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 <[e-mail]>
Acked-by: Ard Biesheuvel <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

arch/arm64/crypto/ghash-ce-glue.c

···
 	put_unaligned_be64(ctx->digest[1], dst);
 	put_unaligned_be64(ctx->digest[0], dst + 8);
 
-	*ctx = (struct ghash_desc_ctx){};
+	memzero_explicit(ctx, sizeof(*ctx));
 	return 0;
 }
 

arch/arm64/crypto/poly1305-glue.c

···
 	}
 
 	poly1305_emit(&dctx->h, dst, dctx->s);
-	*dctx = (struct poly1305_desc_ctx){};
+	memzero_explicit(dctx, sizeof(*dctx));
 }
 EXPORT_SYMBOL(poly1305_final_arch);
 

arch/arm64/crypto/sha3-ce-glue.c

···
 	if (digest_size & 4)
 		put_unaligned_le32(sctx->st[i], (__le32 *)digest);
 
-	*sctx = (struct sha3_state){};
+	memzero_explicit(sctx, sizeof(*sctx));
 	return 0;
 }
 

arch/x86/crypto/poly1305_glue.c

···
 	}
 
 	poly1305_simd_emit(&dctx->h, dst, dctx->s);
-	*dctx = (struct poly1305_desc_ctx){};
+	memzero_explicit(dctx, sizeof(*dctx));
 }
 EXPORT_SYMBOL(poly1305_final_arch);
 

include/crypto/sha1_base.h

···
 #include <crypto/sha.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
+#include <linux/string.h>
 
 #include <asm/unaligned.h>
 
···
 	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;
 }
 

include/crypto/sha256_base.h

···
 #include <crypto/sha.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
+#include <linux/string.h>
 
 #include <asm/unaligned.h>
 
···
 	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;
 }
 

include/crypto/sha512_base.h

···
 #include <crypto/sha.h>
 #include <linux/crypto.h>
 #include <linux/module.h>
+#include <linux/string.h>
 
 #include <asm/unaligned.h>
 
···
 	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;
 }
 

include/crypto/sm3_base.h

···
 #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);
···
 	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;
 }