[PATCH] lib/rsa: avoid -Wdiscarded-qualifiers

[Heinrich Schuchardt]

The return type of EVP_PKEY_get0_RSA() is const struct rsa_st *.
Our code drops the const qualifier leading to

In file included from tools/lib/rsa/rsa-sign.c:1:
./tools/../lib/rsa/rsa-sign.c: In function ‘rsa_add_verify_data’:
./tools/../lib/rsa/rsa-sign.c:631:13: warning:
assignment discards ‘const’ qualifier from pointer target type
[-Wdiscarded-qualifiers]
  631 |         rsa = EVP_PKEY_get0_RSA(pkey);
      |             ^

Add a type conversion.

Signed-off-by: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
---
 lib/rsa/rsa-sign.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 44f21416ce..3b6e5f0f86 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -628,7 +628,7 @@ int rsa_add_verify_data(struct image_sign_info *info, void 
*keydest)
        if (ret)
                goto err_get_pub_key;
 
-       rsa = EVP_PKEY_get0_RSA(pkey);
+       rsa = (RSA *)EVP_PKEY_get0_RSA(pkey);
        ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus, &r_squared);
        if (ret)
                goto err_get_params;
-- 
2.33.1