From d5c3b17898993c3461fb3f0497f45098ffd72ac6 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 30 Mar 2018 09:55:44 -0700
Subject: crypto: ecc - Actually remove stack VLA usage
On the quest to remove all VLAs from the kernel[1], this avoids VLAs
by just using the maximum allocation size (4 bytes) for stack arrays.
All the VLAs in ecc were either 3 or 4 bytes (or a multiple), so just
make it 4 bytes all the time. Initialization routines are adjusted to
check that ndigits does not end up larger than the arrays.
This includes a removal of the earlier attempt at this fix from
commit a963834b4742 ("crypto/ecc: Remove stack VLA usage")
[1] https://lkml.org/lkml/2018/3/7/621
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
crypto/ecc.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
(limited to 'crypto/ecc.h')
diff --git a/crypto/ecc.h b/crypto/ecc.h
index e4fd4492c765..f75a86baa3bd 100644
--- a/crypto/ecc.h
+++ b/crypto/ecc.h
@@ -26,7 +26,9 @@
#ifndef _CRYPTO_ECC_H
#define _CRYPTO_ECC_H
-#define ECC_MAX_DIGITS 4 /* 256 */
+#define ECC_CURVE_NIST_P192_DIGITS 3
+#define ECC_CURVE_NIST_P256_DIGITS 4
+#define ECC_MAX_DIGITS ECC_CURVE_NIST_P256_DIGITS
#define ECC_DIGITS_TO_BYTES_SHIFT 3
--
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