From patchwork Mon Nov 27 19:08:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 13470211 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="LxNH0Bbd" Received: from bedivere.hansenpartnership.com (bedivere.hansenpartnership.com [96.44.175.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58DF510D8; Mon, 27 Nov 2023 11:14:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1701112485; bh=AFTu4kCVpQW+240gbyhTAzKqckFwaJgY5sujDYN2wQg=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References:From; b=LxNH0BbdnnellSzVKtGNDxp4DoNyx2xDDdQPlr21yr+YfbqO774gfIpwNtnZ7G4w2 FD6IA4/HYXv7tQAqbNwztgDd990jfxdhk2RZE3jW6zOqo8cX96+iSJHHz0SLcOCHTH g9Hvg+zxb+Jq5oIlQ24OFkx4Ve0mzmLvqMBsRWUQ= Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 06B001286376; Mon, 27 Nov 2023 14:14:45 -0500 (EST) Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavis, port 10024) with ESMTP id p2-0o9hCDmsz; Mon, 27 Nov 2023 14:14:44 -0500 (EST) Received: from lingrow.int.hansenpartnership.com (unknown [153.66.160.227]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 5E3C81285EC7; Mon, 27 Nov 2023 14:14:44 -0500 (EST) From: James Bottomley To: linux-integrity@vger.kernel.org Cc: Jarkko Sakkinen , keyrings@vger.kernel.org, Ard Biesheuvel Subject: [PATCH v5 10/17] tpm: add buffer function to point to returned parameters Date: Mon, 27 Nov 2023 14:08:47 -0500 Message-Id: <20231127190854.13310-11-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20231127190854.13310-1-James.Bottomley@HansenPartnership.com> References: <20231127190854.13310-1-James.Bottomley@HansenPartnership.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Replace all instances of &buf.data[TPM_HEADER_SIZE] with a new function tpm_buf_parameters() because encryption sessions change where the return parameters are located in the buffer since if a return session is present they're 4 bytes beyond the header with those 4 bytes giving the parameter length. If there is no return session, then they're in the usual place immediately after the header. Signed-off-by: James Bottomley Reviewed-by: Stefan Berger --- v4: add kdoc v5: update kdoc add review --- drivers/char/tpm/tpm-buf.c | 28 ++++++++++++++++++++++++++++ include/linux/tpm.h | 2 ++ 2 files changed, 30 insertions(+) diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c index 32619e9ab4fa..bb81180495d1 100644 --- a/drivers/char/tpm/tpm-buf.c +++ b/drivers/char/tpm/tpm-buf.c @@ -220,3 +220,31 @@ u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset) return be32_to_cpu(value); } EXPORT_SYMBOL_GPL(tpm_buf_read_u32); + +static u16 tpm_buf_tag(struct tpm_buf *buf) +{ + struct tpm_header *head = (struct tpm_header *)buf->data; + + return be16_to_cpu(head->tag); +} + +/** + * tpm_buf_parameters - return the TPM response parameters area of the tpm_buf + * @buf: tpm_buf to use + * + * Where the parameters are located depends on the tag of a TPM + * command (it's immediately after the header for TPM_ST_NO_SESSIONS + * or 4 bytes after for TPM_ST_SESSIONS). Evaluate this and return a + * pointer to the first byte of the parameters area. + * + * @return: pointer to parameters area + */ +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 e8172f81c562..6be263509e81 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -344,6 +344,8 @@ u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset); u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset); u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset); +u8 *tpm_buf_parameters(struct tpm_buf *buf); + /* * Check if TPM device is in the firmware upgrade mode. */