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fs: Provide function telling whether file_remove_privs() will do anything

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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: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Jan Kara 2015-05-21 16:05:54 +02:00 committed by Al Viro
parent 5fa8e0a1c6
commit dbfae0cdcd
2 changed files with 33 additions and 12 deletions
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44
fs/inode.c
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@ -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);

1
include/linux/fs.h
View File

@ -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)