From patchwork Thu Jul 4 08:57:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13723495 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 7FF6D17084A; Thu, 4 Jul 2024 08:57:29 +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=1720083449; cv=none; b=VWhtbjiquRAf6jsNYLlegBB+aBk1U2uDUgw1JjN0UuhNddv6JDBhLSYY+mb8bh57fmDZQ2v/vv9oZEtKUTn3YRWrndyBTzQjvl07UgbB+JD2cMKS2LwnxM/kH/zy3BDg5pg+XSdEKX0B02hd2q5K5qf2yrO+zTEw6dw2O14IXSQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720083449; c=relaxed/simple; bh=urQk/W7QgAkmeUdca4VhY2EisitaIXwv21mu/blon6o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=twntbI8ZQvO345OPHY14zwEdd+6Vn+8/OcHd2g8SgajVTNYaQwz6izdqPdl8El/wF1jjiF+a/fcFHAE/ce4dGR5B0/ENYgM2fH6OkME61qmmq9MQMGlj6IuA2L0hYxWm9pIboXNjVCNfK2lizESEaMtsex1jLJ5QszoqEf79Pq4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XaGrUAJe; 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="XaGrUAJe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFD5BC3277B; Thu, 4 Jul 2024 08:57:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720083449; bh=urQk/W7QgAkmeUdca4VhY2EisitaIXwv21mu/blon6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XaGrUAJeFZW6Pjxa2pWT6qViw8ngk7vdm11z4lV3A3edk5pYhABC1Yp5FAHieIWjp 5cpFfMzVvLhN9/oPKlAXjCkEA3k1H6Rp6LczpINw3J9c2Yi3UKE9W7lzwFwIJxneOB Det7u3bKk7Lr3jpQclllLzzoEhEPZLYrG8iaLBZAufUXvSTG9SVm8FhMY2trVPjBLO flLoDTw+B4QJbLp5Mi/tX6DM/9pxHFFbUzqPzBt0EWNto3M79FD7gYn/iLcJV8iTYK y0xrDjYd0g/3hkd2SuEeseh2iTlZDNcg4dFwtUZSKxugMYfXTd6DsFFYu9EI1XWT8h jDrM5mNsHBqpQ== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: Thorsten Leemhuis , Linus Torvalds , Jarkko Sakkinen , stable@vger.kernel.org, Stefan Berger , James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/3] tpm: Address !chip->auth in tpm2_*_auth_session() Date: Thu, 4 Jul 2024 11:57:02 +0300 Message-ID: <20240704085708.661142-2-jarkko@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240704085708.661142-1-jarkko@kernel.org> References: <20240704085708.661142-1-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 Thu Jul 4 08:57:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13723496 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 45D4716FF27; Thu, 4 Jul 2024 08:57:34 +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=1720083454; cv=none; b=MxcqZD9oprtsgD4ILvbEGCzekX+s+dLWd5cuQ8HUaOPjhq2FwxlmdVXlEutiqKxJerNK+Pg8t62C8eHj5wzXofXLLZFWvzzSkAqBEq4IH2+kjxoFEGMIOrwxf/CEmz7zpf183rwQSegfAODyIbbKbjeYZsNnqhwfE9fv995ZfWU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720083454; c=relaxed/simple; bh=NNLcwcCssGvjSm08rU9j5/39P2BCFR+lB+1OFhZuoPY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XjSAsJsoffEo3n/JeTBI2B2+zR41GquHEBGkGMAOxPYRjxtQhWpN/JB0qIvSe2zUcpwVROITWtXc9f8RHddmWZvfT8mRrgHLZdp4zImtVa12C57JWGGm/RW3cebAl6MfLCvmG0AS1w+BaUhYQy9QgB/Kritfr2QBt9gYKXSZnII= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CUfOvfJM; 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="CUfOvfJM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8461DC3277B; Thu, 4 Jul 2024 08:57:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720083453; bh=NNLcwcCssGvjSm08rU9j5/39P2BCFR+lB+1OFhZuoPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CUfOvfJMNEFFuiFKqrF1sAtW9hVOeqS5JiQbsKLM1VYY/TXvTlBTaWZIXeCY7Q97n nJXHn5jVZ6YZ6pM3vVj59A+FpQcugEONo98qPFKSEnBJYdZRfsoDwjhlfpe+WSk0mV IrOYO0CUiAlr5DSkTZ6vrytOPuH/hSCGFPRZ1wbXJfiT4nY1vIGtBDuv/kW147to3Z TDdsIwKYKOjdQ3RqdTVvUSUsct1T5fHkFW97FZ5uBCUxvkrTohDYo0Ge/E7Ufdp8oC 7XNBJcnyd3SWBTJURPPv5cmqFQ9wxgjt9CGk60bGmxSI7GGDl0WAZHsY5Y1MgCf9Gh tkHX0azeXT/lg== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: Thorsten Leemhuis , Linus Torvalds , Jarkko Sakkinen , stable@vger.kernel.org, Stefan Berger , James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 2/3] tpm: Address !chip->auth in tpm_buf_append_name() Date: Thu, 4 Jul 2024 11:57:03 +0300 Message-ID: <20240704085708.661142-3-jarkko@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240704085708.661142-1-jarkko@kernel.org> References: <20240704085708.661142-1-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 # v6.10+ 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 --- v3: * Address: https://lore.kernel.org/linux-integrity/922603265d61011dbb23f18a04525ae973b83ffd.camel@HansenPartnership.com/ v2: * N/A --- drivers/char/tpm/Makefile | 2 +- drivers/char/tpm/tpm2-sessions.c | 217 +++++++++++++++++-------------- include/linux/tpm.h | 14 +- 3 files changed, 121 insertions(+), 112 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..179bcaac06ce 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -83,9 +83,6 @@ #define AES_KEY_BYTES AES_KEYSIZE_128 #define AES_KEY_BITS (AES_KEY_BYTES*8) -static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy, - u32 *handle, u8 *name); - /* * This is the structure that carries all the auth information (like * session handle, nonces, session key and auth) from use to use it is @@ -148,6 +145,7 @@ struct tpm2_auth { u8 name[AUTH_MAX_NAMES][2 + SHA512_DIGEST_SIZE]; }; +#ifdef CONFIG_TCG_TPM2_HMAC /* * Name Size based on TPM algorithm (assumes no hash bigger than 255) */ @@ -163,6 +161,120 @@ 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; +} +#endif /* CONFIG_TCG_TPM2_HMAC */ + +/** + * 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 __maybe_unused mso = tpm2_handle_mso(handle); + struct tpm2_auth __maybe_unused *auth; + int __maybe_unused slot; + + if (!__and(IS_ENABLED(CONFIG_TCG_TPM2_HMAC), chip->auth)) { + tpm_buf_append_u32(buf, handle); + /* count the number of handles in the upper bits of flags */ + buf->handles++; + return; + } + +#ifdef CONFIG_TCG_TPM2_HMAC + slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE) / 4; + if (slot >= AUTH_MAX_NAMES) { + dev_err(&chip->dev, "TPM: too many handles\n"); + return; + } + auth = chip->auth; + 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)); +#endif /* CONFIG_TCG_TPM2_HMAC */ +} +EXPORT_SYMBOL_GPL(tpm_buf_append_name); + +#ifdef CONFIG_TCG_TPM2_HMAC + +static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy, + u32 *handle, u8 *name); + /* * 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 +679,6 @@ 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 +1325,4 @@ 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..d9a6991b247d 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -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 Thu Jul 4 08:57:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13723497 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 E817F1AB521; Thu, 4 Jul 2024 08:57:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Thu, 4 Jul 2024 08:57:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720083458; bh=1R1l/jh/2sVbYXEuHFTT6vinE3yiZu+gRxbg7eWhc4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f9VZUILxFQlQsYkDK5sjS4MXCR40r/4MWt6lsSedyN2b573OFxRYKCDROoxC7pO48 iyfM6g/OjzHZXu73ERxx4BFtQSG8cUjGrTGQJp9LU8iPUfhzxmXlCidQv6G6rHynYE sUhfp1x5m42Jkj62+x6M5JLiIlohItWprZA/FXhk/rlLlccD1ZOxfduKNE3NQPb3xo nZJiHdk7PUH1kbOGTQEeeKtyJX1tFXZN0UPjGv88yR4vvBETFJgq7EJIFpD6yK84EP SkJqLLCFUvkfBe7B5hxunEmjHcLroAhkuCYGdi68C7gXEOXnu6FPUCjtqxnmYqdQgZ iMcWadP/GJppA== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: Thorsten Leemhuis , Linus Torvalds , Jarkko Sakkinen , stable@vger.kernel.org, Stefan Berger , James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/3] tpm: Address !chip->auth in tpm_buf_append_hmac_session*() Date: Thu, 4 Jul 2024 11:57:04 +0300 Message-ID: <20240704085708.661142-4-jarkko@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240704085708.661142-1-jarkko@kernel.org> References: <20240704085708.661142-1-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 --- v3: * Address: https://lore.kernel.org/linux-integrity/922603265d61011dbb23f18a04525ae973b83ffd.camel@HansenPartnership.com/ v2: * Use auth in place of chip->auth. --- drivers/char/tpm/tpm2-sessions.c | 184 ++++++++++++++++++------------- include/linux/tpm.h | 68 ++++-------- 2 files changed, 128 insertions(+), 124 deletions(-) diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 179bcaac06ce..e0be22b8ae70 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -270,6 +270,108 @@ 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) +{ + u8 __maybe_unused nonce[SHA256_DIGEST_SIZE]; + struct tpm2_auth __maybe_unused *auth; + u32 __maybe_unused len; + + if (!__and(IS_ENABLED(CONFIG_TCG_TPM2_HMAC), chip->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; + } + +#ifdef CONFIG_TCG_TPM2_HMAC + /* + * 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 = chip->auth; + 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); +#endif /* CONFIG_TCG_TPM2_HMAC */ +} +EXPORT_SYMBOL_GPL(tpm_buf_append_hmac_session); + #ifdef CONFIG_TCG_TPM2_HMAC static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy, @@ -455,82 +557,6 @@ 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 @@ -561,6 +587,9 @@ 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; @@ -719,6 +748,9 @@ 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 d9a6991b247d..e47f5d65935e 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -493,10 +493,6 @@ 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); @@ -506,9 +502,27 @@ static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip, u8 *passphrase, int passphraselen) { - tpm_buf_append_hmac_session(chip, buf, attributes, passphrase, - passphraselen); + struct tpm_header *head; + int offset; + + if (__and(IS_ENABLED(CONFIG_TCG_TPM2_HMAC), chip->auth)) { + tpm_buf_append_hmac_session(chip, buf, attributes, passphrase, passphraselen); + } else { + offset = buf->handles * 4 + TPM_HEADER_SIZE; + 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); + } } + +#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 +537,6 @@ 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) {