Kernel uses at most a single HMAC authorization at a time. >From that basis, remove the unused machinery for managing multiple authorizations.
Signed-off-by: Jarkko Sakkinen <[email protected]> --- v8: - Rewrote the commit message. - Added an inline comment explaining why unconditional sha256_update() call for the name is safe. --- drivers/char/tpm/tpm2-sessions.c | 40 ++++++++++++++------------------ 1 file changed, 18 insertions(+), 22 deletions(-) diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 3bc3c31cf512..98cea20040cf 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -72,9 +72,6 @@ #include <crypto/sha2.h> #include <crypto/utils.h> -/* 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) @@ -136,8 +133,8 @@ struct tpm2_auth { * handle, but they are part of the session by name, which * we must compute and remember */ - u8 name[AUTH_MAX_NAMES][TPM2_MAX_NAME_SIZE]; - u16 name_size_tbl[AUTH_MAX_NAMES]; + u8 name[TPM2_MAX_NAME_SIZE]; + u16 name_size; }; #ifdef CONFIG_TCG_TPM2_HMAC @@ -261,11 +258,14 @@ EXPORT_SYMBOL_GPL(tpm2_read_public); int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, u32 handle, u8 *name, u16 name_size) { -#ifdef CONFIG_TCG_TPM2_HMAC struct tpm2_auth *auth; - int slot; int ret; -#endif + + if (tpm_buf_length(buf) != TPM_HEADER_SIZE) { + dev_err(&chip->dev, "too many handles\n"); + ret = -EIO; + goto err; + } if (!tpm2_chip_auth(chip)) { tpm_buf_append_handle(chip, buf, handle); @@ -273,12 +273,6 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, } #ifdef CONFIG_TCG_TPM2_HMAC - slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE) / 4; - if (slot >= AUTH_MAX_NAMES) { - dev_err(&chip->dev, "too many handles\n"); - ret = -EIO; - goto err; - } auth = chip->auth; if (auth->session != tpm_buf_length(buf)) { dev_err(&chip->dev, "session state malformed"); @@ -287,16 +281,14 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, } tpm_buf_append_u32(buf, handle); auth->session += 4; - memcpy(auth->name[slot], name, name_size); - auth->name_size_tbl[slot] = name_size; + memcpy(auth->name, name, name_size); + auth->name_size = name_size; #endif return 0; -#ifdef CONFIG_TCG_TPM2_HMAC err: tpm2_end_auth_session(chip); return ret; -#endif } EXPORT_SYMBOL_GPL(tpm_buf_append_name); @@ -662,14 +654,18 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf) } sha256_init(&sctx); - /* ordinal is already BE */ sha256_update(&sctx, (u8 *)&head->ordinal, sizeof(head->ordinal)); - /* add the handle names */ - for (i = 0; i < handles; i++) - sha256_update(&sctx, auth->name[i], auth->name_size_tbl[i]); + + /* + * If tpm2_buf_append_name() has not been called, this is a no-op, as + * auth->name_size is zero. + */ + sha256_update(&sctx, auth->name, auth->name_size); + if (offset_s != tpm_buf_length(buf)) sha256_update(&sctx, &buf->data[offset_s], tpm_buf_length(buf) - offset_s); + sha256_final(&sctx, cphash); /* now calculate the hmac */ -- 2.39.5
