| Message ID | 20230216201410.15010-6-James.Bottomley@HansenPartnership.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | add integrity and security to TPM2 transactions | expand |
On Thu, Feb 16, 2023 at 03:14:03PM -0500, James Bottomley wrote: > Introducing encryption sessions changes where the return parameters > are located in the buffer because if a return session is present > they're 4 bytes beyond the header with those 4 bytes showing the > parameter length. If there is no return session, then they're in the > usual place immediately after the header. The tpm_buf_parameters() > encapsulates this calculation and should be used everywhere > &buf.data[TPM_HEADER_SIZE] is used now > > Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> > --- > drivers/char/tpm/tpm-buf.c | 10 ++++++++++ > include/linux/tpm.h | 2 ++ > 2 files changed, 12 insertions(+) > > diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c > index b76158f9bcd0..2518b675e866 100644 > --- a/drivers/char/tpm/tpm-buf.c > +++ b/drivers/char/tpm/tpm-buf.c > @@ -183,3 +183,13 @@ u32 tpm_get_inc_u32(const u8 **ptr) > return val; > } > EXPORT_SYMBOL_GPL(tpm_get_inc_u32); > + > +u8 *tpm_buf_parameters(struct tpm_buf *buf) kdoc > +{ > + int offset = TPM_HEADER_SIZE; > + > + if (tpm_buf_tag(buf) == TPM2_ST_SESSIONS) > + offset += 4; > + > + return &buf->data[offset]; > +} > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > index f7cff1d114b0..fa8d1f932c0f 100644 > --- a/include/linux/tpm.h > +++ b/include/linux/tpm.h > @@ -339,6 +339,8 @@ u8 tpm_get_inc_u8(const u8 **ptr); > u16 tpm_get_inc_u16(const u8 **ptr); > u32 tpm_get_inc_u32(const u8 **ptr); > > +u8 *tpm_buf_parameters(struct tpm_buf *buf); > + > /* > * Check if TPM device is in the firmware upgrade mode. > */ > -- > 2.35.3 > BR, Jarkko
diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c index b76158f9bcd0..2518b675e866 100644 --- a/drivers/char/tpm/tpm-buf.c +++ b/drivers/char/tpm/tpm-buf.c @@ -183,3 +183,13 @@ u32 tpm_get_inc_u32(const u8 **ptr) return val; } EXPORT_SYMBOL_GPL(tpm_get_inc_u32); + +u8 *tpm_buf_parameters(struct tpm_buf *buf) +{ + int offset = TPM_HEADER_SIZE; + + if (tpm_buf_tag(buf) == TPM2_ST_SESSIONS) + offset += 4; + + return &buf->data[offset]; +} diff --git a/include/linux/tpm.h b/include/linux/tpm.h index f7cff1d114b0..fa8d1f932c0f 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -339,6 +339,8 @@ u8 tpm_get_inc_u8(const u8 **ptr); u16 tpm_get_inc_u16(const u8 **ptr); u32 tpm_get_inc_u32(const u8 **ptr); +u8 *tpm_buf_parameters(struct tpm_buf *buf); + /* * Check if TPM device is in the firmware upgrade mode. */
Introducing encryption sessions changes where the return parameters are located in the buffer because if a return session is present they're 4 bytes beyond the header with those 4 bytes showing the parameter length. If there is no return session, then they're in the usual place immediately after the header. The tpm_buf_parameters() encapsulates this calculation and should be used everywhere &buf.data[TPM_HEADER_SIZE] is used now Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> --- drivers/char/tpm/tpm-buf.c | 10 ++++++++++ include/linux/tpm.h | 2 ++ 2 files changed, 12 insertions(+)