crypto: hash - Use memzero_explicit() for clearing state

Without the barrier_data() inside memzero_explicit(), the compiler may
optimize away the state-clearing if it can tell that the state is not
used afterwards.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

4 files changed, 8 insertions, 4 deletions

diff --git a/include/crypto/sha1_base.h b/include/crypto/sha1_base.h
index 20fd1f7468af..a5d6033efef7 100644
--- a/include/crypto/sha1_base.h
+++ b/include/crypto/sha1_base.h
@@ -12,6 +12,7 @@
 #include <crypto/sha.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
+#include <linux/string.h>
 
 #include <asm/unaligned.h>
 
@@ -101,7 +102,7 @@ static inline int sha1_base_finish(struct shash_desc *desc, u8 *out)
 	for (i = 0; i < SHA1_DIGEST_SIZE / sizeof(__be32); i++)
 		put_unaligned_be32(sctx->state[i], digest++);
 
-	*sctx = (struct sha1_state){};
+	memzero_explicit(sctx, sizeof(*sctx));
 	return 0;
 }
 
diff --git a/include/crypto/sha256_base.h b/include/crypto/sha256_base.h
index 6ded110783ae..93f9fd21cc06 100644
--- a/include/crypto/sha256_base.h
+++ b/include/crypto/sha256_base.h
@@ -12,6 +12,7 @@
 #include <crypto/sha.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
+#include <linux/string.h>
 
 #include <asm/unaligned.h>
 
@@ -105,7 +106,7 @@ static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
 	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
 		put_unaligned_be32(sctx->state[i], digest++);
 
-	*sctx = (struct sha256_state){};
+	memzero_explicit(sctx, sizeof(*sctx));
 	return 0;
 }
 
diff --git a/include/crypto/sha512_base.h b/include/crypto/sha512_base.h
index fb19c77494dc..93ab73baa38e 100644
--- a/include/crypto/sha512_base.h
+++ b/include/crypto/sha512_base.h
@@ -12,6 +12,7 @@
 #include <crypto/sha.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
+#include <linux/string.h>
 
 #include <asm/unaligned.h>
 
@@ -126,7 +127,7 @@ static inline int sha512_base_finish(struct shash_desc *desc, u8 *out)
 	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be64))
 		put_unaligned_be64(sctx->state[i], digest++);
 
-	*sctx = (struct sha512_state){};
+	memzero_explicit(sctx, sizeof(*sctx));
 	return 0;
 }
 
diff --git a/include/crypto/sm3_base.h b/include/crypto/sm3_base.h
index 1cbf9aa1fe52..2f3a32ab97bb 100644
--- a/include/crypto/sm3_base.h
+++ b/include/crypto/sm3_base.h
@@ -13,6 +13,7 @@
 #include <crypto/sm3.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
+#include <linux/string.h>
 #include <asm/unaligned.h>
 
 typedef void (sm3_block_fn)(struct sm3_state *sst, u8 const *src, int blocks);
@@ -104,7 +105,7 @@ static inline int sm3_base_finish(struct shash_desc *desc, u8 *out)
 	for (i = 0; i < SM3_DIGEST_SIZE / sizeof(__be32); i++)
 		put_unaligned_be32(sctx->state[i], digest++);
 
-	*sctx = (struct sm3_state){};
+	memzero_explicit(sctx, sizeof(*sctx));
 	return 0;
 }