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@xxxxxxx>
---
fs/inode.c | 44 ++++++++++++++++++++++++++++++++------------
include/linux/fs.h | 1 +
2 files changed, 33 insertions(+), 12 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 3490389dc813..6807a2707828 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1598,7 +1598,32 @@ 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 = dentry->d_inode;
+ 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;
@@ -1618,23 +1643,18 @@ int file_remove_privs(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
- 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->i_sb->s_flags & MS_NOSEC) &&
!is_sxid(inode->i_mode))
inode->i_flags |= S_NOSEC;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 96b2d6a9a6cb..aac707cced66 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2429,6 +2429,7 @@ 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)
--
1.8.1.4
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