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authorAl Viro <viro@zeniv.linux.org.uk>2019-04-10 14:03:45 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-25 18:23:42 +0200
commit9a0467e1f67155c126e5857b1d3ae2ac8b009aa5 (patch)
tree53b91cdfee09ea22f821e502407458970b55cde6 /security/inode.c
parent900bf351dd8467ef0354312eedad8811d16ea507 (diff)
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securityfs: fix use-after-free on symlink traversal
[ Upstream commit 46c874419652bbefdfed17420fd6e88d8a31d9ec ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'security/inode.c')
-rw-r--r--security/inode.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/security/inode.c b/security/inode.c
index 8dd9ca8848e4..829f15672e01 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -26,17 +26,22 @@
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)