diff options
| author | Eric Biggers <ebiggers@kernel.org> | 2025-08-09 10:19:39 -0700 |
|---|---|---|
| committer | Jarkko Sakkinen <jarkko@kernel.org> | 2025-09-27 21:05:06 +0300 |
| commit | eed0e3d305530066b4fc5370107cff8ef1a0d229 (patch) | |
| tree | a0c27772822b9234c1d01b986134d9d8ae595376 | |
| parent | fec734e8d564d55fb6bd4909ae2e68814d21d0a1 (diff) | |
KEYS: trusted_tpm1: Compare HMAC values in constant time
To prevent timing attacks, HMAC value comparison needs to be constant
time. Replace the memcmp() with the correct function, crypto_memneq().
[For the Fixes commit I used the commit that introduced the memcmp().
It predates the introduction of crypto_memneq(), but it was still a bug
at the time even though a helper function didn't exist yet.]
Fixes: d00a1c72f7f4 ("keys: add new trusted key-type")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
| -rw-r--r-- | security/keys/trusted-keys/trusted_tpm1.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index 89c9798d1800..e73f2c6c817a 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -7,6 +7,7 @@ */ #include <crypto/hash_info.h> +#include <crypto/utils.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/parser.h> @@ -241,7 +242,7 @@ int TSS_checkhmac1(unsigned char *buffer, if (ret < 0) goto out; - if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE)) + if (crypto_memneq(testhmac, authdata, SHA1_DIGEST_SIZE)) ret = -EINVAL; out: kfree_sensitive(sdesc); @@ -334,7 +335,7 @@ static int TSS_checkhmac2(unsigned char *buffer, TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0); if (ret < 0) goto out; - if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { + if (crypto_memneq(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { ret = -EINVAL; goto out; } @@ -343,7 +344,7 @@ static int TSS_checkhmac2(unsigned char *buffer, TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0); if (ret < 0) goto out; - if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE)) + if (crypto_memneq(testhmac2, authdata2, SHA1_DIGEST_SIZE)) ret = -EINVAL; out: kfree_sensitive(sdesc); |