commit ee618b4619b72527aaed765f0f0b74072b281159 upstream. [Please apply to 3.18-stable.]

As the previous patch did for encrypted-keys, zero sensitive any potentially sensitive data related to the "trusted" key type before it is freed. Notably, we were not zeroing the tpm_buf structures in which the actual key is stored for TPM seal and unseal, nor were we zeroing the trusted_key_payload in certain error paths.

Cc: Mimi Zohar zohar@linux.vnet.ibm.com Cc: David Safford safford@us.ibm.com Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: James Morris james.l.morris@oracle.com --- security/keys/trusted.c | 49 ++++++++++++++++++++++--------------------------- 1 file changed, 22 insertions(+), 27 deletions(-)

diff --git a/security/keys/trusted.c b/security/keys/trusted.c index aeb38f1a12e7..917453895cbc 100644 --- a/security/keys/trusted.c +++ b/security/keys/trusted.c @@ -69,7 +69,7 @@ static int TSS_sha1(const unsigned char *data, unsigned int datalen, }

ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest); - kfree(sdesc); + kzfree(sdesc); return ret; }

@@ -113,7 +113,7 @@ static int TSS_rawhmac(unsigned char *digest, const unsigned char *key, if (!ret) ret = crypto_shash_final(&sdesc->shash, digest); out: - kfree(sdesc); + kzfree(sdesc); return ret; }

@@ -164,7 +164,7 @@ static int TSS_authhmac(unsigned char *digest, const unsigned char *key, paramdigest, TPM_NONCE_SIZE, h1, TPM_NONCE_SIZE, h2, 1, &c, 0, 0); out: - kfree(sdesc); + kzfree(sdesc); return ret; }

@@ -245,7 +245,7 @@ static int TSS_checkhmac1(unsigned char *buffer, if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE)) ret = -EINVAL; out: - kfree(sdesc); + kzfree(sdesc); return ret; }

@@ -346,7 +346,7 @@ static int TSS_checkhmac2(unsigned char *buffer, if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE)) ret = -EINVAL; out: - kfree(sdesc); + kzfree(sdesc); return ret; }

@@ -563,7 +563,7 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, *bloblen = storedsize; } out: - kfree(td); + kzfree(td); return ret; }

@@ -677,7 +677,7 @@ static int key_seal(struct trusted_key_payload *p, if (ret < 0) pr_info("trusted_key: srkseal failed (%d)\n", ret);

- kfree(tb); + kzfree(tb); return ret; }

@@ -702,7 +702,7 @@ static int key_unseal(struct trusted_key_payload *p, /* pull migratable flag out of sealed key */ p->migratable = p->key[--p->key_len];

- kfree(tb); + kzfree(tb); return ret; }

@@ -961,12 +961,12 @@ static int trusted_instantiate(struct key *key, if (!ret && options->pcrlock) ret = pcrlock(options->pcrlock); out: - kfree(datablob); - kfree(options); + kzfree(datablob); + kzfree(options); if (!ret) rcu_assign_keypointer(key, payload); else - kfree(payload); + kzfree(payload); return ret; }

@@ -975,8 +975,7 @@ static void trusted_rcu_free(struct rcu_head *rcu) struct trusted_key_payload *p;

p = container_of(rcu, struct trusted_key_payload, rcu); - memset(p->key, 0, p->key_len); - kfree(p); + kzfree(p); }

/* @@ -1018,9 +1017,10 @@ static int trusted_update(struct key *key, struct key_preparsed_payload *prep) ret = datablob_parse(datablob, new_p, new_o); if (ret != Opt_update) { ret = -EINVAL; - kfree(new_p); + kzfree(new_p); goto out; } + /* copy old key values, and reseal with new pcrs */ new_p->migratable = p->migratable; new_p->key_len = p->key_len; @@ -1031,22 +1031,22 @@ static int trusted_update(struct key *key, struct key_preparsed_payload *prep) ret = key_seal(new_p, new_o); if (ret < 0) { pr_info("trusted_key: key_seal failed (%d)\n", ret); - kfree(new_p); + kzfree(new_p); goto out; } if (new_o->pcrlock) { ret = pcrlock(new_o->pcrlock); if (ret < 0) { pr_info("trusted_key: pcrlock failed (%d)\n", ret); - kfree(new_p); + kzfree(new_p); goto out; } } rcu_assign_keypointer(key, new_p); call_rcu(&p->rcu, trusted_rcu_free); out: - kfree(datablob); - kfree(new_o); + kzfree(datablob); + kzfree(new_o); return ret; }

@@ -1075,24 +1075,19 @@ static long trusted_read(const struct key *key, char __user *buffer, for (i = 0; i < p->blob_len; i++) bufp = hex_byte_pack(bufp, p->blob[i]); if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) { - kfree(ascii_buf); + kzfree(ascii_buf); return -EFAULT; } - kfree(ascii_buf); + kzfree(ascii_buf); return 2 * p->blob_len; }

/* - * trusted_destroy - before freeing the key, clear the decrypted data + * trusted_destroy - clear and free the key's payload */ static void trusted_destroy(struct key *key) { - struct trusted_key_payload *p = key->payload.data; - - if (!p) - return; - memset(p->key, 0, p->key_len); - kfree(key->payload.data); + kzfree(key->payload.data); }

struct key_type key_type_trusted = {