linux-kernel - [PATCH 2/7] crypto: powerpc/sha1 - remove unused temporary workspace

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Message-Id: <20200502182427.104383-3-ebiggers@kernel.org>
Date:   Sat,  2 May 2020 11:24:22 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     linux-crypto@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        "Jason A . Donenfeld" <Jason@...c4.com>,
        Theodore Ts'o <tytso@....edu>, linuxppc-dev@...ts.ozlabs.org,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Paul Mackerras <paulus@...ba.org>
Subject: [PATCH 2/7] crypto: powerpc/sha1 - remove unused temporary workspace

From: Eric Biggers <ebiggers@...gle.com>

The PowerPC implementation of SHA-1 doesn't actually use the 16-word
temporary array that's passed to the assembly code.  This was probably
meant to correspond to the 'W' array that lib/sha1.c uses.  However, in
sha1-powerpc-asm.S these values are actually stored in GPRs 16-31.

Referencing SHA_WORKSPACE_WORDS from this code also isn't appropriate,
since it's an implementation detail of lib/sha1.c.

Therefore, just remove this unneeded array.

Tested with:

	export ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu-
	make mpc85xx_defconfig
	cat >> .config << EOF
	# CONFIG_MODULES is not set
	# CONFIG_CRYPTO_MANAGER_DISABLE_TESTS is not set
	CONFIG_DEBUG_KERNEL=y
	CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y
	CONFIG_CRYPTO_SHA1_PPC=y
	EOF
	make olddefconfig
	make -j32
	qemu-system-ppc -M mpc8544ds -cpu e500 -nographic \
		-kernel arch/powerpc/boot/zImage \
		-append "cryptomgr.fuzz_iterations=1000 cryptomgr.panic_on_fail=1"

Cc: linuxppc-dev@...ts.ozlabs.org
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Paul Mackerras <paulus@...ba.org>
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 arch/powerpc/crypto/sha1.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/crypto/sha1.c b/arch/powerpc/crypto/sha1.c
index 7b43fc352089b1..db46b6130a9642 100644
--- a/arch/powerpc/crypto/sha1.c
+++ b/arch/powerpc/crypto/sha1.c
@@ -16,12 +16,11 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mm.h>
-#include <linux/cryptohash.h>
 #include <linux/types.h>
 #include <crypto/sha.h>
 #include <asm/byteorder.h>
 
-extern void powerpc_sha_transform(u32 *state, const u8 *src, u32 *temp);
+void powerpc_sha_transform(u32 *state, const u8 *src);
 
 static int sha1_init(struct shash_desc *desc)
 {
@@ -47,7 +46,6 @@ static int sha1_update(struct shash_desc *desc, const u8 *data,
 	src = data;
 
 	if ((partial + len) > 63) {
-		u32 temp[SHA_WORKSPACE_WORDS];
 
 		if (partial) {
 			done = -partial;
@@ -56,12 +54,11 @@ static int sha1_update(struct shash_desc *desc, const u8 *data,
 		}
 
 		do {
-			powerpc_sha_transform(sctx->state, src, temp);
+			powerpc_sha_transform(sctx->state, src);
 			done += 64;
 			src = data + done;
 		} while (done + 63 < len);
 
-		memzero_explicit(temp, sizeof(temp));
 		partial = 0;
 	}
 	memcpy(sctx->buffer + partial, src, len - done);
-- 
2.26.2