[03/17] tpm-buf: add cursor based functions for response parsing

Commit Message

James Prestwood May 18, 2020, 5:26 p.m. UTC

From: James Bottomley <[e-mail]>

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 <[e-mail]>
---
 drivers/char/tpm/tpm-buf.c | 26 ++++++++++++++++++++++++++
 drivers/char/tpm/tpm.h     |  4 ++++
 2 files changed, 30 insertions(+)

Patch

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 dfa03b63d8ee..c75340dc3bce 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -165,6 +165,10 @@  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;