evm: Translate user/group ids relative to s_user_ns when computing HMAC

The EVM HMAC should be calculated using the on disk user and
group ids, so the k[ug]ids in the inode must be translated
relative to the s_user_ns of the inode's super block.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 30b6b7d0429fc98f92bbf9e8169f60116c66019a..11c1d30bd705a93450dc2b275581fc63cd3b8c77 100644 (file)
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -151,8 +151,8 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
        memset(&hmac_misc, 0, sizeof(hmac_misc));
        hmac_misc.ino = inode->i_ino;
        hmac_misc.generation = inode->i_generation;
-       hmac_misc.uid = from_kuid(&init_user_ns, inode->i_uid);
-       hmac_misc.gid = from_kgid(&init_user_ns, inode->i_gid);
+       hmac_misc.uid = from_kuid(inode->i_sb->s_user_ns, inode->i_uid);
+       hmac_misc.gid = from_kgid(inode->i_sb->s_user_ns, inode->i_gid);
        hmac_misc.mode = inode->i_mode;
        crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof(hmac_misc));
        if (evm_hmac_attrs & EVM_ATTR_FSUUID)