From 195aba96b854dd664768f382cd1db375d8181f88 Mon Sep 17 00:00:00 2001 From: "Matthew R. Ochs" Date: Wed, 22 May 2024 15:06:40 +0300 Subject: [PATCH 1/4] tpm_tis_spi: Account for SPI header when allocating TPM SPI xfer buffer The TPM SPI transfer mechanism uses MAX_SPI_FRAMESIZE for computing the maximum transfer length and the size of the transfer buffer. As such, it does not account for the 4 bytes of header that prepends the SPI data frame. This can result in out-of-bounds accesses and was confirmed with KASAN. Introduce SPI_HDRSIZE to account for the header and use to allocate the transfer buffer. Fixes: a86a42ac2bd6 ("tpm_tis_spi: Add hardware wait polling") Signed-off-by: Matthew R. Ochs Tested-by: Carol Soto Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm_tis_spi_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/char/tpm/tpm_tis_spi_main.c b/drivers/char/tpm/tpm_tis_spi_main.c index 3f9eaf27b41b..c9eca24bbad4 100644 --- a/drivers/char/tpm/tpm_tis_spi_main.c +++ b/drivers/char/tpm/tpm_tis_spi_main.c @@ -37,6 +37,7 @@ #include "tpm_tis_spi.h" #define MAX_SPI_FRAMESIZE 64 +#define SPI_HDRSIZE 4 /* * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short, @@ -247,7 +248,7 @@ static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr, int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy, int irq, const struct tpm_tis_phy_ops *phy_ops) { - phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + phy->iobuf = devm_kmalloc(&spi->dev, SPI_HDRSIZE + MAX_SPI_FRAMESIZE, GFP_KERNEL); if (!phy->iobuf) return -ENOMEM; From f3d7ba9e1bc0c9080834f263d4887bd9c9ea491f Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Mon, 27 May 2024 13:56:27 +0300 Subject: [PATCH 2/4] tpm: Open code tpm_buf_parameters() With only single call site, this makes no sense (slipped out of the radar during the review). Open code and document the action directly to the site, to make it more readable. Fixes: 1b6d7f9eb150 ("tpm: add session encryption protection to tpm2_get_random()") Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm-buf.c | 26 -------------------------- drivers/char/tpm/tpm2-cmd.c | 10 +++++++++- include/linux/tpm.h | 2 -- 3 files changed, 9 insertions(+), 29 deletions(-) diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c index 647c6ca92ac3..cad0048bcc3c 100644 --- a/drivers/char/tpm/tpm-buf.c +++ b/drivers/char/tpm/tpm-buf.c @@ -223,30 +223,4 @@ u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset) } 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/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 0cdf892ec2a7..1e856259219e 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -281,6 +281,7 @@ struct tpm2_get_random_out { int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max) { struct tpm2_get_random_out *out; + struct tpm_header *head; struct tpm_buf buf; u32 recd; u32 num_bytes = max; @@ -288,6 +289,7 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max) int total = 0; int retries = 5; u8 *dest_ptr = dest; + off_t offset; if (!num_bytes || max > TPM_MAX_RNG_DATA) return -EINVAL; @@ -320,7 +322,13 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max) goto out; } - out = (struct tpm2_get_random_out *)tpm_buf_parameters(&buf); + head = (struct tpm_header *)buf.data; + offset = TPM_HEADER_SIZE; + /* Skip the parameter size field: */ + if (be16_to_cpu(head->tag) == TPM2_ST_SESSIONS) + offset += 4; + + out = (struct tpm2_get_random_out *)&buf.data[offset]; recd = min_t(u32, be16_to_cpu(out->size), num_bytes); if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + diff --git a/include/linux/tpm.h b/include/linux/tpm.h index c17e4efbb2e5..b3217200df28 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -437,8 +437,6 @@ 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. */ From f09fc6cee0dcfc38148ee6b6dd04f93e353d22f2 Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Tue, 28 May 2024 12:52:21 +0300 Subject: [PATCH 3/4] tpm: Rename TPM2_OA_TMPL to TPM2_OA_NULL_KEY and make it local Rename and document TPM2_OA_TMPL, as originally requested in the patch set review, but left unaddressed without any appropriate reasoning. The new name is TPM2_OA_NULL_KEY, has a documentation and is local only to tpm2-sessions.c. Link: https://lore.kernel.org/linux-integrity/ddbeb8111f48a8ddb0b8fca248dff6cc9d7079b2.camel@HansenPartnership.com/ Link: https://lore.kernel.org/linux-integrity/CZCKTWU6ZCC9.2UTEQPEVICYHL@suppilovahvero/ Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm2-sessions.c | 21 +++++++++++++++++++-- include/linux/tpm.h | 15 --------------- 2 files changed, 19 insertions(+), 17 deletions(-) diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index ea8860661876..907ac9956a78 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -80,6 +80,9 @@ /* maximum number of names the TPM must remember for authorization */ #define AUTH_MAX_NAMES 3 +#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); @@ -954,6 +957,20 @@ int tpm2_start_auth_session(struct tpm_chip *chip) } EXPORT_SYMBOL(tpm2_start_auth_session); +/* + * A mask containing the object attributes for the kernel held null primary key + * used in HMAC encryption. For more information on specific attributes look up + * to "8.3 TPMA_OBJECT (Object Attributes)". + */ +#define TPM2_OA_NULL_KEY ( \ + TPM2_OA_NO_DA | \ + TPM2_OA_FIXED_TPM | \ + TPM2_OA_FIXED_PARENT | \ + TPM2_OA_SENSITIVE_DATA_ORIGIN | \ + TPM2_OA_USER_WITH_AUTH | \ + TPM2_OA_DECRYPT | \ + TPM2_OA_RESTRICTED) + /** * tpm2_parse_create_primary() - parse the data returned from TPM_CC_CREATE_PRIMARY * @@ -1018,7 +1035,7 @@ static int tpm2_parse_create_primary(struct tpm_chip *chip, struct tpm_buf *buf, val = tpm_buf_read_u32(buf, &offset_t); /* object properties */ - if (val != TPM2_OA_TMPL) + if (val != TPM2_OA_NULL_KEY) return -EINVAL; /* auth policy (empty) */ @@ -1178,7 +1195,7 @@ static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy, tpm_buf_append_u16(&template, TPM_ALG_SHA256); /* object properties */ - tpm_buf_append_u32(&template, TPM2_OA_TMPL); + tpm_buf_append_u32(&template, TPM2_OA_NULL_KEY); /* sauth policy (empty) */ tpm_buf_append_u16(&template, 0); diff --git a/include/linux/tpm.h b/include/linux/tpm.h index b3217200df28..21a67dc9efe8 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -394,21 +394,6 @@ enum tpm2_object_attributes { TPM2_OA_SIGN = BIT(18), }; -/* - * definitions for the canonical template. These are mandated - * by the TCG key template documents - */ - -#define AES_KEY_BYTES AES_KEYSIZE_128 -#define AES_KEY_BITS (AES_KEY_BYTES*8) -#define TPM2_OA_TMPL (TPM2_OA_NO_DA | \ - TPM2_OA_FIXED_TPM | \ - TPM2_OA_FIXED_PARENT | \ - TPM2_OA_SENSITIVE_DATA_ORIGIN | \ - TPM2_OA_USER_WITH_AUTH | \ - TPM2_OA_DECRYPT | \ - TPM2_OA_RESTRICTED) - enum tpm2_session_attributes { TPM2_SA_CONTINUE_SESSION = BIT(0), TPM2_SA_AUDIT_EXCLUSIVE = BIT(1), From d3e43a8fa43effdbb62c7edc206df7ac67772205 Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Tue, 28 May 2024 12:58:41 +0300 Subject: [PATCH 4/4] tpm: Enable TCG_TPM2_HMAC by default only for X86_64 Given the not fully root caused performance issues on non-x86 platforms, enable the feature by default only for x86-64. That is the platform it brings the most value and has gone most of the QA. Can be reconsidered later and can be obviously opt-in enabled too on any arch. Link: https://lore.kernel.org/linux-integrity/bf67346ef623ff3c452c4f968b7d900911e250c3.camel@gmail.com/#t Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig index e63a6a17793c..cf0be8a7939d 100644 --- a/drivers/char/tpm/Kconfig +++ b/drivers/char/tpm/Kconfig @@ -29,7 +29,7 @@ if TCG_TPM config TCG_TPM2_HMAC bool "Use HMAC and encrypted transactions on the TPM bus" - default y + default X86_64 select CRYPTO_ECDH select CRYPTO_LIB_AESCFB select CRYPTO_LIB_SHA256