All exported functions lack the check for non-nullity of chip->auth. Add the guard for each. Link: https://lore.kernel.org/linux-integrity/9f86a167074d9b522311715c567f1c19b88e3ad4.camel@xxxxxxxxxx/ Cc: Stefan Berger <stefanb@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Fixes: 1085b8276bb4 ("tpm: Add the rest of the session HMAC API") Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> --- drivers/char/tpm/tpm2-sessions.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 907ac9956a78..d833db20531a 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -377,6 +377,9 @@ void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf, u32 len; struct tpm2_auth *auth = chip->auth; + if (!auth) + return; + /* * The Architecture Guide requires us to strip trailing zeros * before computing the HMAC @@ -449,6 +452,9 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf) u8 cphash[SHA256_DIGEST_SIZE]; struct sha256_state sctx; + if (!auth) + return; + /* save the command code in BE format */ auth->ordinal = head->ordinal; @@ -639,6 +645,9 @@ void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf, struct tpm2_auth *auth = chip->auth; int slot; + if (!auth) + return; + slot = (tpm_buf_length(buf) - TPM_HEADER_SIZE)/4; if (slot >= AUTH_MAX_NAMES) { dev_err(&chip->dev, "TPM: too many handles\n"); @@ -705,6 +714,9 @@ int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf, u32 cc = be32_to_cpu(auth->ordinal); int parm_len, len, i, handles; + if (!auth) + return rc; + if (auth->session >= TPM_HEADER_SIZE) { WARN(1, "tpm session not filled correctly\n"); goto out; @@ -824,8 +836,13 @@ EXPORT_SYMBOL(tpm_buf_check_hmac_response); */ void tpm2_end_auth_session(struct tpm_chip *chip) { - tpm2_flush_context(chip, chip->auth->handle); - memzero_explicit(chip->auth, sizeof(*chip->auth)); + struct tpm2_auth *auth = chip->auth; + + if (!auth) + return; + + tpm2_flush_context(chip, auth->handle); + memzero_explicit(auth, sizeof(*auth)); } EXPORT_SYMBOL(tpm2_end_auth_session); @@ -907,6 +924,11 @@ int tpm2_start_auth_session(struct tpm_chip *chip) int rc; u32 null_key; + if (!auth) { + pr_warn_once("%s: encryption is not active\n", __func__); + return 0; + } + rc = tpm2_load_null(chip, &null_key); if (rc) goto out; -- 2.45.2
