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Commit 439c6109 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'driver-core-3.15-rc6' of... 

Merge tag 'driver-core-3.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are two driver core (well, sysfs) fixes for 3.15-rc6 that resolve
  some reported issues and a regression from 3.13"

* tag 'driver-core-3.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  sysfs: make sure read buffer is zeroed
  kernfs, sysfs, cgroup: restrict extra perm check on open to sysfs
parents 957cf258 f5c16f29

fs/kernfs/file.c

+10 −7
Original line number Diff line number Diff line
@@ -610,6 +610,7 @@ static void kernfs_put_open_node(struct kernfs_node *kn, 
static int kernfs_fop_open(struct inode *inode, struct file *file)

{

	struct kernfs_node *kn = file->f_path.dentry->d_fsdata;

	struct kernfs_root *root = kernfs_root(kn);

	const struct kernfs_ops *ops;

	struct kernfs_open_file *of;

	bool has_read, has_write, has_mmap;
@@ -624,7 +625,8 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) 
	has_write = ops->write || ops->mmap;

	has_mmap = ops->mmap;



	/* check perms and supported operations */

	/* see the flag definition for details */

	if (root->flags & KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK) {

		if ((file->f_mode & FMODE_WRITE) &&

		    (!(inode->i_mode & S_IWUGO) || !has_write))

			goto err_out;
@@ -632,6 +634,7 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) 
		if ((file->f_mode & FMODE_READ) &&

		    (!(inode->i_mode & S_IRUGO) || !has_read))

			goto err_out;

	}



	/* allocate a kernfs_open_file for the file */

	error = -ENOMEM;

fs/sysfs/file.c

+2 −1
Original line number Diff line number Diff line
@@ -47,12 +47,13 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v) 
	ssize_t count;

	char *buf;



	/* acquire buffer and ensure that it's >= PAGE_SIZE */

	/* acquire buffer and ensure that it's >= PAGE_SIZE and clear */

	count = seq_get_buf(sf, &buf);

	if (count < PAGE_SIZE) {

		seq_commit(sf, -1);

		return 0;

	}

	memset(buf, 0, PAGE_SIZE);



	/*

	 * Invoke show().  Control may reach here via seq file lseek even

fs/sysfs/mount.c

+2 −1
Original line number Diff line number Diff line
@@ -63,7 +63,8 @@ int __init sysfs_init(void) 
{

	int err;



	sysfs_root = kernfs_create_root(NULL, 0, NULL);

	sysfs_root = kernfs_create_root(NULL, KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK,

					NULL);

	if (IS_ERR(sysfs_root))

		return PTR_ERR(sysfs_root);

include/linux/kernfs.h

+18 −1
Original line number Diff line number Diff line
@@ -50,7 +50,24 @@ enum kernfs_node_flag { 


/* @flags for kernfs_create_root() */

enum kernfs_root_flag {

	/*

	 * kernfs_nodes are created in the deactivated state and invisible.

	 * They require explicit kernfs_activate() to become visible.  This

	 * can be used to make related nodes become visible atomically

	 * after all nodes are created successfully.

	 */

	KERNFS_ROOT_CREATE_DEACTIVATED		= 0x0001,



	/*

	 * For regular flies, if the opener has CAP_DAC_OVERRIDE, open(2)

	 * succeeds regardless of the RW permissions.  sysfs had an extra

	 * layer of enforcement where open(2) fails with -EACCES regardless

	 * of CAP_DAC_OVERRIDE if the permission doesn't have the

	 * respective read or write access at all (none of S_IRUGO or

	 * S_IWUGO) or the respective operation isn't implemented.  The

	 * following flag enables that behavior.

	 */

	KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK	= 0x0002,

};



/* type-specific structures for kernfs_node union members */