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Commit dbfae0cd authored by Jan Kara's avatar Jan Kara Committed by Al Viro
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fs: Provide function telling whether file_remove_privs() will do anything 



Provide function telling whether file_remove_privs() will do anything.
Currently we only have should_remove_suid() and that does something
slightly different.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5fa8e0a1

fs/inode.c

+32 −12
Original line number Diff line number Diff line
@@ -1673,7 +1673,32 @@ int should_remove_suid(struct dentry *dentry) 
}

EXPORT_SYMBOL(should_remove_suid);



static int __remove_suid(struct dentry *dentry, int kill)

/*

 * Return mask of changes for notify_change() that need to be done as a

 * response to write or truncate. Return 0 if nothing has to be changed.

 * Negative value on error (change should be denied).

 */

int file_needs_remove_privs(struct file *file)

{

	struct dentry *dentry = file->f_path.dentry;

	struct inode *inode = d_inode(dentry);

	int mask = 0;

	int ret;



	if (IS_NOSEC(inode))

		return 0;



	mask = should_remove_suid(dentry);

	ret = security_inode_need_killpriv(dentry);

	if (ret < 0)

		return ret;

	if (ret)

		mask |= ATTR_KILL_PRIV;

	return mask;

}

EXPORT_SYMBOL(file_needs_remove_privs);



static int __remove_privs(struct dentry *dentry, int kill)

{

	struct iattr newattrs;
@@ -1693,23 +1718,18 @@ int file_remove_privs(struct file *file) 
{

	struct dentry *dentry = file->f_path.dentry;

	struct inode *inode = d_inode(dentry);

	int killsuid;

	int killpriv;

	int kill;

	int error = 0;



	/* Fast path for nothing security related */

	if (IS_NOSEC(inode))

		return 0;



	killsuid = should_remove_suid(dentry);

	killpriv = security_inode_need_killpriv(dentry);



	if (killpriv < 0)

		return killpriv;

	if (killpriv)

		error = security_inode_killpriv(dentry);

	if (!error && killsuid)

		error = __remove_suid(dentry, killsuid);

	kill = file_needs_remove_privs(file);

	if (kill < 0)

		return kill;

	if (kill)

		error = __remove_privs(dentry, kill);

	if (!error)

		inode_has_no_xattr(inode);

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -2554,6 +2554,7 @@ extern struct inode *new_inode(struct super_block *sb); 
extern void free_inode_nonrcu(struct inode *inode);

extern int should_remove_suid(struct dentry *);

extern int file_remove_privs(struct file *);

extern int file_needs_remove_privs(struct file *file);



extern void __insert_inode_hash(struct inode *, unsigned long hashval);

static inline void insert_inode_hash(struct inode *inode)