From patchwork Wed Jul 3 18:24:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13722689 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 53A6D1849EB; Wed, 3 Jul 2024 18:25:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031107; cv=none; b=WkVPy9CYqa5HyDphp1N8lRgd4nP196a4CerBsyTQwqRWav0l1hc2Mt93Vt2PR5ecQmZUG+pJnsvnthSM0p5fQawEOuqrn3qZLmRL5+nRYVy2nprTbhT2FaFdpJ3TaewoG4eRG23WtSl9unE6z9rW7+jiZ+qyWkcmNu0WxK0crnw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031107; c=relaxed/simple; bh=dabt/tzhuwy8245opiXUk9KD0F5uSrCDuSRV408xIe4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JQ7Gs/NSep1SUDzfrxKDsB87QSHZJ7hZUMM8VZOf341fza/W9hsrDVMgKBmeoa0wKaHvnLc6zs0x8RDlm5iNjyy7H6FWRyA2xUIbgtKVYpsM14KX9el6uMjMXZl8YPk3vKnpvldRlJ9E00h5d1WVD14fiR6DSCA0WcHlDCmhnQ4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IZ9JNtkw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IZ9JNtkw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79894C2BD10; Wed, 3 Jul 2024 18:25:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720031106; bh=dabt/tzhuwy8245opiXUk9KD0F5uSrCDuSRV408xIe4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IZ9JNtkw1SB3EzvrBGY8goTjBoUvdDrw8wgKwsXNoysGkMQaIqM/yVrVBWGJfWifa 5+2h4i+9VfsGlGdVRV6oAtTr0EvSAUVt4T5GNvzM+BORuEtK/wBFSW2XLdTiKvcl1m eN0nBIZNRjfRg224l+0fq050FvnYhbPiOnEJbpw1EP96uC0CGY3t0J0ft4FATe2DjR +pQQGdQF3VvnR2gZL1p3w1asxDAcm5syVB5kamD8IcWuXsoOBt8FEzOU4qKC1EvF7R BrMW5CKLMXL+Ik6qwcqhisHbRIRibwoAIR0HOBTP0P7Czl07g/qiwDxL2u2AYOdtF8 4LXaaHwfrQhQA== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: Thorsten Leemhuis , Linus Torvalds , Jarkko Sakkinen , stable@vger.kernel.org, Stefan Berger , Peter Huewe , Jason Gunthorpe , James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , Ard Biesheuvel , linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v2 1/3] tpm: Address !chip->auth in tpm2_*_auth_session() Date: Wed, 3 Jul 2024 21:24:48 +0300 Message-ID: <20240703182453.1580888-2-jarkko@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240703182453.1580888-1-jarkko@kernel.org> References: <20240703182453.1580888-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Unless tpm_chip_bootstrap() was called by the driver, !chip->auth can cause a null derefence in tpm2_*_auth_session(). Thus, address !chip->auth in tpm2_*_auth_session(). Cc: stable@vger.kernel.org # v6.9+ Reported-by: Stefan Berger Closes: https://lore.kernel.org/linux-integrity/20240617193408.1234365-1-stefanb@linux.ibm.com/ Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions") Signed-off-by: Jarkko Sakkinen --- v2: - Use dev_warn_once() instead of pr_warn_once(). --- drivers/char/tpm/tpm2-sessions.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 907ac9956a78..2f1d96a5a5a7 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -824,8 +824,13 @@ EXPORT_SYMBOL(tpm_buf_check_hmac_response); */ void tpm2_end_auth_session(struct tpm_chip *chip) { - tpm2_flush_context(chip, chip->auth->handle); - memzero_explicit(chip->auth, sizeof(*chip->auth)); + struct tpm2_auth *auth = chip->auth; + + if (!auth) + return; + + tpm2_flush_context(chip, auth->handle); + memzero_explicit(auth, sizeof(*auth)); } EXPORT_SYMBOL(tpm2_end_auth_session); @@ -907,6 +912,11 @@ int tpm2_start_auth_session(struct tpm_chip *chip) int rc; u32 null_key; + if (!auth) { + dev_warn_once(&chip->dev, "auth session is not active\n"); + return 0; + } + rc = tpm2_load_null(chip, &null_key); if (rc) goto out; From patchwork Wed Jul 3 18:24:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13722690 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FD671849EB; Wed, 3 Jul 2024 18:25:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031112; cv=none; b=mENyg0xrer5TelitNVsYsDFmlBKwo3R5IfDvtPHEqBZySx9m9Awvv9SoD3BFgQAu1JUlRIIDDZumP7LZBjRggzK/ku6/Qa752+TBJeOCgpSxosFMkpST2QA2iYtMaNI4kh1XqaZnMIUsJI+Vl/ubuQbUhYcqZH8DateHKg7F8wo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031112; c=relaxed/simple; bh=s8bNAJx6+OLBWKemBM18n5pNaFOTy89B3uBlg32MasU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Vz5RpbojCWOVj5ptwhe+EtlUBzeuj0klmR/ApPZ7DpF+6QFGx9N8wkcOC8vt9PiYqnYYzDmXGcn3BcULgiY1vfGxfQg1LlMB6CLfL5DFWf63uJzKcKQD+BoB7hcfgCnDDAnFCTYbL0XDO1Ec8kRY2Wl2Pf126Q6FIdOuuB4THeY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Aj4+CsA7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Aj4+CsA7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 859BEC2BD10; Wed, 3 Jul 2024 18:25:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720031111; bh=s8bNAJx6+OLBWKemBM18n5pNaFOTy89B3uBlg32MasU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Aj4+CsA7RJpI2npws6RhDu8wcdlvM62h6Dqo5/a7+/ITKX/oBG/GnHSU4WN8rXwZ5 80fdPuD5ZpD8YdStDz5fK+5/3dQZDgeTBrpxLiTeVaouc4zO1eUfuXXbmxKf0QdwSr T6llZQKm+36ZEmJp0PUyG6+LkKQPvdcCntUOM0bJMIh0zPsMDbI+/wiHK2IzVVHzjP 0mMOc91tkjiBSl7/VJVh8mPkGgTElTrZGuxEz9L4ygs/EBp3P/3WUaPmpekKrHthvS +F2ir98L5wxOYz/sZY8ORNre3R/peeeNH3Ytj7S5RS05Z8w9ShzJzLNAXs8UGFdvbR WuAlMkyF6A1hw== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: Thorsten Leemhuis , Linus Torvalds , Jarkko Sakkinen , stable@vger.kernel.org, Stefan Berger , Peter Huewe , Jason Gunthorpe , James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , Ard Biesheuvel , Mario Limonciello , linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v2 2/3] tpm: Address !chip->auth in tpm_buf_append_name() Date: Wed, 3 Jul 2024 21:24:49 +0300 Message-ID: <20240703182453.1580888-3-jarkko@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240703182453.1580888-1-jarkko@kernel.org> References: <20240703182453.1580888-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Unless tpm_chip_bootstrap() was called by the driver, !chip->auth can cause a null derefence in tpm_buf_append_name(). Thus, address !chip->auth in tpm_buf_append_name() and remove the fallback implementation for !TCG_TPM2_HMAC. Cc: stable@vger.kernel.org # v6.9+ Reported-by: Stefan Berger Closes: https://lore.kernel.org/linux-integrity/20240617193408.1234365-1-stefanb@linux.ibm.com/ Fixes: d0a25bb961e6 ("tpm: Add HMAC session name/handle append") Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/Makefile | 2 +- drivers/char/tpm/tpm2-sessions.c | 205 ++++++++++++++++--------------- include/linux/tpm.h | 16 +-- 3 files changed, 113 insertions(+), 110 deletions(-) diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile index 4c695b0388f3..9bb142c75243 100644 --- a/drivers/char/tpm/Makefile +++ b/drivers/char/tpm/Makefile @@ -16,8 +16,8 @@ tpm-y += eventlog/common.o tpm-y += eventlog/tpm1.o tpm-y += eventlog/tpm2.o tpm-y += tpm-buf.o +tpm-y += tpm2-sessions.o -tpm-$(CONFIG_TCG_TPM2_HMAC) += tpm2-sessions.o tpm-$(CONFIG_ACPI) += tpm_ppi.o eventlog/acpi.o tpm-$(CONFIG_EFI) += eventlog/efi.o tpm-$(CONFIG_OF) += eventlog/of.o diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 2f1d96a5a5a7..06d0f10a2301 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -163,6 +163,112 @@ static u8 name_size(const u8 *name) return size_map[alg] + 2; } +static int tpm2_parse_read_public(char *name, struct tpm_buf *buf) +{ + struct tpm_header *head = (struct tpm_header *)buf->data; + off_t offset = TPM_HEADER_SIZE; + u32 tot_len = be32_to_cpu(head->length); + u32 val; + + /* we're starting after the header so adjust the length */ + tot_len -= TPM_HEADER_SIZE; + + /* skip public */ + val = tpm_buf_read_u16(buf, &offset); + if (val > tot_len) + return -EINVAL; + offset += val; + /* name */ + val = tpm_buf_read_u16(buf, &offset); + if (val != name_size(&buf->data[offset])) + return -EINVAL; + memcpy(name, &buf->data[offset], val); + /* forget the rest */ + return 0; +} + +static int tpm2_read_public(struct tpm_chip *chip, u32 handle, char *name) +{ + struct tpm_buf buf; + int rc; + + rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC); + if (rc) + return rc; + + tpm_buf_append_u32(&buf, handle); + rc = tpm_transmit_cmd(chip, &buf, 0, "read public"); + if (rc == TPM2_RC_SUCCESS) + rc = tpm2_parse_read_public(name, &buf); + + tpm_buf_destroy(&buf); + + return rc; +} + +/** + * tpm_buf_append_name() - add a handle area to the buffer + * @chip: the TPM chip structure + * @buf: The buffer to be appended + * @handle: The handle to be appended + * @name: The name of the handle (may be NULL) + * + * In order to compute session HMACs, we need to know the names of the + * objects pointed to by the handles. For most objects, this is simply + * the actual 4 byte handle or an empty buf (in these cases @name + * should be NULL) but for volatile objects, permanent objects and NV + * areas, the name is defined as the hash (according to the name + * algorithm which should be set to sha256) of the public area to + * which the two byte algorithm id has been appended. For these + * objects, the @name pointer should point to this. If a name is + * required but @name is NULL, then TPM2_ReadPublic() will be called + * on the handle to obtain the name. + * + * As with most tpm_buf operations, success is assumed because failure + * will be caused by an incorrect programming model and indicated by a + * kernel message. + */ +void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, + u32 handle, u8 *name) +{ + enum tpm2_mso_type mso = tpm2_handle_mso(handle); + struct tpm2_auth *auth = chip->auth; + int slot; + + if (!chip->auth) { + tpm_buf_append_u32(buf, handle); + /* count the number of handles in the upper bits of flags */ + buf->handles++; + return; + } + + slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE) / 4; + if (slot >= AUTH_MAX_NAMES) { + dev_err(&chip->dev, "TPM: too many handles\n"); + return; + } + WARN(auth->session != tpm_buf_length(buf), + "name added in wrong place\n"); + tpm_buf_append_u32(buf, handle); + auth->session += 4; + + if (mso == TPM2_MSO_PERSISTENT || + mso == TPM2_MSO_VOLATILE || + mso == TPM2_MSO_NVRAM) { + if (!name) + tpm2_read_public(chip, handle, auth->name[slot]); + } else { + if (name) + dev_err(&chip->dev, "TPM: Handle does not require name but one is specified\n"); + } + + auth->name_h[slot] = handle; + if (name) + memcpy(auth->name[slot], name, name_size(name)); +} +EXPORT_SYMBOL_GPL(tpm_buf_append_name); + +#ifdef CONFIG_TCG_TPM2_HMAC /* * It turns out the crypto hmac(sha256) is hard for us to consume * because it assumes a fixed key and the TPM seems to change the key @@ -567,104 +673,6 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf) } EXPORT_SYMBOL(tpm_buf_fill_hmac_session); -static int tpm2_parse_read_public(char *name, struct tpm_buf *buf) -{ - struct tpm_header *head = (struct tpm_header *)buf->data; - off_t offset = TPM_HEADER_SIZE; - u32 tot_len = be32_to_cpu(head->length); - u32 val; - - /* we're starting after the header so adjust the length */ - tot_len -= TPM_HEADER_SIZE; - - /* skip public */ - val = tpm_buf_read_u16(buf, &offset); - if (val > tot_len) - return -EINVAL; - offset += val; - /* name */ - val = tpm_buf_read_u16(buf, &offset); - if (val != name_size(&buf->data[offset])) - return -EINVAL; - memcpy(name, &buf->data[offset], val); - /* forget the rest */ - return 0; -} - -static int tpm2_read_public(struct tpm_chip *chip, u32 handle, char *name) -{ - struct tpm_buf buf; - int rc; - - rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC); - if (rc) - return rc; - - tpm_buf_append_u32(&buf, handle); - rc = tpm_transmit_cmd(chip, &buf, 0, "read public"); - if (rc == TPM2_RC_SUCCESS) - rc = tpm2_parse_read_public(name, &buf); - - tpm_buf_destroy(&buf); - - return rc; -} - -/** - * tpm_buf_append_name() - add a handle area to the buffer - * @chip: the TPM chip structure - * @buf: The buffer to be appended - * @handle: The handle to be appended - * @name: The name of the handle (may be NULL) - * - * In order to compute session HMACs, we need to know the names of the - * objects pointed to by the handles. For most objects, this is simply - * the actual 4 byte handle or an empty buf (in these cases @name - * should be NULL) but for volatile objects, permanent objects and NV - * areas, the name is defined as the hash (according to the name - * algorithm which should be set to sha256) of the public area to - * which the two byte algorithm id has been appended. For these - * objects, the @name pointer should point to this. If a name is - * required but @name is NULL, then TPM2_ReadPublic() will be called - * on the handle to obtain the name. - * - * As with most tpm_buf operations, success is assumed because failure - * will be caused by an incorrect programming model and indicated by a - * kernel message. - */ -void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, - u32 handle, u8 *name) -{ - enum tpm2_mso_type mso = tpm2_handle_mso(handle); - struct tpm2_auth *auth = chip->auth; - int slot; - - slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE)/4; - if (slot >= AUTH_MAX_NAMES) { - dev_err(&chip->dev, "TPM: too many handles\n"); - return; - } - WARN(auth->session != tpm_buf_length(buf), - "name added in wrong place\n"); - tpm_buf_append_u32(buf, handle); - auth->session += 4; - - if (mso == TPM2_MSO_PERSISTENT || - mso == TPM2_MSO_VOLATILE || - mso == TPM2_MSO_NVRAM) { - if (!name) - tpm2_read_public(chip, handle, auth->name[slot]); - } else { - if (name) - dev_err(&chip->dev, "TPM: Handle does not require name but one is specified\n"); - } - - auth->name_h[slot] = handle; - if (name) - memcpy(auth->name[slot], name, name_size(name)); -} -EXPORT_SYMBOL(tpm_buf_append_name); - /** * tpm_buf_check_hmac_response() - check the TPM return HMAC for correctness * @chip: the TPM chip structure @@ -1311,3 +1319,4 @@ int tpm2_sessions_init(struct tpm_chip *chip) return rc; } +#endif /* CONFIG_TCG_TPM2_HMAC */ diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 21a67dc9efe8..2844fea4a12a 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -211,8 +211,8 @@ struct tpm_chip { u8 null_key_name[TPM2_NAME_SIZE]; u8 null_ec_key_x[EC_PT_SZ]; u8 null_ec_key_y[EC_PT_SZ]; - struct tpm2_auth *auth; #endif + struct tpm2_auth *auth; }; #define TPM_HEADER_SIZE 10 @@ -490,11 +490,13 @@ static inline void tpm_buf_append_empty_auth(struct tpm_buf *buf, u32 handle) { } #endif -#ifdef CONFIG_TCG_TPM2_HMAC -int tpm2_start_auth_session(struct tpm_chip *chip); void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, u32 handle, u8 *name); + +#ifdef CONFIG_TCG_TPM2_HMAC + +int tpm2_start_auth_session(struct tpm_chip *chip); void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf, u8 attributes, u8 *passphrase, int passphraselen); @@ -521,14 +523,6 @@ static inline int tpm2_start_auth_session(struct tpm_chip *chip) static inline void tpm2_end_auth_session(struct tpm_chip *chip) { } -static inline void tpm_buf_append_name(struct tpm_chip *chip, - struct tpm_buf *buf, - u32 handle, u8 *name) -{ - tpm_buf_append_u32(buf, handle); - /* count the number of handles in the upper bits of flags */ - buf->handles++; -} static inline void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf, u8 attributes, u8 *passphrase, From patchwork Wed Jul 3 18:24:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13722691 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E38EB187556; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tx6D6B1I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 668B3C2BD10; Wed, 3 Jul 2024 18:25:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720031116; bh=vGuO+9bbdYk7rQq5wisNYXsobZUocrZsZ3QmZB07RL8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tx6D6B1Ifxq0LFfdki24k6AQfsBvRxiRxOu+e+XAvR0rWvSJzg/4LiFD/odyUWsW5 pe1iwQBK6KYv+sc+xflC0qd65VvSH+e/KdeS09WKTVQY+3zTXX2PYk5tX3LQ4gzJhd eAWWqCy5VLQCoCnI7jbr1zVv8iwJBvZrE9U3tYkcXTfkBUHpsb7SDBAF48z6vqTmyi cscor6E9RxxedWHT5JduMRG+2eYeirkpmCSREJAH7rJrAnvJxd5bZpuSntdCCZ3kAU lnRJE+aaVUTGASAF+0yIHNfnQ1gJNSLFN02HRDqf9v9DRdldk3q9DWrwQckyKKCF6t N49B++EbqXnXw== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: Thorsten Leemhuis , Linus Torvalds , Jarkko Sakkinen , stable@vger.kernel.org, Stefan Berger , Peter Huewe , Jason Gunthorpe , James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , Ard Biesheuvel , Mario Limonciello , linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v2 3/3] tpm: Address !chip->auth in tpm_buf_append_hmac_session*() Date: Wed, 3 Jul 2024 21:24:50 +0300 Message-ID: <20240703182453.1580888-4-jarkko@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240703182453.1580888-1-jarkko@kernel.org> References: <20240703182453.1580888-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Unless tpm_chip_bootstrap() was called by the driver, !chip->auth can cause a null derefence in tpm_buf_hmac_session*(). Thus, address !chip->auth in tpm_buf_hmac_session*() and remove the fallback implementation for !TCG_TPM2_HMAC. Cc: stable@vger.kernel.org # v6.9+ Reported-by: Stefan Berger Closes: https://lore.kernel.org/linux-integrity/20240617193408.1234365-1-stefanb@linux.ibm.com/ Fixes: 1085b8276bb4 ("tpm: Add the rest of the session HMAC API") Signed-off-by: Jarkko Sakkinen --- v2: - Use auth in place of chip->auth. --- drivers/char/tpm/tpm2-sessions.c | 181 ++++++++++++++++++------------- include/linux/tpm.h | 67 ++++-------- 2 files changed, 124 insertions(+), 124 deletions(-) diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 06d0f10a2301..304247090b56 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -268,6 +268,105 @@ void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, } EXPORT_SYMBOL_GPL(tpm_buf_append_name); +/** + * tpm_buf_append_hmac_session() - Append a TPM session element + * @chip: the TPM chip structure + * @buf: The buffer to be appended + * @attributes: The session attributes + * @passphrase: The session authority (NULL if none) + * @passphrase_len: The length of the session authority (0 if none) + * + * This fills in a session structure in the TPM command buffer, except + * for the HMAC which cannot be computed until the command buffer is + * complete. The type of session is controlled by the @attributes, + * the main ones of which are TPM2_SA_CONTINUE_SESSION which means the + * session won't terminate after tpm_buf_check_hmac_response(), + * TPM2_SA_DECRYPT which means this buffers first parameter should be + * encrypted with a session key and TPM2_SA_ENCRYPT, which means the + * response buffer's first parameter needs to be decrypted (confusing, + * but the defines are written from the point of view of the TPM). + * + * Any session appended by this command must be finalized by calling + * tpm_buf_fill_hmac_session() otherwise the HMAC will be incorrect + * and the TPM will reject the command. + * + * As with most tpm_buf operations, success is assumed because failure + * will be caused by an incorrect programming model and indicated by a + * kernel message. + */ +void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf, + u8 attributes, u8 *passphrase, + int passphrase_len) +{ + struct tpm2_auth *auth = chip->auth; + u8 nonce[SHA256_DIGEST_SIZE]; + u32 len; + + if (!auth) { + /* offset tells us where the sessions area begins */ + int offset = buf->handles * 4 + TPM_HEADER_SIZE; + u32 len = 9 + passphrase_len; + + if (tpm_buf_length(buf) != offset) { + /* not the first session so update the existing length */ + len += get_unaligned_be32(&buf->data[offset]); + put_unaligned_be32(len, &buf->data[offset]); + } else { + tpm_buf_append_u32(buf, len); + } + /* auth handle */ + tpm_buf_append_u32(buf, TPM2_RS_PW); + /* nonce */ + tpm_buf_append_u16(buf, 0); + /* attributes */ + tpm_buf_append_u8(buf, 0); + /* passphrase */ + tpm_buf_append_u16(buf, passphrase_len); + tpm_buf_append(buf, passphrase, passphrase_len); + return; + } + + /* + * The Architecture Guide requires us to strip trailing zeros + * before computing the HMAC + */ + while (passphrase && passphrase_len > 0 && passphrase[passphrase_len - 1] == '\0') + passphrase_len--; + + auth->attrs = attributes; + auth->passphrase_len = passphrase_len; + if (passphrase_len) + memcpy(auth->passphrase, passphrase, passphrase_len); + + if (auth->session != tpm_buf_length(buf)) { + /* we're not the first session */ + len = get_unaligned_be32(&buf->data[auth->session]); + if (4 + len + auth->session != tpm_buf_length(buf)) { + WARN(1, "session length mismatch, cannot append"); + return; + } + + /* add our new session */ + len += 9 + 2 * SHA256_DIGEST_SIZE; + put_unaligned_be32(len, &buf->data[auth->session]); + } else { + tpm_buf_append_u32(buf, 9 + 2 * SHA256_DIGEST_SIZE); + } + + /* random number for our nonce */ + get_random_bytes(nonce, sizeof(nonce)); + memcpy(auth->our_nonce, nonce, sizeof(nonce)); + tpm_buf_append_u32(buf, auth->handle); + /* our new nonce */ + tpm_buf_append_u16(buf, SHA256_DIGEST_SIZE); + tpm_buf_append(buf, nonce, SHA256_DIGEST_SIZE); + tpm_buf_append_u8(buf, auth->attrs); + /* and put a placeholder for the hmac */ + tpm_buf_append_u16(buf, SHA256_DIGEST_SIZE); + tpm_buf_append(buf, nonce, SHA256_DIGEST_SIZE); +} +EXPORT_SYMBOL_GPL(tpm_buf_append_hmac_session); + #ifdef CONFIG_TCG_TPM2_HMAC /* * It turns out the crypto hmac(sha256) is hard for us to consume @@ -449,82 +548,6 @@ static void tpm_buf_append_salt(struct tpm_buf *buf, struct tpm_chip *chip) crypto_free_kpp(kpp); } -/** - * tpm_buf_append_hmac_session() - Append a TPM session element - * @chip: the TPM chip structure - * @buf: The buffer to be appended - * @attributes: The session attributes - * @passphrase: The session authority (NULL if none) - * @passphrase_len: The length of the session authority (0 if none) - * - * This fills in a session structure in the TPM command buffer, except - * for the HMAC which cannot be computed until the command buffer is - * complete. The type of session is controlled by the @attributes, - * the main ones of which are TPM2_SA_CONTINUE_SESSION which means the - * session won't terminate after tpm_buf_check_hmac_response(), - * TPM2_SA_DECRYPT which means this buffers first parameter should be - * encrypted with a session key and TPM2_SA_ENCRYPT, which means the - * response buffer's first parameter needs to be decrypted (confusing, - * but the defines are written from the point of view of the TPM). - * - * Any session appended by this command must be finalized by calling - * tpm_buf_fill_hmac_session() otherwise the HMAC will be incorrect - * and the TPM will reject the command. - * - * As with most tpm_buf operations, success is assumed because failure - * will be caused by an incorrect programming model and indicated by a - * kernel message. - */ -void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf, - u8 attributes, u8 *passphrase, - int passphrase_len) -{ - u8 nonce[SHA256_DIGEST_SIZE]; - u32 len; - struct tpm2_auth *auth = chip->auth; - - /* - * The Architecture Guide requires us to strip trailing zeros - * before computing the HMAC - */ - while (passphrase && passphrase_len > 0 - && passphrase[passphrase_len - 1] == '\0') - passphrase_len--; - - auth->attrs = attributes; - auth->passphrase_len = passphrase_len; - if (passphrase_len) - memcpy(auth->passphrase, passphrase, passphrase_len); - - if (auth->session != tpm_buf_length(buf)) { - /* we're not the first session */ - len = get_unaligned_be32(&buf->data[auth->session]); - if (4 + len + auth->session != tpm_buf_length(buf)) { - WARN(1, "session length mismatch, cannot append"); - return; - } - - /* add our new session */ - len += 9 + 2 * SHA256_DIGEST_SIZE; - put_unaligned_be32(len, &buf->data[auth->session]); - } else { - tpm_buf_append_u32(buf, 9 + 2 * SHA256_DIGEST_SIZE); - } - - /* random number for our nonce */ - get_random_bytes(nonce, sizeof(nonce)); - memcpy(auth->our_nonce, nonce, sizeof(nonce)); - tpm_buf_append_u32(buf, auth->handle); - /* our new nonce */ - tpm_buf_append_u16(buf, SHA256_DIGEST_SIZE); - tpm_buf_append(buf, nonce, SHA256_DIGEST_SIZE); - tpm_buf_append_u8(buf, auth->attrs); - /* and put a placeholder for the hmac */ - tpm_buf_append_u16(buf, SHA256_DIGEST_SIZE); - tpm_buf_append(buf, nonce, SHA256_DIGEST_SIZE); -} -EXPORT_SYMBOL(tpm_buf_append_hmac_session); - /** * tpm_buf_fill_hmac_session() - finalize the session HMAC * @chip: the TPM chip structure @@ -555,6 +578,9 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf) u8 cphash[SHA256_DIGEST_SIZE]; struct sha256_state sctx; + if (!auth) + return; + /* save the command code in BE format */ auth->ordinal = head->ordinal; @@ -713,6 +739,9 @@ int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf, u32 cc = be32_to_cpu(auth->ordinal); int parm_len, len, i, handles; + if (!auth) + return rc; + if (auth->session >= TPM_HEADER_SIZE) { WARN(1, "tpm session not filled correctly\n"); goto out; diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 2844fea4a12a..912fd0d2646d 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -493,22 +493,35 @@ static inline void tpm_buf_append_empty_auth(struct tpm_buf *buf, u32 handle) void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, u32 handle, u8 *name); - -#ifdef CONFIG_TCG_TPM2_HMAC - -int tpm2_start_auth_session(struct tpm_chip *chip); void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf, u8 attributes, u8 *passphrase, int passphraselen); + static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip, struct tpm_buf *buf, u8 attributes, u8 *passphrase, int passphraselen) { - tpm_buf_append_hmac_session(chip, buf, attributes, passphrase, - passphraselen); + struct tpm_header *head = (struct tpm_header *)buf->data; + int offset = buf->handles * 4 + TPM_HEADER_SIZE; + + if (chip->auth) { + tpm_buf_append_hmac_session(chip, buf, attributes, passphrase, + passphraselen); + } else { + /* + * If the only sessions are optional, the command tag must change to + * TPM2_ST_NO_SESSIONS. + */ + if (tpm_buf_length(buf) == offset) + head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS); + } } + +#ifdef CONFIG_TCG_TPM2_HMAC + +int tpm2_start_auth_session(struct tpm_chip *chip); void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf); int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf, int rc); @@ -523,48 +536,6 @@ static inline int tpm2_start_auth_session(struct tpm_chip *chip) static inline void tpm2_end_auth_session(struct tpm_chip *chip) { } -static inline void tpm_buf_append_hmac_session(struct tpm_chip *chip, - struct tpm_buf *buf, - u8 attributes, u8 *passphrase, - int passphraselen) -{ - /* offset tells us where the sessions area begins */ - int offset = buf->handles * 4 + TPM_HEADER_SIZE; - u32 len = 9 + passphraselen; - - if (tpm_buf_length(buf) != offset) { - /* not the first session so update the existing length */ - len += get_unaligned_be32(&buf->data[offset]); - put_unaligned_be32(len, &buf->data[offset]); - } else { - tpm_buf_append_u32(buf, len); - } - /* auth handle */ - tpm_buf_append_u32(buf, TPM2_RS_PW); - /* nonce */ - tpm_buf_append_u16(buf, 0); - /* attributes */ - tpm_buf_append_u8(buf, 0); - /* passphrase */ - tpm_buf_append_u16(buf, passphraselen); - tpm_buf_append(buf, passphrase, passphraselen); -} -static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip, - struct tpm_buf *buf, - u8 attributes, - u8 *passphrase, - int passphraselen) -{ - int offset = buf->handles * 4 + TPM_HEADER_SIZE; - struct tpm_header *head = (struct tpm_header *) buf->data; - - /* - * if the only sessions are optional, the command tag - * must change to TPM2_ST_NO_SESSIONS - */ - if (tpm_buf_length(buf) == offset) - head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS); -} static inline void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf) {