FAILED: patch "[PATCH] crypto: drbg - Fix ineffective sanity check" failed to apply to 6.12-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 040ad83b0e8aa065fd2fc641cacba8491a8b186d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071532-mutual-applause-01cd@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 040ad83b0e8aa065fd2fc641cacba8491a8b186d Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@kernel.org>
Date: Sun, 19 Apr 2026 23:33:47 -0700
Subject: [PATCH] crypto: drbg - Fix ineffective sanity check

Fix drbg_healthcheck_sanity() to correctly check the return value of
drbg_generate().  drbg_generate() returns 0 on success, or a negative
errno value on failure.  drbg_healthcheck_sanity() incorrectly assumed
that it returned a positive value on success.

This didn't make the sanity check fail, but it made it ineffective.

Fixes: cde001e4c3c3 ("crypto: rng - RNGs must return 0 in success case")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/drbg.c b/crypto/drbg.c
index de4c69032155..f23b431bd490 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1737,7 +1737,6 @@ static int drbg_kcapi_seed(struct crypto_rng *tfm,
  */
 static inline int __init drbg_healthcheck_sanity(void)
 {
-	int len = 0;
 #define OUTBUFLEN 16
 	unsigned char buf[OUTBUFLEN];
 	struct drbg_state *drbg = NULL;
@@ -1782,11 +1781,11 @@ static inline int __init drbg_healthcheck_sanity(void)
 	max_request_bytes = drbg_max_request_bytes(drbg);
 	drbg_string_fill(&addtl, buf, max_addtllen + 1);
 	/* overflow addtllen with additional info string */
-	len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
-	BUG_ON(0 < len);
+	ret = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
+	BUG_ON(ret == 0);
 	/* overflow max_bits */
-	len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
-	BUG_ON(0 < len);
+	ret = drbg_generate(drbg, buf, max_request_bytes + 1, NULL);
+	BUG_ON(ret == 0);
 
 	/* overflow max addtllen with personalization string */
 	ret = drbg_seed(drbg, &addtl, false);