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-rw-r--r--fs/inode.c66
1 files changed, 46 insertions, 20 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 069721f0cc0e..d30640f7a193 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -841,7 +841,11 @@ unsigned int get_next_ino(void)
}
#endif
- *p = ++res;
+ res++;
+ /* get_next_ino should not provide a 0 inode number */
+ if (unlikely(!res))
+ res++;
+ *p = res;
put_cpu_var(last_ino);
return res;
}
@@ -1674,7 +1678,31 @@ 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 dentry_needs_remove_privs(struct dentry *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(dentry_needs_remove_privs);
+
+static int __remove_privs(struct dentry *dentry, int kill)
{
struct iattr newattrs;
@@ -1686,33 +1714,32 @@ static int __remove_suid(struct dentry *dentry, int kill)
return notify_change(dentry, &newattrs, NULL);
}
-int file_remove_suid(struct file *file)
+/*
+ * Remove special file priviledges (suid, capabilities) when file is written
+ * to or truncated.
+ */
+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);
- if (!error && (inode->i_sb->s_flags & MS_NOSEC))
- inode->i_flags |= S_NOSEC;
+ 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);
return error;
}
-EXPORT_SYMBOL(file_remove_suid);
+EXPORT_SYMBOL(file_remove_privs);
/**
* file_update_time - update mtime and ctime time
@@ -1967,9 +1994,8 @@ EXPORT_SYMBOL(inode_dio_wait);
* inode is being instantiated). The reason for the cmpxchg() loop
* --- which wouldn't be necessary if all code paths which modify
* i_flags actually followed this rule, is that there is at least one
- * code path which doesn't today --- for example,
- * __generic_file_aio_write() calls file_remove_suid() without holding
- * i_mutex --- so we use cmpxchg() out of an abundance of caution.
+ * code path which doesn't today so we use cmpxchg() out of an abundance
+ * of caution.
*
* In the long run, i_mutex is overkill, and we should probably look
* at using the i_lock spinlock to protect i_flags, and then make sure