From patchwork Mon Nov 27 19:08:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 13470194 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="w9/t5Ddv" Received: from bedivere.hansenpartnership.com (bedivere.hansenpartnership.com [IPv6:2607:fcd0:100:8a00::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE894D5D; Mon, 27 Nov 2023 11:12:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1701112322; bh=B5x/0D2Tjpcday6Z/hf7mIF1khP/vscYwie2pM+QlM8=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References:From; b=w9/t5DdvDI9EMPVPHHaT5peWK4zJgR1IZVwNJVXAhIcHq2q93e01ZUKSKc2phJc2Z ZWDSeD/hn74Na1NjCl8u/6Iv+tDjysF9emu5p53IAZvCaKg6kJfP7tedBTK7mVAKaI h6q/gx/3lszgEWggvk6PJqfvGbCAs4gH77PobH0g= Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 838FE128174C; Mon, 27 Nov 2023 14:12:02 -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 9UzVSTd73ZPU; Mon, 27 Nov 2023 14:12:02 -0500 (EST) Received: from lingrow.int.hansenpartnership.com (unknown [153.66.160.227]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id DAB341280087; Mon, 27 Nov 2023 14:12:01 -0500 (EST) From: James Bottomley To: linux-integrity@vger.kernel.org Cc: Jarkko Sakkinen , keyrings@vger.kernel.org, Ard Biesheuvel Subject: [PATCH v5 07/17] tpm: Add tpm_buf_read_{u8,u16,u32} Date: Mon, 27 Nov 2023 14:08:44 -0500 Message-Id: <20231127190854.13310-8-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 From: Jarkko Sakkinen Declare reader functions for the instances of struct tpm_buf. If the read goes out of boundary, TPM_BUF_BOUNDARY_ERROR is set, and subsequent read will do nothing. Signed-off-by: Jarkko Sakkinen Signed-off-by: James Bottomley --- drivers/char/tpm/tpm-buf.c | 79 +++++++++++++++++++++++++++++++++++++- include/linux/tpm.h | 5 +++ 2 files changed, 83 insertions(+), 1 deletion(-) diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c index 099b4a56c5d5..32619e9ab4fa 100644 --- a/drivers/char/tpm/tpm-buf.c +++ b/drivers/char/tpm/tpm-buf.c @@ -107,7 +107,7 @@ void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length) return; if ((buf->length + new_length) > PAGE_SIZE) { - WARN(1, "tpm_buf: overflow\n"); + WARN(1, "tpm_buf: write overflow\n"); buf->flags |= TPM_BUF_OVERFLOW; return; } @@ -143,3 +143,80 @@ void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value) tpm_buf_append(buf, (u8 *)&value2, 4); } EXPORT_SYMBOL_GPL(tpm_buf_append_u32); + +/** + * tpm_buf_read() - Read from a TPM buffer + * @buf: &tpm_buf instance + * @offset: offset within the buffer + * @count: the number of bytes to read + * @output: the output buffer + */ +static void tpm_buf_read(struct tpm_buf *buf, off_t *offset, size_t count, void *output) +{ + off_t next_offset; + + /* Return silently if overflow has already happened. */ + if (buf->flags & TPM_BUF_BOUNDARY_ERROR) + return; + + next_offset = *offset + count; + if (next_offset > buf->length) { + WARN(1, "tpm_buf: read out of boundary\n"); + buf->flags |= TPM_BUF_BOUNDARY_ERROR; + return; + } + + memcpy(output, &buf->data[*offset], count); + *offset = next_offset; +} + +/** + * tpm_buf_read_u8() - Read 8-bit word from a TPM buffer + * @buf: &tpm_buf instance + * @offset: offset within the buffer + * + * Return: next 8-bit word + */ +u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset) +{ + u8 value; + + tpm_buf_read(buf, offset, sizeof(value), &value); + + return value; +} +EXPORT_SYMBOL_GPL(tpm_buf_read_u8); + +/** + * tpm_buf_read_u16() - Read 16-bit word from a TPM buffer + * @buf: &tpm_buf instance + * @offset: offset within the buffer + * + * Return: next 16-bit word + */ +u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset) +{ + u16 value; + + tpm_buf_read(buf, offset, sizeof(value), &value); + + return be16_to_cpu(value); +} +EXPORT_SYMBOL_GPL(tpm_buf_read_u16); + +/** + * tpm_buf_read_u32() - Read 32-bit word from a TPM buffer + * @buf: &tpm_buf instance + * @offset: offset within the buffer + * + * Return: next 32-bit word + */ +u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset) +{ + u32 value; + + tpm_buf_read(buf, offset, sizeof(value), &value); + + return be32_to_cpu(value); +} +EXPORT_SYMBOL_GPL(tpm_buf_read_u32); diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 715db4a91c1f..e8172f81c562 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -302,6 +302,8 @@ enum tpm_buf_flags { TPM_BUF_OVERFLOW = BIT(0), /* TPM2B format: */ TPM_BUF_TPM2B = BIT(1), + /* read out of boundary: */ + TPM_BUF_BOUNDARY_ERROR = BIT(2), }; /* @@ -338,6 +340,9 @@ void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length); void tpm_buf_append_u8(struct tpm_buf *buf, const u8 value); void tpm_buf_append_u16(struct tpm_buf *buf, const u16 value); void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value); +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); /* * Check if TPM device is in the firmware upgrade mode.