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authorAl Viro <viro@zeniv.linux.org.uk>2019-04-10 14:03:45 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2019-04-10 14:03:45 -0400
commit46c874419652bbefdfed17420fd6e88d8a31d9ec (patch)
tree9dc4a5c095b24ac15b73ab85c8f5542df63eec83
parent6af1c849dfb1f1d326fbdd157c9bc882b921f450 (diff)
securityfs: fix use-after-free on symlink traversal
symlink body shouldn't be freed without an RCU delay. Switch securityfs 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/inode.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/security/inode.c b/security/inode.c
index b7772a9b315e..421dd72b5876 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -27,17 +27,22 @@
static struct vfsmount *mount;
static int mount_count;
-static void securityfs_evict_inode(struct inode *inode)
+static void securityfs_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 securityfs_destroy_inode(struct inode *inode)
+{
+ call_rcu(&inode->i_rcu, securityfs_i_callback);
}
static const struct super_operations securityfs_super_operations = {
.statfs = simple_statfs,
- .evict_inode = securityfs_evict_inode,
+ .destroy_inode = securityfs_destroy_inode,
};
static int fill_super(struct super_block *sb, void *data, int silent)