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Message-ID: <1568031558.6613.32.camel@HansenPartnership.com>
Subject: [PATCH v6 03/12] tpm-buf: add cursor based functions for response
 parsing
From:   James Bottomley <James.Bottomley@HansenPartnership.com>
To:     linux-integrity@vger.kernel.org
Cc:     linux-crypto@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Date:   Mon, 09 Sep 2019 13:19:18 +0100
In-Reply-To: <1568031408.6613.29.camel@HansenPartnership.com>
References: <1568031408.6613.29.camel@HansenPartnership.com>
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Sender: linux-crypto-owner@vger.kernel.org
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It's very convenient when parsing responses to have a cursor you
simply move over the response extracting the data.  Add such cursor
functions for the TPM unsigned integer types.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 drivers/char/tpm/tpm-buf.c | 26 ++++++++++++++++++++++++++
 drivers/char/tpm/tpm.h     |  4 ++++
 2 files changed, 30 insertions(+)

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index 8c1ed8a14e01..553adb84b0ac 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -163,3 +163,29 @@ void tpm_buf_append_2b(struct tpm_buf *buf, struct tpm_buf *tpm2b)
 }
 EXPORT_SYMBOL_GPL(tpm_buf_append_2b);
 
+/* functions for unmarshalling data and moving the cursor */
+u8 tpm_get_inc_u8(const u8 **ptr)
+{
+	return *((*ptr)++);
+}
+EXPORT_SYMBOL_GPL(tpm_get_inc_u8);
+
+u16 tpm_get_inc_u16(const u8 **ptr)
+{
+	u16 val;
+
+	val = get_unaligned_be16(*ptr);
+	*ptr += sizeof(val);
+	return val;
+}
+EXPORT_SYMBOL_GPL(tpm_get_inc_u16);
+
+u32 tpm_get_inc_u32(const u8 **ptr)
+{
+	u32 val;
+
+	val = get_unaligned_be32(*ptr);
+	*ptr += sizeof(val);
+	return val;
+}
+EXPORT_SYMBOL_GPL(tpm_get_inc_u32);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 7627917db345..d942188debc9 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -302,6 +302,10 @@ void tpm_buf_append_u16(struct tpm_buf *buf, const u16 value);
 void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value);
 void tpm_buf_append_2b(struct tpm_buf *buf, struct tpm_buf *tpm2b);
 
+u8 tpm_get_inc_u8(const u8 **ptr);
+u16 tpm_get_inc_u16(const u8 **ptr);
+u32 tpm_get_inc_u32(const u8 **ptr);
+
 extern struct class *tpm_class;
 extern struct class *tpmrm_class;
 extern dev_t tpm_devt;
-- 
2.16.4