linux-kernel - [PATCH 3.16 13/99] crypto: pcrypt - Fix user-after-free on module unload

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Message-ID: <lsq.1589984008.387874454@decadent.org.uk>
Date:   Wed, 20 May 2020 15:13:41 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Herbert Xu" <herbert@...dor.apana.org.au>
Subject: [PATCH 3.16 13/99] crypto: pcrypt - Fix user-after-free on module
 unload

3.16.84-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Herbert Xu <herbert@...dor.apana.org.au>

commit 07bfd9bdf568a38d9440c607b72342036011f727 upstream.

On module unload of pcrypt we must unregister the crypto algorithms
first and then tear down the padata structure.  As otherwise the
crypto algorithms are still alive and can be used while the padata
structure is being freed.

Fixes: 5068c7a883d1 ("crypto: pcrypt - Add pcrypt crypto...")
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 crypto/pcrypt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -552,11 +552,12 @@ err:
 
 static void __exit pcrypt_exit(void)
 {
+	crypto_unregister_template(&pcrypt_tmpl);
+
 	pcrypt_fini_padata(&pencrypt);
 	pcrypt_fini_padata(&pdecrypt);
 
 	kset_unregister(pcrypt_kset);
-	crypto_unregister_template(&pcrypt_tmpl);
 }
 
 module_init(pcrypt_init);