct dentry *dentry;
int error;
+ struct qstr q = QSTR_INIT(name, strlen(name));
pr_debug("debugfs: creating file '%s'\n",name);
@@ -268,11 +269,19 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
parent = debugfs_mount->mnt_root;
mutex_lock(&parent->d_inode->i_mutex);
- dentry = lookup_one_len(name, parent, strlen(name));
- if (!IS_ERR(dentry) && dentry->d_inode) {
+ dentry = d_hash_and_lookup(parent, &q);
+ if (!dentry) {
+ dentry = d_alloc(parent, &q);
+ if (!dentry) {
+ dentry = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+ }
+ if (dentry->d_inode) {
dput(dentry);
dentry = ERR_PTR(-EEXIST);
}
+out:
if (IS_ERR(dentry))
mutex_unlock(&parent->d_inode->i_mutex);
return dentry;
@@ -340,7 +349,7 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
inode->i_mode = mode;
inode->i_fop = fops ? fops : &debugfs_file_operations;
inode->i_private = data;
- d_instantiate(dentry, inode);
+ d_add(dentry, inode);
fsnotify_create(dentry->d_parent->d_inode, dentry);
return end_creating(dentry);
}
@@ -422,7 +431,7 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
- d_instantiate(dentry, inode);
+ d_add(dentry, inode);
inc_nlink(dentry->d_parent->d_inode);
fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
return end_creating(dentry);
--
1.9.3
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