[PATCH 1/3] fscrypt-crypt-util: fix HKDF self-test with latest OpenSSL

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

In OpenSSL 3.0, EVP_PKEY_derive() fails if the output is zero-length.
Therefore, update test_hkdf_sha512() to not test this case.

This only affects the algorithm self-tests within fscrypt-crypt-util,
which are not compiled by default.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 src/fscrypt-crypt-util.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/fscrypt-crypt-util.c b/src/fscrypt-crypt-util.c
index 087ae09a..4bb4f4e5 100644
--- a/src/fscrypt-crypt-util.c
+++ b/src/fscrypt-crypt-util.c
@@ -975,7 +975,9 @@ static void test_hkdf_sha512(void)
 		size_t ikmlen = 1 + (rand() % sizeof(ikm));
 		size_t saltlen = rand() % (1 + sizeof(salt));
 		size_t infolen = rand() % (1 + sizeof(info));
-		size_t outlen = rand() % (1 + sizeof(actual_output));
+		// Don't test zero-length outputs, since OpenSSL 3.0 and later
+		// returns an error for those.
+		size_t outlen = 1 + (rand() % sizeof(actual_output));
 
 		rand_bytes(ikm, ikmlen);
 		rand_bytes(salt, saltlen);
-- 
2.40.0