Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 4fce1da..87846aa 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -19,6 +19,7 @@
#include <linux/atomic.h>
#include <linux/device.h>
#include <linux/poll.h>
+#include <linux/security.h>
#include "internal.h"
@@ -136,6 +137,25 @@
}
EXPORT_SYMBOL_GPL(debugfs_file_put);
+/*
+ * Only permit access to world-readable files when the kernel is locked down.
+ * We also need to exclude any file that has ways to write or alter it as root
+ * can bypass the permissions check.
+ */
+static bool debugfs_is_locked_down(struct inode *inode,
+ struct file *filp,
+ const struct file_operations *real_fops)
+{
+ if ((inode->i_mode & 07777) == 0444 &&
+ !(filp->f_mode & FMODE_WRITE) &&
+ !real_fops->unlocked_ioctl &&
+ !real_fops->compat_ioctl &&
+ !real_fops->mmap)
+ return false;
+
+ return security_locked_down(LOCKDOWN_DEBUGFS);
+}
+
static int open_proxy_open(struct inode *inode, struct file *filp)
{
struct dentry *dentry = F_DENTRY(filp);
@@ -147,6 +167,11 @@
return r == -EIO ? -ENOENT : r;
real_fops = debugfs_real_fops(filp);
+
+ r = debugfs_is_locked_down(inode, filp, real_fops);
+ if (r)
+ goto out;
+
real_fops = fops_get(real_fops);
if (!real_fops) {
/* Huh? Module did not clean up after itself at exit? */
@@ -272,6 +297,11 @@
return r == -EIO ? -ENOENT : r;
real_fops = debugfs_real_fops(filp);
+
+ r = debugfs_is_locked_down(inode, filp, real_fops);
+ if (r)
+ goto out;
+
real_fops = fops_get(real_fops);
if (!real_fops) {
/* Huh? Module did not cleanup after itself at exit? */
@@ -394,12 +424,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_u8(const char *name, umode_t mode,
struct dentry *parent, u8 *value)
@@ -440,12 +469,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_u16(const char *name, umode_t mode,
struct dentry *parent, u16 *value)
@@ -486,12 +514,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value)
@@ -533,12 +560,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_u64(const char *name, umode_t mode,
struct dentry *parent, u64 *value)
@@ -582,12 +608,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
struct dentry *parent, unsigned long *value)
@@ -850,12 +875,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_bool(const char *name, umode_t mode,
struct dentry *parent, bool *value)
@@ -904,12 +928,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_blob(const char *name, umode_t mode,
struct dentry *parent,
@@ -1004,24 +1027,19 @@
* @array as data. If the @mode variable is so set it can be read from.
* Writing is not supported. Seek within the file is also not supported.
* Once array is created its size can not be changed.
- *
- * The function returns a pointer to dentry on success. If debugfs is not
- * enabled in the kernel, the value -%ENODEV will be returned.
*/
-struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
- struct dentry *parent,
- u32 *array, u32 elements)
+void debugfs_create_u32_array(const char *name, umode_t mode,
+ struct dentry *parent, u32 *array, u32 elements)
{
struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
if (data == NULL)
- return NULL;
+ return;
data->array = array;
data->elements = elements;
- return debugfs_create_file_unsafe(name, mode, parent, data,
- &u32_array_fops);
+ debugfs_create_file_unsafe(name, mode, parent, data, &u32_array_fops);
}
EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
@@ -1102,12 +1120,11 @@
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
+ * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
*
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned. It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
*/
struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
struct dentry *parent,