From: Stefan Berger <stefanb@linux.ibm.com>
To: Mimi Zohar <zohar@linux.ibm.com>, linux-integrity@vger.kernel.org
Subject: Re: [ima-evm-utils PATCH v3 09/13] Use a local hash algorithm variable when verifying file signatures
Date: Tue, 9 Jan 2024 12:21:43 -0500 [thread overview]
Message-ID: <208ceeb6-cdd8-4f43-89e5-439d6c8ec119@linux.ibm.com> (raw)
In-Reply-To: <20240104190558.3674008-10-zohar@linux.ibm.com>
On 1/4/24 14:05, Mimi Zohar wrote:
> Instead of relying on the "imaevm_params.algo" global variable, which
> is not concurrency-safe, define and use a local variable.
>
> Update static verify_hash_v2(), verify_hash_v3(), and verify_hash_common()
> function definitions to include a hash algorithm argument.
>
> Similarly update ima_verify_signature2() and ima_calc_hash2() to define
> and use a local hash algorithm variable.
>
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
> ---
> src/libimaevm.c | 48 ++++++++++++++++++++++++++++--------------------
> 1 file changed, 28 insertions(+), 20 deletions(-)
>
> diff --git a/src/libimaevm.c b/src/libimaevm.c
> index 214c656d6eba..48bce59fba43 100644
> --- a/src/libimaevm.c
> +++ b/src/libimaevm.c
> @@ -485,7 +485,8 @@ void init_public_keys(const char *keyfiles)
> * (Note: signature_v2_hdr struct does not contain the 'type'.)
> */
> static int verify_hash_common(struct public_key_entry *public_keys,
> - const char *file, const unsigned char *hash,
> + const char *file, const char *hash_algo,
> + const unsigned char *hash,
> int size, unsigned char *sig, int siglen)
> {
> int ret = -1;
> @@ -496,7 +497,7 @@ static int verify_hash_common(struct public_key_entry *public_keys,
> const char *st;
>
> if (imaevm_params.verbose > LOG_INFO) {
> - log_info("hash(%s): ", imaevm_params.hash_algo);
> + log_info("hash(%s): ", hash_algo);
> log_dump(hash, size);
> }
>
> @@ -527,7 +528,8 @@ static int verify_hash_common(struct public_key_entry *public_keys,
> if (!EVP_PKEY_verify_init(ctx))
> goto err;
> st = "EVP_get_digestbyname";
> - if (!(md = EVP_get_digestbyname(imaevm_params.hash_algo)))
> + md = EVP_get_digestbyname(hash_algo);
> + if (!md)
> goto err;
> st = "EVP_PKEY_CTX_set_signature_md";
> if (!EVP_PKEY_CTX_set_signature_md(ctx, md))
> @@ -563,11 +565,12 @@ err:
> * Return: 0 verification good, 1 verification bad, -1 error.
> */
> static int verify_hash_v2(struct public_key_entry *public_keys,
> - const char *file, const unsigned char *hash,
> + const char *file, const char *hash_algo,
> + const unsigned char *hash,
> int size, unsigned char *sig, int siglen)
> {
> /* note: signature_v2_hdr does not contain 'type', use sig + 1 */
> - return verify_hash_common(public_keys, file, hash, size,
> + return verify_hash_common(public_keys, file, hash_algo, hash, size,
> sig + 1, siglen - 1);
> }
>
> @@ -578,19 +581,20 @@ static int verify_hash_v2(struct public_key_entry *public_keys,
> * Return: 0 verification good, 1 verification bad, -1 error.
> */
> static int verify_hash_v3(struct public_key_entry *public_keys,
> - const char *file, const unsigned char *hash,
> + const char *file, const char *hash_algo,
> + const unsigned char *hash,
> int size, unsigned char *sig, int siglen)
> {
> unsigned char sigv3_hash[MAX_DIGEST_SIZE];
> int ret;
>
> - ret = calc_hash_sigv3(sig[0], NULL, hash, sigv3_hash);
> + ret = calc_hash_sigv3(sig[0], hash_algo, hash, sigv3_hash);
> if (ret < 0)
> return ret;
>
> /* note: signature_v2_hdr does not contain 'type', use sig + 1 */
> - return verify_hash_common(public_keys, file, sigv3_hash, size,
> - sig + 1, siglen - 1);
> + return verify_hash_common(public_keys, file, hash_algo, sigv3_hash,
> + size, sig + 1, siglen - 1);
> }
>
> #define HASH_MAX_DIGESTSIZE 64 /* kernel HASH_MAX_DIGESTSIZE is 64 bytes */
> @@ -633,8 +637,10 @@ int calc_hash_sigv3(enum evm_ima_xattr_type type, const char *algo,
> return -EINVAL;
> }
>
> - if (!algo)
> - algo = imaevm_params.hash_algo;
> + if (!algo) {
> + log_err("Hash algorithm unspecified\n");
> + return -EINVAL;
> + }
>
> if ((hash_algo = imaevm_get_hash_algo(algo)) < 0) {
> log_err("Hash algorithm %s not supported\n", algo);
> @@ -754,10 +760,10 @@ int imaevm_verify_hash(struct public_key_entry *public_keys, const char *file,
> return -1;
> #endif
> } else if (sig[1] == DIGSIG_VERSION_2) {
> - return verify_hash_v2(public_keys, file, hash, size,
> + return verify_hash_v2(public_keys, file, hash_algo, hash, size,
> sig, siglen);
> } else if (sig[1] == DIGSIG_VERSION_3) {
> - return verify_hash_v3(public_keys, file, hash, size,
> + return verify_hash_v3(public_keys, file, hash_algo, hash, size,
> sig, siglen);
> } else
> return -1;
> @@ -766,8 +772,8 @@ int imaevm_verify_hash(struct public_key_entry *public_keys, const char *file,
> int verify_hash(const char *file, const unsigned char *hash, int size,
> unsigned char *sig, int siglen)
> {
> - return imaevm_verify_hash(g_public_keys, file, NULL, hash, size,
> - sig, siglen);
> + return imaevm_verify_hash(g_public_keys, file, imaevm_params.hash_algo,
> + hash, size, sig, siglen);
> }
>
> int ima_verify_signature2(struct public_key_entry *public_keys, const char *file,
> @@ -776,6 +782,7 @@ int ima_verify_signature2(struct public_key_entry *public_keys, const char *file
> {
> unsigned char hash[MAX_DIGEST_SIZE];
> int hashlen, sig_hash_algo;
> + const char *hash_algo;
>
> if (sig[0] != EVM_IMA_XATTR_DIGSIG && sig[0] != IMA_VERITY_DIGSIG) {
> log_err("%s: xattr ima has no signature\n", file);
> @@ -793,22 +800,23 @@ int ima_verify_signature2(struct public_key_entry *public_keys, const char *file
> return -1;
> }
> /* Use hash algorithm as retrieved from signature */
> - imaevm_params.hash_algo = imaevm_hash_algo_by_id(sig_hash_algo);
> + hash_algo = imaevm_hash_algo_by_id(sig_hash_algo);
>
> /*
> * Validate the signature based on the digest included in the
> * measurement list, not by calculating the local file digest.
> */
> if (digest && digestlen > 0)
> - return imaevm_verify_hash(public_keys, file, NULL, digest,
> - digestlen, sig, siglen);
> + return imaevm_verify_hash(public_keys, file,
> + hash_algo, digest, digestlen,
> + sig, siglen);
>
> - hashlen = ima_calc_hash(file, hash);
> + hashlen = ima_calc_hash2(file, hash_algo, hash);
> if (hashlen <= 1)
> return hashlen;
> assert(hashlen <= sizeof(hash));
>
> - return imaevm_verify_hash(public_keys, file, NULL, hash, hashlen,
> + return imaevm_verify_hash(public_keys, file, hash_algo, hash, hashlen,
> sig, siglen);
> }
>
next prev parent reply other threads:[~2024-01-09 17:48 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-04 19:05 [ima-evm-utils PATCH v3 00/13] Address non concurrency-safe libimaevm global variables Mimi Zohar
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 01/13] Rename "public_keys" to "g_public_keys" Mimi Zohar
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 02/13] Free public keys list Mimi Zohar
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 03/13] Update library function definitions to include a "public_keys" parameter Mimi Zohar
2024-01-09 16:18 ` Stefan Berger
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 04/13] Update imaevm_verify_hash() definition to include "hash_algo" parameter Mimi Zohar
2024-01-09 16:34 ` Stefan Berger
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 05/13] Update cmd_verify_ima() to define and use a local list of public keys Mimi Zohar
2024-01-09 16:37 ` Stefan Berger
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 06/13] Update cmd_verify_evm " Mimi Zohar
2024-01-09 17:00 ` Stefan Berger
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 07/13] Update ima_measurements " Mimi Zohar
2024-01-09 17:07 ` Stefan Berger
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 08/13] Define library ima_calc_hash2() function with a hash algorithm parameter Mimi Zohar
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 09/13] Use a local hash algorithm variable when verifying file signatures Mimi Zohar
2024-01-09 17:21 ` Stefan Berger [this message]
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 10/13] Update EVM signature verification to use a local hash algorithm variable Mimi Zohar
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 11/13] Use a file specific hash algorithm variable for signing files Mimi Zohar
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 12/13] Update sign_hash_v*() definition to include the key password Mimi Zohar
2024-01-04 19:05 ` [ima-evm-utils PATCH v3 13/13] Define and use a file specific "keypass" variable Mimi Zohar
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