From 6e9722e9a7bfe1bbad649937c811076acf86e1fd Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Sun, 30 Nov 2025 21:07:12 +0200 Subject: tpm2-sessions: Fix out of range indexing in name_size 'name_size' does not have any range checks, and it just directly indexes with TPM_ALG_ID, which could lead into memory corruption at worst. Address the issue by only processing known values and returning -EINVAL for unrecognized values. Make also 'tpm_buf_append_name' and 'tpm_buf_fill_hmac_session' fallible so that errors are detected before causing any spurious TPM traffic. End also the authorization session on failure in both of the functions, as the session state would be then by definition corrupted. Cc: stable@vger.kernel.org # v6.10+ Fixes: 1085b8276bb4 ("tpm: Add the rest of the session HMAC API") Reviewed-by: Jonathan McDowell Signed-off-by: Jarkko Sakkinen --- security/keys/trusted-keys/trusted_tpm2.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) (limited to 'security') diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 8bc6efa8accb..5b205279584b 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -268,7 +268,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip, goto out_put; } - tpm_buf_append_name(chip, &buf, options->keyhandle, NULL); + rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL); + if (rc) + goto out; + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT, options->keyauth, TPM_DIGEST_SIZE); @@ -316,7 +319,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip, goto out; } - tpm_buf_fill_hmac_session(chip, &buf); + rc = tpm_buf_fill_hmac_session(chip, &buf); + if (rc) + goto out; + rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data"); rc = tpm_buf_check_hmac_response(chip, &buf, rc); if (rc) @@ -427,7 +433,10 @@ static int tpm2_load_cmd(struct tpm_chip *chip, return rc; } - tpm_buf_append_name(chip, &buf, options->keyhandle, NULL); + rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL); + if (rc) + goto out; + tpm_buf_append_hmac_session(chip, &buf, 0, options->keyauth, TPM_DIGEST_SIZE); @@ -439,7 +448,10 @@ static int tpm2_load_cmd(struct tpm_chip *chip, goto out; } - tpm_buf_fill_hmac_session(chip, &buf); + rc = tpm_buf_fill_hmac_session(chip, &buf); + if (rc) + goto out; + rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob"); rc = tpm_buf_check_hmac_response(chip, &buf, rc); if (!rc) @@ -484,7 +496,9 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip, return rc; } - tpm_buf_append_name(chip, &buf, blob_handle, NULL); + rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL); + if (rc) + goto out; if (!options->policyhandle) { tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT, @@ -509,7 +523,10 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip, NULL, 0); } - tpm_buf_fill_hmac_session(chip, &buf); + rc = tpm_buf_fill_hmac_session(chip, &buf); + if (rc) + goto out; + rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing"); rc = tpm_buf_check_hmac_response(chip, &buf, rc); -- cgit v1.2.3 From b7960b90486139022d2d39caad90db252c469bab Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Tue, 30 Sep 2025 23:44:19 +0300 Subject: tpm2-sessions: Open code tpm_buf_append_hmac_session() Open code 'tpm_buf_append_hmac_session_opt' to the call site, as it only masks a call sequence and does otherwise nothing particularly useful. Signed-off-by: Jarkko Sakkinen Reviewed-by: Jonathan McDowell --- security/keys/trusted-keys/trusted_tpm2.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'security') diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 5b205279584b..a7ea4a1c3bed 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -481,8 +481,10 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip, struct trusted_key_options *options, u32 blob_handle) { + struct tpm_header *head; struct tpm_buf buf; u16 data_len; + int offset; u8 *data; int rc; @@ -519,8 +521,14 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip, tpm2_buf_append_auth(&buf, options->policyhandle, NULL /* nonce */, 0, 0, options->blobauth, options->blobauth_len); - tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT, - NULL, 0); + if (tpm2_chip_auth(chip)) { + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT, NULL, 0); + } else { + offset = buf.handles * 4 + TPM_HEADER_SIZE; + head = (struct tpm_header *)buf.data; + if (tpm_buf_length(&buf) == offset) + head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS); + } } rc = tpm_buf_fill_hmac_session(chip, &buf); -- cgit v1.2.3