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-rw-r--r--fs/debugfs/inode.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index b7f2e971ecbc..2fcf66473436 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -35,6 +35,7 @@
static struct vfsmount *debugfs_mount;
static int debugfs_mount_count;
static bool debugfs_registered;
+static unsigned int debugfs_allow = DEFAULT_DEBUGFS_ALLOW_BITS;
/*
* Don't allow access attributes to be changed whilst the kernel is locked down
@@ -266,6 +267,9 @@ static struct dentry *debug_mount(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data)
{
+ if (!(debugfs_allow & DEBUGFS_ALLOW_API))
+ return ERR_PTR(-EPERM);
+
return mount_single(fs_type, flags, data, debug_fill_super);
}
@@ -311,6 +315,9 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
struct dentry *dentry;
int error;
+ if (!(debugfs_allow & DEBUGFS_ALLOW_API))
+ return ERR_PTR(-EPERM);
+
pr_debug("creating file '%s'\n", name);
if (IS_ERR(parent))
@@ -385,6 +392,11 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
if (IS_ERR(dentry))
return dentry;
+ if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
+ failed_creating(dentry);
+ return ERR_PTR(-EPERM);
+ }
+
inode = debugfs_get_inode(dentry->d_sb);
if (unlikely(!inode)) {
pr_err("out of free dentries, can not create file '%s'\n",
@@ -541,6 +553,11 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
if (IS_ERR(dentry))
return dentry;
+ if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
+ failed_creating(dentry);
+ return ERR_PTR(-EPERM);
+ }
+
inode = debugfs_get_inode(dentry->d_sb);
if (unlikely(!inode)) {
pr_err("out of free dentries, can not create directory '%s'\n",
@@ -583,6 +600,11 @@ struct dentry *debugfs_create_automount(const char *name,
if (IS_ERR(dentry))
return dentry;
+ if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
+ failed_creating(dentry);
+ return ERR_PTR(-EPERM);
+ }
+
inode = debugfs_get_inode(dentry->d_sb);
if (unlikely(!inode)) {
pr_err("out of free dentries, can not create automount '%s'\n",
@@ -786,10 +808,27 @@ bool debugfs_initialized(void)
}
EXPORT_SYMBOL_GPL(debugfs_initialized);
+static int __init debugfs_kernel(char *str)
+{
+ if (str) {
+ if (!strcmp(str, "on"))
+ debugfs_allow = DEBUGFS_ALLOW_API | DEBUGFS_ALLOW_MOUNT;
+ else if (!strcmp(str, "no-mount"))
+ debugfs_allow = DEBUGFS_ALLOW_API;
+ else if (!strcmp(str, "off"))
+ debugfs_allow = 0;
+ }
+
+ return 0;
+}
+early_param("debugfs", debugfs_kernel);
static int __init debugfs_init(void)
{
int retval;
+ if (!(debugfs_allow & DEBUGFS_ALLOW_MOUNT))
+ return -EPERM;
+
retval = sysfs_create_mount_point(kernel_kobj, "debug");
if (retval)
return retval;