Hi Ilias,
On Tue, Jan 18, 2022 at 01:12:37PM +0200, Ilias Apalodimas wrote:
> Right now the code explicitly limits us to sha1,256 hashes with RSA2048
> encryption. But the limitation is artificial since U-Boot supports
> a wider range of algorithms.
>
> The internal image_get_[checksum|crypto]_algo() functions expect an
> argument in the format of <checksum>,<crypto>. So let's remove the size
> checking and create the needed string on the fly in order to support
> more hash/signing combinations.
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodi...@linaro.org>
> ---
> lib/crypto/public_key.c | 27 +++++++++++++--------------
> 1 file changed, 13 insertions(+), 14 deletions(-)
>
> diff --git a/lib/crypto/public_key.c b/lib/crypto/public_key.c
> index df6033cdb499..b783c63f5a51 100644
> --- a/lib/crypto/public_key.c
> +++ b/lib/crypto/public_key.c
> @@ -97,6 +97,7 @@ int public_key_verify_signature(const struct public_key
> *pkey,
> const struct public_key_signature *sig)
> {
> struct image_sign_info info;
> + char algo[256];
> int ret;
>
> pr_devel("==>%s()\n", __func__);
> @@ -108,29 +109,27 @@ int public_key_verify_signature(const struct public_key
> *pkey,
> return -EINVAL;
>
> memset(&info, '\0', sizeof(info));
> + memset(algo, 0, sizeof(algo));
> info.padding = image_get_padding_algo("pkcs-1.5");
> /*
> * Note: image_get_[checksum|crypto]_algo takes a string
> * argument like "<checksum>,<crypto>"
> * TODO: support other hash algorithms
> */
If this patch is applied, the TODO comment above will make no sense :)
> - if (strcmp(sig->pkey_algo, "rsa") || (sig->s_size * 8) != 2048) {
> - pr_warn("Encryption is not RSA2048: %s%d\n",
> - sig->pkey_algo, sig->s_size * 8);
> - return -ENOPKG;
> - }
> - if (!strcmp(sig->hash_algo, "sha1")) {
> - info.checksum = image_get_checksum_algo("sha1,rsa2048");
> - info.name = "sha1,rsa2048";
> - } else if (!strcmp(sig->hash_algo, "sha256")) {
> - info.checksum = image_get_checksum_algo("sha256,rsa2048");
> - info.name = "sha256,rsa2048";
> - } else {
> - pr_warn("unknown msg digest algo: %s\n", sig->hash_algo);
> + if (strcmp(sig->pkey_algo, "rsa")) {
> + pr_err("Encryption is not RSA: %s\n", sig->pkey_algo);
> return -ENOPKG;
> }
> + ret = snprintf(algo, sizeof(algo), "%s,%s%d", sig->hash_algo,
> + sig->pkey_algo, sig->s_size * 8);
I'm not sure that this naming rule, in particular the latter part, will
always hold in the future while all the existing algo's observe it.
(Maybe we need some note somewhere?)
-Takahiro Akashi
> +
> + if (ret >= sizeof(algo))
> + return -EINVAL;
> +
> + info.checksum = image_get_checksum_algo((const char *)algo);
> + info.name = (const char *)algo;
> info.crypto = image_get_crypto_algo(info.name);
> - if (IS_ERR(info.checksum) || IS_ERR(info.crypto))
> + if (!info.checksum || !info.crypto)
> return -ENOPKG;
>
> info.key = pkey->key;
> --
> 2.30.2
>
