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authorAl Viro <viro@zeniv.linux.org.uk>2019-04-10 14:04:34 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2019-04-10 14:04:34 -0400
commitf51dcd0f621caac5380ce90fbbeafc32ce4517ae (patch)
tree294cee0590e9e27a93bc9fd6122c50b78da44b99
parent46c874419652bbefdfed17420fd6e88d8a31d9ec (diff)
apparmorfs: fix use-after-free on symlink traversal
symlink body shouldn't be freed without an RCU delay. Switch apparmorfs to ->destroy_inode() and use of call_rcu(); free both the inode and symlink body in the callback. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--security/apparmor/apparmorfs.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index fefee040bf79..b9298d2e8165 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -123,17 +123,22 @@ static int aafs_show_path(struct seq_file *seq, struct dentry *dentry)
return 0;
}
-static void aafs_evict_inode(struct inode *inode)
+static void aafs_i_callback(struct rcu_head *head)
{
- truncate_inode_pages_final(&inode->i_data);
- clear_inode(inode);
+ struct inode *inode = container_of(head, struct inode, i_rcu);
if (S_ISLNK(inode->i_mode))
kfree(inode->i_link);
+ free_inode_nonrcu(inode);
+}
+
+static void aafs_destroy_inode(struct inode *inode)
+{
+ call_rcu(&inode->i_rcu, aafs_i_callback);
}
static const struct super_operations aafs_super_ops = {
.statfs = simple_statfs,
- .evict_inode = aafs_evict_inode,
+ .destroy_inode = aafs_destroy_inode,
.show_path = aafs_show_path,
};