| Message ID | 20240528210823.28798-4-jarkko@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | KEYS: asymmetric: tpm2_key_{rsa,ecdsa} | expand |
On 5/28/24 17:08, Jarkko Sakkinen wrote: > TPM2 ASN.1 format is required for trusted keys and asymmetric keys. Move it > to crypto in order to make it available for both. Implement validation with > coverage of all TPMT_PUBLIC shared fields. Key type specific fields must be > covered by the different subsystems using this. > > A Kconfig option CRYPTO_TPM2_KEY can be used to select the feature, which > depends only crypto subsystem itself and ASN.1 parser. > > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> > --- > v6: > * Relocate to crypto. Validate the shared part and provide > accessor functions. Use a fixed buffer size. > v2: > * Do not allocate blob twice. Use the one inside struct tpm2_key. > --- > crypto/Kconfig | 7 ++ > crypto/Makefile | 6 + > crypto/tpm2_key.asn1 | 11 ++ > crypto/tpm2_key.c | 134 ++++++++++++++++++++ > include/crypto/tpm2_key.h | 46 +++++++ > security/keys/trusted-keys/Kconfig | 2 +- > security/keys/trusted-keys/Makefile | 2 - > security/keys/trusted-keys/tpm2key.asn1 | 11 -- > security/keys/trusted-keys/trusted_tpm2.c | 141 +++++----------------- > 9 files changed, 235 insertions(+), 125 deletions(-) > create mode 100644 crypto/tpm2_key.asn1 > create mode 100644 crypto/tpm2_key.c > create mode 100644 include/crypto/tpm2_key.h > delete mode 100644 security/keys/trusted-keys/tpm2key.asn1 > > diff --git a/crypto/Kconfig b/crypto/Kconfig > index 5688d42a59c2..c8989bc71f57 100644 > --- a/crypto/Kconfig > +++ b/crypto/Kconfig > @@ -5,6 +5,13 @@ > config XOR_BLOCKS > tristate > > +config CRYPTO_TPM2_KEY > + bool > + depends on CRYPTO > + select ASN1 > + select OID_REGISTRY > + default n > + > # > # async_tx api: hardware offloaded memory transfer/transform support > # > diff --git a/crypto/Makefile b/crypto/Makefile > index edbbaa3ffef5..d932fdb72319 100644 > --- a/crypto/Makefile > +++ b/crypto/Makefile > @@ -216,3 +216,9 @@ obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o > # Key derivation function > # > obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o > + > +ifdef CONFIG_CRYPTO_TPM2_KEY > +$(obj)/tpm2_key.asn1.o: $(obj)/tpm2_key.asn1.h $(obj)/tpm2_key.asn1.c > +$(obj)/tpm2_key.o: $(obj)/tpm2_key.asn1.h > +obj-y += tpm2_key.o tpm2_key.asn1.o > +endif > diff --git a/crypto/tpm2_key.asn1 b/crypto/tpm2_key.asn1 > new file mode 100644 > index 000000000000..b235d02ab78e > --- /dev/null > +++ b/crypto/tpm2_key.asn1 > @@ -0,0 +1,11 @@ > +--- > +--- ASN.1 for TPM 2.0 keys > +--- > + > +TPMKey ::= SEQUENCE { > + type OBJECT IDENTIFIER ({tpm2_key_get_type}), > + emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, > + parent INTEGER ({tpm2_key_get_parent}), > + pubkey OCTET STRING ({tpm2_get_public}), > + privkey OCTET STRING ({tpm2_get_private}) > + } > diff --git a/crypto/tpm2_key.c b/crypto/tpm2_key.c > new file mode 100644 > index 000000000000..78f55478d046 > --- /dev/null > +++ b/crypto/tpm2_key.c > @@ -0,0 +1,134 @@ > +// SPDX-License-Identifier: GPL-2.0-only > + > +#include <crypto/tpm2_key.h> > +#include <linux/oid_registry.h> > +#include <linux/slab.h> > +#include <linux/types.h> > +#include <asm/unaligned.h> > +#include "tpm2_key.asn1.h" > + > +#undef pr_fmt > +#define pr_fmt(fmt) "tpm2_key: "fmt > + > +struct tpm2_key_decoder_context { > + u32 parent; > + const u8 *pub; > + u32 pub_len; > + const u8 *priv; > + u32 priv_len; > + enum OID oid; > +}; > + > +int tpm2_key_get_parent(void *context, size_t hdrlen, > + unsigned char tag, > + const void *value, size_t vlen) > +{ > + struct tpm2_key_decoder_context *decoder = context; > + const u8 *v = value; > + int i; > + > + decoder->parent = 0; > + for (i = 0; i < vlen; i++) { > + decoder->parent <<= 8; > + decoder->parent |= v[i]; > + } > + > + return 0; > +} > + > +int tpm2_key_get_type(void *context, size_t hdrlen, > + unsigned char tag, > + const void *value, size_t vlen) > +{ > + struct tpm2_key_decoder_context *decoder = context; > + > + decoder->oid = look_up_OID(value, vlen); > + return 0; > +} > + > +static inline bool tpm2_key_is_valid(const void *value, size_t vlen) > +{ > + if (vlen < 2 || vlen > TPM2_KEY_BYTES_MAX) > + return false; > + > + if (get_unaligned_be16(value) != vlen - 2) > + return false; > + > + return true; > +} > + > +int tpm2_get_public(void *context, size_t hdrlen, unsigned char tag, > + const void *value, size_t vlen) > +{ > + struct tpm2_key_decoder_context *decoder = context; > + > + if (!tpm2_key_is_valid(value, vlen)) > + return -EBADMSG; > + > + if (sizeof(struct tpm2_key_desc) > vlen - 2) > + return -EBADMSG; > + > + decoder->pub = value; > + decoder->pub_len = vlen; > + return 0; > +} > + > +int tpm2_get_private(void *context, size_t hdrlen, unsigned char tag, > + const void *value, size_t vlen) > +{ > + struct tpm2_key_decoder_context *decoder = context; > + > + if (!tpm2_key_is_valid(value, vlen)) > + return -EBADMSG; > + > + decoder->priv = value; > + decoder->priv_len = vlen; > + return 0; > +} > + > +/** > + * tpm_key_decode() - Decode TPM2 ASN.1 key > + * @src: ASN.1 source. > + * @src_len: ASN.1 source length. > + * > + * Decodes the TPM2 ASN.1 key and validates that the public key data has all > + * the shared fields of TPMT_PUBLIC. This is full coverage of the memory that > + * can be validated before doing any key type specific validation. I am not sure what the last sentence means. > + * > + * Return: > + * - TPM2 ASN.1 key on success. > + * - -EBADMSG when decoding fails. > + * - -ENOMEM when OOM while allocating struct tpm2_key. > + */ > +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len) > +{ > + struct tpm2_key_decoder_context decoder; > + struct tpm2_key *key; > + u8 *data; > + int ret; > + > + memset(&decoder, 0, sizeof(decoder)); > + ret = asn1_ber_decoder(&tpm2_key_decoder, &decoder, src, src_len); > + if (ret < 0) { > + if (ret != -EBADMSG) > + pr_info("Decoder error %d\n", ret); > + > + return ERR_PTR(-EBADMSG); > + } > + > + key = kzalloc(sizeof(*key), GFP_KERNEL); > + if (!key) > + return ERR_PTR(-ENOMEM); > + > + data = &key->data[0]; > + memcpy(&data[0], decoder.priv, decoder.priv_len); > + memcpy(&data[decoder.priv_len], decoder.pub, decoder.pub_len); > + > + key->oid = decoder.oid; > + key->priv_len = decoder.priv_len; > + key->pub_len = decoder.pub_len; > + key->parent = decoder.parent; > + key->desc = (struct tpm2_key_desc *)&data[decoder.priv_len + 2]; > + return key; > +} > +EXPORT_SYMBOL_GPL(tpm2_key_decode); > diff --git a/include/crypto/tpm2_key.h b/include/crypto/tpm2_key.h > new file mode 100644 > index 000000000000..74debaf707bf > --- /dev/null > +++ b/include/crypto/tpm2_key.h > @@ -0,0 +1,46 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +#ifndef __LINUX_TPM2_KEY_H__ > +#define __LINUX_TPM2_KEY_H__ > + > +#include <linux/oid_registry.h> > +#include <linux/slab.h> > + > +#define TPM2_KEY_BYTES_MAX 1024 > + > +/* TPM2 Structures 12.2.4: TPMT_PUBLIC */ > +struct tpm2_key_desc { > + __be16 type; > + __be16 name_alg; > + __be32 object_attributes; > + __be16 policy_size; > +} __packed; > + > +/* Decoded TPM2 ASN.1 key. */ > +struct tpm2_key { > + u8 data[2 * TPM2_KEY_BYTES_MAX]; > + struct tpm2_key_desc *desc; > + u16 priv_len; > + u16 pub_len; > + u32 parent; > + enum OID oid; > + char oid_str[64]; > +}; > + > +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len); > + > +static inline const void *tpm2_key_data(const struct tpm2_key *key) > +{ > + return &key->data[0]; > +} > + > +static inline u16 tpm2_key_type(const struct tpm2_key *key) > +{ > + return be16_to_cpu(key->desc->type); > +} > + > +static inline int tpm2_key_policy_size(const struct tpm2_key *key) > +{ > + return be16_to_cpu(key->desc->policy_size); > +} > + > +#endif /* __LINUX_TPM2_KEY_H__ */ > diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig > index 1fb8aa001995..00d9489384ac 100644 > --- a/security/keys/trusted-keys/Kconfig > +++ b/security/keys/trusted-keys/Kconfig > @@ -9,9 +9,9 @@ config TRUSTED_KEYS_TPM > select CRYPTO_HMAC > select CRYPTO_SHA1 > select CRYPTO_HASH_INFO > + select CRYPTO_TPM2_KEY > select ASN1_ENCODER > select OID_REGISTRY > - select ASN1 > select HAVE_TRUSTED_KEYS > help > Enable use of the Trusted Platform Module (TPM) as trusted key > diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile > index f0f3b27f688b..2674d5c10fc9 100644 > --- a/security/keys/trusted-keys/Makefile > +++ b/security/keys/trusted-keys/Makefile > @@ -7,9 +7,7 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o > trusted-y += trusted_core.o > trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm1.o > > -$(obj)/trusted_tpm2.o: $(obj)/tpm2key.asn1.h > trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o > -trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o > > trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o > > diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1 > deleted file mode 100644 > index f57f869ad600..000000000000 > --- a/security/keys/trusted-keys/tpm2key.asn1 > +++ /dev/null > @@ -1,11 +0,0 @@ > ---- > ---- ASN.1 for TPM 2.0 keys > ---- > - > -TPMKey ::= SEQUENCE { > - type OBJECT IDENTIFIER ({tpm2_key_type}), > - emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, > - parent INTEGER ({tpm2_key_parent}), > - pubkey OCTET STRING ({tpm2_key_pub}), > - privkey OCTET STRING ({tpm2_key_priv}) > - } > diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c > index 06c8fa7b21ae..b9e505e99e8c 100644 > --- a/security/keys/trusted-keys/trusted_tpm2.c > +++ b/security/keys/trusted-keys/trusted_tpm2.c > @@ -13,11 +13,10 @@ > > #include <keys/trusted-type.h> > #include <keys/trusted_tpm.h> > +#include <crypto/tpm2_key.h> > > #include <asm/unaligned.h> > > -#include "tpm2key.asn1.h" > - > static struct tpm2_hash tpm2_hash_map[] = { > {HASH_ALGO_SHA1, TPM_ALG_SHA1}, > {HASH_ALGO_SHA256, TPM_ALG_SHA256}, > @@ -98,106 +97,6 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, > return ret; > } > > -struct tpm2_key_context { > - u32 parent; > - const u8 *pub; > - u32 pub_len; > - const u8 *priv; > - u32 priv_len; > -}; > - > -static int tpm2_key_decode(struct trusted_key_payload *payload, > - struct trusted_key_options *options, > - u8 **buf) > -{ > - int ret; > - struct tpm2_key_context ctx; > - u8 *blob; > - > - memset(&ctx, 0, sizeof(ctx)); > - > - ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob, > - payload->blob_len); > - if (ret < 0) > - return ret; > - > - if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE) > - return -E2BIG; > - > - blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL); > - if (!blob) > - return -ENOMEM; > - > - *buf = blob; > - options->keyhandle = ctx.parent; > - > - memcpy(blob, ctx.priv, ctx.priv_len); > - blob += ctx.priv_len; > - > - memcpy(blob, ctx.pub, ctx.pub_len); > - > - return 0; > -} > - > -int tpm2_key_parent(void *context, size_t hdrlen, > - unsigned char tag, > - const void *value, size_t vlen) > -{ > - struct tpm2_key_context *ctx = context; > - const u8 *v = value; > - int i; > - > - ctx->parent = 0; > - for (i = 0; i < vlen; i++) { > - ctx->parent <<= 8; > - ctx->parent |= v[i]; > - } > - > - return 0; > -} > - > -int tpm2_key_type(void *context, size_t hdrlen, > - unsigned char tag, > - const void *value, size_t vlen) > -{ > - enum OID oid = look_up_OID(value, vlen); > - > - if (oid != OID_TPMSealedData) { > - char buffer[50]; > - > - sprint_oid(value, vlen, buffer, sizeof(buffer)); > - pr_debug("OID is \"%s\" which is not TPMSealedData\n", > - buffer); > - return -EINVAL; > - } > - > - return 0; > -} > - > -int tpm2_key_pub(void *context, size_t hdrlen, > - unsigned char tag, > - const void *value, size_t vlen) > -{ > - struct tpm2_key_context *ctx = context; > - > - ctx->pub = value; > - ctx->pub_len = vlen; > - > - return 0; > -} > - > -int tpm2_key_priv(void *context, size_t hdrlen, > - unsigned char tag, > - const void *value, size_t vlen) > -{ > - struct tpm2_key_context *ctx = context; > - > - ctx->priv = value; > - ctx->priv_len = vlen; > - > - return 0; > -} > - > /** > * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer. > * > @@ -387,22 +286,43 @@ static int tpm2_load_cmd(struct tpm_chip *chip, > struct trusted_key_options *options, > u32 *blob_handle) > { > - struct tpm_buf buf; > unsigned int private_len; > unsigned int public_len; > unsigned int blob_len; > - u8 *blob, *pub; > - int rc; > + struct tpm2_key *key; > + const u8 *blob, *pub; > + struct tpm_buf buf; > u32 attrs; > + int rc; > > - rc = tpm2_key_decode(payload, options, &blob); > - if (rc) { > - /* old form */ > + key = tpm2_key_decode(payload->blob, payload->blob_len); > + if (IS_ERR(key)) { > + /* Get the error code and reset the pointer to the key: */ > + rc = PTR_ERR(key); > + key = NULL; > + > + if (rc == -ENOMEM) > + return -ENOMEM; > + > + /* A sanity check, as only -EBADMSG or -ENOMEM are expected: */ > + if (rc != -EBADMSG) > + pr_err("tpm2_key_decode(): spurious error code %d\n", rc); tpm2_key_decode seems simple enough that it only returns key, -ENOMEM or EBADMSG. > + > + /* Fallback to the legacy format: */ > blob = payload->blob; > payload->old_format = 1; > + } else { > + blob = tpm2_key_data(key); > + if (key->oid != OID_TPMSealedData) { > + kfree(key); > + return -EBADMSG; > + } > } > > - /* new format carries keyhandle but old format doesn't */ > + /* > + * Must be non-zero here, either extracted from the ASN.1 for the new > + * format or specified on the command line for the old. sentence seems incomplete: ... for the old one. OR ... for the old format. > + */ > if (!options->keyhandle) > return -EINVAL; > > @@ -464,8 +384,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip, > (__be32 *) &buf.data[TPM_HEADER_SIZE]); > > out: > - if (blob != payload->blob) > - kfree(blob); > + kfree(key); > tpm_buf_destroy(&buf); > > if (rc > 0)
On Fri May 31, 2024 at 3:35 AM EEST, Stefan Berger wrote: > > > On 5/28/24 17:08, Jarkko Sakkinen wrote: > > TPM2 ASN.1 format is required for trusted keys and asymmetric keys. Move it > > to crypto in order to make it available for both. Implement validation with > > coverage of all TPMT_PUBLIC shared fields. Key type specific fields must be > > covered by the different subsystems using this. > > > > A Kconfig option CRYPTO_TPM2_KEY can be used to select the feature, which > > depends only crypto subsystem itself and ASN.1 parser. > > > > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> > > --- > > v6: > > * Relocate to crypto. Validate the shared part and provide > > accessor functions. Use a fixed buffer size. > > v2: > > * Do not allocate blob twice. Use the one inside struct tpm2_key. > > --- > > crypto/Kconfig | 7 ++ > > crypto/Makefile | 6 + > > crypto/tpm2_key.asn1 | 11 ++ > > crypto/tpm2_key.c | 134 ++++++++++++++++++++ > > include/crypto/tpm2_key.h | 46 +++++++ > > security/keys/trusted-keys/Kconfig | 2 +- > > security/keys/trusted-keys/Makefile | 2 - > > security/keys/trusted-keys/tpm2key.asn1 | 11 -- > > security/keys/trusted-keys/trusted_tpm2.c | 141 +++++----------------- > > 9 files changed, 235 insertions(+), 125 deletions(-) > > create mode 100644 crypto/tpm2_key.asn1 > > create mode 100644 crypto/tpm2_key.c > > create mode 100644 include/crypto/tpm2_key.h > > delete mode 100644 security/keys/trusted-keys/tpm2key.asn1 > > > > diff --git a/crypto/Kconfig b/crypto/Kconfig > > index 5688d42a59c2..c8989bc71f57 100644 > > --- a/crypto/Kconfig > > +++ b/crypto/Kconfig > > @@ -5,6 +5,13 @@ > > config XOR_BLOCKS > > tristate > > > > +config CRYPTO_TPM2_KEY > > + bool > > + depends on CRYPTO > > + select ASN1 > > + select OID_REGISTRY > > + default n > > + > > # > > # async_tx api: hardware offloaded memory transfer/transform support > > # > > diff --git a/crypto/Makefile b/crypto/Makefile > > index edbbaa3ffef5..d932fdb72319 100644 > > --- a/crypto/Makefile > > +++ b/crypto/Makefile > > @@ -216,3 +216,9 @@ obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o > > # Key derivation function > > # > > obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o > > + > > +ifdef CONFIG_CRYPTO_TPM2_KEY > > +$(obj)/tpm2_key.asn1.o: $(obj)/tpm2_key.asn1.h $(obj)/tpm2_key.asn1.c > > +$(obj)/tpm2_key.o: $(obj)/tpm2_key.asn1.h > > +obj-y += tpm2_key.o tpm2_key.asn1.o > > +endif > > diff --git a/crypto/tpm2_key.asn1 b/crypto/tpm2_key.asn1 > > new file mode 100644 > > index 000000000000..b235d02ab78e > > --- /dev/null > > +++ b/crypto/tpm2_key.asn1 > > @@ -0,0 +1,11 @@ > > +--- > > +--- ASN.1 for TPM 2.0 keys > > +--- > > + > > +TPMKey ::= SEQUENCE { > > + type OBJECT IDENTIFIER ({tpm2_key_get_type}), > > + emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, > > + parent INTEGER ({tpm2_key_get_parent}), > > + pubkey OCTET STRING ({tpm2_get_public}), > > + privkey OCTET STRING ({tpm2_get_private}) > > + } > > diff --git a/crypto/tpm2_key.c b/crypto/tpm2_key.c > > new file mode 100644 > > index 000000000000..78f55478d046 > > --- /dev/null > > +++ b/crypto/tpm2_key.c > > @@ -0,0 +1,134 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > + > > +#include <crypto/tpm2_key.h> > > +#include <linux/oid_registry.h> > > +#include <linux/slab.h> > > +#include <linux/types.h> > > +#include <asm/unaligned.h> > > +#include "tpm2_key.asn1.h" > > + > > +#undef pr_fmt > > +#define pr_fmt(fmt) "tpm2_key: "fmt > > + > > +struct tpm2_key_decoder_context { > > + u32 parent; > > + const u8 *pub; > > + u32 pub_len; > > + const u8 *priv; > > + u32 priv_len; > > + enum OID oid; > > +}; > > + > > +int tpm2_key_get_parent(void *context, size_t hdrlen, > > + unsigned char tag, > > + const void *value, size_t vlen) > > +{ > > + struct tpm2_key_decoder_context *decoder = context; > > + const u8 *v = value; > > + int i; > > + > > + decoder->parent = 0; > > + for (i = 0; i < vlen; i++) { > > + decoder->parent <<= 8; > > + decoder->parent |= v[i]; > > + } > > + > > + return 0; > > +} > > + > > +int tpm2_key_get_type(void *context, size_t hdrlen, > > + unsigned char tag, > > + const void *value, size_t vlen) > > +{ > > + struct tpm2_key_decoder_context *decoder = context; > > + > > + decoder->oid = look_up_OID(value, vlen); > > + return 0; > > +} > > + > > +static inline bool tpm2_key_is_valid(const void *value, size_t vlen) > > +{ > > + if (vlen < 2 || vlen > TPM2_KEY_BYTES_MAX) > > + return false; > > + > > + if (get_unaligned_be16(value) != vlen - 2) > > + return false; > > + > > + return true; > > +} > > + > > +int tpm2_get_public(void *context, size_t hdrlen, unsigned char tag, > > + const void *value, size_t vlen) > > +{ > > + struct tpm2_key_decoder_context *decoder = context; > > + > > + if (!tpm2_key_is_valid(value, vlen)) > > + return -EBADMSG; > > + > > + if (sizeof(struct tpm2_key_desc) > vlen - 2) > > + return -EBADMSG; > > + > > + decoder->pub = value; > > + decoder->pub_len = vlen; > > + return 0; > > +} > > + > > +int tpm2_get_private(void *context, size_t hdrlen, unsigned char tag, > > + const void *value, size_t vlen) > > +{ > > + struct tpm2_key_decoder_context *decoder = context; > > + > > + if (!tpm2_key_is_valid(value, vlen)) > > + return -EBADMSG; > > + > > + decoder->priv = value; > > + decoder->priv_len = vlen; > > + return 0; > > +} > > + > > +/** > > + * tpm_key_decode() - Decode TPM2 ASN.1 key > > + * @src: ASN.1 source. > > + * @src_len: ASN.1 source length. > > + * > > + * Decodes the TPM2 ASN.1 key and validates that the public key data has all > > + * the shared fields of TPMT_PUBLIC. This is full coverage of the memory that > > + * can be validated before doing any key type specific validation. > > I am not sure what the last sentence means. I think the whole paragraph should be rewritten. So what it does is that it takes the private and public parts and concanates them together so maybe just write: "Load TPMT_PUBLIC and TPMT_PRIVATE from ASN.1 file, and concatenate the blobs together as a single blob, as this is expected format for the TPM2 commands. In addition, validate TPMT_PUBLIC fields so that they make sense for trusted and asymmetric keys." What you think of this? > > > + * > > + * Return: > > + * - TPM2 ASN.1 key on success. > > + * - -EBADMSG when decoding fails. > > + * - -ENOMEM when OOM while allocating struct tpm2_key. > > + */ > > +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len) > > +{ > > + struct tpm2_key_decoder_context decoder; > > + struct tpm2_key *key; > > + u8 *data; > > + int ret; > > + > > + memset(&decoder, 0, sizeof(decoder)); > > + ret = asn1_ber_decoder(&tpm2_key_decoder, &decoder, src, src_len); > > + if (ret < 0) { > > + if (ret != -EBADMSG) > > + pr_info("Decoder error %d\n", ret); > > + > > + return ERR_PTR(-EBADMSG); > > + } > > + > > + key = kzalloc(sizeof(*key), GFP_KERNEL); > > + if (!key) > > + return ERR_PTR(-ENOMEM); > > + > > + data = &key->data[0]; > > + memcpy(&data[0], decoder.priv, decoder.priv_len); > > + memcpy(&data[decoder.priv_len], decoder.pub, decoder.pub_len); > > + > > + key->oid = decoder.oid; > > + key->priv_len = decoder.priv_len; > > + key->pub_len = decoder.pub_len; > > + key->parent = decoder.parent; > > + key->desc = (struct tpm2_key_desc *)&data[decoder.priv_len + 2]; > > + return key; > > +} > > +EXPORT_SYMBOL_GPL(tpm2_key_decode); > > diff --git a/include/crypto/tpm2_key.h b/include/crypto/tpm2_key.h > > new file mode 100644 > > index 000000000000..74debaf707bf > > --- /dev/null > > +++ b/include/crypto/tpm2_key.h > > @@ -0,0 +1,46 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > +#ifndef __LINUX_TPM2_KEY_H__ > > +#define __LINUX_TPM2_KEY_H__ > > + > > +#include <linux/oid_registry.h> > > +#include <linux/slab.h> > > + > > +#define TPM2_KEY_BYTES_MAX 1024 > > + > > +/* TPM2 Structures 12.2.4: TPMT_PUBLIC */ > > +struct tpm2_key_desc { > > + __be16 type; > > + __be16 name_alg; > > + __be32 object_attributes; > > + __be16 policy_size; > > +} __packed; > > + > > +/* Decoded TPM2 ASN.1 key. */ > > +struct tpm2_key { > > + u8 data[2 * TPM2_KEY_BYTES_MAX]; > > + struct tpm2_key_desc *desc; > > + u16 priv_len; > > + u16 pub_len; > > + u32 parent; > > + enum OID oid; > > + char oid_str[64]; > > +}; > > + > > +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len); > > + > > +static inline const void *tpm2_key_data(const struct tpm2_key *key) > > +{ > > + return &key->data[0]; > > +} > > + > > +static inline u16 tpm2_key_type(const struct tpm2_key *key) > > +{ > > + return be16_to_cpu(key->desc->type); > > +} > > + > > +static inline int tpm2_key_policy_size(const struct tpm2_key *key) > > +{ > > + return be16_to_cpu(key->desc->policy_size); > > +} > > + > > +#endif /* __LINUX_TPM2_KEY_H__ */ > > diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig > > index 1fb8aa001995..00d9489384ac 100644 > > --- a/security/keys/trusted-keys/Kconfig > > +++ b/security/keys/trusted-keys/Kconfig > > @@ -9,9 +9,9 @@ config TRUSTED_KEYS_TPM > > select CRYPTO_HMAC > > select CRYPTO_SHA1 > > select CRYPTO_HASH_INFO > > + select CRYPTO_TPM2_KEY > > select ASN1_ENCODER > > select OID_REGISTRY > > - select ASN1 > > select HAVE_TRUSTED_KEYS > > help > > Enable use of the Trusted Platform Module (TPM) as trusted key > > diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile > > index f0f3b27f688b..2674d5c10fc9 100644 > > --- a/security/keys/trusted-keys/Makefile > > +++ b/security/keys/trusted-keys/Makefile > > @@ -7,9 +7,7 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o > > trusted-y += trusted_core.o > > trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm1.o > > > > -$(obj)/trusted_tpm2.o: $(obj)/tpm2key.asn1.h > > trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o > > -trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o > > > > trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o > > > > diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1 > > deleted file mode 100644 > > index f57f869ad600..000000000000 > > --- a/security/keys/trusted-keys/tpm2key.asn1 > > +++ /dev/null > > @@ -1,11 +0,0 @@ > > ---- > > ---- ASN.1 for TPM 2.0 keys > > ---- > > - > > -TPMKey ::= SEQUENCE { > > - type OBJECT IDENTIFIER ({tpm2_key_type}), > > - emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, > > - parent INTEGER ({tpm2_key_parent}), > > - pubkey OCTET STRING ({tpm2_key_pub}), > > - privkey OCTET STRING ({tpm2_key_priv}) > > - } > > diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c > > index 06c8fa7b21ae..b9e505e99e8c 100644 > > --- a/security/keys/trusted-keys/trusted_tpm2.c > > +++ b/security/keys/trusted-keys/trusted_tpm2.c > > @@ -13,11 +13,10 @@ > > > > #include <keys/trusted-type.h> > > #include <keys/trusted_tpm.h> > > +#include <crypto/tpm2_key.h> > > > > #include <asm/unaligned.h> > > > > -#include "tpm2key.asn1.h" > > - > > static struct tpm2_hash tpm2_hash_map[] = { > > {HASH_ALGO_SHA1, TPM_ALG_SHA1}, > > {HASH_ALGO_SHA256, TPM_ALG_SHA256}, > > @@ -98,106 +97,6 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, > > return ret; > > } > > > > -struct tpm2_key_context { > > - u32 parent; > > - const u8 *pub; > > - u32 pub_len; > > - const u8 *priv; > > - u32 priv_len; > > -}; > > - > > -static int tpm2_key_decode(struct trusted_key_payload *payload, > > - struct trusted_key_options *options, > > - u8 **buf) > > -{ > > - int ret; > > - struct tpm2_key_context ctx; > > - u8 *blob; > > - > > - memset(&ctx, 0, sizeof(ctx)); > > - > > - ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob, > > - payload->blob_len); > > - if (ret < 0) > > - return ret; > > - > > - if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE) > > - return -E2BIG; > > - > > - blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL); > > - if (!blob) > > - return -ENOMEM; > > - > > - *buf = blob; > > - options->keyhandle = ctx.parent; > > - > > - memcpy(blob, ctx.priv, ctx.priv_len); > > - blob += ctx.priv_len; > > - > > - memcpy(blob, ctx.pub, ctx.pub_len); > > - > > - return 0; > > -} > > - > > -int tpm2_key_parent(void *context, size_t hdrlen, > > - unsigned char tag, > > - const void *value, size_t vlen) > > -{ > > - struct tpm2_key_context *ctx = context; > > - const u8 *v = value; > > - int i; > > - > > - ctx->parent = 0; > > - for (i = 0; i < vlen; i++) { > > - ctx->parent <<= 8; > > - ctx->parent |= v[i]; > > - } > > - > > - return 0; > > -} > > - > > -int tpm2_key_type(void *context, size_t hdrlen, > > - unsigned char tag, > > - const void *value, size_t vlen) > > -{ > > - enum OID oid = look_up_OID(value, vlen); > > - > > - if (oid != OID_TPMSealedData) { > > - char buffer[50]; > > - > > - sprint_oid(value, vlen, buffer, sizeof(buffer)); > > - pr_debug("OID is \"%s\" which is not TPMSealedData\n", > > - buffer); > > - return -EINVAL; > > - } > > - > > - return 0; > > -} > > - > > -int tpm2_key_pub(void *context, size_t hdrlen, > > - unsigned char tag, > > - const void *value, size_t vlen) > > -{ > > - struct tpm2_key_context *ctx = context; > > - > > - ctx->pub = value; > > - ctx->pub_len = vlen; > > - > > - return 0; > > -} > > - > > -int tpm2_key_priv(void *context, size_t hdrlen, > > - unsigned char tag, > > - const void *value, size_t vlen) > > -{ > > - struct tpm2_key_context *ctx = context; > > - > > - ctx->priv = value; > > - ctx->priv_len = vlen; > > - > > - return 0; > > -} > > - > > /** > > * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer. > > * > > @@ -387,22 +286,43 @@ static int tpm2_load_cmd(struct tpm_chip *chip, > > struct trusted_key_options *options, > > u32 *blob_handle) > > { > > - struct tpm_buf buf; > > unsigned int private_len; > > unsigned int public_len; > > unsigned int blob_len; > > - u8 *blob, *pub; > > - int rc; > > + struct tpm2_key *key; > > + const u8 *blob, *pub; > > + struct tpm_buf buf; > > u32 attrs; > > + int rc; > > > > - rc = tpm2_key_decode(payload, options, &blob); > > - if (rc) { > > - /* old form */ > > + key = tpm2_key_decode(payload->blob, payload->blob_len); > > + if (IS_ERR(key)) { > > + /* Get the error code and reset the pointer to the key: */ > > + rc = PTR_ERR(key); > > + key = NULL; > > + > > + if (rc == -ENOMEM) > > + return -ENOMEM; > > + > > + /* A sanity check, as only -EBADMSG or -ENOMEM are expected: */ > > + if (rc != -EBADMSG) > > + pr_err("tpm2_key_decode(): spurious error code %d\n", rc); > > tpm2_key_decode seems simple enough that it only returns key, -ENOMEM or > EBADMSG. So what is your suggestion here? The reasoning here is that asymmetric keys use -EBADMSG not only as error but also iterator, when probing which can load a specific key. > > > + > > + /* Fallback to the legacy format: */ > > blob = payload->blob; > > payload->old_format = 1; > > + } else { > > + blob = tpm2_key_data(key); > > + if (key->oid != OID_TPMSealedData) { > > + kfree(key); > > + return -EBADMSG; > > + } > > } > > > > - /* new format carries keyhandle but old format doesn't */ > > + /* > > + * Must be non-zero here, either extracted from the ASN.1 for the new > > + * format or specified on the command line for the old. > > sentence seems incomplete: ... for the old one. OR ... for the old format. Yep, I think it is a plain mistake. > > > + */ > > if (!options->keyhandle) > > return -EINVAL; > > > > @@ -464,8 +384,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip, > > (__be32 *) &buf.data[TPM_HEADER_SIZE]); > > > > out: > > - if (blob != payload->blob) > > - kfree(blob); > > + kfree(key); > > tpm_buf_destroy(&buf); > > > > if (rc > 0) Thanks for the feedback. BR, Jarkko
On 6/4/24 13:23, Jarkko Sakkinen wrote: > On Fri May 31, 2024 at 3:35 AM EEST, Stefan Berger wrote: >> >>> >>> - rc = tpm2_key_decode(payload, options, &blob); >>> - if (rc) { >>> - /* old form */ >>> + key = tpm2_key_decode(payload->blob, payload->blob_len); >>> + if (IS_ERR(key)) { >>> + /* Get the error code and reset the pointer to the key: */ >>> + rc = PTR_ERR(key); >>> + key = NULL; >>> + >>> + if (rc == -ENOMEM) >>> + return -ENOMEM; >>> + >>> + /* A sanity check, as only -EBADMSG or -ENOMEM are expected: */ >>> + if (rc != -EBADMSG) >>> + pr_err("tpm2_key_decode(): spurious error code %d\n", rc); >> >> tpm2_key_decode seems simple enough that it only returns key, -ENOMEM or >> EBADMSG. > > So what is your suggestion here? You can remove the check resuling in pr_err(). > > The reasoning here is that asymmetric keys use -EBADMSG not only as > error but also iterator, when probing which can load a specific key. >
On Tue Jun 4, 2024 at 9:41 PM EEST, Stefan Berger wrote: > > > On 6/4/24 13:23, Jarkko Sakkinen wrote: > > On Fri May 31, 2024 at 3:35 AM EEST, Stefan Berger wrote: > >> > > >>> > >>> - rc = tpm2_key_decode(payload, options, &blob); > >>> - if (rc) { > >>> - /* old form */ > >>> + key = tpm2_key_decode(payload->blob, payload->blob_len); > >>> + if (IS_ERR(key)) { > >>> + /* Get the error code and reset the pointer to the key: */ > >>> + rc = PTR_ERR(key); > >>> + key = NULL; > >>> + > >>> + if (rc == -ENOMEM) > >>> + return -ENOMEM; > >>> + > >>> + /* A sanity check, as only -EBADMSG or -ENOMEM are expected: */ > >>> + if (rc != -EBADMSG) > >>> + pr_err("tpm2_key_decode(): spurious error code %d\n", rc); > >> > >> tpm2_key_decode seems simple enough that it only returns key, -ENOMEM or > >> EBADMSG. > > > > So what is your suggestion here? > > You can remove the check resuling in pr_err(). OK, I think so too. Just had to (sanity) check. > > > > > The reasoning here is that asymmetric keys use -EBADMSG not only as > > error but also iterator, when probing which can load a specific key. > > BR, Jarkko
diff --git a/crypto/Kconfig b/crypto/Kconfig index 5688d42a59c2..c8989bc71f57 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -5,6 +5,13 @@ config XOR_BLOCKS tristate +config CRYPTO_TPM2_KEY + bool + depends on CRYPTO + select ASN1 + select OID_REGISTRY + default n + # # async_tx api: hardware offloaded memory transfer/transform support # diff --git a/crypto/Makefile b/crypto/Makefile index edbbaa3ffef5..d932fdb72319 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -216,3 +216,9 @@ obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o # Key derivation function # obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o + +ifdef CONFIG_CRYPTO_TPM2_KEY +$(obj)/tpm2_key.asn1.o: $(obj)/tpm2_key.asn1.h $(obj)/tpm2_key.asn1.c +$(obj)/tpm2_key.o: $(obj)/tpm2_key.asn1.h +obj-y += tpm2_key.o tpm2_key.asn1.o +endif diff --git a/crypto/tpm2_key.asn1 b/crypto/tpm2_key.asn1 new file mode 100644 index 000000000000..b235d02ab78e --- /dev/null +++ b/crypto/tpm2_key.asn1 @@ -0,0 +1,11 @@ +--- +--- ASN.1 for TPM 2.0 keys +--- + +TPMKey ::= SEQUENCE { + type OBJECT IDENTIFIER ({tpm2_key_get_type}), + emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, + parent INTEGER ({tpm2_key_get_parent}), + pubkey OCTET STRING ({tpm2_get_public}), + privkey OCTET STRING ({tpm2_get_private}) + } diff --git a/crypto/tpm2_key.c b/crypto/tpm2_key.c new file mode 100644 index 000000000000..78f55478d046 --- /dev/null +++ b/crypto/tpm2_key.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <crypto/tpm2_key.h> +#include <linux/oid_registry.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <asm/unaligned.h> +#include "tpm2_key.asn1.h" + +#undef pr_fmt +#define pr_fmt(fmt) "tpm2_key: "fmt + +struct tpm2_key_decoder_context { + u32 parent; + const u8 *pub; + u32 pub_len; + const u8 *priv; + u32 priv_len; + enum OID oid; +}; + +int tpm2_key_get_parent(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + const u8 *v = value; + int i; + + decoder->parent = 0; + for (i = 0; i < vlen; i++) { + decoder->parent <<= 8; + decoder->parent |= v[i]; + } + + return 0; +} + +int tpm2_key_get_type(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + + decoder->oid = look_up_OID(value, vlen); + return 0; +} + +static inline bool tpm2_key_is_valid(const void *value, size_t vlen) +{ + if (vlen < 2 || vlen > TPM2_KEY_BYTES_MAX) + return false; + + if (get_unaligned_be16(value) != vlen - 2) + return false; + + return true; +} + +int tpm2_get_public(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + + if (!tpm2_key_is_valid(value, vlen)) + return -EBADMSG; + + if (sizeof(struct tpm2_key_desc) > vlen - 2) + return -EBADMSG; + + decoder->pub = value; + decoder->pub_len = vlen; + return 0; +} + +int tpm2_get_private(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + + if (!tpm2_key_is_valid(value, vlen)) + return -EBADMSG; + + decoder->priv = value; + decoder->priv_len = vlen; + return 0; +} + +/** + * tpm_key_decode() - Decode TPM2 ASN.1 key + * @src: ASN.1 source. + * @src_len: ASN.1 source length. + * + * Decodes the TPM2 ASN.1 key and validates that the public key data has all + * the shared fields of TPMT_PUBLIC. This is full coverage of the memory that + * can be validated before doing any key type specific validation. + * + * Return: + * - TPM2 ASN.1 key on success. + * - -EBADMSG when decoding fails. + * - -ENOMEM when OOM while allocating struct tpm2_key. + */ +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len) +{ + struct tpm2_key_decoder_context decoder; + struct tpm2_key *key; + u8 *data; + int ret; + + memset(&decoder, 0, sizeof(decoder)); + ret = asn1_ber_decoder(&tpm2_key_decoder, &decoder, src, src_len); + if (ret < 0) { + if (ret != -EBADMSG) + pr_info("Decoder error %d\n", ret); + + return ERR_PTR(-EBADMSG); + } + + key = kzalloc(sizeof(*key), GFP_KERNEL); + if (!key) + return ERR_PTR(-ENOMEM); + + data = &key->data[0]; + memcpy(&data[0], decoder.priv, decoder.priv_len); + memcpy(&data[decoder.priv_len], decoder.pub, decoder.pub_len); + + key->oid = decoder.oid; + key->priv_len = decoder.priv_len; + key->pub_len = decoder.pub_len; + key->parent = decoder.parent; + key->desc = (struct tpm2_key_desc *)&data[decoder.priv_len + 2]; + return key; +} +EXPORT_SYMBOL_GPL(tpm2_key_decode); diff --git a/include/crypto/tpm2_key.h b/include/crypto/tpm2_key.h new file mode 100644 index 000000000000..74debaf707bf --- /dev/null +++ b/include/crypto/tpm2_key.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __LINUX_TPM2_KEY_H__ +#define __LINUX_TPM2_KEY_H__ + +#include <linux/oid_registry.h> +#include <linux/slab.h> + +#define TPM2_KEY_BYTES_MAX 1024 + +/* TPM2 Structures 12.2.4: TPMT_PUBLIC */ +struct tpm2_key_desc { + __be16 type; + __be16 name_alg; + __be32 object_attributes; + __be16 policy_size; +} __packed; + +/* Decoded TPM2 ASN.1 key. */ +struct tpm2_key { + u8 data[2 * TPM2_KEY_BYTES_MAX]; + struct tpm2_key_desc *desc; + u16 priv_len; + u16 pub_len; + u32 parent; + enum OID oid; + char oid_str[64]; +}; + +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len); + +static inline const void *tpm2_key_data(const struct tpm2_key *key) +{ + return &key->data[0]; +} + +static inline u16 tpm2_key_type(const struct tpm2_key *key) +{ + return be16_to_cpu(key->desc->type); +} + +static inline int tpm2_key_policy_size(const struct tpm2_key *key) +{ + return be16_to_cpu(key->desc->policy_size); +} + +#endif /* __LINUX_TPM2_KEY_H__ */ diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig index 1fb8aa001995..00d9489384ac 100644 --- a/security/keys/trusted-keys/Kconfig +++ b/security/keys/trusted-keys/Kconfig @@ -9,9 +9,9 @@ config TRUSTED_KEYS_TPM select CRYPTO_HMAC select CRYPTO_SHA1 select CRYPTO_HASH_INFO + select CRYPTO_TPM2_KEY select ASN1_ENCODER select OID_REGISTRY - select ASN1 select HAVE_TRUSTED_KEYS help Enable use of the Trusted Platform Module (TPM) as trusted key diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index f0f3b27f688b..2674d5c10fc9 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -7,9 +7,7 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o trusted-y += trusted_core.o trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm1.o -$(obj)/trusted_tpm2.o: $(obj)/tpm2key.asn1.h trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o -trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1 deleted file mode 100644 index f57f869ad600..000000000000 --- a/security/keys/trusted-keys/tpm2key.asn1 +++ /dev/null @@ -1,11 +0,0 @@ ---- ---- ASN.1 for TPM 2.0 keys ---- - -TPMKey ::= SEQUENCE { - type OBJECT IDENTIFIER ({tpm2_key_type}), - emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, - parent INTEGER ({tpm2_key_parent}), - pubkey OCTET STRING ({tpm2_key_pub}), - privkey OCTET STRING ({tpm2_key_priv}) - } diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 06c8fa7b21ae..b9e505e99e8c 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -13,11 +13,10 @@ #include <keys/trusted-type.h> #include <keys/trusted_tpm.h> +#include <crypto/tpm2_key.h> #include <asm/unaligned.h> -#include "tpm2key.asn1.h" - static struct tpm2_hash tpm2_hash_map[] = { {HASH_ALGO_SHA1, TPM_ALG_SHA1}, {HASH_ALGO_SHA256, TPM_ALG_SHA256}, @@ -98,106 +97,6 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, return ret; } -struct tpm2_key_context { - u32 parent; - const u8 *pub; - u32 pub_len; - const u8 *priv; - u32 priv_len; -}; - -static int tpm2_key_decode(struct trusted_key_payload *payload, - struct trusted_key_options *options, - u8 **buf) -{ - int ret; - struct tpm2_key_context ctx; - u8 *blob; - - memset(&ctx, 0, sizeof(ctx)); - - ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob, - payload->blob_len); - if (ret < 0) - return ret; - - if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE) - return -E2BIG; - - blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL); - if (!blob) - return -ENOMEM; - - *buf = blob; - options->keyhandle = ctx.parent; - - memcpy(blob, ctx.priv, ctx.priv_len); - blob += ctx.priv_len; - - memcpy(blob, ctx.pub, ctx.pub_len); - - return 0; -} - -int tpm2_key_parent(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - struct tpm2_key_context *ctx = context; - const u8 *v = value; - int i; - - ctx->parent = 0; - for (i = 0; i < vlen; i++) { - ctx->parent <<= 8; - ctx->parent |= v[i]; - } - - return 0; -} - -int tpm2_key_type(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - enum OID oid = look_up_OID(value, vlen); - - if (oid != OID_TPMSealedData) { - char buffer[50]; - - sprint_oid(value, vlen, buffer, sizeof(buffer)); - pr_debug("OID is \"%s\" which is not TPMSealedData\n", - buffer); - return -EINVAL; - } - - return 0; -} - -int tpm2_key_pub(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - struct tpm2_key_context *ctx = context; - - ctx->pub = value; - ctx->pub_len = vlen; - - return 0; -} - -int tpm2_key_priv(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - struct tpm2_key_context *ctx = context; - - ctx->priv = value; - ctx->priv_len = vlen; - - return 0; -} - /** * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer. * @@ -387,22 +286,43 @@ static int tpm2_load_cmd(struct tpm_chip *chip, struct trusted_key_options *options, u32 *blob_handle) { - struct tpm_buf buf; unsigned int private_len; unsigned int public_len; unsigned int blob_len; - u8 *blob, *pub; - int rc; + struct tpm2_key *key; + const u8 *blob, *pub; + struct tpm_buf buf; u32 attrs; + int rc; - rc = tpm2_key_decode(payload, options, &blob); - if (rc) { - /* old form */ + key = tpm2_key_decode(payload->blob, payload->blob_len); + if (IS_ERR(key)) { + /* Get the error code and reset the pointer to the key: */ + rc = PTR_ERR(key); + key = NULL; + + if (rc == -ENOMEM) + return -ENOMEM; + + /* A sanity check, as only -EBADMSG or -ENOMEM are expected: */ + if (rc != -EBADMSG) + pr_err("tpm2_key_decode(): spurious error code %d\n", rc); + + /* Fallback to the legacy format: */ blob = payload->blob; payload->old_format = 1; + } else { + blob = tpm2_key_data(key); + if (key->oid != OID_TPMSealedData) { + kfree(key); + return -EBADMSG; + } } - /* new format carries keyhandle but old format doesn't */ + /* + * Must be non-zero here, either extracted from the ASN.1 for the new + * format or specified on the command line for the old. + */ if (!options->keyhandle) return -EINVAL; @@ -464,8 +384,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip, (__be32 *) &buf.data[TPM_HEADER_SIZE]); out: - if (blob != payload->blob) - kfree(blob); + kfree(key); tpm_buf_destroy(&buf); if (rc > 0)
TPM2 ASN.1 format is required for trusted keys and asymmetric keys. Move it to crypto in order to make it available for both. Implement validation with coverage of all TPMT_PUBLIC shared fields. Key type specific fields must be covered by the different subsystems using this. A Kconfig option CRYPTO_TPM2_KEY can be used to select the feature, which depends only crypto subsystem itself and ASN.1 parser. Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> --- v6: * Relocate to crypto. Validate the shared part and provide accessor functions. Use a fixed buffer size. v2: * Do not allocate blob twice. Use the one inside struct tpm2_key. --- crypto/Kconfig | 7 ++ crypto/Makefile | 6 + crypto/tpm2_key.asn1 | 11 ++ crypto/tpm2_key.c | 134 ++++++++++++++++++++ include/crypto/tpm2_key.h | 46 +++++++ security/keys/trusted-keys/Kconfig | 2 +- security/keys/trusted-keys/Makefile | 2 - security/keys/trusted-keys/tpm2key.asn1 | 11 -- security/keys/trusted-keys/trusted_tpm2.c | 141 +++++----------------- 9 files changed, 235 insertions(+), 125 deletions(-) create mode 100644 crypto/tpm2_key.asn1 create mode 100644 crypto/tpm2_key.c create mode 100644 include/crypto/tpm2_key.h delete mode 100644 security/keys/trusted-keys/tpm2key.asn1