linux-kernel - [PATCH V3] crypto: Mark intermediary memory as clean

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Message-ID: <tencent_65C6578989EEED6EE78C8B67E586DE92EB06@qq.com>
Date: Mon, 18 Aug 2025 21:24:17 +0800
From: Edward Adam Davis <eadavis@...com>
To: smueller@...onox.de
Cc: davem@...emloft.net,
	eadavis@...com,
	herbert@...dor.apana.org.au,
	linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	syzbot+e8bcd7ee3db6cb5cb875@...kaller.appspotmail.com,
	syzkaller-bugs@...glegroups.com
Subject: [PATCH V3] crypto: Mark intermediary memory as clean

This is not a leak! The stack memroy is hashed and fed into the
entropy pool. We can't recover the original kernel memory from it.

Reported-by: syzbot+e8bcd7ee3db6cb5cb875@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e8bcd7ee3db6cb5cb875
Signed-off-by: Edward Adam Davis <eadavis@...com>
---
V1 -> V2: mark it as unpoison
V2 -> V3: replace to sizeof, minimize the possibilities where inconsistencies can occur

 crypto/jitterentropy-kcapi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c
index 1266eb790708..4020a6e41b0e 100644
--- a/crypto/jitterentropy-kcapi.c
+++ b/crypto/jitterentropy-kcapi.c
@@ -117,6 +117,7 @@ int jent_hash_time(void *hash_state, __u64 time, u8 *addtl,
 		pr_warn_ratelimited("Unexpected digest size\n");
 		return -EINVAL;
 	}
+	kmsan_unpoison_memory(intermediary, sizeof(intermediary));
 
 	/*
 	 * This loop fills a buffer which is injected into the entropy pool.
-- 
2.43.0