[PATCH 1/2] tpm2-sessions: Add full HMAC and encrypt/decrypt session handling

On Mon, Mar 05, 2018 at 01:35:33PM +0200, Jarkko Sakkinen wrote:

On Fri, Mar 02, 2018 at 10:06:15PM -0800, James Bottomley wrote:

quoted

diff --git a/drivers/char/tpm/tpm2b.h b/drivers/char/tpm/tpm2b.h
new file mode 100644
index 000000000000..c7726f2895aa
--- /dev/null
+++ b/drivers/char/tpm/tpm2b.h

@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TPM2_TPM2B_H
+#define _TPM2_TPM2B_H
+/*
+ * Handing for tpm2b structures to facilitate the building of commands
+ */
+
+#include "tpm.h"
+
+#include <asm/unaligned.h>
+
+struct tpm2b {
+	struct tpm_buf buf;
+};
+
+/* opaque structure, holds auth session parameters like the session key */
+struct tpm2_auth;
+
+static inline int tpm2b_init(struct tpm2b *buf)
+{
+	return tpm_buf_init(&buf->buf, 0, 0);
+}
+
+static inline void tpm2b_reset(struct tpm2b *buf)
+{
+	struct tpm_input_header *head;
+
+	head = (struct tpm_input_header *)buf->buf.data;
+	head->length = cpu_to_be32(sizeof(*head));
+}
+
+static inline void tpm2b_append(struct tpm2b *buf, const unsigned char *data,
+				unsigned int len)
+{
+	tpm_buf_append(&buf->buf, data, len);
+}
+
+#define TPM2B_APPEND(type) \
+	static inline void tpm2b_append_##type(struct tpm2b *buf, const type value) { tpm_buf_append_##type(&buf->buf, value); }
+
+TPM2B_APPEND(u8)
+TPM2B_APPEND(u16)
+TPM2B_APPEND(u32)
+
+static inline void *tpm2b_buffer(const struct tpm2b *buf)
+{
+	return buf->buf.data + sizeof(struct tpm_input_header);
+}
+
+static inline u16 tpm2b_len(struct tpm2b *buf)
+{
+	return tpm_buf_length(&buf->buf) - sizeof(struct tpm_input_header);
+}
+
+static inline void tpm2b_destroy(struct tpm2b *buf)
+{
+	tpm_buf_destroy(&buf->buf);
+}
+
+static inline void tpm_buf_append_2b(struct tpm_buf *buf, struct tpm2b *tpm2b)
+{
+	u16 len = tpm2b_len(tpm2b);
+
+	tpm_buf_append_u16(buf, len);
+	tpm_buf_append(buf, tpm2b_buffer(tpm2b), len);
+	/* clear the buf for reuse */
+	tpm2b_reset(tpm2b);
+}
+
+/* Macros for unmarshalling known size BE data */
+#define GET_INC(type)					\
+static inline u##type get_inc_##type(const u8 **ptr) {	\
+	u##type val;					\
+	val = get_unaligned_be##type(*ptr);		\
+	*ptr += sizeof(val);				\
+	return val;					\
+}
+
+GET_INC(16)
+GET_INC(32)
+
+#endif

-- 
2.12.3

Some meta stuff:

* Add me to TO-field because I should probably review and eventually
  test these, right?
* CC to linux-security-module
* Why there is no RFC tag given that these are so quite large changes?
* Why in hell tpm2b.h?

/Jarkko

Some other large scale level stuff that I saw:

* Do not document functions in the file header.
* Make the stuff in the header (expect functio descriptions) as
  documentation block:
  https://www.kernel.org/doc/Documentation/kernel-doc-nano-HOWTO.txt
  If you don't want to do this, then just move the documentation to
  the commit message. I rather do not have the documentation at all
  in the files than have it in unmaintanable form.
* Create structs for complex things that you add inside TPM commands
  and declare these helpers right before the function and add them
  with tpm_buf_append(). A good metric for this is when you see your
  self?adding field names as a comment. This should make these patches
  a factor cleaner. We use this approach in some places such as
  tpm2_get_pcr_allocation().
* Please, oh please get rid of this tpm2b.h. It is a definitive NAK (OK
  I said it already above but cannot really over emphasize it).
* Short summary should be "tpm: add encrypted and integrity protected
  sessions" or something along the lines.

I guess this is enough for first review round?

/Jarkko
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html