[PATCH v5 02/11] crypto: cbc: Remove VLA usage
From: Kees Cook <hidden>
Date: 2018-07-17 04:22:03
Also in:
dm-devel, lkml
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
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 <redacted> --- 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