Re: [ima-evm-utils PATCH 04/12] Update a library function definition to include a "hash_algo" parameter

Stefan Berger
2023-11-22T13:16:16Z

On 11/19/23 11:50, Mimi Zohar wrote:
> Instead of relying on a global "hash_algo" variable, which is not
> concurrency-safe, update the verify_hash2() function definition to
> include a "hash_algo" parameter as a place holder.
>
> Export the verify_hash2() definition.
>
> Define verify_hash2(). To avoid library incompatablity, make the existing

-> incompatibility

> function verify_hash() a function wrapper for verify_hash2().
>
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
> ---
> src/imaevm.h | 1 +
> src/libimaevm.c | 9 +++++----
> 2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/src/imaevm.h b/src/imaevm.h
> index 146123ba5c42..1ed2c81d510d 100644
> --- a/src/imaevm.h
> +++ b/src/imaevm.h
> @@ -248,6 +248,7 @@ uint32_t imaevm_read_keyid(const char *certfile);
>
> int sign_hash(const char *algo, const unsigned char *hash, int size, const char *keyfile, const char *keypass, unsigned char *sig);
> int verify_hash(const char *file, const unsigned char *hash, int size, unsigned char *sig, int siglen);
> +int verify_hash2(void *public_keys, const char *file, const char *hash_algo, const unsigned char *hash, int size, unsigned char *sig, int siglen);
> int ima_verify_signature(const char *file, unsigned char *sig, int siglen, unsigned char *digest, int digestlen);
> int ima_verify_signature2(void *public_keys, const char *file, unsigned char *sig, int siglen, unsigned char *digest, int digestlen);
> void free_public_keys(void *public_keys);
> diff --git a/src/libimaevm.c b/src/libimaevm.c
> index bf8c99770ddc..e64d167a2a8a 100644
> --- a/src/libimaevm.c
> +++ b/src/libimaevm.c
> @@ -732,7 +732,7 @@ int imaevm_hash_algo_from_sig(unsigned char *sig)
> return -1;
> }
>
> -int verify_hash2(void *public_keys, const char *file,
> +int verify_hash2(void *public_keys, const char *file, const char *hash_algo,
> const unsigned char *hash, int size,
> unsigned char *sig, int siglen)
> {
> @@ -770,7 +770,7 @@ int verify_hash2(void *public_keys, const char *file,
> int verify_hash(const char *file, const unsigned char *hash, int size,
> unsigned char *sig, int siglen)
> {
> - return verify_hash2(g_public_keys, file, hash, size, sig, siglen);
> + return verify_hash2(g_public_keys, file, NULL, hash, size, sig, siglen);
> }
>
> int ima_verify_signature2(void *public_keys, const char *file,
> @@ -803,7 +803,7 @@ int ima_verify_signature2(void *public_keys, const char *file,
> * measurement list, not by calculating the local file digest.
> */
> if (digest && digestlen > 0)
> - return verify_hash2(public_keys, file, digest, digestlen,
> + return verify_hash2(public_keys, file, NULL, digest, digestlen,
> sig, siglen);
>
> hashlen = ima_calc_hash(file, hash);
> @@ -811,7 +811,8 @@ int ima_verify_signature2(void *public_keys, const char *file,
> return hashlen;
> assert(hashlen <= sizeof(hash));
>
> - return verify_hash2(public_keys, file, hash, hashlen, sig, siglen);
> + return verify_hash2(public_keys, file, NULL, hash, hashlen,
> + sig, siglen);
> }
>
> /*

At this points verify_hash2 becomes a public function (by adding it to
imaevm.h) and it gets an additional parameter but the parameter is not
used at all...