security/keys: properly zero out sensitive key material in big_key

BugLink: http://bugs.launchpad.net/bugs/1721777
commit 910801809b2e40a4baedd080ef5d80b4a180e70e upstream.

Error paths forgot to zero out sensitive material, so this patch changes
some kfrees into a kzfrees.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Eric Biggers <ebiggers3@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kirill Marinushkin <k.marinushkin@gmail.com>
Cc: security@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/security/keys/big_key.c b/security/keys/big_key.c
index 835c1ab30d01eb9a8e94b411fce09b856772efb9..1c93c077d119af0b22bd6e2dfabed568a8c259e5 100644 (file)
--- a/security/keys/big_key.c
+++ b/security/keys/big_key.c
@@ -194,7 +194,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
                *path = file->f_path;
                path_get(path);
                fput(file);
-               kfree(data);
+               kzfree(data);
        } else {
                /* Just store the data in a buffer */
                void *data = kmalloc(datalen, GFP_KERNEL);
@@ -210,9 +210,9 @@ int big_key_preparse(struct key_preparsed_payload *prep)
 err_fput:
        fput(file);
 err_enckey:
-       kfree(enckey);
+       kzfree(enckey);
 error:
-       kfree(data);
+       kzfree(data);
        return ret;
 }
 
@@ -226,7 +226,7 @@ void big_key_free_preparse(struct key_preparsed_payload *prep)
 
                path_put(path);
        }
-       kfree(prep->payload.data[big_key_data]);
+       kzfree(prep->payload.data[big_key_data]);
 }
 
 /*
@@ -258,7 +258,7 @@ void big_key_destroy(struct key *key)
                path->mnt = NULL;
                path->dentry = NULL;
        }
-       kfree(key->payload.data[big_key_data]);
+       kzfree(key->payload.data[big_key_data]);
        key->payload.data[big_key_data] = NULL;
 }
 
@@ -326,7 +326,7 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
 err_fput:
                fput(file);
 error:
-               kfree(data);
+               kzfree(data);
        } else {
                ret = datalen;
                if (copy_to_user(buffer, key->payload.data[big_key_data],