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From:   Zhenzhong Duan <zhenzhong.duan@gmail.com>
To:     linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org
Cc:     horia.geanta@nxp.com, aymen.sghaier@nxp.com,
        herbert@gondor.apana.org.au, davem@davemloft.net,
        Zhenzhong Duan <zhenzhong.duan@gmail.com>
Subject: [PATCH] crypto: caam - fix use after free issue in *_crypt_done
Date:   Tue, 28 Apr 2020 13:14:27 +0800
Message-Id: <20200428051427.508-1-zhenzhong.duan@gmail.com>
Sender: linux-crypto-owner@vger.kernel.org
Precedence: bulk

In both aead_crypt_done and skcipher_crypt_done, edesc->bklog is
referenced after the structure pointed by edesc is freed.

Fix them by moving kfree(edesc) to the end of function call.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com>
---
 drivers/crypto/caam/caamalg.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index b7bb7c30adeb..6d746ef5e650 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -973,8 +973,6 @@ static void aead_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 
 	aead_unmap(jrdev, edesc, req);
 
-	kfree(edesc);
-
 	/*
 	 * If no backlog flag, the completion of the request is done
 	 * by CAAM, not crypto engine.
@@ -983,6 +981,8 @@ static void aead_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 		aead_request_complete(req, ecode);
 	else
 		crypto_finalize_aead_request(jrp->engine, req, ecode);
+
+	kfree(edesc);
 }
 
 static void skcipher_crypt_done(struct device *jrdev, u32 *desc, u32 err,
@@ -1022,8 +1022,6 @@ static void skcipher_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 		     DUMP_PREFIX_ADDRESS, 16, 4, req->dst,
 		     edesc->dst_nents > 1 ? 100 : req->cryptlen, 1);
 
-	kfree(edesc);
-
 	/*
 	 * If no backlog flag, the completion of the request is done
 	 * by CAAM, not crypto engine.
@@ -1032,6 +1030,8 @@ static void skcipher_crypt_done(struct device *jrdev, u32 *desc, u32 err,
 		skcipher_request_complete(req, ecode);
 	else
 		crypto_finalize_skcipher_request(jrp->engine, req, ecode);
+
+	kfree(edesc);
 }
 
 /*
-- 
2.17.1