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Message-Id: <20180629002843.31095-3-keescook@chromium.org>
Date: Thu, 28 Jun 2018 17:28:36 -0700
From: Kees Cook <keescook@...omium.org>
To: Herbert Xu <herbert@...dor.apana.org.au>
Cc: Kees Cook <keescook@...omium.org>,
"Gustavo A. R. Silva" <gustavo@...eddedor.com>,
Arnd Bergmann <arnd@...db.de>,
Eric Biggers <ebiggers@...gle.com>,
Alasdair Kergon <agk@...hat.com>,
Giovanni Cabiddu <giovanni.cabiddu@...el.com>,
Lars Persson <larper@...s.com>,
Mike Snitzer <snitzer@...hat.com>,
Rabin Vincent <rabinv@...s.com>,
Tim Chen <tim.c.chen@...ux.intel.com>,
"David S. Miller" <davem@...emloft.net>,
linux-crypto@...r.kernel.org, qat-linux@...el.com,
dm-devel@...hat.com, linux-kernel@...r.kernel.org
Subject: [PATCH v3 2/9] crypto: cbc: Remove VLA usage
In the quest to remove all stack VLA usage from the kernel[1], this
uses the upper bounds on blocksize. Since this is always a cipher
blocksize, use the existing cipher max blocksize.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <keescook@...omium.org>
---
include/crypto/cbc.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/crypto/cbc.h b/include/crypto/cbc.h
index f5b8bfc22e6d..47db0aac2ab9 100644
--- a/include/crypto/cbc.h
+++ b/include/crypto/cbc.h
@@ -113,7 +113,9 @@ static inline int crypto_cbc_decrypt_inplace(
unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
- u8 last_iv[bsize];
+ u8 last_iv[MAX_CIPHER_BLOCKSIZE];
+
+ BUG_ON(bsize > sizeof(last_iv));
/* Start of the last block. */
src += nbytes - (nbytes & (bsize - 1)) - bsize;
--
2.17.1
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