Messages in this thread |  | | Date | Tue, 9 Jun 2015 12:19:32 +0300 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH v2] tpm: introduce struct tpm_buf |
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On Mon, Jun 08, 2015 at 10:39:32PM +0200, Peter Hüwe wrote: > Hi, > > > Am Mittwoch, 3. Juni 2015, 18:39:14 schrieb Jarkko Sakkinen: > > This patch introduces struct tpm_buf that provides a string buffer for > > constructing TPM commands. This allows to construct variable sized TPM > > commands. This feature is needed for TPM 2.0 commands in order to allow > > policy authentication and algorithmic agility. > > > > The commands in the tpm2-cmd.c have been updated to use struct tpm_buf. > > Lots of awkward length calculations could be dropped because the buffer > > knows its length. > > > > The code is is along the lines of the string buffer code in > > security/trusted/trusted.h. > > > > Changes since v1: > > > > - Fixed potential alignment issues in tpm_buf_tag(). > > > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > > > +static inline void tpm_buf_append(struct tpm_buf *buf, > > + const unsigned char *data, > > + unsigned int len) > > +{ > > + struct tpm_input_header *head = (struct tpm_input_header *) buf->data; > > + > > + BUG_ON((len + tpm_buf_length(buf)) > TPM_BUF_SIZE); > > + > > + memcpy(&buf->data[tpm_buf_length(buf)], data, len); > > + head->length = cpu_to_be32(tpm_buf_length(buf) + len); > > +} > > + > > +static inline void tpm_buf_store(struct tpm_buf *buf, > > + unsigned int pos, > > + const unsigned char *data, > > + unsigned int len) > > +{ > > + BUG_ON((pos + len) > TPM_BUF_SIZE); > > + > > + memcpy(&buf->data[pos], data, len); > > +} > > Don't you have to update the ->length here?
No. Store is for placing value in position, not appending to the end.
> Thanks, > Peter
/Jarkko
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