[PATCH AUTOSEL 4.14 06/21] crypto: simd - correctly take reqsize of wrapped skcipher into account

[Sasha Levin]

From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>

[ Upstream commit 508a1c4df085a547187eed346f1bfe5e381797f1 ]

The simd wrapper's skcipher request context structure consists
of a single subrequest whose size is taken from the subordinate
skcipher. However, in simd_skcipher_init(), the reqsize that is
retrieved is not from the subordinate skcipher but from the
cryptd request structure, whose size is completely unrelated to
the actual wrapped skcipher.

Reported-by: Qian Cai <cai@xxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Tested-by: Qian Cai <cai@xxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 crypto/simd.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/crypto/simd.c b/crypto/simd.c
index 88203370a62f..894c62944106 100644
--- a/crypto/simd.c
+++ b/crypto/simd.c
@@ -126,8 +126,9 @@ static int simd_skcipher_init(struct crypto_skcipher *tfm)
 
 	ctx->cryptd_tfm = cryptd_tfm;
 
-	reqsize = sizeof(struct skcipher_request);
-	reqsize += crypto_skcipher_reqsize(&cryptd_tfm->base);
+	reqsize = crypto_skcipher_reqsize(cryptd_skcipher_child(cryptd_tfm));
+	reqsize = max(reqsize, crypto_skcipher_reqsize(&cryptd_tfm->base));
+	reqsize += sizeof(struct skcipher_request);
 
 	crypto_skcipher_set_reqsize(tfm, reqsize);
 
-- 
2.17.1