linux-kernel - [PATCH 5/6] crypto: DRBG - make drbg_prepare_hrng() handle jent instantiation errors

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Date:   Mon, 25 Oct 2021 11:25:24 +0200
From:   Nicolai Stange <nstange@...e.de>
To:     Stephan Müller <smueller@...onox.de>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Torsten Duwe <duwe@...e.de>, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, Nicolai Stange <nstange@...e.de>
Subject: [PATCH 5/6] crypto: DRBG - make drbg_prepare_hrng() handle jent instantiation errors

Now that drbg_prepare_hrng() doesn't do anything but to instantiate a
jitterentropy crypto_rng instance, it looks a little odd to have the
related error handling at its only caller, drbg_instantiate().

Move the handling of jitterentropy allocation failures from
drbg_instantiate() close to the allocation itself in drbg_prepare_hrng().

There is no change in behaviour.

Signed-off-by: Nicolai Stange <nstange@...e.de>
---
 crypto/drbg.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/crypto/drbg.c b/crypto/drbg.c
index d9f7dddfd683..f5947211e0bf 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1518,6 +1518,14 @@ static int drbg_prepare_hrng(struct drbg_state *drbg)
 		return 0;
 
 	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
+	if (IS_ERR(drbg->jent)) {
+		const int err = PTR_ERR(drbg->jent);
+
+		drbg->jent = NULL;
+		if (fips_enabled || err != -ENOENT)
+			return err;
+		pr_info("DRBG: Continuing without Jitter RNG\n");
+	}
 
 	return 0;
 }
@@ -1573,14 +1581,6 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
 		if (ret)
 			goto free_everything;
 
-		if (IS_ERR(drbg->jent)) {
-			ret = PTR_ERR(drbg->jent);
-			drbg->jent = NULL;
-			if (fips_enabled || ret != -ENOENT)
-				goto free_everything;
-			pr_info("DRBG: Continuing without Jitter RNG\n");
-		}
-
 		reseed = false;
 	}
 
-- 
2.26.2