[PATCH 05/13] efi_loader: signature: make efi_hash_regions more generic

[Heinrich Schuchardt]

On 5/29/20 8:41 AM, AKASHI Takahiro wrote:
> There are a couple of occurrences of hash calculations in which a new
> efi_hash_regions will be commonly used.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
>  lib/efi_loader/efi_signature.c | 44 +++++++++++++---------------------
>  1 file changed, 16 insertions(+), 28 deletions(-)
>
> diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c
> index 35f678de057e..00e442783059 100644
> --- a/lib/efi_loader/efi_signature.c
> +++ b/lib/efi_loader/efi_signature.c
> @@ -30,6 +30,7 @@ const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
>  /**
>   * efi_hash_regions - calculate a hash value
>   * @regs:	List of regions
> + * @count:	Number of regions
>   * @hash:	Pointer to a pointer to buffer holding a hash value
>   * @size:	Size of buffer to be returned
>   *
> @@ -37,18 +38,20 @@ const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
>   *
>   * Return:	true on success, false on error
>   */
> -static bool efi_hash_regions(struct efi_image_regions *regs, void **hash,
> -			     size_t *size)
> +static bool efi_hash_regions(struct image_region *regs, int count,
> +			     void **hash, size_t *size)

What is this size parameter good for if we know all signatures are
SHA256? Should it be eliminiated?

Otherwise
Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

>  {
> -	*size = 0;
> -	*hash = calloc(1, SHA256_SUM_LEN);
>  	if (!*hash) {
> -		debug("Out of memory\n");
> -		return false;
> +		*hash = calloc(1, SHA256_SUM_LEN);
> +		if (!*hash) {
> +			debug("Out of memory\n");
> +			return false;
> +		}
>  	}
> -	*size = SHA256_SUM_LEN;
> +	if (size)
> +		*size = SHA256_SUM_LEN;
>
> -	hash_calculate("sha256", regs->reg, regs->num, *hash);
> +	hash_calculate("sha256", regs, count, *hash);
>  #ifdef DEBUG
>  	debug("hash calculated:\n");
>  	print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1,
> @@ -73,26 +76,10 @@ static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash,
>  {
>  	struct image_region regtmp;
>
> -	*size = 0;
> -	*hash = calloc(1, SHA256_SUM_LEN);
> -	if (!*hash) {
> -		debug("Out of memory\n");
> -		free(msg);
> -		return false;
> -	}
> -	*size = SHA256_SUM_LEN;
> -
>  	regtmp.data = msg->data;
>  	regtmp.size = msg->data_len;
>
> -	hash_calculate("sha256", &regtmp, 1, *hash);
> -#ifdef DEBUG
> -	debug("hash calculated based on contentInfo:\n");
> -	print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1,
> -		       *hash, SHA256_SUM_LEN, false);
> -#endif
> -
> -	return true;
> +	return efi_hash_regions(&regtmp, 1, hash, size);
>  }
>
>  /**
> @@ -168,9 +155,10 @@ static bool efi_signature_verify(struct efi_image_regions *regs,
>  			       false);
>  #endif
>  		/* against contentInfo first */
> +		hash = NULL;
>  		if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) ||
>  				/* for signed image */
> -		    efi_hash_regions(regs, &hash, &size)) {
> +		    efi_hash_regions(regs->reg, regs->num, &hash, &size)) {
>  				/* for authenticated variable */
>  			if (ps_info->msgdigest_len != size ||
>  			    memcmp(hash, ps_info->msgdigest, size)) {
> @@ -238,7 +226,7 @@ bool efi_signature_verify_with_list(struct efi_image_regions *regs,
>  	      regs, signed_info, siglist, valid_cert);
>
>  	if (!signed_info) {
> -		void *hash;
> +		void *hash = NULL;
>  		size_t size;
>
>  		debug("%s: unsigned image\n", __func__);
> @@ -252,7 +240,7 @@ bool efi_signature_verify_with_list(struct efi_image_regions *regs,
>  			goto out;
>  		}
>
> -		if (!efi_hash_regions(regs, &hash, &size)) {
> +		if (!efi_hash_regions(regs->reg, regs->num, &hash, &size)) {
>  			debug("Digesting unsigned image failed\n");
>  			goto out;
>  		}
>