From e68557814c7e9e4943caca924ff5537952bb3b4e Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 2 Mar 2018 14:21:12 -0800 Subject: [PATCH] fscrypto: add authorization check for setting encryption policy commit 163ae1c6ad6299b19e22b4a35d5ab24a89791a98 upstream. On an ext4 or f2fs filesystem with file encryption supported, a user could set an encryption policy on any empty directory(*) to which they had readonly access. This is obviously problematic, since such a directory might be owned by another user and the new encryption policy would prevent that other user from creating files in their own directory (for example). Fix this by requiring inode_owner_or_capable() permission to set an encryption policy. This means that either the caller must own the file, or the caller must have the capability CAP_FOWNER. (*) Or also on any regular file, for f2fs v4.6 and later and ext4 v4.8-rc1 and later; a separate bug fix is coming for that. CVE: CVE-2016-10318 Upstream-Status: Backport Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin Signed-off-by: Andreas Wellving --- fs/ext4/crypto_policy.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c index a6d6291..591fc37 100644 --- a/fs/ext4/crypto_policy.c +++ b/fs/ext4/crypto_policy.c @@ -85,6 +85,9 @@ static int ext4_create_encryption_context_from_policy( int ext4_process_policy(const struct ext4_encryption_policy *policy, struct inode *inode) { + if (!inode_owner_or_capable(inode)) + return -EACCES; + if (policy->version != 0) return -EINVAL; -- 2.7.4