From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Date: Tue, 13 Oct 2020 00:28:13 +0000 Subject: [PATCH v3 1/3] KEYS: trusted: Fix incorrect handling of tpm_get_random() Message-Id: <20201013002815.40256-2-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <20201013002815.40256-1-jarkko.sakkinen@linux.intel.com> In-Reply-To: <20201013002815.40256-1-jarkko.sakkinen@linux.intel.com> To: linux-integrity@vger.kernel.org Cc: David Howells , Mimi Zohar , James Bottomley , Jarkko Sakkinen , stable@vger.kernel.org, "James E.J. Bottomley" , Kent Yoder , James Morris , "Serge E. Hallyn" , David Safford , "H. Peter Anvin" , "open list:KEYS-TRUSTED" , "open list:SECURITY SUBSYSTEM" , open list When tpm_get_random() was introduced, it defined the following API for the return value: 1. A positive value tells how many bytes of random data was generated. 2. A negative value on error. However, in the call sites the API was used incorrectly, i.e. as it would only return negative values and otherwise zero. Returning he positive read counts to the user space does not make any possible sense. Fix this by returning -EIO when tpm_get_random() returns a positive value. Fixes: 41ab999c80f1 ("tpm: Move tpm_get_random api into the TPM device driver") Cc: stable@vger.kernel.org Cc: Mimi Zohar Cc: "James E.J. Bottomley" Cc: David Howells Cc: Kent Yoder Signed-off-by: Jarkko Sakkinen --- security/keys/trusted-keys/trusted_tpm1.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index b9fe02e5f84f..c7b1701cdac5 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -403,9 +403,12 @@ static int osap(struct tpm_buf *tb, struct osapsess *s, int ret; ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE); - if (ret != TPM_NONCE_SIZE) + if (ret < 0) return ret; + if (ret != TPM_NONCE_SIZE) + return -EIO; + tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OSAP); tpm_buf_append_u16(tb, type); tpm_buf_append_u32(tb, handle); @@ -496,8 +499,12 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, goto out; ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE); + if (ret < 0) + return ret; + if (ret != TPM_NONCE_SIZE) - goto out; + return -EIO; + ordinal = htonl(TPM_ORD_SEAL); datsize = htonl(datalen); pcrsize = htonl(pcrinfosize); @@ -601,9 +608,12 @@ static int tpm_unseal(struct tpm_buf *tb, ordinal = htonl(TPM_ORD_UNSEAL); ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE); + if (ret < 0) + return ret; + if (ret != TPM_NONCE_SIZE) { pr_info("trusted_key: tpm_get_random failed (%d)\n", ret); - return ret; + return -EIO; } ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE, enonce1, nonceodd, cont, sizeof(uint32_t), @@ -1013,8 +1023,12 @@ static int trusted_instantiate(struct key *key, case Opt_new: key_len = payload->key_len; ret = tpm_get_random(chip, payload->key, key_len); + if (ret < 0) + goto out; + if (ret != key_len) { pr_info("trusted_key: key_create failed (%d)\n", ret); + ret = -EIO; goto out; } if (tpm2) -- 2.25.1