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| author | Al Viro <viro@zeniv.linux.org.uk> | 2019-04-10 14:03:45 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-04-10 14:03:45 -0400 |
| commit | 46c874419652bbefdfed17420fd6e88d8a31d9ec (patch) | |
| tree | 9dc4a5c095b24ac15b73ab85c8f5542df63eec83 /security/inode.c | |
| parent | 6af1c849dfb1f1d326fbdd157c9bc882b921f450 (diff) | |
| download | lwn-46c874419652bbefdfed17420fd6e88d8a31d9ec.tar.gz lwn-46c874419652bbefdfed17420fd6e88d8a31d9ec.zip | |
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>
Diffstat (limited to 'security/inode.c')
| -rw-r--r-- | security/inode.c | 13 |
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) |